Ceramic proppant and its production method

Aug. 19, 2024

Ceramic proppant and its production method

&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;Technical field

&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;State of the art

&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;.It has been found that ceramic proppants generally have advantageous characteristics relative to many other types of materials, for example, in the context of their strength and uniformity of size and shape.

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evertheless, despite the fact that ceramic proppants are strong enough and effective and can be produced in cost-effective ways, there is a need to create new proppants with improved mechanical characteristics, such as strength, permeability, specific gravity (bulk density), hydrothermal stability and acid resistance, as well as effective methods for their preparation.

&#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;1 &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;-&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 55 &#;&#; 80% &#;&#;&#;./&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#; °&#;.In addition, from the patent of the Russian Federation C1, a method for producing ceramic proppants made of magnesium silicate material with a forsterite content of from 55 to 80% wt./wt. According to this method, the forsterite-based ceramic source material is crushed, granulated and fired at a temperature of to ° C.

&#; &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;2 &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;-&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 40% &#;&#;&#;./&#;&#;&#;. MgO &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 60% &#;&#;&#;./&#;&#;&#;. SiO2. &#;&#;-&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; (Δ&#;&#;&#;&#;&#; &#;&#; 10 &#;&#; 20°&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;.RF patent C2 shows a similar process in which the magnesium silicate precursor consists of magnesium metasilicate with approximately 40% w / w. MgO and approximately 60% w / w. SiO 2 . Due to the very narrow sintering range (Δ&#; max from 10 to 20 ° &#;), the manufacture of such proppants is difficult and expensive. Also, due to the narrow sintering temperature range, firing in a rotary kiln under standard industrial conditions will lead to the production of underburned porous proppant particles and overbaked molten proppant particles.

&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;.Thus, the actually achieved strength, acid resistance and hydrothermal stability of proppants obtained under industrial conditions are noticeably lower than for batches obtained under laboratory conditions. In addition, the narrow sintering range requires a greater exposure of the proppant material to the sintering temperature to achieve a uniform temperature distribution. This leads to the growth of crystals of magnesium metasilicate and phase transformation during the cooling process, which also reduces the quality of the resulting proppant.

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n particular, it is an object of the present invention to provide a new proppant with improved properties and an economical and energy-efficient method for producing a ceramic proppant, which makes it possible to obtain a proppant with increased strength, reduced bulk density, good permeability, hydrothermal stability and acid resistance.

&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;SUMMARY OF THE INVENTION

&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;;a) preparation, including grinding of raw materials containing magnesium-containing material, and auxiliary materials to obtain a mixture;

&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;; &#;b) granulating the mixture to obtain proppant precursor granules; and

&#;) &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;;c) firing the proppant precursor granules to produce proppant granules;

&#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;:In addition, the present invention relates to a method for processing an underground formation, including:

&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;;a) providing a ceramic proppant;

&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; (&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;);b) mixing said ceramic proppant with hydraulic fracturing fluid (hydraulic fracturing fluid);

&#;) &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;) &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;.C) the introduction of the mixture from stage b) into the underground reservoir.

&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;DETAILED DESCRIPTION OF THE INVENTION

&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;. &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;., &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#; (&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;). &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#; &#;.&#;. &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;.In the present description, the proppant or proppant is a granular material, in particular ceramic granules of a substantially spherical shape. Magnesium-containing material, in particular minerals based on magnesium silicates and, possibly, iron (can also be referred to as magnesium silicate materials or magnesia-containing materials), can be used as a starting material for producing a proppant as a result of grinding, granulation, and calcination. Non-limiting examples of such materials include various representatives of minerals of the peridotite class, including olivines, dunite, serpentinite, used as starting materials for ceramic proppants, as well as forsterite, enstatite and fayalite minerals present in them or formed as a result of firing, etc. d. As auxiliary materials, materials and additives are used, for example silica-containing components such as silica sand, hydromica and montmorillonite clays or refractory clays.

&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;) &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 45% &#;&#; 70 &#;&#;&#;&#;. % &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 55 &#;&#;&#;&#;. %, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 30 &#;&#;&#;&#;. % &#;&#; 55 &#;&#;&#;&#;. % &#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;/&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 0 &#;&#; 10 &#;&#;&#;&#;. % &#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; 0 &#;&#; 10 &#;&#;&#;&#;. % &#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;.According to the proposed method for producing a proppant in the first stage a), preparation, for example, grinding or grinding, of starting materials containing magnesium-containing material and auxiliary materials, such as silica-containing components, for example silica sand, is carried out to obtain a mixture of starting materials. Thus, according to the method, step a) of preparing the starting materials may include grinding, for example, grinding the starting materials. According to the proposed method, the amount of starting magnesium-containing material in the charge is from 45% to 70 mass. % and the amount of auxiliary materials is up to 55 mass. %, in particular the mixture may contain silica sand in an amount of from 30 mass. % to 55 mass. % by weight of the mixture, hydromica and / or montmorillonite clay in an amount of from 0 to 10 mass. % by weight of the mixture and refractory clay in an amount of from 0 to 10 mass. % of the mass of the charge.

&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 1% &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 40 &#;&#;&#;, &#;&#;&#; &#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#; 50% &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 10 &#;&#;&#;.Grinding can be carried out by any method known to specialists in this field of technology. Preferably, the grinding is carried out in ball tube mills. It is also preferable to co-grind the magnesium-containing material and the auxiliary material. Before grinding, auxiliary materials can be pre-dried, in particular quartz sand, as a rule, dried to a moisture content of less than 1% in a tumble dryer or similar devices. Preferably, grinding is carried out to a maximum particle size of less than 40 microns, while at least 50% of the particles must be less than 10 microns.

&#;&#;&#;&#;&#;&#; &#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 33-40% &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 30 &#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; (&#;&#;&#;) &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; (&#;&#;&#;&#;&#;-&#;&#;&#;&#;&#;&#;&#;) &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 13-20%. &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;.&#;., &#;&#;&#;&#;&#;&#;&#; &#;.&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, 4-&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;. &#; &#;&#;&#;. &#; &#;.: &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, . - 528 &#;., &#;.&#;. &#;&#;&#;&#;&#;&#;&#;&#; «&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;», &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;. - , &#;.&#;. &#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;. - .Stage a) preparation of the starting materials may also include mixing the crushed starting materials with water to obtain a slip. The specified slip with a moisture content of 33-40% can be further ground, for example, in wet ball mills to a maximum particle size of less than 30 microns. After that, the resulting slip is dried, for example, in tower spray dryers (BRS) to obtain a mixture (press powder) with a moisture content of 13-20%. A detailed description of the techniques for preparing the starting materials and compositions for producing ceramic products can also be found in the books Strelov K.K., Mamykin P.S. Refractory Technology, 4th Edition, Revised. and add. - M.: Metallurgy, .-- 528 p., V.L. Balkevich &#;Technical ceramics&#;, Publishing house of building literature, Moscow. - , K.A. Nohratyan. Drying and firing in the building ceramics industry. State publishing house of literature on construction, architecture and building materials. Moscow. - .

&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;) &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; 0,5-2 &#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;.After the preparation stage, step b) granulating the mixture is carried out to obtain proppant precursor granules with a defined granule size, for example 0.5-2 mm. Granulation can be carried out by any method and in any equipment known to specialists in this field of technology. One example of suitable equipment is plate-type granulators.

&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;) &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; °&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; °&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#;.&#;. &#;&#;&#;&#;&#;&#;&#;, &#;.&#;. &#;&#;&#;&#;&#;&#;&#;&#;, &#;.&#;. &#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;-&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, . &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;.The final step in producing a proppant is step c) firing the proppant precursor granules. Firing is usually carried out at a temperature of from about ° C to about ° C for a period of time sufficient to ensure the production of spherical ceramic granules. The specific time and temperature will vary depending on the source material used and the specific equipment. The optimal firing time and temperature for a specific composition of the starting material can be determined empirically in accordance with the results of physical tests of the obtained granules after firing. Firing is carried out in an oxidizing atmosphere. For example, firing can be carried out in a traditional rotary kiln. Description of firing equipment can also be found in P.S. Mamykin, P.V. Levchenko, K.K. Arrow Furnaces and dried refractories. State Scientific and Technical Publishing House of Literature on Ferrous and Non-Ferrous Metallurgy, Sverdlovsk Branch, Sverdlovsk, . At the end, screening of proppant agent granules of the required size can be carried out and packaging of a commercial product in a storage container.

&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; 900°&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#; °&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;. &#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; (&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;) &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#; (&#;&#;&#;&#;&#;&#;&#;&#;&#;) &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 5 &#;&#;&#;&#;. %, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 2-3 &#;&#;&#;&#;. %. &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;, &#;&#;&#;&#;&#;, &#;&#;&#;&#; &#;&#;&#; &#;&#; &#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;.Further, in the method according to the present invention, the preliminary calcination step is carried out at a temperature of from about 900 ° C to about ° C in a reducing atmosphere. In the present method, a reducing (weakly reducing) atmosphere means a reaction medium (atmosphere) with an oxygen content of less than 5 mass. %, preferably less than 2-3 mass. % A reducing atmosphere in the pre-calcination zone can be achieved by introducing a carbon-containing additive selected from the group including, for example, natural gas, coal, coke, or mixtures thereof. However, it should be noted that the proposed method is not limited to these additives and the specialist in this field can use any means and techniques to ensure a reducing atmosphere in the firing zone.

&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;.Not limited to a specific theory, the authors of the present invention believe that the improvement in the characteristics of the proppant is due to the following factors.

&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; 900°&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; (&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;.), &#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; °&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; (&#;&#;&#;&#;&#;&#;&#;&#;) &#;&#;&#;&#;&#;&#; (Fe2SiO4), &#; &#;&#;&#; &#;&#;&#;&#;&#; FeO, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; MgO &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; FeO &#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;.The inventors found that during preliminary firing at temperatures less than 900 ° C, the magnesium-containing material (dunite, olivine, serpentinite, etc.) does not completely dehydrate, and at temperatures above ° C unwanted interactions can occur, for example, in dunite (olivines ) fayalite (Fe 2 SiO 4 ), including FeO contained in fayalite, can interact with MgO with the formation of magnesioferrite. In this case, the formation of magnesioferrite at the preliminary firing stage is undesirable, since magnesioferrite increases the strength of the material and, therefore, complicates further grinding at the stage of preparing the charge of the starting materials. In addition, magnesioferrite is a passivated element that does not participate in the formation of a given structure during the final firing of proppant precursor granules. Thus, conducting preliminary firing in a reducing atmosphere prevents undesirable oxidation of FeO and, as a result, the formation of magnesioferrite to the stage of final firing.

&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; - &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;.An increase in the characteristics, especially strength, of the proppant is achieved due to the formation of proppant precursor precursor granules in an oxidizing atmosphere during the final firing, along with quartz of other crystalline phases - enstatites with magnesioferrites embedded in magnesioferrites.

(Mgn1,Fem1)2SiO4&#;(Mgn2,Fem2)2SiO4+(Mgn3,Fem3)2SiO3,(Mg n1 , Fe m1 ) 2 SiO 4 &#; (Mg n2 , Fe m2 ) 2 SiO 4 + (Mg n3 , Fe m3 ) 2 SiO 3 ,

&#;&#;&#; n1=n2+m2=n3+m3=1 &#; n1<n2, a m1>m2;where n 1 = n 2 + m 2 = n 3 + m 3 = 1 and n 1 <n 2 , am 1 > m 2 ;

3MgO&#;2SiO2&#;2H2O&#;2MgO&#;SiO2+MgO&#;SiO2+2H2O3MgO&#;2SiO 2 &#;2H 2 O &#; 2MgO&#;SiO 2 + MgO&#;SiO 2 + 2H 2 O

3MgO&#;4SiO2&#;2H2O&#;3(MgO&#;SiO2)+SiO2+2H2O3MgO&#;4SiO 2 &#;2H 2 O &#; 3 (MgO&#;SiO 2 ) + SiO 2 + 2H 2 O

&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; FeO &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; MgO&#;FeO.In this case, iron oxide FeO remains in the form of a solid solution of magnesium oxides and iron oxides MgO&#;FeO.

Mg2SiO4+SiO2&#;2MgO&#;SiO2 Mg 2 SiO 4 + SiO 2 &#; 2MgO&#;SiO 2

2Mg2SiO4+4FeO+O2&#;2MgO&#;SiO2+2MgO&#;Fe2O3 2Mg 2 SiO 4 + 4FeO + O 2 &#; 2MgO&#;SiO 2 + 2MgO&#;Fe 2 O 3

&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; Fe2O3, FeO &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; Mg2SiO4-MgFe2O4 &#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;.In other words, the inventors believe that the incorporation into the crystal lattice of a more active, compared with Fe 2 O 3 , FeO allows you to get a stronger structure. In addition, the inventors also found that the eutectic Mg 2 SiO 4 -MgFe 2 O 4 has a lower melting point and, therefore, reduces energy costs during the firing of the finished product.

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hus, according to the present invention, as a result of the final calcination, the proppant obtained can be characterized by a content of magnesium-containing material, in particular from 50% to 80 mass. % enstatitis (clinoenstatitis) and magnesioferrite 4-8% of the mass. % The composition of the finished proppant may also include magnetite in an amount of from 0.5-2 mass. % The remainder may be diopside, pyroxene, quartz, and other minerals, depending on the presence of impurities in the sand and magnesium-containing material.

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s a result of studies conducted by the authors of the present invention, it was found that a proppant, characterized by a content of enstatite (clinoenstatite) from 50 to 80% and magnesioferrite 4-8%, has advantageous properties, namely, significantly higher strength, reduced bulk density, good permeability as well as hydrothermal stability.

&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;.Therefore, the present invention also relates to a ceramic proppant obtained by the method described above.

&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; (&#;&#;&#;&#;), &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;., &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;. &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;, &#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;. &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; «&#;&#;&#;&#;&#;&#;&#;&#;&#;»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ater-based high-viscosity working fluid used in hydraulic fracturing, as a rule, is additionally thickened using high molecular weight natural resins, such as galactomannan or glucomannan resins (guar), acacia resin karaya, tragacanth, etc., natural polysaccharides, such as, for example, starch cellulose and their derivatives. The working fluid must be chemically stable and viscous enough to hold the proppant in suspension while it is subjected to shear deformation and heating in the surface equipment, in the well pipe system, perforation channels and in the fracture itself, to avoid premature proppant deposition and, as consequence, closing the crack. The composition of the hydraulic fluid can include &#;staplers&#; of a linear gel; destructors providing controlled degradation of the high-viscosity polymer to liquid fluid for simplified hydraulic fluid withdrawal from the well, as well as thermal stabilizers, pH adjusting additives, surfactants, bactericides, emulsifiers and demulsifiers, additives that reduce infiltration, clay stabilizers, etc. .d.

&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;MODES FOR CARRYING OUT THE INVENTION

&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; 1Comparison Example 1

&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; 2Comparison Example 2

&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; 3Comparison Example 3

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&#;&#;&#;&#;&#;&#; 4Example 4

&#;&#;&#;&#;&#;&#; 5Example 5

&#;&#;&#; &#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;.As can be seen from the results of the table, a change in the preliminary firing modes affects the quality indicators of the finished product and the conduct of preliminary heat treatment in a shaft furnace allowed us to obtain more durable proppants.

&#;&#;&#;&#;&#;&#; 6Example 6

&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; 1-3 &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 63,8-67,9% &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 2,4-3,6%. &#;&#;&#; &#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 3,1-4,5%.In the samples of examples 1-3, the content of enstatite was 63.8-67.9% and magnesioferrite 2.4-3.6%. Moreover, magnetites in the amount of 3.1-4.5% are present in the phase composition.

&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#; 4 &#; 5 &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 66,3% &#; 74,6% &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;, &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; 5,2-5,6%, &#;&#;&#;&#;&#;&#;&#;&#;&#; 0,8-1,5%, &#;&#;&#; &#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#; &#; &#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#; &#;&#;&#;&#;&#;&#;&#;&#;&#;.In the samples of examples 4 and 5, the content of enstatite was 66.3% and 74.6%, respectively, magnesioferrites 5.2-5.6%, magnetite 0.8-1.5%, while a high content of magnesioferrites and a low content of magnetite says about a more complete reaction to introduce iron into the crystal lattice of enstatite.

Preparation and characterization of high-performance ...

The influence of sintering temperature and ODCPRs contents on the performance of the proppants

Performance test

To determine the effect of sintering temperature and ODCPRs contents on the physical&#;mechanical performance of proppants and optimize the sintering conditions, proppants were prepared with various ratios of ODCPRs and sintered at different temperatures. The physical and mechanical performances of the proppants, including the bulk density, apparent density, roundness, sphericity, acid solubility and breakage ratio, and acid solubility were analyzed.

As displayed in Fig. 1a,b, when the ODCPRs contents were improved from 20 to 40%, the bulk density and apparent density of proppants decreased in all sintering temperature points, and the breakage ratio showed the opposite tendency. Whereas the acid solubility of the proppants has fluctuated, which was not only impacted by the ODCPRs contents but also the sintering temperature. The acid solubility was closely correlated to the soluble phases in the proppant, and a large amount of alkaline earth metal oxides was significantly improved with the increment of ODCPRs (such as potassium, sodium, and calcium oxide), which would facilitate the formation of liquid phases under a higher sintering temperature. Thus, under the condition of a relatively high temperature or high ODCPRs dosage, more glass phases would be generated, attributing to a higher acid solubility.

Figure 1

The properties of samples with different contents of ODCPRs sintered at various temperatures: (a) bulk density and apparent density; (b) breakage ratio and acid solubility.

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Furthermore, with the increment of sintering temperatures, the optimal sintering temperatures of the A0, B0, and C0 formulas with their lowest breakage ratio and acid solubility all first declined and raised subsequently. The best sintering temperatures of the three formulas could be confirmed as °C, °C, and °C, respectively. According to Table 1, with the increase of the ODCPRs content, both the K value and the molar ratio (Al2O3/SiO2) in initial mixtures were significantly reduced, indicating that the content of flux oxides and silica in the formula was also gradually improved, thus the sintering temperature declined at the higher ODCPRs content. Therefore, formulas of A0 and B0 at °C had exhibited better performance. Noteworthy, the ODCPRs consumption and the cost of raw materials should be comprehensively considered as well, hence formula B0 sintering at °C was identified as the optimal choice with the lowest breakage ratio (6.97%) and acid solubility (4.56%).

Additionally, the photographs of proppants produced in the experiment were displayed in Fig. 2a, it could be observed that the color was darkened as the ODCPRs content or sintering temperature increased. Besides, the Krumbein/Sloss template was used to evaluate the roundness and sphericity of the proppants as shown in Fig. 2b. The average roundness and sphericity degree of all proppants (A0&#;C0) was above 0.8, which could well meet the requirements of the oil and gas industry standard SY/T -.

Figure 2

(a) Photograph of proppants under different sintering temperatures; (b) the Krumbern/Sloss template.

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Phase analysis

Figure 3a showed the XRD patterns of ceramic proppants of the B0 formula in different sintering temperatures. It can be observed that the crystalline phases of these proppants mainly consisted of corundum and a small quantity of mullite, celsian, and anorthite. Corundum was the predominant crystalline phase that was ascribed to the initial mixtures with a high molar ratio (Al2O3/SiO2), resulting in a highly conducive to the generation of the corundum phase. The diffraction peak of the mullite crystal was weak following that mullite has a relatively low content in this sintering temperature range. Corundum with high crystallinity and granulate mullites can improve the toughness of the ceramic proppants attributing to the reduction of breakage ratio28,32. Thus, as the sintering temperature increased from to °C, the diffraction peak intensities of corundum and mullite crystals both enhanced, which would facilitate the development of high-performance ceramic proppants. Nonetheless, owing to masses of metallic oxides in the ODCPRs, some celsian and anorthite were also generated by the reaction between the BaO, CaO, SiO2 in the ODCPRs, and Al2O3 in bauxite. After the sintering temperature raised over °C, the intensity of the celsian and anorthite phases' diffraction peaks was weakened, which could be because the celsian and anorthite phases gradually changed from the solid to the glass phase with the temperature ascending. But too many liquid phases would eventually exist in the amorphousness of the proppants, contributing to a negative influence on the performance of proppants23.

Figure 3

XRD patterns of ceramic proppants: (a) formula B0 sintered at different temperatures, (b) formulas with different ODCPRs contents at their optimum sintering temperatures.

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Additionally, as shown in Fig. 3b, when the ODCPRs content was improved, both the intensities of corundum and mullite diffraction peaks were reduced but the celsian and anorthite phases` diffraction peaks were enhanced at their respective optimal sintering temperature. It was implied that the crystallinity of the corundum and mullite phases decreased with the reduction of the molar ratio (Al2O3/SiO2), while the excessive Ba2+ and Ca2+ in the matrix reacted with Al and Si that formed the celsian and anorthite phases. Conversely, the formation of excessive celsian and anorthite phases might inhibit the development of corundum and mullite phases, and remarkably impair the performance of proppants33. Thereby, the liquid phase was also increased owing to the augment of ODCPRs content, causing the descent of the sintering temperature, such as the formula C0.

Morphology analysis

Figure S4 displayed the cross-sectional microscopic morphology of the proppants before the acid treatment of formula B0 under different sintering temperatures. With the increase of the sintering temperatures, the prevalence of the inner pores initially decreased and then turned to increase. A loose internal structure with less molten phase and high porosity was observed in the proppant when the optimal sintering conditions were not satisfied, as shown in Fig. S4a. When the sintering temperature gradually improved, a denser structure was achieved, on account of more liquid phases filling in the pores, as exhibited in Fig. S4b,c, and the molten phases also formed a cohesion bonding between the crystal particles and strengthened physical and mechanical properties of ceramic matrix34. Howeveduer, as demonstrated in Fig. S4d, when the sintering temperature was increased over °C, more elongated and connected pores appeared in the interior, which was attributed to generating the excessive liquid phase and promoting the expansion of the ceramic body, resulting in the decrease in density and strength of proppants35,36.

As shown in Fig. 4, the inner appearances of the proppants of formula B0 at different sintering temperatures were also investigated after the acid treatment. Compared to the results from Fig. S4, it can be indicated that the whole equilibrium network structure of the proppant matrix was comprised of the residue glass phase and crystal phases. As seen from Fig. 4a, when the proppant was calcined at °C, the after-eroded net-like phases scattered around the incomplete sintered granular crystal particles. With increasing the sintering temperature to °C, the sample was mainly formed by abundant dispersive small corundum grains with loose internal structures, as shown in Fig. 4b. Subsequently, when the sintering temperature reached °C, as presented in Fig. 4c,d, interlocking columnar and granular shapes of crystals occurred, which were corresponding to the growth of the mullite and corundum crystals. Furthermore, the crystals became bigger under a relatively high temperature ( °C), which illustrated that a proper sintering temperature would enhance the development of corundum and mullite phases. Good growth of corundum has the advantages of high hardness, strength, and resistance to chemical erosion37, thus the proppants of formula B0 at a relatively higher sintering temperature showed better performance.

Figure 4

Microscopic cross-sections of the ceramic proppant after the acid treatment of the formula B0 at different sintering temperature: (a) °C; (b) °C; (c) °C; (d) °C.

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Figure S5 displayed the microscopic morphology of the proppants with different ODCPRs contents at their optimum sintering temperature, respectively. Three formulas of the proppants were all well-sintered, meanwhile obvious porous inner structures occurred in all samples as well. Afterward, with the increase of ODCPRs content, more liquid and gas phases were generated during the sintering process. These gas phases were produced from mineral decompositions, leading to an increase in both the number and size of the inner pores of the samples, such as CaCO3 and BaSO4. In parallel with this, the inner crystal appearance of samples with different formulas was also studied after the acid treatment, as displayed in Fig. 5. The results further elaborated that a denser structure composed of granular corundum and rod-like mullite phases was achieved when enough content of Al2O3 and molar ratio (Al2O3/SiO2) was provided, as shown in Fig. 5a,b. However, when ODCPRs contents of the proppant improved beyond 40%, too many ODCPRs in formula C0 formed too much glass phase, as shown in Fig. 5c, causing a relatively higher breakage ratio and acid solubility.

Figure 5

Microscopic cross-sections of the ceramic proppants after the acid treatment with different ODCPRs contents at their optimum sintering temperature: (a) A0 at °C; (b) B0 at °C, (c) C0 at °C.

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The influence of holding time on the performance of the proppants

Performance test

To guarantee the transition of ceramic proppants into a compacter structure through the sintering reaction, it is necessary to explore the effect of holding time on the performance of proppants. As presented in Fig. 6a, the bulk density and apparent density of proppants under different holding times at °C were carried out. The bulk density and apparent density of proppants exhibited the same tendency which was first increased and then decreased observably with the increase of the holding time, the biggest bulk density and apparent density were obtained at °C and heat preservation for 60 min, as 1.48 g/cm3 and 3.03 g/cm3, respectively. Furthermore, the breakage ratio and acid solubility of proppants initially decreased and gradually raised with the extension of the holding time, as shown in Fig. 6b. The lowest breakage ratio (6.97%) and acid solubility (4.56%) of the proppants were acquired by heating preservation for 60 min, which could well meet the standard of SY/T -. Thus, guaranteeing a proper holding time during the calcination process for preparing ODCPRs-based ceramic proppants at the best sintering temperature was beneficial.

Figure 6

The properties of B0 samples sintered at different holding times: (a) bulk density and apparent density; (b) breakage ratio and acid solubility.

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Phase analysis

The XRD patterns of formula B0 under different holding times were also shown in Fig. 7, and the modest heat preservation (holding for 60 min) was advantageous to the formation and growth of corundum and mullite crystals. Meantime, it also resulted in the reduction of bauxite and celsian phases. However, the increase in holding time had no obvious influence on the final phase category of the proppant, which deduced that the variation in the performances of the proppant was mainly caused by the microstructure and glass phase content changes of the ceramic proppant.

Figure 7

The XRD patterns of B0 samples sintered at different holding times.

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Morphology analysis

Figures S6 and 8 displayed the microscopic diagrams of the ceramic proppant before and after the acid treatment of the formula B0, which were sintered with different holding times at °C, respectively. As observed in Fig. S6, with the extension of holding time, the pore characteristics of the proppants before acid treatment were similar. Nevertheless, after the elimination of the glass phase, the microstructure of the crystals resulted in obvious differences. When the holding time was only 30 min, plentiful coarse granular corundum grains and a small amount of needle-shaped mullite were observed. After the holding time was improved to 60&#;90 min, both the corundum and mullite crystals grew bigger (Fig. 8a,b). When the holding time reached 120 min, some coarse granular corundum crystals grow up into big particles, which were with excessive growth and an average grain size of about 20 μm. Over the holding time, the abnormal excessive growth of grains would be adverse to gas exhaustion and easily form internal stress failure, which manifested as a change in density and decrease in porosity and strength38,39. Thus, uniformly distributed and smaller crystals improved the mechanical performance of ceramic proppants better.

Figure 8

Microscopic diagram of the ceramic proppant after the acid treatment of the formula B0 sintered at different holding times: (a) 30 min; (b) 60 min, (c) 90 min; (d) 120 min.

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The influence of additives on the performance of the proppants

Performance test

Metallic oxide sintering additives were used to promote the liquid phase formation and the liquid viscosity alteration of the ceramic system, which can significantly improve the performance of proppants40,41. In this section, the performances of ODCPRs ceramic proppants with different mass fractions of V2O5 and MnO2 additives at various sintering temperatures were studied.

As plotted in Fig. 9a, when the sintering temperature was below °C, with an increase in V2O5 dosage, the bulk density and apparent density of formula B0 were first increased slightly and then decreased significantly. Moreover, the density of proppants turned out to be much lower when the sintering temperature rose beyond °C. Furthermore, the whole series of BV samples showed a distinct decrease in breakage ratio and acid solubility when the sintering temperature reached °C, as displayed in Fig. 9b. Thereinto, sample BV2 presented the minimum value of breakage ratio (8.40%), and sample BV1 presented the minimum value of acid solubility (4.33%). Although the sintering temperature of the proppant was reduced after the incorporation of V2O5 additives that could reduce the energy consumption, the results also elucidated that the mechanical and acid resistance performance was still undesirable in comparison with sample B0 under its optimum sintering condition. This was ascribed to the promotion effect of the sintering reaction, because of the addition of V2O5, which led to more densification of the proppants with an appropriate amount of liquid phase. However, when under high-temperature conditions, too many liquid phases formed42, while O2 from the decomposition of V2O5 would also happen at a high temperature, finally resulting in the decline of the mechanical performance of the proppant42.

Figure 9

The properties of proppant samples with different dosages of V2O5 and MnO2 additives sintered at various temperatures: (a,c) bulk density, and (b,d) breakage ratio.

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Figure 9c showed the bulk density and apparent density of formula B0 with different dosages of MnO2. With the increase in the MnO2 dosage, the sintering temperature and the density showed a descending tendency, indicating that a low-temperature liquid phase was formed during the sintering process, on account of the excellent sintering ability of MnO227,41. Simultaneously, variations of breakage ratio and acid solubility with the sintering temperature of proppants were shown in Fig. 9d. It can be found that the breakage ratio and the acid solubility of the proppants decreased with a sintering temperature up to °C and followed by an increase with a sintering temperature up to °C. The minimum breakage ratio and acid solubility was achieved by formula BM1 as 5.25% and 4.80% at °C, respectively, which was much better than formula B0.

Phase analysis

Figure 10 gave the XRD patterns of proppant samples added with different contents of V2O5 and MnO2 at their optimum temperatures, indicating there were no new diffraction peaks detected in the crystalline phases in the product after the addition of V2O5 or MnO2. It also can be observed from Fig. 10a, the diffraction peak intensity of crystal phases has no obvious change with the augment of the V2O5 additive dosage. This implied that the addition of V2O5 additives has no observable influence on the phase composition of the proppant, which would be attributed to V2O5 easily entering the lattice of mullite crystals as a solid solution and promoting the formation of the liquid phase during the high-temperature sintering process43,44,45,46.

Figure 10

XRD patterns of ceramic proppants under different sintering temperatures added with (a) V2O5 additives and (b) MnO2 additives.

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According to Fig. 10b, the peak intensity of corundum and mullite phases of samples containing MnO2 additives were very similar to formula B0. The reason was Mn4+ was able to dissolve into the corundum phase and replace Al3+ to form a finite solid solution during the sintering process, which caused the lattice distortion and promotion of grain growth, reduction of sintering temperature, and the densification of structure27,36,41,47. Whereas, the peak intensity of anorthite and celsian was enhanced with the increase of the MnO2 additive, indicating the addition of MnO2 could facilitate the generation of the anorthite and celsian. The formation of celsian and anorthite was related to the abundant BaO and CaO in the ODCPRs, and the excessive glassy phase was generated owing to the fluxing effect of the MnO2 additive could further stimulate the growth of celsian and anorthite48,49.

Morphology analysis

Figures S7 and S8 showed the cross-sectional microscopic images of the proppants with different dosages of V2O5 and MnO2 after the acid treatment, severally. The results from Fig. S7 revealed that the addition of V2O5 has a remarkable influence on the formation of mullite. The sample without V2O5 only contained a few needle-like mullite crystals (Fig. S7a). As the dosage of V2O5 increased within the range of 0.5&#;1 wt%, anisotropic mullite crystals in significant amounts appeared among the granular corundum particles (refer to Fig. S7b,c) which contributed to enhancing the mechanical strength and acid resistance of the ceramic proppant. With further improvement of the V2O5 dosage, the needle-like mullite crystals changed into bigger rod-like mullite (Fig. S7d). This denoted that V2O5 additives can dramatically drive the in-situ development of spearhead columnar mullite, on account of the increase of liquid phase in the reaction system, which was corresponding to the analysis of XRD results.42, which was corresponding to the analysis of XRD results.

The microscopic diagrams of the ODCPRs proppants with various MnO2 dosages were exhibited in Fig. S8. The observation of corundum phases in samples containing MnO2 was consistent with the B0 sample. Multiple corundum grains were gathered together to form a granular shape, while only a small number of acicular mullite was distributed among the corundum grains, indicating that the addition of MnO2 does not influence the growth of mullite crystals but promoted the development of corundum. Noteworthy, as shown in Fig. S8b, at the MnO2 dosage of 2 wt%, the cluster shape of celsian was observed, which was in accordance with the results of XRD. With further increase in the MnO2 dosage at 3 wt%, the liquid phase dramatically increased and gradually englued the crystal grains, and some incompleted porous glassy phase dispersed in the matrix after the acid treatment, as the remnants left after being corroded that would seriously affect the mechanical strength and density of the ceramic proppants.

Thermal behaviors analysis

The mass change and sintering behaviors of the raw materials were comprehensively evaluated through TG-DSC experiments. As depicted in Fig. 11a,b, the pure bauxite has presented negligible weight variation during the calcination process, indicating a relatively stable chemical structure. However, an exothermic phenomenon occurred above °C, leading to the recrystallization of Al2O3 at high temperatures. Meanwhile, as shown in Fig. 11b, distinct weight reduction stages were observed at 25&#;495 °C, 495&#;698 °C, and 698&#; °C for the ODCPRs, which corresponded to three different sintering processes: firstly, when the heating temperature was raised from room temperature to 495 °C, a primary weight loss of 5.94% occurred according to the evaporation of free, absorbing and crystal water as well as combustion of residue organic constituents (such as oil)50. Subsequently, a steep weight loss of 4.78% occurred when the temperature was above 698 °C that corresponded to an obvious endothermic peak (664 °C), which would be attributed to the violent decomposition of carbonates51,52. Thirdly, an dramatic weight quality loss of 10.53% occurred from 698 °C to °C, and an endothermic peak ( °C) was observed, which might be related to the solid-phase reaction, on account of the generation of a liquid phase or the transformation between crystal forms of salt substances at high temperatures (such as the decomposition of BaSO4)53,54.

Figure 11

TG-DSC curves of samples (a) bauxite; (b) ODCPRs; (c) A0; (d) B0; (e) C0; and (f) BM1.

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The thermal behavior of the mixtures with 20 wt%, 30 wt%, and 40 wt% ODCPRs were displayed in Fig. 11c&#;e respectively, which have shown a similar weight descending trend with the pure ODCPRs sample, and all samples included three different weight loss stages. The results suggested that with the increase of the ODCPRs content, greater weight loss of the samples can be achieved. Meantime, the appearance of endothermic peaks was also delayed because more energy was consumed for thermal decomposition reactions. Specifically, the most significant increase in weight loss occurred during the solid-phase reaction process, and the greatest mass loss (6.32%) was generated by C0, which may be attributed to the formation of more molten phases that accelerated the growth of corundum.

Moreover, the thermal behavior of BM1 was demonstrated in Fig. 11f, with the addition of MnO2 powders, a new weight loss stage emerged between 697 and 903 °C. This could be attributed to the decomposition of MnO2 powders, which act as a sintering aid in the raw material and induce molten action between the solid phase within the high-temperature range40. Combined with Fig. 11b, no new phase formation has been observed following the incorporation of MnO2. This phenomenon can be ascribed to the increased formation of the liquid phase at high temperatures, which was caused by the melting of aluminosilicate, on account of the distortion of Mn2+ into the corundum lattice and solid solution formation41. This further promoted the liquid&#;solid reactions, resulting in a greater mass change within the 903&#; °C stage. Consequently, the proppant density and strength were enhanced by optimizing and shrinking the interface among solid phases through the addition of MnO2. Based on the preceding discussions, the proppant underwent various reactions during sintering, including water evaporation, hydrocarbon combustion, carbonate and sulfate decomposition, glass phase melting, and corundum recrystallization, as follows41,52,53,54,55,56:

$${\text{H}}_{{2}} O(l)\mathop{\longrightarrow}\limits^{{100 - 200\;^\circ {\text{C}}}}H_{2} O \uparrow $$

(1)

$$CxHy({\text{hydrocarbon}}) + O_{2} \mathop{\longrightarrow}\limits^{200 - 600^\circ C}CO_{2} \uparrow + H_{2} O \uparrow$$

(2)

$$CaCO_{3} \mathop{\longrightarrow}\limits^{{650 - 750\;^\circ {\text{C}}}}CaO + CO_{2} \uparrow$$

(3)

$$Al_{2} O_{3} ({\text{pseudocorundum}})\mathop{\longrightarrow}\limits^{{900 - \;^\circ {\text{C}}}}Al_{2} O_{3} ({\text{corundum}})$$

(4)

$$ BaSO_{3} + RO_{x} ({\text{metallic oxide}})\mathop{\longrightarrow}\limits^{{ - \;^\circ {\text{C}}}}BaRO_{y} + SO_{2} \uparrow $$

(5)

$$ MnO_{2} \mathop{\longrightarrow}\limits^{{460 - 570\;^\circ {\text{C}}}}Mn_{2} O_{3} \mathop{\longrightarrow}\limits^{{926\;^\circ {\text{C}}}}Mn_{3} O_{4} \mathop{\longrightarrow}\limits^{{\;^\circ {\text{C}}}}MnO$$

(6)

$$2MnO\mathop{\longrightarrow}\limits^{{Al_{2} O_{3} }}2Mn_{{_{Al} }}^{`} + V_{O}^{``} + 2O_{O}^{X}$$

(7)

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