METHOD OF RECYCLING OFF-GRADE POLYMER-COATED CERAMIC PROPPANTS (VERSIONS) Russian patent published in 2013 - IPC C09K8/80 B09B3/00 

FIELD: chemistry.

SUBSTANCE: invention relates to production of proppants for use in oil extraction industry as proppants, and specifically to recycling off-grade ceramic proppants. In the method of recycling off-grade polymer-coated ceramic proppants, said proppant is added to starting material for producing a proppant of similar chemical composition, with the following ratio of components, wt %: starting material 90-99, polymer-coated proppant 1-10, wherein the off-grade polymer-coated proppant is pre-ground to particle size of 5 mm or less, and then fed for mixed grinding with the starting material; also at the grinding step, 0.05-0.15 wt % of powdered phenol binder is added to the mixture, after which the ground material is granulated, dried and fired. In another version of the method of recycling off-grade polymer-coated ceramic proppants, said proppant with particle size of 5 mm or less is fed into a furnace during preliminary firing of the starting material of similar chemical composition, with the following ratio of components, wt %: starting material 90-99, polymer-coated proppant 1-10; the obtained mixture is then ground, granulated, dried and fired. Said proppant is fed into a revolving furnace immediately in the firing zone through the hot end of the furnace.

EFFECT: high efficiency of recycling proppant.

3 cl, 2 ex, 1 tbl