BLEND FOR MANUFACTURING REFRACTORY HIGH-STRENGTH SPHERICAL GRANULES AND A METHOD FOR FABRICATION THEREOF Russian patent published in 2003 - IPC

FIELD: manufacture of building materials. SUBSTANCE: invention relates to refractory granular materials intended for use as propping agent in oil and gas production involving hydraulic fracturing of formation. Kaolin and bauxite are preliminarily fired and fired kaolin (33-67%) and bauxite are jointly ground to give mixture wherein alumina-to-silica weight ratio is 1: 1. Starting kaolin contains 40-45% alumina and no more than 5% free quartz. Firing is carried out at 1400-1500 C to water absorption no higher than 5%, preferably no higher than 4%. Temperature of preliminary bauxite firing depends on alumina content: 1500- 1700 C (preferably 1600-1650 C) to water absorption no higher than 5% at alumina content 60-65% and 1100-1400 C (preferably 1250-1300 C) to water absorption 20-35% at alumina content at most 65%. Grinding of fired materials is conducted to achieve average particle size below 100 mcm, preferably below 5 mcm. Ground mixture is subjected to granulation, granules are dried and riddled to isolate desired fraction, which is then fired at 1500-1600 C (preferably 1550-1600 C) and reriddled to give commercial product. EFFECT: improved reliability of process and stabilized characteristics of produce. 9 cl, 2 tbl, 30 ex