FIELD: chemical technology. SUBSTANCE: invention relates to method for precipitation of different forms of silica from hydrothermal separate that can be used under conditions of geoelectric power plants, geoheating and power plants and in hydrothermal layers. This method can be used for treatment a separate at 20-160 C and pH value from 7.0 to 9.6. Method involves preparing solution supersaturated by amorphous silica, ageing and polymerization with addition of coagulating agents and stirring solution for formation of flakes and precipitation of silica, separation of flakes from cleared solution and preparing flake slime. At the stage of silica precipitation seawater is added to solution with lime simultaneously and seawater must contain total concentration of calcium and magnesium cations from 800 to 1200 mg/kg. Seawater consumption depends on lime consumption and required level of residual concentration of silica in solution after treatment and calcium concentration in precipitated material. Addition of seawater allows reducing lime consumption and to diminish alternation of pH index of solution after treatment with lime. Method provides the possibility to carry out stable precipitation of silica in small consumption of lime and consumption below critical that provides reduction of calcium part in precipitated material to value below 1.0 weight %. EFFECT: improved precipitation method. 1 dwg, 5 tbl, 3 ex
