Abstract:Aluminum concentrate can be prepared from pyrite tailings bearing a large amount of aluminum, silicon and titanium by chemical desiliconization. Regenerated alkaline solution and calcium silicate can be simultaneously obtained from desiliconization leachate by adding lime milk. Regenerated alkaline solution with NaOH concentration of 120 g/L is returned to desiliconization leaching process for recycling. The optimum conditions for synthesis of calcium silicate include CaO dosage of 1.1 times of theoretical amount, reaction time of 120 min, and reaction temperature of 90 ℃. Precipitation rate of SiO2 and Al2O3 is 95.64% and 84.93% respectively under the optimum conditions. The calcium silicate product with whiteness of 95%~98% and particle diameter of about 20 μm can be used in papermaking, as building materials, insulation materials and so on.