PEROVSKITE CONCENTRATE PROCESSING METHOD Russian patent published in 2005 - IPC

FIELD: mining industry.

SUBSTANCE: perovskite concentrate, which can be used for manufacture of pigment titanium dioxide for paints, paper, enamels, and plastics, is processed as follows. 1 kg of concentrate is treated under atmosphere conditions with concentrated HCl at 90-100^оС for 10 to 20 h to solubilize 75-85% of titanium, radioactive, and other acid-soluble components. Concentration of HCl is then lowered by diluting it with 1-5% HCl solution until TiO₂ concentration 50-100 g/L. Thermohydrolysis of solution at 100-105^оС accompanied by distilling away HCl leads to residual HCl concentration 20-100 g/L. Distilled HCl is sent to processing of perovskite concentrate. Titanium-containing precipitate is separated from mother liquor, washed first with 15-37% HCl solution and then with water to pH 3. Washed precipitate is treated with aluminum acid phosphate with pH 2-4. Aluminum acid phosphate uptake (on conversion to Al₂O₃) constitutes 0.5 to 5.0% content of TiO₂. Treated precipitate is separated and calcined at 850-870^оС to give pigment titanium dioxide. From mother liquor (after separation of Ti-containing precipitate), radioactive components are isolated by 4-6-step extraction with tributyl phosphate. Organic phase-to-water phase ratio is (1.5-2.0):1. Degree of titanium recovery is at least 98%, whiteness at least 96.5 conv. units, brightening power 1650-1800 conv. units, spreading capacity 38.0-40.0 g/m², oil capacity 25-27 g/100 g pigment. Yield of pigment TiO₂ is 95.7-98.0%. Amount of radioactive precipitate does not exceed 0.06 kg.

EFFECT: optimized perovskite concentrate processing parameters.

12 cl, 4 ex