METHOD OF PRODUCING REFRACTORY METAL OXIDES FROM LAPARITE CONCENTRATE Russian patent published in 2000 - IPC

FIELD: hydrometallurgical processing of laparite concentrate. SUBSTANCE: method includes grinding of concentrate to particles sizing at least 0.075 mm with classification; breaking down of laparite concentrate with concentrated inorganic acid at atmospheric pressure and temperature above 100 C; formation from products of concentrate breaking down of fluoride compounds of tantalum and niobium under the effect of hydrofluoric acid and their extraction; extraction of titanium dioxide. In this case, breaking down is carried out with the help of concentrated nitric acid with obtaining of hydrate cake of refractory metal oxides. Fluoride compounds of tantalum and niobium are produced by dissolving of hydrate cake with hydrofluoric acid with concentration at least 40% with formation of fluorotitanic acid. Tantalum and niobium are extracted with the aid of octyl alcohol. Oxides are recovered from their reextracts by high-temperature pyrolysis at temperature of 600-650 C. Then, raffinate is boiled down by 1.5-2.0 times and titanium dioxide is recovered by high-temperature pyrolysis. In this case, gaseous products of pyrolysis are subjected to cooling for absorption of vapors of hydrogen fluoride with water to obtain hydrofluoric acid which is returned to process for dissolving of hydrate cake. EFFECT: simplified process, higher process efficiency and economy. 1 tbl, 2 ex