Winning of molybdenum tri:oxide from ores etc. - by hot leaching with alkali to obtain soln. which is acidified and heated to ppte. anhydrous molybdenum tri:oxide

摘要

A raw material contg. Mo, and in a finely-divided form, is leached with a hot aq. liq. (A) contg. an alkali-carbonate, -bicarbonate or hydroxide, to obtain an alkaline soln. (B) of Mo, which is sepd. from solid gangue or "deads" (C). Soln. (B) is acidified and then heated to min. 120 deg. C to ppte. anhydrous Mo03. After converting Mo into Mo04 ions, and sulphur into SO4 ions, soln. (B) pref. contains less than 100 g/l CO3 or HCO3 ions, or less than 150 g/l OH ions cntd. esp. from Na or K salts. Leaching is pref. at below 250 deg.C, esp. at 80-250 deg.C in the presence of an oxidant and a catalyst promoting oxidn. The acidification of soln. (B) is pref. achieved using HN03, HCl, or H2SO4. A simple and rapid process.