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IMPROVEMENT IN A PROCESS FOR THE PRODUCTION OF RARE EARTH HYDROXIDES BY THE TREATMENT OF ORES CONTAINING RARE EARTH PHOSPHATES
IMPROVEMENT IN A PROCESS FOR THE PRODUCTION OF RARE EARTH HYDROXIDES BY THE TREATMENT OF ORES CONTAINING RARE EARTH PHOSPHATES
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机译:通过处理含稀土磷酸盐的矿石来改进稀土氢氧化物的生产工艺
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摘要
The rare earth hydroxides are improvedly prepared by (i) treating a rare earth phosphate mineral, e.g., monazite or xenotime, with an aqueous solution of an alkali metal hydroxide, (ii) separating therefrom rare earth hydroxide solids and a liquid phase essentially consisting of alkali metal phosphate and alkali metal hydroxide, (iii) crystallizing alkali metal phosphate from said liquid phase, (iv) separating the mother liquor of crystallization therefrom which contains said alkali metal hydroxide, (v) adding calcium oxide or hydroxide to the mother liquor thus separated to form a precipitate therein, (vi) separating said formed precipitate, and (vii) recycling the mother liquor of separation to said treatment step (i).
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