METHOD FOR OPENING OF MONAZITE CONCENTRATE Russian patent published in 2004 - IPC

FIELD: opening of rare-earth element concentrates from natural phosphor-bearing concentrates.

SUBSTANCE: method involves producing burden from mixture of monazite concentrate and calcined soda; providing thermal processing and performing aqueous processing of product obtained after thermal processing of said mixture; separating total of lanthanides and thorium in the form of oxides washed off from phosphor; before preparing of burden, grinding monazite concentrate to -100 mesh (-0.15 mm) size; selecting weight ratio of monazite concentrate to calcined soda in said mixture within the range of from 1:0.5 to 0.65, with soda excess making 10-40%. Thermal processing is provided in hermetically sealed continuously operated electrically heated furnaces. Aqueous processing is performed at temperature of 80-95⁰C and at solid:liquid ratio of 1:4. Reaction waste gases are cleaned from thoron released during opening procedure. Method allows extraction of total of rare-earth metals and thorium into phosphor-free pure sediment to reach 99%.

EFFECT: increased extent of extracting of rare-earth metals and thorium, reduced consumption of reactants, such as soda, and provision for obtaining of additional commercial product of trisodium phosphate.

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