METHOD FOR PROCESSING FLUORIDE RARE-EARTH CONCENTRATE Russian patent published in 2019 - IPC C22B59/00 C22B3/06 C22B3/24 

FIELD: technological processes.

SUBSTANCE: invention relates to processing of fluorine-containing concentrates of rare-earth elements (REE). Bastnaesite concentrate is treated with a low-concentration mineral acid at high temperature in the presence of a sulphoxide cationite with conversion of rare-earth elements, calcium and thorium to a sulphoxide cationite, and fluorine into an acidic solution. Treatment of the concentrate is carried out until concentration of rare-earth oxide is found in the cationite of at least 40 g/l. Cationite is then separated from the acid solution which is used in the concentrate acid treatment solution to achieve a fluoride concentration of 10–15 g/l. Cationite is regenerated to obtain a strippant which is subjected to stepwise neutralization with an alkaline compound with sequential deposition and separation of thorium, a rare-earth concentrate and a calcium-containing precipitate.

EFFECT: disclosed method enables to efficiently process bastnaesite concentrate with high (up to 96,7 %) degree of extraction of rare-earth elements into a non-radioactive concentrate and use of more readily available and cheap mineral acids, the use of which in circulation reduces the amount of waste formed.

1 cl, 9 ex