METHOD OF PHOSPHITE PROCESSING Russian patent published in 2015 - IPC C22B59/00 C22B3/08 

FIELD: chemistry.

SUBSTANCE: method includes water processing, leaching of phosphate with sulphuric acid solution with concentration 3-6 wt % with conversion of REE, calcium and thorium into leaching solution and with obtaining gypsum product, extraction of REE, calcium and thorium from leaching solution by sorption with sulphoxide cationite. Leaching is carried out with sulphuric acid solution and L:S not less than 1.4:1. Sorption of REE, calcium and thorium is realised in stages. At first stage leaching solution is passed through cationite before beginning of REE breakthrough into forming primary depleted sulphuric acid solution. After that, desorption of calcium and thorium from saturated cationite with primary depleted sulphuric acid solution is carried out with obtaining primary calcium-thorium-containing strippant. At second stage remaining leaching solution is passed through cationite before REE breakthrough into secondary depleted sulphuric acid solution, which is applied for calcium and thorium desorption with obtaining secondary calcium-thorium-containing strippant. Then desorption of REE with solution of ammonium nitrate and precipitation of REE from strippant at pH 7.35-7.5 are realised.

EFFECT: obtaining non-radioactive rare earth concentrate with extraction of REE from phosphogypsum into non-radioactive concentrate and with reduction of applied sorbent consumption.

6 cl, 5 ex