EXTRACTION OF YTTRIUM FROM FERRUGINOUS SANDSTONE, SOUTHWESTERN SINAI, EGYPT

摘要

The Ferruginous sandstone ore was obtained from Ramlet Hemeyir area, Southwestern Sinai, Egypt, was found to contain 10% rare earth elements (REE). A representative sample has been subjected to sulfuric acid agitation leaching. About 93% of the REE content was released by mixing the ground sample to -100 mesh with concentrated H_2SO_4 at solid/liquid (S/L) ratio of 1/2 for 5h at a temperature ranged from 250 to 300℃. The REE was precipitated from the prepared sulfate leach liquor of pH 1.0 by adding 35% oxalic acid at 25℃. The precipitation yielded 98% REE. For selective separation of yttrium, the rare earth cake was leached with 31.5% nitric acid. Next, the aqueous solution was contacted with di-(2-ethylhexyl) phosphoric acid (D2EHPA) where 98% yttrium extraction was achieved. Stripping was done with hot H_2O (80℃). Finally, a precipitation with oxalic acid was done followed by ignition at 950℃. A yield of 95% yttrium oxide was produced.