Studies on Valued Components Extraction from Titanium-Magnesium Production Wastes

Abstract

Based on the results of studies on the extraction of rare-earth elements from exhausted molten titanium chlorinators and the production of carnallite from chloride waste from titanium-magnesium production, the possibility to obtain REE production solution suitable for their separation and synthetic carnallite intended for chlorination of titanium slags is demonstrated. A purified water leaching solution from the exhausted molten titanium chlorinator (EMTC) was obtained to isolate synthetic carnallite with the addition of hydrochloric acid and magnesium electrolysis cell sludge up to pH 6.8-7.6. Physicochemical analysis of EMTC showed that the composition contains rare-earth elements in the form of oxides and water-soluble chlorides. The optimal EMTC water leaching mode was established: S:L ratio = 1:0.7, temperature 20-25 °С, duration-60 min. In this case, a solution was obtained with a concentration of 0.532 g/dm 3 of the sum of rare-earth elements, 122.8 g/dm 3 of iron, pH 0.76. The separation of iron from a chloride solution during precipitation with a solution of potassium hydroxide in the range of pH 2.6-3.1 at a temperature of 80 °C. The precipitation of REEs from the solution with oxalic acid in an amount of 150% of the amount required stoichiometrically in the form of oxalates with a pulp exposure time of oxalates of 4 hours. The precipitate formed from oxalates was washed on the filter with a 2% oxalic acid solution at S:L = 1:8. Obtaining a collective REE concentrate in the processing of exhausted molten titanium chlorinators. The throughout recovery of rare-earth elements from EMTC into collective concentrate was 66%.