Study On Extracting Of Scandium From Hydrochloric Acid Leaching Solution Of Red Mud

Scandium is a typical scattered rare earth elements. Since scandium has a high chemical activity, electrical conductivity good, soft and easy to cut and so on, making it in the defense, electric light, the metallurgical industry, aerospace, electronics industry, chemical industry, nuclear technology, superconducting technology, glass industry, medical and other important areas have access to a wide range of applications. Sc in the earth's crust, the average grace is 3.6 x 10-3%, mainly in Tianomagnetite, bauxite, rare earth ore, V-Ti magnetite and gangue and other ores. The content of Scandium in China's bauxite of 40～150μg·g-1 is 1to 4 times higher than foreign.Red mud of alumina production process is the emission of waste, the emissions from large, is alkaline and complex chemical composition, which contains large amounts of valuable metals, particularly rare earth elements, there is a great recycling value.98% of the scandium of bauxite is concentrated in the red mud. The content of scandium in the red mud used in this study is of scandium oxide containing 160g/t. The average Sc content of red mud in most of the more than 100g/t,200g/t and even some large. Recently, two scandium ores were discovered of scandium oxide 66g/t as two independent deposit in Yunnan Province, Large scandium mineral found in Zhejiang scandium content of scandium oxide 22g/t, scandium is not very high grade. Thus, extracting scandium from red mud are of great significance for the comprehensive utilization of solid waste non-ferrous metallurgy and the development and recovery of scandium resources.The leaching solution of red mud was given a pretreatment first, In a leaching pretreatment process, the efficiency of desilication increased with increasing temperature, when the temperature reaches 60℃, the removal of silicon efficiency increases is limited. When the concentration of Na2Ok reachs 280 g/L, the concentration of alumina in sodium aluminate solution does not change with the increase of pressure, It is identified that the dissolution with alkali Na2Ok to be 280g/L.Study mainly on extraction conditions and extraction mechanism in the Extraction process. In the P204 extraction Sc(Ⅲ) system, with the extractant concentration increasing, a slight increase in distribution ratio and the separation factor decreased. With the liquid acidity increasing, in the low acid concentration, the distribution ratio decreases, at this time carried out by cation exchange, increasing the acid concentration is not conducive to the conduct of extraction; in the high acid concentration, the distribution ratio of the increases, at this time the extraction system mainly of solvent mechanism extraction. Distribution ratio and separation factor have declined by heated liquid, and produce the emulsion layer, the extraction should be carried out at room temperature.Low acidity P204 extraction reaction is:High acidity P204 extraction reaction is:P507 has good selective, it almost has no effect on the extraction of iron and aluminum. In the P507 extraction Sc(III) system, the distribution ratio changed little as the extractant concentration increases; solution acidity and temperature on the extraction are similar to the P204 extraction system. The emulsication is serious in P507 extraction system, pretreatment of leachate is essential.Low acidity P507 extraction reaction is:High acidity P507 extraction reaction is:In the P204 and P507 synergistic extraction system, when the concentration of P204 and P507 ratio of 2:1, the distribution ratio of maximum. The effect of acidity and temperature on extraction is the same to single extraction system. Synergistic extraction using a strong extraction combined capacity of P204 and a better selectivity of P507, is a kind of synergistic extraction system of research value.P204 and P507 synergistic extraction reaction is:...