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Niobium, tantalum and rare and precious metal, metal and alloys have been widely used in iron and steel, electronics and other high-tech fields. The existing niobium-tantalum ore processing methods for the high concentration of hydrofluoric acid decomposition and extraction separation process, but the process will result in serious pollution of fluoride and low resource utilization difficult to break down the mine. To this end, the Institute of Process Engineering, Chinese Academy of Sciences to develop the production of new technology on the sub-molten salt method niobium tantalum clean niobium-tantalum ore difficult to break down the decomposition rate increased by 10% compared with the current hydrofluoric, and new processes are intermediate products - niobium tantalum hydrated oxide may be close to the theoretical amount of a low concentration of hydrofluoric acid, hydrofluoric acid used in an amount which is expected to significantly reduce, and niobium and tantalum extraction separation achieved in the low concentration of hydrofluoric acid system, and then in a great extent reduction of fluorine pollution and achieve cleaner production. Niobium-tantalum low concentration of hydrofluoric acid extraction system in process is sub-molten salt niobium-tantalum Clean Production Control fluorine pollution and guarantee product quality niobium-tantalum key technologies. This thesis is based on preliminary research results of the sub-molten salt cleaner production processes, niobium-tantalum low concentration of hydrofluoric acid extraction system in process systems research, and has been optimized niobium-tantalum extraction separation and impurity conditions, and to carry out the Mechanism, the main work and progress as follows: (1) determine the selective extraction using methyl isobutyl ketone (MIBK) tantalum niobium-tantalum there are differences in the shape and nature of the low concentration of hydrofluoric acid system to tantalum and niobium separation processes. (2) the use of multicomponent spectral fitting (MSF) method, ICP-AES, establish a reasonable MSF model, effectively correcting the extract high concentrations of tantalum-based body of niobium of spectral interference, to establish a suitable for this experimental system niobium elements of accurate determination of the method, which provides a guarantee for the accuracy of the follow-up analysis of the experimental process. (3) in a low concentration of hydrofluoric acid system, the use of MIBK extraction separation of tantalum and niobium, influences the contact time, extraction compared to the concentration of hydrofluoric acid concentration of niobium, tantalum, tantalum, niobium and mass ratio, H2SO4 concentration, temperature, and other factors of tantalum , the niobium extraction rate and the separation factor of tantalum and niobium. The results show that: in the contact time of 5 min, a single-stage extraction compared to hydrofluoric acid concentration of 0.5 mo1 · L-1, tantalum and niobium concentration 60 g · L-1, the mass ratio of tantalum and niobium 2, tantalum, niobium The extraction rate was 96.01%, 0.048%, tantalum, niobium and separation factor of nearly 50,000. Therefore, in a low concentration of hydrofluoric acid system, to MIBK as extractant, can be realized tantalum, niobium efficient extraction separation. 3 mol · L-1 sulfuric acid washing the organic phase containing tantalum, compared to 1:1, washed twice to All to remove the trace amounts of niobium. Also investigated the behavior of the impurities of Fe, Si, A1, Ti, etc. in the extraction process, the results show that the impurities not substantially enter the tantalum-containing organic phase. The process for the preparation of high purity tantalum foundation. (4) The use of niobium oxalate crystals purified raffinate of niobium, Nb and the effective separation of the impurities can be achieved, and ultimately of Fe, the content of impurities of Si, Ti, Al, etc. have reached the industry requirements. (5) a preliminary study the mechanism of MIBK extraction tantalum. Determination of the extracted complexes by the slope method and the saturation capacity by means of infrared spectroscopy and nuclear magnetic resonance spectroscopy analysis before and after extraction MIBK. The results show that: and hydrofluoric 0.5 mo1 · L-1 under, Tantalum mainly to HTaF6 form of existence, there is only a small part of the HTaF7. The extractant MIBK extraction Ta mechanism for solvation extraction the the extraction equation may be abbreviated as: 3 MIBK HTaF6 = the HTaF6 · 3MIBK.
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