| With the rapid development of high technology and new materials,scandium has become more and more important in the national economy.Scandium has many excellent properties and is widely used in metallurgy,aerospace,defense,electronics,chemical,medical,nuclear technology,electric light and superconductors and many other important areas.The role of scandium in many areas is irreplaceable.Qinglong Guizhou anatase reserves of 23 million tons,with great value of development and utilization.The content of Sc2O3 is 84.7g/t and the content of TiO2 is 5.3%.The main minerals are kaolinite,sericite,quartz,anatase,limonite.The five minerals accounted for 95.6%of the total.Scandium does not exist in the form of an independent mineral.Scandium mainly in the form of isomorphism exists in kaolinite,sericite,limonite and anatase minerals.A large number of experimental results show that the size of anatase in Guizhou Qinglong is very fine.Conventional mineral processing methods are unable to process and can only be used for leaching.The best conditions of scandium leaching process determined by leaching experiment.The validation test proves that the optimum leaching process parameters are reliable.The leaching rate of Sc is 90.14%,the leaching rate of Ti is 38.70%,the leaching rate of Fe is 96.66%and the leaching rate of Al is 80.27%.The two stage leaching test can effectively extract anatase from the leaching residue and make the leaching rate of Ti increased significantly.The thermodynamic calculation results show that the sulfuric acid leaching of scandium is feasible in theory.The test results of temperature conditions of leaching kinetics showed that sulfuric acid leaching process of scandium is chemical reaction control process.The apparent activation energy of the leaching reaction is 43.9kJ/mol.The results of leaching kinetics test showed that the control step of scandium was changed from chemical reaction control to internal diffusion control with the increase of sulfuric acid concentration.The apparent reaction order of the leaching reaction is 1.0717.X ray diffraction analysis results show that the main composition of the raw ore is kaolinite,sericite and limonite.The main components of leaching residue are silica and anatase.The main component of the leaching residue in the two stage leaching test is silica.The results also showed that anatase and sulfuric acid were difficult to react.SEM-EDS analysis showed that limonite and anatase disappeared completely with the sulfuric acid reaction as the leaching process proceeded.However,the reaction of kaolinite and sericite with sulfuric acid is not completely dissolved,leaving a layer of silica which is insoluble in sulfuric acid.It is called amorphous silica,which makes the structure of mineral particles become porous.By using 2#reagent as the extractant test results show that the extraction rate of Sc is 98.47%,and the extraction rate of Ti,Fe and Al is very low.That is to say 2#extraction agent can realize the selective extraction of scandium.The results of stripping test show that the stripping rate of Sc is above 99%.The experimental results are ideal,laying the foundation for the subsequent process of scandium. |
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