Study On Preparation Of Phosphotungstic Heteropoly Acid From Sorbite By Acid Decomposition Extraction

It has been explored reserves of1million tons of scheelite, wolframite only200000tons in our country at present. For a long time, due to the restriction of production technology level, China’s tungsten smelting production is mainly wolframite. But the domestic wolframite resource has nearly been exhausted, the scheelite form but also has these characteristics such as complex component, low grade, existence associated with other metal and be difficult to be developed and utilized, the wastewater discharge problem also exist in the process of scheelite smelting, thus to realize water closed-circuit circulation of the scheelite smelting process,which is very necessary to carry out new technology research of extracting tungsten from scheelite.This paper summarizes the recovery research achievements of tungsten from scheelite. And according to the occurrence and taste characteristics of tungsten in the scheelite, to improve the concentration of tungsten of the scheelite smelting process and achieve closed-circuit circulation of water, Proposed and studied"hydrochloric acid decomposition-extraction-sulphuric acid regeneration" process to deal with the scheelite.Through a large number of experimental research, it is determined that the scheelite hydrochloric acid complexation leaching reaction is a liquid-solid phase reaction of the contraction at the end of the non-catalytic model, the whole reaction process belongs to the chemical reaction control, then we can calculate the chelating reaction of the apparent activation energy is59.8kJ/mol, its reaction kinetics equation is K=4.85×108CHCl0.62CPO3-40.505exp(-59800/RT); Under the optimal process parameters, scheelite complexing decomposed by hydrochloric acid, the tungsten decomposition rate can reach99.6%; Without removing impurities, adjusting acidity, using N235to extract the mixed acid decomposition liquid directly, tungsten and phosphorus are extracted first at the form of phosphotungstic heteropoly acid root [PW12O40]3-, hydrochloric acid second, phosphoric acid almost no extracted, the tungsten extraction percentage reaches as high as99.9%,the separation of tungsten and other impurities effect is also very good; Loaded organic phase is back extracted with NaOH, tungsten back extraction rate reaches98%; Using sulphuric acid which is1.2times dosage of theory, hydrochloric acid regeneration rate reached93.5%.