INORGANICCHEMICALSINDUSTRY ›› 2012, Vol. 44 ›› Issue (12): 1-.

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Preparation of trivalent chromium compounds from chromite by acid-leaching technique

 JI   Zhu   

  1. CNOOC Tianjin Chemical Research & Design Institute,Tianjin 300131, China
  • Published:2012-12-11

Abstract: There are three basic routes for producing chromium compounds from chromite,i.e.alkaline oxidation route,high temperature reduction route,and acid-leaching route(chromite directly react with sulfuric acid to prepare chromium sulfate solution,and other trivalent chromium compounds can be obtained after separation of impurities as well as double decomposition reaction).Acid-leaching route is the most reasonable one in theory because there is only acid-leaching in the whole process without intense oxidation or reduction reaction process.However,picotite is extremely resistant to chemical erosion and leaching solution contains a lot of impurities,which are difficult to separate cheaply and efficiently,resulting in the chromium sulfate product can not compete with alkaline oxidation route both in quality and in cost.With the development of science and the improvement of the energy saving and consumption reducing requirements,acid-leaching technique has been noticed again and some new techniques appeared.The acid-leaching technique′s progress including acid leaching method of chromite,the catalytic and oxidizing action of chromic anhydride during the acid-leaching,and the process and method of separating chromium from leaching solution etc.was summarized.It was also pointed out that new progress had been achieved in enhancing yield of chromium and in separation of chromium-iron,and if the further study could be continued,the industrialization of acid-leaching technique would be realized soon.Some advisable points about acid-leaching were summed up from the high cited literatures.

Key words: chromite, acid-leaching, chromium sulfate, trivalent chromium compounds, catalyst-oxidizer

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