用盐水溶液浸取新工艺铬渣研究

Leaching of hexavalent chromium contained in solid waste from new production process of potassium chromate using salt solutions

针对中科院过程所开发的铬铁矿液相氧化生产铬酸钾工艺过程中产生的一种含铬固体废物,采用硫酸铵、硫酸钠、氯化铵、氯化钠及其混合水溶液浸取的方法对其进行解毒处理。利用配方实验设计方法,通过间歇浸取实验表明,这些盐溶液对该铬渣中的六价铬浸取效果并无明显差别,效果与USEPA Method 3060A碱浸取方法相当。进一步用均匀设计方法考察了浸取时间、硫酸铵浓度以及浸取温度对浸取效果的影响,结果表明,硫酸铵最佳浓度约为1.5 mol/L,六价铬浸取量随温度升高而明显增大。

The aim of the work is to detoxify one of the solid wastes containing hexavalent chromium（Cr6＋） discharged from the production process of potassium chromate by oxidization of chromite ore in liquid phase,developed by The Institute of Process Engineering,Chinese Academy of Sciences. Aqueous solution of ammonium sulphate,sodium sulphate,ammonium chloride,sodium chloride or their mixtures were adopted to extract Cr6＋from the waste.The method of mixture design was used to plan the experiments and the results indicated that the constituents of the solutions had no substantial different effect on the extraction of Cr6＋and the leaching yields of Cr6＋were parallel to that of the USEPA Method 3060 A.Furthermore,the method of uniform design was used to plan the experiments to optimize leaching time,solution concentration,and leaching temperature.Modeling and simulation showed that the optimal concentration of the ammonium sulphate was about 1.5 mol/L,and the leaching yield raised substantially with the increase of leaching temperature.