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用 H_2O_2作络合均相沉淀法的络合剂,使钨、钼各自形成过钨酸和过钼酸,不产生钨钼杂多核络合物,因此在 H_2WO_4沉淀时,可除去部分微量钼。过钨酸有许多分解方法,本文比较了钨钼自身催化分解、光分解以及 SO_2分解法。催化分解法除钼效果,当钨沉淀率为90%时,钼沉淀率为9%;当钨沉淀率为96%时,钼沉淀率为11%。光分解法是钨沉淀率为95%时,钼沉淀率为30%。SO_2法是钨沉淀率为94%时,钼沉淀率为50%。前二种方法费时较长,难于工业应用,而SO_2法有工业应用价值。本文对三种方法的分解机理进行了讨论。
H_2O_2 is used as a complexing agent for the complex phase precipitation method to make tungsten and molybdenum each form peroxo-tungstic acid and peroxo-molybdic acid, and does not produce heteropoly-tungsten-tungsten complex. Therefore, some trace amounts of molybdenum can be removed during the precipitation of H_2WO_4. There are many decomposition methods of tungstic acid, this article compares the tungsten-molybdenum its own catalytic decomposition, photolysis and SO2 decomposition method. The catalytic decomposition of molybdenum removal effect, when the tungsten deposition rate of 90%, the molybdenum precipitation rate of 9%; when the tungsten deposition rate of 96%, the molybdenum precipitation rate of 11%. Photolysis method is tungsten deposition rate of 95%, the molybdenum precipitation rate of 30%. SO_2 method is a tungsten precipitation rate of 94%, the molybdenum precipitation rate of 50%. The first two methods take longer time and are difficult to be applied industrially, while the SO_2 method has industrial application value. This article discusses the decomposition mechanism of the three methods.