复合钠盐对硅质页岩提钒的强化及协同作用

Synergistic and strengthen effect of composite sodium salt on vanadium extraction of siliceous shale

从钒氧化角度研究复合钠盐对硅质页岩提钒的强化及协同作用。结果表明:Na_2CO_3在复合钠盐中的添加量小于复合盐总质量的40%时,与NaCl共同促进长石生成和消耗的过程,并进一步促进钒加速氧化,产生正向协同作用并使钒氧化率提高。Na_2SO_4在复合盐中所占比例的改变对钒氧化影响不明显,且与NaCl和Na_2CO_3无明显协同作用,可加入20%~40%Na_2SO_4代替NaCl。Na_2CO_3和Na_2SO_4作为替代品最多可使焙烧添加剂中NaCl的用量减少60%左右。要保证焙烧产物中钒氧化率大于70%,复合添加剂中3种盐添加量由大至小的顺序应遵循NaCl、Na_2CO_3、Na_2SO_4的原则。将混料实验得到的焙烧产物钒氧化率采用特殊三次方模型拟合优化,得到的最优方案如下,NaCl添加量4.96%,Na_2CO_3添加量2.71%,Na_2SO_4添加量2.33%,此时产物钒氧化率达71.56%。

The synergistic and strengthen effect of composite sodium salt on vanadium extraction from siliceous shale of roasting were investigated. The results show that, when the added amount of Na2CO3 is less than 40% of the total mass of the composite sodium salt, Na2CO3 and NaCl will jointly promote the formation and consumption of feldspar. The change of Na2SO4 content of composite salts has no obvious effect on vanadium oxidation. It can be added with 20%-40% Na2SO4 in composite salts in place of NaCl. Without reducing vanadium oxidation rate, the two salts can replace up to 60% NaCl. To get more than 70% of vanadium oxidation rate, the order for content with each salt in composite salts from high to low should follow the principle of NaCl, Na2CO3, Na2SO4. The special cubic model was used to optimize the vanadium oxidation rate. The results show that with 4.96%（mass fraction） NaCl, 2.33% Na2SO4 and 2.71% Na2CO3, vanadium oxidation rate is 71.56%.