Al2O3对含钒钢渣中钒富集行为的影响

INFLUENCE OF Al_2O_3 ON VANADIUM CONCENTRATION IN V-BEARING STEELMAKING SLAG

为能有效富集含钒钢渣中的钒,针对Al_2O_3作用于钒富集过程的行为进行了相关热力学研究.结果表明,用Al_2O_3高温改性后的含钒钢渣在缓冷过程中,固溶有钒和磷的硅酸二钙相会先期析出.在1623 K附近,该矿物与熔渣中Al_2O_3反应生成富钒矿物—钒磷酸钙(固溶有Ca和Si组分)和钙铝黄长石.平衡体系中的硅酸二钙会随渣中Al_2O_3的增加而减少直至消失,剩下钒磷酸钙和钙铝黄长石与熔渣平衡共存.其中,钙铝黄长石的生成趋势更为占优,如渣中Al_2O_3足量,已生成的钒磷酸钙中的部分Ca和Si组分,还会继续与渣中Al_2O_3结合,再次生成钙铝黄长石,使磷酸钙中的钒品位进一步提高,这也是渣中钒和磷结合后含有较少杂质而生成高品位富钒相的最本质原因.

The influence of Al2O3 on vanadium concentration in the slag was studied based on experimental data according to the thermodynamic analysis. The results show that the phase of Ca2SiO4 （s） with dissoluted by V and P is preferentially precipitated when V-bearing steelmaking slag modified by Al2O3 is cooled slowly. At about 1623 K, the phase of Ca2SiO4（s） reacts with Al2O3 to produce gehlenite and a new V-bearing mineral, named calcium phosphate-calcium vanadate solid solution （V-concentrated phase）, which can be also dissoluted by Ca and Si. With the content of Al2O3 increasing, Ca2SiO4 vanished finally, and calcium phosphate -calcium vanadate and gehlenite will coexist with melt in the equilibrium system, thereinto the tendency to form gehlenite is the largest. If the content of Al2O3 is large enough in the slag, the Ca and Si in calcium phosphate-calcium vanadate will continue to react with Al2O3 in the slag to produce gehlenite, which can heighten the concentration of vanadium in the calcium phosphate -calcium vanadate solid solution and is the fundamental reasons of low content of impurity in the V-concentrated phase.