硅酸镁在氢氧化钠亚熔盐体系中的溶解行为

Dissolution behavior of magnesium silicate in NaOH sub-molten salt system

采用液相法合成硅酸镁(MgSiO3),研究其在氢氧化钠高浓介质体系中的溶解行为,探讨了液固比、氢氧化钠初始浓度和反应温度对硅酸镁中氧化硅反应率的影响,用液-固多相收缩未反应核模型研究其在氢氧化钠高浓介质体系中的反应动力学.结果表明:硅酸镁在氢氧化钠高浓介质体系中溶解过程的控制步骤为界面化学反应控制,硅酸镁脱硅反应的表观活化能为31.664 kJ/mol,反应级数为1.98.此方法研究硅酸镁的溶解行为,为中低品位红土镍矿的合理利用提供理论依据.

The dissolution behavior of magnesium silicate prepared by liquid phase reaction in high NaOH concentration medium system was studied.The effects of mass ratio of alkali to magnesium silicate,initial NaOH concentration,and reaction temperature on the reaction rate of SiO2 from MgSiO3 were investigated,and the kinetics of MgSiO3 reaction behavior in high NaOH concentration medium system was approached using the shrinking unreacted core model for the reaction of liquid-solid.The results show that the interfacial chemical reaction is the rate limiting step in the process of magnesium silicate dissolution behavior in high NaOH concentration medium system,the apparent activation energy （E） of magnisium silicate desiliconization is 31.664 kJ/mol and the reaction order（n） is 1.98.