刚柔组合桨强化软锰矿浸出过程的反应动力学特性

在软锰矿湿法浸出过程中，采用传统搅拌桨反应器，容易出现流体“打旋”现象，导致传质效果差，进而降低反应效率。因而，本研究将刚柔组合桨应用于软锰矿的还原浸出过程，强化浸出过程的传质行为，提高锰矿浸出率。结果表明，在黄铁矿与软锰矿质量比为0.20，硫酸浓度为1.5 mol/L，液固比为10，温度为363 K下，软锰矿中锰的浸出率达到90.12%，与传统桨叶相比，锰浸出率提高5.5%。同时，研究发现浸出过程遵循核收缩模型且受表面化学反应控制，黄铁矿与软锰矿质量比、初始硫酸浓度、液固比的反应级数分别为1.2679、0.4182、1.1959，反应动力学方程为1- （1-X）^1/3=0.96×10³（m_{\mathrm{F}\mathrm{e}{\mathrm{S}}_{\mathrm{2}}}/m_{\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{2}}}）^1.2679 [H₂SO₄]^0.4182（L/S）^1.1959exp（-41.75 ×10³/RT）t，浸出反应的表观活化能为41.75 kJ/mol。刚柔组合桨体系下的软锰矿浸出反应表观活化能相比传统搅拌体系下的软锰矿浸出反应表观活化能的文献报道值降低4.515~20.54 kJ/mol。

Reaction kinetics characteristics of pyrolusite leaching process enhanced by rigid-flexible combined impeller

In the process of wet leaching of pyrolusite, the traditional stirring blade reactor is prone to fluid “swirling”, which leads to poor mass transfer effects and lower reaction efficiency. In this paper, rigid-flexible combined impeller was applied to reduction leaching process of pyrolusite to enhance manganese ore leaching efficiency. The results show that under the condition of pyrite-to-pyrolusite mass ratio is 0.20, the sulfuric acid concentration is 1.5 mol/L, the liquid-to-solid mass ratio is 10, and the temperature is 363 K, the leaching rate of manganese in pyrolusite reaches 90.12%, which is 5.5% higher than that of traditional impeller. Simultaneously, it is also found that the leaching process follows the shrinking core model and is controlled by the surface chemical reaction. The reaction orders of pyrite-to-pyrolusite mass ratio, sulfuric acid concentration and liquid-to-solid ratio are 1.2679, 0.4182 and 1.1959, respectively, and kinetic equation is 1- (1-X)^1/3=0.96×10³(m_{\mathrm{F}\mathrm{e}{\mathrm{S}}_{\mathrm{2}}}/m_{\mathrm{M}\mathrm{n}{\mathrm{O}}_{\mathrm{2}}})^1.2679×[H₂SO₄]^0.4182(L/S)^1.1959exp(-41.75×10³/RT)t, the apparent activation energy of the leaching process is 41.75 kJ /mol. The apparent activation energy of pyrolusite leaching reaction in rigid-flexible combined impeller system is 4.515—20.54 kJ/mol lower than that in regular agitation system.