以稻草为还原剂硫酸浸出软锰矿动力学研究

以稻草为还原剂,采用硫酸浸出软锰矿,设计了单因素和正交实验,考察了稻草粒径及用量、硫酸浓度、浸出时间及温度对锰浸出率的影响,并分析了浸出过程动力学。结果表明,30 g粒径为100 μm的稻草,在363 K下,用1.4 mol/L的硫酸浸出50 g软锰矿5 h,锰浸出率可达90.74%。浸出过程实质是稻草水解产物与软锰矿发生氧化还原反应,该反应可用未反应收缩核模型描述,表观活化能为39.8 kJ/mol,反应速率受界面化学反应控制。按先水解稻草再浸出矿料的步骤可提高锰浸出率。

Kinetics of Sulfuric Acid Leaching of Pyrolusite with Straw as a Reducing Agent

A single factor and orthogonal experiments were designed for sulfuric acid leaching of pyrolusite with straw as a reducing agent. Effects of grain size and dosage of straw, sulfuric acid concentration, leaching time and temperature on manganese leaching rate were investigated, and kinetics of leaching process was analyzed. Results showed that 50 g pyrolusite was leached with 1.4 mol/L sulfuric acid at a temperature of 363 K for 5 h, with 30 g straw at a size of 100 μm, resulting in the manganese leaching rate up to 90.74%. During the leaching process, a redox reaction occurred between straw hydrolyzate and pyrolusite, which could be described with an unreacted shrinking-core model. The apparent activation energy was 39.8 kJ/mol and reaction rate was controlled by the interface chemical reaction. It is suggested that the process of hydrolysis of straw followed by leaching can improve the manganese leaching rate.