甲酸还原硫酸浸出低品位氧化锰矿

Leaching of Low-grade Manganese Oxide Ore in Sulfuric Acid with Formic Acid as Reductant

研究了甲酸作为还原剂在硫酸介质中还原浸出低品位氧化锰矿的工艺。采用单因素试验研究了甲酸用量、硫酸浓度、反应温度、反应时间及液固比对锰、铁、铝3种金属浸出率的影响。利用XRD和SEM对矿粉和矿渣的成分和表面形貌进行了分析和表征,利用响应曲面法对还原浸出条件进行了优化。结果表明,各因素影响浸出率的主次顺序为甲酸用量>硫酸浓度>反应温度>反应时间。当硫酸体积分数为15%,液固比为6,甲酸用量0.4 m L/g,反应时间2 h,反应温度90℃时,锰浸出率最大,为90.05%,此时铁和铝浸出率为80.07%和31.55%。

The process of manganese extraction from low-grade manganese oxide ore in sulfuric acid medium with formic acid as reductant was investigated. Firstly,the single-factor experiments were performed to explore the effects of dosage of formic acid,concentration of sulfuric acid,liquid to solid ratio（ L / S）,leaching time and temperature on leaching rate of manganese,iron and aluminum. XRD and SEM were then employed to analyze and characterize the mineral and slag powder. The reductive leaching process conditions were finally optimized by using response surface method. Results show that dosage of formic acid has the biggest impact on the leaching rate,which is followed by the concentration of sulfuric acid,reaction temperature and reaction time. The process with 15% H_2SO_4（ v /v）,0.4 m L/g formic acid,and liquid to solid ratio at 6,reaction at 90 ℃ for 2 h,can result in the manganese leaching rate up to 90.05%,being the highest,followed by the leaching rate of iron and aluminum at 80.07% and 31.55%,respectively.