低品位软锰矿碱浸预脱硅-流化焙烧制备锰酸钠

来源期刊:中国有色金属学报(英文版)2018年第5期

论文作者:邓祥意 冯雅丽 李浩然 杜竹玮 康金星 郭成林

文章页码:1045 - 1052

关键词:低品位软锰矿;脱硅;流化焙烧;锰酸钠

Key words:low-grade pyrolusite; desilication; fluidized roasting; sodium manganate

摘    要:采用低浓度碱浸对低品位软锰矿进行预脱硅处理,考察NaOH浓度、液固比、浸出温度、浸出时间及搅拌速率对硅浸出率的影响,研究碱浸过程动力学。结果表明:在NaOH起始浓度为20%、液固比为4:1、浸出温度为180 °C、浸出时间为4 h、搅拌速率为300 r/min的条件下,硅浸出率达到91.2%。缩核模型表明,碱浸过程受化学表面反应控制,其表观反应活化能为53.31 kJ/mol。通过正交试验对脱硅渣流化焙烧制备锰酸钠的条件进行优化,在硅浸出率为91.2%、NaOH/MnO2质量比为3:1、焙烧温度为500 °C、焙烧时间为4 h的条件下,锰酸钠的转化率为89.7%,且锰酸钠转化率随硅浸出率的升高而增加。

Abstract: Low concentration alkaline leaching was used for predesilication treatment of low-grade pyrolusite. The effects of initial NaOH concentration, liquid-to-solid ratio, leaching temperature, leaching time and stirring speed on silica leaching rate were investigated and the kinetics of alkaline leaching process was studied. The results show that silica leaching rate reached 91.2% under the conditions of initial NaOH concentration of 20%, liquid-to-solid ratio of 4:1, leaching temperature of 180 °C, leaching time of 4 h and stirring speed of 300 r/min. Shrinking-core model showed that the leaching process was controlled by the chemical surface reaction with activation energy Ea of 53.31 kJ/mol. The fluidized roasting conditions for preparation of sodium manganate were optimized by the orthogonal experiments using the desiliconized residue. The conversion rate of sodium manganate was obtained to be 89.7% under the conditions of silica leaching rate of 91.2%, NaOH/MnO2 mass ratio of 3:1, roasting temperature of 500 °C and roasting time of 4 h, and it increased with the increase of silicon leaching rate.

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