低品位钼精矿钙化焙烧的反应机理

来源期刊:中国有色金属学报(英文版)2016年第11期

论文作者:甘敏 范晓慧 陈许玲 吴程骞 季志云 王送荣 汪国靖 邱冠周 姜涛

文章页码:3015 - 3023

关键词:钼精矿;钙化焙烧;反应机理;热力学研究;相变

Key words:molybdenum concentrate; calcification roasting; reaction mechanism; thermodynamic analysis; phase transformation

摘    要:研究了钙基添加剂对低品位钼精矿焙烧性能的影响。结果表明,钙基添加剂可与钼精矿反应生成CaSO4和CaMoO4。450 °C时MoS2开始氧化,500 °C以上生成CaMoO4和CaSO4,600~650 °C时钙化反应基本完成;进一步提高焙烧温度有利于CaMoO4的生成,但会降低焙烧过程固硫率和钼保留率。钙基添加剂焙烧效果依次为Ca(OH)2>CaO>CaCO3。随着Ca(OH)2用量的增加,钼保留率和固硫率均呈上升趋势,但过多的钙基添加剂会使酸浸过程硫酸的消耗增加,Ca(OH)2与钼精矿适宜的质量比为1:1。在650 °C下焙烧90 min时,低品位钼精矿钙化焙烧过程中钼保留率为100%、固硫率为92.92%,经硫酸浸出后钼的浸出率达到99.12%。

Abstract: The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The results show that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. The initial oxidation temperature of MoS2 is 450 °C, while the formation of CaMoO4 and CaSO4 occurs above 500 °C. The whole calcification reactions are nearly completed between 600 and 650 °C. However, raising the temperature further helps for the formation of CaMoO4 but is disadvantageous to sulfur fixing rate and molybdenum retention rate. Calcification efficiency of Ca-based additives follows the order: Ca(OH)2>CaO>CaCO3. With increasing the dosage of Ca(OH)2, the molybdenum retention rate and sulfur-fixing rate rise, but excessive dosages would consume more acid during leaching process. The appropriate mass ratio of Ca(OH)2 to molybdenum concentrate is 1:1. When roasted at 650 °C for 90 min, the molybdenum retention rate and the sulfur-fixing rate of low-grade molybdenum concentrate reach 100% and 92.92%, respectively, and the dissolution rate of molybdenum achieves 99.12% with calcines being leached by sulphuric acid.

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