氯化焙烧-水浸法从富铷锂云母矿中提取Li、Rb

Extraction of lithium and rubidium from rubidiumrich lithium mica ore by chlorination roastingwater leaching process

由于低铷锂云母中的Rb赋存形态差异较大,且含量低,提Rb工艺参数稳定性差,难以实现工业化生产。本文以澳大利亚富铷锂云母矿为原料,采用NaCl-CaCl_(2)焙烧-水浸法进行了提取Li、Rb的试验研究,考察焙烧温度、配料比、时间和浸出液固质量比、时间、温度对Li、Rb提取的影响。结果表明,在富铷锂云母矿:NaCl:CaCl_(2)的质量比为1:0.6:0.4、焙烧温度为800℃、焙烧时间为1.5 h、水浸温度为25℃、液固比4:1、浸出时间15 min的条件下,Li、Rb浸出效果最佳,Li、Rb浸出率分别达87.8%和94.9%。焙砂及浸出渣的X射线衍射(XRD)分析表明,氯化焙烧后,锂云母中的Li和Rb矿相转化为可溶性的LiCl和RbCl相,同时生成KCl和难溶物CaAl_(2)Si_(2)O_(8)、NaAlSi_(3)O_(8)、CaF_(2)。△GΘT-T和△HΘT-T关系图表明,NaCl-CaCl_(2)与碱金属氧化物的反应顺序为Rb>K>Li;矿石中的SiO_(2)与Al_(2)O_(3)参与对碱金属的氯化反应有促进作用。

It is difficult to achieve industrial production of low rubidium lepidolite because of the large differences in the occurrence forms of Rb.In this paper,the extraction of Li and Rb from rubidiumrich lepidolite ore in Australia was studied by using NaCl-CaCl_(2)roastingwater leaching method.The effects of roasting temperature,ingredient ratio,time and leaching liquidsolid mass ratio,leaching time and temperature on the extraction of Li and Rb were investigated.The results show that under the conditions of rubidiumrich lepidolite ore:NaCl:CaCl_(2)mass ratio of 1:0.6:0.4,roasting temperature of 800℃,roasting time of 1.5 h,water leaching temperature of 25℃,liquidtosolid ratio of 4:1 and leaching time of 15 min,the leaching effect of Li and Rb is the best.The leaching rates of Li and Rb were 87.8%and 94.9%,respectively.Xray diffraction(XRD)analysis of calcinate and leaching residue showed that Li and Rb mineral phases in lepidolite transformed into soluble LiCl and RbCl phases after chlorination roasting,meanwhile KCl and insoluble substances CaAl_(2)Si_(2)O_(8),NaAlSi_(3)O_(8),CaF_(2)were generated.The△GΘT-T and△HΘT-T diagrams showed that the reaction order of NaCl-CaCl_(2)with alkali metal oxides was Rb>K>Li.The participation of SiO_(2)and AlO phase in ores promoted the chlorination reaction for alkali metals.