白云母伴生铷矿氯化焙烧-水浸法提铷的动力学研究

Kinetic studies of rubidium extraction from muscovite using chlorination roasting-water leaching process

采用了氯化钙氯化焙烧-水浸法提取白云母中铷的方法.通过氯化焙烧热重-差热分析曲线可知,用氯化钙混合白云母进行氯化反应的温度要比用氯化钠低100℃左右,且用CaCl2氯化比Na Cl更有效率.接着考察了氯化焙烧温度对铷提取率的影响,结果表明,只有当氯化焙烧温度提高至800℃后,才可能取得明显的铷的氯化效果,铷的提取率即达96.71%,随氯化焙烧温度升高,铷的氯化速率不断增大,特别是800℃后,铷的氯化速率明显增大,这说明高温有利于铷的氯化焙烧.最终对白云母与氯化钙氯化焙烧过程进行了动力学研究.结果表明,三维界面反应方程能较好地描述该氯化焙烧反应体系,根据阿仑尼乌斯公式计算出来的活化能为42.22 k J·mol^（-1）,说明白云母和CaCl2的氯化过程的确受界面化学反应控制.

Rubidium is a very active and highly dispersed rare alkali metal,which has a wide range of applications in space technology,electronics,bioengineering,and materials science. To date,no single mineral with the industrial exploitation of rubidium has been found. Rubidium is mainly associated with cesium lithium mica,pollucite,carnallite,potash,seawater,and salt lake brine. In recent years,a large amount of rubidium muscovite has been found in China,and they have become an important resource for extracting rubidium. If comprehensively explored,they will alleviate the shortage of rubidium resources in China. Therefore,it is imperative to develop a simple and highly efficient process for rubidium muscovite exploration. Here,a chlorination roasting process was proposed to recover rubidium from the distinctive rubidium-containing muscovite. According to the differential thermal analysis and thermogravimetric analysis（ DTA-TG） curves of chlorinated roasting,the temperature of the chlorination reaction using calcium chloride is about 100℃ lower than that of sodium chloride,and the chlorination is more efficient with CaCl_2 than Na Cl. Subsequently,the impact of chlorination temperature on the rubidium extraction rate was investigated. The results show that the rubidium can be chlorinated only when the chlorination temperature reaches 800 ℃,whereby the rubidium extraction rate is 96. 71%. The rubidium chlorination rate largely increases with,especially after 800 ℃; this shows that the high temperature is beneficial to the chlorination roasting of rubidium. Finally,the kinetics results of the chlorination roasting of the kaolin ore show that the extraction rate of rubidium is controlled by the chemical reaction,and the activation energy in the roasting temperature range is 42. 22 k J·mol^（-1）.