The mineral composition of copper tailings was examined, and the phase analysis of gallium was conducted for recovery of the rare scattered metal gallium from copper tailings. The reaction characteristics and kinetics...The mineral composition of copper tailings was examined, and the phase analysis of gallium was conducted for recovery of the rare scattered metal gallium from copper tailings. The reaction characteristics and kinetics of gallium in the chlorination roasting of copper tailings were investigated in a tube furnace apparatus under different conditions, including roasting temperature, quantity of chlorination agent,roasting time, and airflow. Calcium chloride was chosen for the chlorination reaction because it is highly effective for volatilization of metals. The results show that gallium mainly exists in limonites in the form of oxides, and increases in roasting temperature, quantity of chlorination agent, and roasting time are conducive to increasing the chloridizing volatilization rate of gallium. The tailings gradually melt when the roasting temperature exceeds 900℃, resulting in a decrease in the chloridizing volatilization rate of gallium. The chloridizing volatilization rate of gallium reaches 78.86%at roasting temperature of 900℃ for 40 min, airflow of 0.1 m^(3)·h^(-1), and calcium content of 33.33 wt%. Study of the reaction kinetics of gallium in chlorination roasting shows that the values of activation energy both for chemically controlled anddiffusion-controlled reactionsare44.64and11.93 kJ·mol^(-1), respectively. This indicates that the chemical reaction serves an important function in the chlorination volatilization of gallium. Taken together, the results reveal the usefulness of tailings as a source of rare metals and provide a basis for gallium recovery and environmentally friendly disposal of copper tailings.展开更多
研究了氯化铵焙烧法氯化氧化钆制备无水氯化钆的适宜条件和动力学。结果表明：采用氯化铵焙烧氯化氧化钆制备无水氯化钆的适宜条件为nNH4Cl∶nGd2O3=12∶1、T=340~350℃和t=40 min,氧化钆的氯化率为100%;氯化铵与氧化钆的物质的量之比...研究了氯化铵焙烧法氯化氧化钆制备无水氯化钆的适宜条件和动力学。结果表明：采用氯化铵焙烧氯化氧化钆制备无水氯化钆的适宜条件为nNH4Cl∶nGd2O3=12∶1、T=340~350℃和t=40 min,氧化钆的氯化率为100%;氯化铵与氧化钆的物质的量之比是影响氯化率的最主要因素,使用过量的氯化铵是制备高纯度无水氯化钆的关键。氯化反应是气-固多相区域反应,动力学曲线符合Bagdasarrym模型,反应进度遵从Erofeev方程ln[-ln（1-αRE）]=lnk＋nlnt,反应的表观活化能Ea为68.254 k J·mol^-1,频率因子A0为1.3×10^5,氯化反应的过程限制环节属于界面化学反应控制。展开更多
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...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.展开更多
基金financially supported by the Key Project of the Chinese Academy of Sciences Comprehensive Strategic Cooperation with Guangdong Province (No. 2012B090400030)Guangdong Natural Science Funds for Distinguished Young Scholar (No. S2013050014122)the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (GIGCAS) 135 Project (No.Y234021001)。
文摘The mineral composition of copper tailings was examined, and the phase analysis of gallium was conducted for recovery of the rare scattered metal gallium from copper tailings. The reaction characteristics and kinetics of gallium in the chlorination roasting of copper tailings were investigated in a tube furnace apparatus under different conditions, including roasting temperature, quantity of chlorination agent,roasting time, and airflow. Calcium chloride was chosen for the chlorination reaction because it is highly effective for volatilization of metals. The results show that gallium mainly exists in limonites in the form of oxides, and increases in roasting temperature, quantity of chlorination agent, and roasting time are conducive to increasing the chloridizing volatilization rate of gallium. The tailings gradually melt when the roasting temperature exceeds 900℃, resulting in a decrease in the chloridizing volatilization rate of gallium. The chloridizing volatilization rate of gallium reaches 78.86%at roasting temperature of 900℃ for 40 min, airflow of 0.1 m^(3)·h^(-1), and calcium content of 33.33 wt%. Study of the reaction kinetics of gallium in chlorination roasting shows that the values of activation energy both for chemically controlled anddiffusion-controlled reactionsare44.64and11.93 kJ·mol^(-1), respectively. This indicates that the chemical reaction serves an important function in the chlorination volatilization of gallium. Taken together, the results reveal the usefulness of tailings as a source of rare metals and provide a basis for gallium recovery and environmentally friendly disposal of copper tailings.
文摘研究了氯化铵焙烧法氯化氧化钆制备无水氯化钆的适宜条件和动力学。结果表明：采用氯化铵焙烧氯化氧化钆制备无水氯化钆的适宜条件为nNH4Cl∶nGd2O3=12∶1、T=340~350℃和t=40 min,氧化钆的氯化率为100%;氯化铵与氧化钆的物质的量之比是影响氯化率的最主要因素,使用过量的氯化铵是制备高纯度无水氯化钆的关键。氯化反应是气-固多相区域反应,动力学曲线符合Bagdasarrym模型,反应进度遵从Erofeev方程ln[-ln（1-αRE）]=lnk＋nlnt,反应的表观活化能Ea为68.254 k J·mol^-1,频率因子A0为1.3×10^5,氯化反应的过程限制环节属于界面化学反应控制。
文摘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.
