砷酸钙与碳粉混合共热解过程解析  

Analysis of Co-pyrolysis Process of Calcium Arsenate and Carbon Powder

作　　者：熊民 史冠勇 田磊[1] 刘重伟 徐志峰[1] XIONG Min;SHI Guan-yong;TIAN Lei;LIU Chong-wei;XU Zhi-feng(Institute of Green Metallurgy and Process Intensification,Jiangxi University of Science and Technology,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西理工大学绿色冶金与过程强化研究所,江西赣州341000

出　　处：《有色金属（冶炼部分）》2021年第1期75-79,共5页Nonferrous Metals（Extractive Metallurgy)

基　　金：国家自然科学基金资助项目(52074136);国家重点研发计划项目(2019YFC1907405)。

摘　　要：研究了砷酸钙与碳粉体系共热解反应过程。利用热重分析仪监测不同升温速率下,砷酸钙与碳粉质量比为4∶1混合物在氩气气氛、加热区间温度30~1 200℃过程中的失重情况,并采用XRD表征各失重阶段残余物。结果表明,混合体系失重过程分为三个阶段:第一失重阶段,温度240~325℃,Ca2As2O7·H2O脱水生成Ca2As2O7;第二失重阶段,温度560~668℃,Ca2As5O7到Ca3(AsO4)2的晶型转变及Ca5(AsO4)3OH和Ca(OH)2失水生成Ca5(AsO4)3和CaO;第三失重阶段,温度904~1 120℃,碳还原砷酸钙反应生成CaO和砷蒸气。动力学模型拟合结果表明:相边界反应动力学模型能较好地解释砷酸钙与碳粉共热解第三个失重阶段的反应机制。Co-pyrolysis process of calcium arsenate and carbon powder system was studied.Weight loss of mixture with mass ratio of 4∶1of calcium arsenate to carbon powder in argon atmosphere at 30-1 200℃was measured by thermogravimetric analyzer under different heating rates.Residues in each weight loss stage were characterized by XRD.The results show that weight loss process of mixed system is divided into three stages.At the first weightless stage at temperature of 240-325℃,Ca2As2O7·H2O dehydrates to produce Ca2As2O7;at the second weightless stage at temperature of 560-668℃,crystal form transition from Ca2As5O7to Ca3(AsO4)2,and Ca5(AsO4)3OH and Ca(OH)2loses water to produce Ca5(AsO4)3and CaO;at the third weight loss stage at temperature of 904-1 120℃,calcium arsenate is reduced by carbon to form CaO and arsenic vapor.The results of kinetic model fitting show that reaction mechanism of third weight loss stage of co-pyrolysis of calcium arsenate and carbon powder can be explained with phase boundary reaction kinetic model.

关 键 词：砷酸钙 碳还原 共热解 动力学模型 

分 类 号：TF803.13[冶金工程—有色金属冶金]