氢氧化钠焙烧钙热还原氟化稀土还原渣及其热力学分析  

Thermodynamics Analysis for NaOH Roasting of Reduction Residue from Calcium Thermal Reduction of Fluorinated Rare Earth

作　　者：夏侯斌 刘玉城 刘道斌 吴希 XIA Hou-bin;LIU Yu-cheng;LIU Dao-bin;WU Xi(Jiangxi Institute of Tungsten and Rare Earth,Ganzhou 341000,Jiangxi,China;Jiangxi Center of Quality Supervision and Inspection for Tungsten and Rare Earth Products,Ganzhou 341000,Jiangxi,China;Jiangxi Test and Evaluation Center for New Materials Co Ltd,Ganzhou 341000,Jiangxi,China)

机构地区：[1]江西省钨与稀土研究院,江西赣州341000 [2]江西省钨与稀土产品质量监督检验中心,江西赣州341000 [3]江西泰斯特新材料测试评价中心有限公司,江西赣州341000

出　　处：《矿冶工程》2021年第4期109-112,116,共5页Mining and Metallurgical Engineering

基　　金：赣州市科技计划项目(赣市科发[2018]50号,赣市科发[2019]60号)。

摘　　要：针对钙热还原氟化稀土还原渣,开展了直接酸浸实验、氢氧化钠焙烧-酸浸实验。结果表明,直接酸浸时稀土提取率约72%,而氢氧化钠焙烧-酸浸稀土提取率达92.3%。热力学分析和实验结果共同表明:在298~1300 K温度范围内,氢氧化钠与渣中DyF_(3)、CaCO_(3)和CaF_(2)反应,生成Dy2O_(3)、NaF、CaO、Na_(2)CO_(3)和CO_(2);氢氧化钠能将氟化稀土转化为氧化稀土,这是稀土提取率提高的主要原因。Aiming at the reduction residue generated after the calcium thermal reduction of fluorinated rare earth,experiments were performed with direct acid leaching process and a combined process of NaOH roasting and acid leaching.It is shown that the extraction rate of rare earth is around 72%by direct acid leaching process,but can reach 92.3%by the combined process.Both thermodynamics analysis and the experimental results indicate that at the temperature ranging from 298 K to 1300 K,NaOH reacts with DyF_(3),CaCO_(3) and CaF_(2) in the residue,producing Dy2O_(3),NaF,CaO,Na_(2)CO_(3) and CO_(2);sodium hydroxide can convert fluorinated rare earth to oxidized rare earth,which contribute substantially to the increase of the extraction rate of rare earth.

关 键 词：稀土 氟化稀土 氧化稀土 镝 酸浸 热力学 钙热还原稀土还原渣 焙烧 吉布斯函数 

分 类 号：TF111[冶金工程—冶金物理化学]