真空蒸馏—区域熔炼联合法制备高纯锡的研究
发布时间:2018-10-24 09:28
【摘要】:高纯锡广泛应用于航空航天、电子信息、核工业等领域,已成为支撑人类高科技发展的关键材料。本文综述了我国锡资源、性质、用途以及制备高纯金属、高纯锡的方法。并对真空蒸馏-区域熔炼联合法制备高纯金属过程进行了理论分析。在真空蒸馏理论分析过程中,研究了粗锡中各杂质纯物质的沸点和饱和蒸气压,得知粗锡中杂质As、Zn、Mg、Ca、Bi、Pb、Sb挥发进入气相,而Al、Cu、Ni、Au、Fe、Co和Sn留在残留物中;并从热力学角度说明了粗锡中杂质的挥发规律,得到蒸馏温度、蒸发面积、残压等因素对粗锡中组元挥发速率的影响关系。在区域熔炼理论分析过程中,阐述了区熔次数、区熔速度和平衡分配系数与粗锡中杂质元素分布规律的影响关系。采用响应曲面,以97.4185%的粗锡为原料开展真空蒸馏实验研究,在压力15Pa以下,蒸馏温度1400℃,保温时间60min时,锡被提纯至99.8752%,其中杂质含量Pb0.012%、Sb0.045%、Bi0.0005%、As0.0005%,而粗锡中的Fe和Cu元素基本没有变化,Sn直收率99.89%。采用单因素分析的方法,以4N锡为原料,开展区域熔炼实验研究,当熔炼次数从5次提高到20次时,原料中Sn含量从99.9968%升高到99.9977%,说明熔炼次数并不是决定性的影响因素。当区熔速度由1.4mm/min降低到0.6mm/min时,锭中金属的纯度从原料的99.9968%升高到99.99906%,说明熔区熔速度越慢,金属提纯效果越好。实验最终结果表明Ag、Al、As、Bi、Ca、Cu、Fe、Ni、Pb、Au、Co、Zn的平衡分配系数小于1,而其中Sb的平衡分配系数虽然大于1,但与1较为接近。真空蒸馏-区域熔炼联合法制备高纯金属锡过程中,在蒸馏温度1600℃、压力20Pa以下、保温时间60min的条件下,可以将锡含量为97.4185%的粗锡提纯至99.95857%,再经过10次区域熔炼、区熔速度0.6mm/min的条件,可以将99.95857%的锡提纯至99.99312%,其中Pb、Bi、As、Cu、Fe、Ag、Ni等主要杂质有明显降低,且分布趋势明显。
[Abstract]:High-purity tin has been widely used in aerospace, electronic information, nuclear industry and other fields, and has become a key material to support the development of human high-tech. In this paper, the resources, properties, applications and preparation methods of high-purity metal and high-purity tin in China are reviewed. The process of preparing high-purity metal by vacuum distillation-region melting method was analyzed theoretically. During the theoretical analysis of vacuum distillation, the boiling point and saturated vapor pressure of pure impurity in crude tin were studied. It was found that the impurity As,Zn,Mg,Ca,Bi,Pb,Sb in crude tin volatilized into the gas phase, while Al,Cu,Ni,Au,Fe,Co and Sn remained in the residue. From the point of view of thermodynamics, the volatilization law of impurities in crude tin was explained, and the influence of distillation temperature, evaporation area and residual pressure on the volatilization rate of components in crude tin was obtained. In the course of theoretical analysis of regional melting, the influence of the times of zone melting, the rate of zone melting and the equilibrium partition coefficient on the distribution of impurity elements in coarse tin was discussed. The vacuum distillation experiment was carried out with 97.4185% crude tin as raw material by using response surface. Under pressure 15Pa, the distillation temperature was 1400 鈩,
本文编号:2290993
[Abstract]:High-purity tin has been widely used in aerospace, electronic information, nuclear industry and other fields, and has become a key material to support the development of human high-tech. In this paper, the resources, properties, applications and preparation methods of high-purity metal and high-purity tin in China are reviewed. The process of preparing high-purity metal by vacuum distillation-region melting method was analyzed theoretically. During the theoretical analysis of vacuum distillation, the boiling point and saturated vapor pressure of pure impurity in crude tin were studied. It was found that the impurity As,Zn,Mg,Ca,Bi,Pb,Sb in crude tin volatilized into the gas phase, while Al,Cu,Ni,Au,Fe,Co and Sn remained in the residue. From the point of view of thermodynamics, the volatilization law of impurities in crude tin was explained, and the influence of distillation temperature, evaporation area and residual pressure on the volatilization rate of components in crude tin was obtained. In the course of theoretical analysis of regional melting, the influence of the times of zone melting, the rate of zone melting and the equilibrium partition coefficient on the distribution of impurity elements in coarse tin was discussed. The vacuum distillation experiment was carried out with 97.4185% crude tin as raw material by using response surface. Under pressure 15Pa, the distillation temperature was 1400 鈩,
本文编号:2290993
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