【摘要】：高純錫廣泛應(yīng)用于航空航天、電子信息、核工業(yè)等領(lǐng)域,已成為支撐人類高科技發(fā)展的關(guān)鍵材料。本文綜述了我國錫資源、性質(zhì)、用途以及制備高純金屬、高純錫的方法。并對真空蒸餾-區(qū)域熔煉聯(lián)合法制備高純金屬過程進行了理論分析。在真空蒸餾理論分析過程中,研究了粗錫中各雜質(zhì)純物質(zhì)的沸點和飽和蒸氣壓,得知粗錫中雜質(zhì)As、Zn、Mg、Ca、Bi、Pb、Sb揮發(fā)進入氣相,而Al、Cu、Ni、Au、Fe、Co和Sn留在殘留物中;并從熱力學(xué)角度說明了粗錫中雜質(zhì)的揮發(fā)規(guī)律,得到蒸餾溫度、蒸發(fā)面積、殘壓等因素對粗錫中組元揮發(fā)速率的影響關(guān)系。在區(qū)域熔煉理論分析過程中,闡述了區(qū)熔次數(shù)、區(qū)熔速度和平衡分配系數(shù)與粗錫中雜質(zhì)元素分布規(guī)律的影響關(guān)系。采用響應(yīng)曲面,以97.4185%的粗錫為原料開展真空蒸餾實驗研究,在壓力15Pa以下,蒸餾溫度1400℃,保溫時間60min時,錫被提純至99.8752%,其中雜質(zhì)含量Pb0.012%、Sb0.045%、Bi0.0005%、As0.0005%,而粗錫中的Fe和Cu元素基本沒有變化,Sn直收率99.89%。采用單因素分析的方法,以4N錫為原料,開展區(qū)域熔煉實驗研究,當(dāng)熔煉次數(shù)從5次提高到20次時,原料中Sn含量從99.9968%升高到99.9977%,說明熔煉次數(shù)并不是決定性的影響因素。當(dāng)區(qū)熔速度由1.4mm/min降低到0.6mm/min時,錠中金屬的純度從原料的99.9968%升高到99.99906%,說明熔區(qū)熔速度越慢,金屬提純效果越好。實驗最終結(jié)果表明Ag、Al、As、Bi、Ca、Cu、Fe、Ni、Pb、Au、Co、Zn的平衡分配系數(shù)小于1,而其中Sb的平衡分配系數(shù)雖然大于1,但與1較為接近。真空蒸餾-區(qū)域熔煉聯(lián)合法制備高純金屬錫過程中,在蒸餾溫度1600℃、壓力20Pa以下、保溫時間60min的條件下,可以將錫含量為97.4185%的粗錫提純至99.95857%,再經(jīng)過10次區(qū)域熔煉、區(qū)熔速度0.6mm/min的條件,可以將99.95857%的錫提純至99.99312%,其中Pb、Bi、As、Cu、Fe、Ag、Ni等主要雜質(zhì)有明顯降低,且分布趨勢明顯。
[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，

本文編號：2290993