一种快速高效溶解粗金属铑的新技术(英文)

A Novel Technology for Rapid and Efficient Dissolution of Metallic Rhodium

高效快速的溶解金属铑或铑基合金废料,一直是铂族金属冶金中人们公认的技术难题。通常使用的高温氯化,熔铝碎化,NaHSO4熔融等方法,有一次溶解率很低（一般不到30%）,需反复多次处理,周期很长,金属损失大,环境污染严重,能源及试剂消耗大等缺点。金属表面呈化学惰性的结晶结构及可能形成某种惰性氧化物,是难溶的原因。针对粗金属铑（含Rh 85.78%）研究了高效快速溶解的新技术：①用熔锍及活性金属转态活化;②酸溶及过滤分离贱金属溶液;③HCl溶液中直接加固体氧化剂溶解铑。在较短周期（24～48 h）内,铑的一次溶解率〉99%,贱金属溶液中Rh浓度〈0.0005 g/L,全过程铑回收率〉99%。

The rapid and efficient dissolution of metallic Rh or Rh-base alloy scraps was recognized as a difficult technical problem in the circle of platinum group metals. Generally, the methods to dissolve these scraps include the high-temperature chlorination, fragmentation through alloying with Al, and melting with NaHSO4,which possess a series of disadvantages, such as lower dissolution percentage（usually, less than 30% for one time dissolution）, longer period, serious environmental pollution and larger consumption of energy and chemicals. The special crystal structure, which is chemical inert, on the surface of metals and some kinds of inert oxides formed on the surface may be the seasons for the difficult dissolution of crude Rh or Rh-base alloy scraps. A new process for rapid and efficient dissolution of crude rhodium was introduced in this paper. It consists of ① changing chemical reaction activation of precious metals by smelting matte and activated metals; ② separating base metals through acid dissolution and then filtration; ③ dissolving of Rh by directly addition of solid oxidants in HCl solution. The Rh dissolution percentage of more then 99% for one time dissolution could be reached in 24～48 hours. The concentration of Rh in the solution of base metals was less than 0.0005 g/L. This method is note for its rapid and efficient, more simples, less consumption of energy and chemical reagents and friendly environment. The recovery ratio of Rh for the whole process was 〉99%.