以生产硝酸的失效铂-铑催化剂为原料制备高纯硝酸铂

Preparation of high purity platinum nitrate using spent Pt-Rh catalyst from the production of nitric acid

以生产硝酸的失效铂-铑催化剂为原料,用王水浸出并分离出铑后,加氯化铵得到铂的铵盐沉淀,沉淀经煅烧得到海绵铂,海绵铂经酸溶赶硝得到氯铂酸,氯铂酸依次经氯化钾沉淀、草酸钾还原得到氯亚铂酸钾,再经氢氧化钾水解、氯钾等杂离子去除、硝酸中和,得到高纯硝酸铂。研究反应温度、浓度、时间和pH对中间产物和终产物纯度和收率的影响,并得到了较优的工艺条件。在较优工艺条件下,硝酸铂收率为94%,Pt2+含量大于15%,Cl-,K+的含量远小于0.005%。研究了氯铂酸钾制氯亚铂酸钾的反应动力学和热力学,得到PtCl62-的反应级数为1.39,C2O42-的反应级数为1.55,活化能为35.13 kJ/mol。

Preparation of high purity platinum nitrate using spent Pt-Rh catalyst from the production of nitric acid was studied, including separation of rhodium from aqua regia leaching solution, precipitation with ammonium chloride to obtain ammonium chloroplatinate precipitate, calcination of precipitate to obtain sponge platinum, dissolving with aqua regia and removing nitric acid to obtain chloroplatinic acid, precipitation with potassium chloride and reduction with potassium oxalate to obtain potassium chloroplatinite, hydrolysis with potassium hydroxide, removal of potassium and chloride, and neutralization with nitric acid. Effects of temperature, concentration, time and pH on the purity and yield of intermediate and final products were investigated and the suitable operating conditions were obtained. The yield of platinum nitrate is 94%, the mass fraction of Pt2+in platinum nitrate is greater than 15%, and the mass fractions of Cl-and K+are far less than 0.005%. The reaction kinetics and thermodynamics of potassium chloroplatinate to potassium chloroplatinite was studied, and the reaction order is 1.39 for PtCl62-and 1.55 for C2O42-, and the activation energy is 35.13 kJ/mol.