Abstract:The shortcomings of the traditional platinum refining process of aqua regia solution - ammonium chloride precipitation were studied. The effects of different reducing agents and their concentrations on removal rate of rhodium and iridium in crude ammonium chloroplatinate were investigated. The denitrification process without evaporation was studied and the end point of denitrification was tried to quantify. The results show that the removal rate of rhodium and iridium in crude ammonium chlorplatinate by using 10% hydrazine hydrate and 5% hydrochloric acid is higher, and the one-step removal rate of rhodium and iridium can reach 91.18% and 95.88% respectively; The denitration time of 40% alcohol + 8% urea solution is only 1.3 h, the denitration time is shortened by more than 89.2%, and the qualified rate of burning loss is more than 95%, which is the best denitration process. The solution potential of 590—600 mV can be used as the judgment basis of denitration end point. After the application of this process, the refining cycle of sponge platinum is shortened by about 75%, the direct yield of platinum is increased by 0.26 percentage points, and qualified high purity sponge platinum can be produced stably, which has a good value of popularization and application.