固体王水を用いた使用済み触媒からの白金回収に関する基礎的研究

抄録

In this paper, a novel method for recovering platinum using molten FeCl₃-KCl system as “dry aqua regia” is presented. The method consists of the dissolution of platinum by molten FeCl₃-KCl system and the recovery of dissolved platinum by the solvent leaching of frozen FeCl₃-KCl, using the different solubility between platinum compounds and iron compounds for the solvents. Platinum dissolution was conducted in the molten FeCl₃-KCl system at 585-655 K. The maximum dissolution rate of platinum was 0.45 mol･m⁻²･h⁻¹, which is fast enough compared with the hydrometallurgy process using aqua regia or electrochemical dissolution process in ionic liquid. And dissolved platinum recovered as K₂(PtCl₆) by the solvent leaching of frozen FeCl₃-KCl using water or ethanol. This “dry aqua regia” process have a number of advantages, including low energy consumption, easy operation and low toxicity of chemicals compared with pyrometallurgy process and hydrometallurgy process, as recycling process of platinum.