Aqueous chlorination technique was used to dissolve pure rhodium powder in hydrochloric acid-sodium chlorate system,and the impacts of various factors on the dissolution rate were investigated.These factors included the reaction temperature and time,acidity,amount of sodium chlorate and liquid-solid ratio.The results indicated that,after it had been chlorinated at 85℃ for 2 h,the primary dissolution rate of rhodium powder reached more than 95％,when hydrochloric acid was set at 8～9 mol/L and 250 mL of the saturated sodium chlorate solution was added into the dissolving system and the liquid-solid ratio was 45 mL/g.The dissolution mechanism was also explored.It is believed that Rh is oxidized by active chlorine produced from ClO3-in HCl solution and then coordinated with Cl-to form a stable complex [RhCl6]3-.The formation of [RhCl6]3-facilitates the dissolution of rhodium,in return.%采用水溶液氯化法,在盐酸-氯酸钠体系中溶解铑粉,考察了反应温度、酸度、氧化剂用量、时间、液固比等因素对铑溶解率的影响.结果表明,浓盐酸升温至 85℃后开始加氯酸钠,酸度为8～9 mol/L,饱和氯酸钠溶液用量为250 mL,液固比为45 mL/g,反应时间2 h,铑粉的一次溶解率达到95％以上.机理探讨认为,充当氧化剂的ClO3-在酸性条件下产生的活性[Cl],将金属态的铑氧化,并与体系中的Cl-配位形成[RhCl3]3-.
展开▼
