Effect of Rhodium Powder Particle Size on Its Dissolution

Rhodium is one of the most insoluble platinum group metals,but rhodium dissolution is an indispensable key link in the extraction and application of rhodium.Research shows that rhodium particle size has a direct effect on rhodium dissolution.The effect of rhodium powder particle size and surface state on the dissolution of rhodium was studied.The experimental results show that,the dissolution rate of rhodium powders is negatively correlated with the particle size,rhodium powders of ≥ 100 μm are substantially insoluble,the rhodium powders of ≤ 10 μm have very high dissolution rate.EDX analysis results show that there is no oxidation formation on the surface of the dissolved rhodium powders by aqua regia,the slightly soluble phenomenon occurred at rhodium powder dissolved,due to small particles rhodium is firstly dissolved in rhodium powder,when the small particles rhodium powder has dissolved,the remaining large particles of rhodium powder insoluble.