Oxidative Dissolution of Nickel Metal in Hydrogenated Hydrothermal Solutions

摘要

A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of metallic nickel in hydrogenated ammonia and sodium hydroxide solutions between 175 and 315oC. The solubility measurements were interpreted by means of an oxidative dissolution reaction followed by a sequence of Ni(II) ion hydrolysis reactions: Ni(s) + 2H+(aq) = Ni2+(aq) + H2(g) and Ni2+(aq) + nH2O = Ni(OH)n 2-n(aq) + nH+(aq). where n = 1 and 2. Gibbs energies associated with these reaction equilibria were determined from a least-squares analysis of the data.