閃亜鉛鉱の銅活性化反応のpH依存性に関する考察

抄録

The pH dependence of copper activation on sphalerite was studied by measuring the adsorption of copper ion as a function of pH. The adsorption of copper ion was maximum at about pH=5-6 and decreased rapidly in both the acid and alkaline region. From the result, it was recognized that the pH dependence for the adsorption of copper ion on sphalerite was remarkable.
The cause for the decrease of the copper ion adsorption in the alkaline region was investigated. The dependence of copper ion concentration for the copper ion adsorption on sphalerite was examined. As a result, it was recognized that the copper ion adsorption on sphalerite decreased with lowering copper ion concentration.
Then, the kinetics for the adsorption of copper ion on sphalerite was investigated. The reaction rate of the copper ion adsorption on sphalerite was shown by the reaction equation of 1st order, and the log-log plot of relations between the copper ion adsorption rate and the agitation rate was characterized by a straight line.
The above results presented that the decrease of the copper ion adsorption in the alkaline region might be due to the decrease of the copper ion concentration with the increase of the pH value, and consequently to the decrease of diffusion rate at which copper ion diffused to the surface of sphalerite from the bulk in solution.
The cause for the decrease of the copper ion in the acid region was analysed experimentally. As a consequence, it was surmised that the copper sulphide formation led to the decrease of the copper ion concentration in solution. Accordingly, the decrease of the copper ion adsorption in the acid region might be due to the decrease of the copper ion concentration and to the diffusion rate of copperion.