Study on the Precipitation of Copper Powder from Aqueous Cupric Sulphate Solution by Hydrogen Pressure Reduction

Abstract

This paper is concerned with the precipitation of copper powder from aqueous cupric sulphate solution by hydrogen pressure reduction. Experiments have been done in 3l stainless autoclave, equipped with the sampling device and the magnetic induction agitation system. The results obtained are as follows: (1) It is easy to precipitate metallic copper from acidic copper sulphate solution, but the addition of certain organic compounds to the reduction charge is indispensable to prevent the plating and plastering of copper on the wall of the autoclave. A kind of acryl compounds have been used in this research. The addition of this dispersion agent effects the reduction rate and the physical characteristics of the precipitated powder. (2) Although the reaction proceeds without catalyst, the addition of fine copper powder as seed increases the rate a little.(3) The addition of ammonium sulphate to the reduction charge effects a marked buffering action to depress the increase of the acidity from the reaction. The reduction rate increases with the amount of ammonium sulphate added and the initial reduction rate is in proportion to it, (4) The initial reduction rate is proportional to the hydrogen partial pressure and the initial copper concentration.(5) The following reducing conditions appear to be optimum: Cu 50g/l, dispersion agent 0.1g/l. (NH4)2SO4/Cu=1 (molar ratio), 150°C, PH2 20-30kg/cmcm2.(6) From the results as stated above, the initial reduction rate can be represented by an equation of the form:(Received June 4, 1965)