ANODE-SUPPORT SYSTEM FOR THE DIRECT ELECTROREFINING OF CEMENT COPPER .1. PROCESS CONDITIONS USING HORIZONTAL ROTARY CATHODES

This paper describes a preliminary study towards a modified anode-supp ort system for the direct electrorefining of cement copper. The propos ed system is an alternative process for small mines that produce cemen t after leaching of copper oxide minerals. It is feasible to utilize a cell provided with a horizontal AISI-316 stainless steel mesh covered with a layer of cement copper as anode system. As cathode system, sev eral horizontal rotary cylinders of AISI-316 stainless steel can be us ed. The rotary cylinders, partially immersed in acidic copper sulphate electrolyte, must have an internal electrical contact with a copper s haft and two or more isolated slots at the surface to permit the strip ping of the copper deposits in the form of thin sheets. The cement cop per must be maintained wet to avoid rapid oxidation. The use of pulsed current permits control of the formation of a non-conductive copper s ulphate layer on the cement surface, avoiding a continuous increase in cell voltage. As operating conditions a solution of CuSO4.5H(2)O (160 g dm(-3)) and H2SO4 (50 g dm(-3)) with j(c) = 5.0 A dm(-2), T = 40 de grees C, u = 200 rpm; and pulsed current with t(d) = 3 min and t(d)/t( 0) = 20 can be used. At this stage of the study cement copper (90-95% purity) was utilized.