City Research Online

Abstract

Copper can be recovered from dilute solutions both by electrochemical and non-electrochemical methods. The electrochemist, in dealing with the recovery of copper from dilute solutions,is faced with two major problems which decrease the efficiency of recovery:

(a) Hydrogen evolution reaction
(b) Mass transport

These difficulties are currently being overcome by using new cellsdesigned to create increased turbulent flow in the electrochemical reactor.

Results during the course of this work show that copper can be deposited more efficiently in the presence of chloride ions. Furthermore, the results show that carrying out the electrolysis, constant current, at current densities higher than the limiting current resultsin the formation of a high surface area powdery | deposit. The higher surface area will decrease the polarization of the copper electrode and hence add to the improvement of current efficiency.

Partial chemical reduction of the cupric ion to the cuprous state, followed by electrochemical reduction to the copper metal, results in very high current efficiencies. ‘he presence of chloride ions is essential in the integrated chemical - electrochemical process because it stabilizes the cuprous ions formed during the chemical reduction.

Hydrazine and sodium sulphite were two reducing agents used to achieve the partial reduction of the cupric ions to the cuprous ions. Furthermore the efficiency of the process is pH dependent.

Publication Type:	Thesis (Doctoral)
Subjects:	Q Science > QD Chemistry
Departments:	School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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