GB420248A - Improvements in or relating to the production of nickel by electrolytic deposition from nickel salt solutions - Google Patents

Abstract

420,248. Electrodeposition of nickel. FALCONBRIDGE NIKKELVERK AKTIESELSKAP, Kristianssand, Norway. Aug. 18, 1933, No. 23091. Convention date, Sept. 3, 1932. [Class 41] Nickel of high purity is obtained by first preparing a nickel salt solution which may contain dissolved iron salts together with impurities such as arsenic, copper, and lead, but which is of a degree of purity generally considered sufficient for the electrodeposition of nickel, subsequently depositing nickel from this solution in two or more steps, in the first step or steps of which a comparatively small amount of nickel, for example, 3 to 5 per cent of the total quantity, is deposited, this initial deposit containing most of the impurities in the original solution, and thereafter depositing a comparatively pure nickel from the solution which remains. The preparatory treatment for the removal of the impurities may be effected either with soluble nickel anodes substantially free from foreign metals, or with impure nickel anodes in a cell having the anode compartments separated from the cathode compartments by Hybinette bags. When using soluble nickel anodes, for example, anodes containing nickel oxide or carbon, the pH value of the electrolyte may be adjusted by varying the current density and total current employed in proportion to the flow of solution. The electrolyte may be brought into intimate contact with the cathodes by violent agitation with air and by employing a large cathode surface in relation to the quantity of electrolyte flowing through the tanks. The current density and the current employed may be so regulated as to permit neutralization of the electrolyte to such a degree as to allow practically all the iron to be precipitated on subsequent oxidation and hydrolysis. The preparatory treatment for removal of the impurities may be carried out in two or more steps, in the first of which an impure nickel is deposited, and in the succeeding step or steps a comparatively pure nickel enriched in cobalt. Two or more preparatory treatments may also be employed, resulting, in the first preparatory treatment, in the production of an impure nickel enriched in cobalt, and in the succeeding treatment or treatments in a comparatively pure nickel also enriched in cobalt. Examples are given. Specification 372,958 is referred to. The Specification as open to inspection under Sect. 91 comprises also diagrams showing arrangements of cells and electrodes for carrying out the process, and also a flow sheet illustrating a cyclic method which can be employed when iron is to be precipitated from the solution. This subject-matter does not appear in the Specification as accepted.