GB227125A - Process and installation for the electrolytic extraction of tin contained in bronzes, recovering copper at the same time - Google Patents

Abstract

227,125. Scarpa, O. Jan. 5, 1924, [Convention date]. Copper sulphate; tin oxide.-In the recovery of tin and copper from bronze by electrolytic deposition of the copper in a copper sulphate bath, the spent electrolyte, containing oxygenated tin compounds in colloidal solution, is withdrawn from the cell and heated, and is either diluted or the acid therein partially or completely neutralized in order to precipitate or coagulate the tin compounds. The neutralization may be effected by sodium or other alkaline hydroxide or carbonate or by copper oxide, hydroxide, or carbonate, or by mixtures of these. An improved deposit of copper is obtained by this means. In the arrangement of plant shown, the spent electrolyte is circulated by a pump 2 to a container 20, whence part of it passes by a pipe 15 to a tank 12', where it is heated at a temperature near its boiling point and diluted. It then passes through a high-speed centrifuge 7, where the precipitated matter is removed, to an evaporator 11, from which it falls into a tower 13, where its free acid is neutralized by copper scrap oxidized by hot air and steam injected through a pipe 14. The liquid leaving the tower is passed by a pump 17 through a filter 18 or a centrifuge to a container 21, where it is mixed with a part of the spent electrolyte proceeding directly from the container 20 by a pipe 16. It is then returned by a pump 21 through a tank 23, where sodium salts may be added and the copper content adjusted, to the electrolytic cell 1. A temperature between 20‹ C. and 60‹ C. is maintained during electrolysis by beaters placed in the cell or in the tank 23. The heating and dilution in the tank 12<1> may be carried out by steam generated in the evaporator 11 and led therefrom by a pipe 24. Filters may be replaced by centrifuges or vice versa. In a modification, the whole of the liquid is passed through the precipitating and regenerating apparatus. In another modification, two precipitating and filtering plants are provided, which are connected in the circulating system alternately in addition to apparatus, whereby the electrolyte may be regenerated without precipitation during the first period, when the tin content is not too high.