GB823436A - - Google Patents

Abstract

823,436. Producing metal oxides by electrolysis. MAGNETO-CHEMIE N.V. Jan. 22, 1957, No. 2254/57. Class 41. A process for the coprecipitation of metal oxides containing 80 mol per cent or more of iron oxide by reacting the metal ions in predetermined ratios with a solution of an alkali metal salt comprising electrolysing the solution while introducing oxygen or an oxidation agent into the electrolysis vessel employing an anode of an alloy of iron containing the metals the oxides of which are to be precipitated, or employing an iron anode and separate anodes of the metals and adjusting the current strengths to the anodes so that the precipitated oxide contains the oxides in the desired ratios. Metals mentioned are Cu, Al, Ni, Mg, Zn, Cr, and oxidation agents mentioned are air, ozone, chlorine, hydrogen peroxide, nitric acid and aqueous solutions of nitrates and ammonium nitrite. Where separate anodes are employed, each anode is connected through a variable resistance and an ammeter to the current source. Electrolytes mentioned are potassium bromide or iodide and sodium bromide, preferably at a pH of 5.0 to 6.8. The temperature may be raised to 90‹ C., e.g. by passing A.C. through the bath via the electrodes or via auxiliary electrodes. In an example, the anodes were Fe, Cu, Zn, Ni, Mg and an iron cathode was employed, the electrolyte being sodium sulphate in distilled water. The current was adjusted so that 80% was received by the iron anode and a 1% solution of hydrogen peroxide was added to the electrolyte, this concentration being maintained. Specification 520,690 is referred to.