A method for directly preparing a trivalent chromium compound by electrochemical oxidation of ferrochrome is provided. The method includes: putting ferrochrome as an anode, and placing the anode into an electrolyte solution containing a complexing agent together with a cathode, then turning on a power supply for electrolysis reaction so that chromium and iron in ferrochrome are directly converted into free Cr.sup.3+ and Fe.sup.3+ respectively, allowing one of Cr.sup.3+ and fe.sup.3+ to form a stable soluble metal complex together with the complexing agent, and allowing the other of Cr.sup.3+ and Fe.sup.3+ to form a metal hydroxide solid together with OH.sup. generated by electrolysis reaction, so as to obtain an electrolysis completion slurry. Compared with the prior art, the present application has no hexavalent chromium salt stage, thereby shortening the process flow and avoiding the generation of chromium-containing waste residue.

A method for directly preparing a trivalent chromium compound by electrochemical oxidation of ferrochrome is provided. The method includes: putting ferrochrome as an anode, and placing the anode into an electrolyte solution containing a complexing agent together with a cathode, then turning on a power supply for electrolysis reaction so that chromium and iron in ferrochrome are directly converted into free Cr.sup.3+ and Fe.sup.3+ respectively, allowing one of Cr.sup.3+ and fe.sup.3+ to form a stable soluble metal complex together with the complexing agent, and allowing the other of Cr.sup.3+ and Fe.sup.3+ to form a metal hydroxide solid together with OH.sup. generated by electrolysis reaction, so as to obtain an electrolysis completion slurry. Compared with the prior art, the present application has no hexavalent chromium salt stage, thereby shortening the process flow and avoiding the generation of chromium-containing waste residue.

Processes are provided in which successive steps of hydrometallurgical value extraction may be carried out using the products of carbon capture and an electrolytic reagent-generating process. The electrolytic process provides an acid leachant and an alkali hydroxide, with the alkali hydroxide then available for use either directly as a precipitant in the hydrometallurgical steps, or available for conversion by carbon capture to an alkali metal carbonate that can in turn be used as the precipitant in the selective hydrometallurgical steps.

Processes are provided in which successive steps of hydrometallurgical value extraction may be carried out using the products of carbon capture and an electrolytic reagent-generating process. The electrolytic process provides an acid leachant and an alkali hydroxide, with the alkali hydroxide then available for use either directly as a precipitant in the hydrometallurgical steps, or available for conversion by carbon capture to an alkali metal carbonate that can in turn be used as the precipitant in the selective hydrometallurgical steps.

The invention relates to a method for treating a residue obtained from the chloride process, wherein the residue comprises the components titanium dioxide, coke, an inert metal oxide, and an iron-containing component. Further, the invention refers to the use of this method to separate the components contained in said residue, and to the use of the separated components in the chloride process for obtaining titanium dioxide.

The invention relates to a method for treating a residue obtained from the chloride process, wherein the residue comprises the components titanium dioxide, coke, an inert metal oxide, and an iron-containing component. Further, the invention refers to the use of this method to separate the components contained in said residue, and to the use of the separated components in the chloride process for obtaining titanium dioxide.