Abstract: The present invention provides a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous alkaline slurry or solution of zinc oxide or any other compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell and wherein sodium bisulfide (NaSH) is added to the aqueous alkaline slurry or solution. The present invention also provides a process for preparing zinc dithionite, which comprises reacting zinc metal with sulfur dioxide, wherein the zinc metal is produced by the aforementioned electrochemical process.

Abstract: Disclosed is a process for preparing zinc dithionite comprising reacting zinc metal with sulfur dioxide, wherein the zinc metal used in the reaction is produced by electrochemical reduction in an undivided electrochemical cell of an aqueous alkaline slurry or solution of zinc oxide or any other zinc compound that reacts with aqueous base to form zinc oxide.

Abstract: The present invention provides a process for the separation and removal of iron ions from a basic zinc solution. The process involves: treating an aqueous basic zinc solution with a solid ion exchange resin containing an insoluble cross-linked polymer which contains at least one pendant phosphonate group, at a pH of from about 8 to about 12, and a temperature of from about 10° C. to about 90° C., for a time period sufficient to form solid phase-bound iron ions and a liquid phase containing the aqueous basic zinc solution having an iron ion concentration that is substantially reduced; separating the solid phase-bound iron ions and the liquid phase; and treating the solid phase-bound iron ions with an aqueous acidic solution under conditions sufficient to regenerate the solid ion exchange resin. The present invention also provides a process for preparing zinc oxide that is substantially free of iron ions.

Abstract: Disclosed is a low corrosion electrochemical process for preparing zinc metal which comprises electrochemically reducing an aqueous basic solution or slurry of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, wherein the electrochemical process is carried out in an undivided electrochemical cell, and wherein air or nitrogen is bubbled in through the solution or slurry of zinc oxide or said other zinc compound during said electrochemical process.

Abstract: The present invention relates to a continuous electrochemical process for preparing zinc powder. The process involves providing to an electrochemical cell a suspension in a 1.25 Molar to 10.0 Molar aqueous alkaline solution of zinc oxide or any other zinc compound that reacts with an aqueous alkaline solution to produce zinc oxide, such that the solution or suspension comprises at least 2 millimoles of solubilized zinc based species per 100 grams of electrolyte. Current is passed to the cell at a current density of about 500 to 40,000 A/m2, for a time period sufficient to electrochemically reduce the solubilized zinc based species to zinc powder, while continuously or intermittently adding a sufficient amount of the zinc oxide or the other zinc compound to the cell to maintain the concentration of the solubilized zinc based species at a level of at least 2 millimoles per 100 grams of electrolyte.

Abstract: Disclosed is an electrochemical process for preparing zinc powder which involves: a) providing to an electrochemical cell a basic solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the basic solution prepared by dissolving the zinc oxide or the other zinc compound in an aqueous 2.5 to 10.0 M base solution; and b) passing current to the cell at a current density of about 10,000 to about 40,000 A/m2 for a time period sufficient to electrochemically reduce the zinc oxide to zinc powder, wherein the electrochemical process has a current efficiency of at least 70% and is substantially free from electrode corrosion.

Abstract: The present invention provides a composition comprising a saturated solution of zinc oxide in an aqueous sodium or potassium hydroxide solution wherein the concentrations of the zinc oxide and the sodium hydroxide in said solution are as set forth in FIG. 1, and the concentrations of the zinc oxide and potassium hydroxide are as set forth in FIG. 2.

Abstract: The present invention provides a process for the separation and removal of iron ions from a basic zinc solution. The process involves: treating an aqueous basic zinc solution with a solid ion exchange resin containing an insoluble cross-linked polymer which contains at least one pendant phosphonate group, at a pH of from about 8 to about 12, and a temperature of from about 10° C. to about 90° C., for a time period sufficient to form solid phase-bound iron ions and a liquid phase containing the aqueous basic zinc solution having an iron ion concentration that is substantially reduced; separating the solid phase-bound iron ions and the liquid phase; and treating the solid phase-bound iron ions with an aqueous acidic solution under conditions sufficient to regenerate the solid ion exchange resin.

Abstract: Disclosed is a continuous electrochemical process for preparing zinc powder which involves: providing to an electrochemical cell a solution or suspension in an aqueous 1.25 Molar to 10.

Abstract: Disclosed is an electrochemical process for preparing zinc powder which involves: a) providing to an electrochemical cell a basic solution of zinc oxide or any other zinc compound that reacts with an aqueous base to produce zinc oxide, the basic solution prepared by dissolving the zinc oxide or the other zinc compound in an aqueous 2.5 to 10.0 M base solution; and b) passing current to the cell at a current density of about 10,000 to about 40,000 A/m2 for a time period sufficient to electrochemically reduce the zinc oxide to zinc powder, wherein the electrochemical process has a current efficiency of at least 70% and is substantially free from electrode corrosion.