Process for the preparation of an alkaline-zinc slurry for use in batteries

A process for the regeneration of an at least partially-spent alkaline-zinc slurry having a dissolved phase and an undissolved please for use in metal-air batteries, which slurry comprises an admixture of:

• (a) zinc which has been at least partly oxidized to an oxidation product selected from the group consisting of zinc oxide, zinc hydroxide and zincates;
• (b) an aqueous solution of at least one Group Ia metal comprising anions selected from the group consisting of hydroxide and zincate;
• and
• (c) an inorganic or organic inhibitor, effective to inhibit the interaction of zinc and at least one Group Ia metal hydroxide in aqueous solution, which would otherwise result in the evolution of hydrogen gas;
• said process comprising subjecting said at least partially-spent slurry, after optional dilution with aqueous Group Ia metal hydroxide and water and the optional addition of an inorganic or organic inhibitor, to the steps of:
• optionally separating said dissolved and undissolved phases;
• providing an electrolyte selected from the group consisting of said at least partially-spent slurry and said optionally-separated dissolved phase;
• electrolyzing said electrolyte in a cell with a corrosion-resistant anode and a non-zinc-adherent cathode such that the zinc which deposits on said cathode self-detaches or is removable by a method selected from the group consisting of brushing, scraping, vibrating and the use of liquid jets, until no more than a preselected amount of zinc remains in the solution, provided that the current density at the cathode is preselected so that in conjunction with the non-zinc-adherent characteristic of the cathode, the electrowon zinc will have, after homogenizing into particles, a density within the range 0.2-2.0 g/cc and a surface area within the range 0.5-6.0 m.sup.2 /g;
• removing zinc from the cathode and homogenizing it into particles;
• combining said homogenized zinc particles with additional aqueous Group Ia metal hydroxide and optionally with other makeup components selected from the group consisting of water and inhibitor, thereby regenerating reconstituted charged slurry;
• optionally analyzing said reconstituted charged slurry in order to ascertain whether at least the values of zinc, the Group Ia metal hydroxide and the inhibitor lie within preset limits;
• and
• optionally adjusting the values of at least one of said aforementioned zinc, Group Ia metal hydroxide or inhibitor lie within preset limits for said reconstituted charged slurry.