Nickel pigments preparation by spent nickel-plating electrolyte precipitation

Abstract

A way to recycle spent waste sulfuric acid nickel electrolytes by nickel compounds extracting is offered and in this paper. The nickel (II) ions con centration was defined by chemical analysis and solid phase composition were determined by elemental analysis. Slightly soluble nickel (II) compounds were precipitated with sodium hydroxide solution and satu-rated sodium orthophosphate solution during boiling. Also waste degreasing solution containing sodium hydroxide, sodium carbonate and sodium phosphate was used. Nickel (II) ions extraction degree for degreasing solution precipitation was 97%, and for sodium hydroxide solution or sodium orthophosphate solution precipitation – 99.9%. For nickel (II) compo unds obtained X-ray analysis, elemental analysis and thermal analysis were carried out, their IR-abs orption spectra micrographs were obtained. Colored compounds obtained from waste electrolytes had various shades of green colour scheme and high concentration of chromofore ions. That made them possible for pigments producing. The precipitates obtained were dried, calcinated, milled, sifted and then used as pigment compositions.