Studies were conducted on the production of chromium(III) silicates, the green pro-ecological pigments. The pigments were precipitated from sodium silicate and chromium(III) sulphate solutions in the system of two emulsions prepared in hexane in the presence of a non-ionic surfactant as an emulsifier. The chromium(III) sulphate represented a reduction product of chromate(VI) compounds present in post-galvanic wastes. The reduction agent involved metanal in an acidic medium. The obtained products were subjected to a comprehensive physicochemical analysis, their dispersive and morphological properties were determined. The precipitated green products exhibiting intense colour, were uniform and their particles manifested a low tendency to form agglomerate structures.
- green pigments
- precipitated chromium(III) silicates
- emulsion system
- post-galvanic wastes