Process for reclaiming chromium from roasted chromium ash containing hexavalent chromium

摘要

The invention provides a process for reclaiming chromium from roasted chromium ash containing chromium in substantially completely the hexavalent state, comprising: mixing the ash with sulfuric acid and water to form an acid-ash slurry; adding a reducing agent to the slurry to convert the hexavalent chromium to the trivalent state; filtering out an extract solution; water-washing the residue; and applying the water-wash to use as one of waste treatment processing, a component of a pickling agent, and a re-cycled solution; the extract solution providing reclaimed chromium.;This procedure not only produces an appropriate chrome tanning liquor with specific tanning properties, but also results in an inert residue which is safely disposable, non-polluting, and even useful as a filler material in the leather manufacturing process or as a form of clay.