Method for stabilizing chromium-contaminated materials
AssigneeRMT, Inc.
InventorAjit K. Chowdhury
Life of this patent
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Abstract
A method for stabilizing chromium in a chromium-contaminated waste matrix characterized by high concentrations of alkaline material (such as lime) includes the steps of contacting a source of hexavalent chromium with a source of ferrous ions to produce ferric ions; oxidizing iron pyrite to produce ferrous sulfate and sulfuric acid; and contacting the alkaline chromium-contaminated particulate matter with the ferrous sulfate and the sulfuric acid for a time sufficient to convert ferrous sulfate into ferric sulfate and to reduce mobile hexavalent chromium to non-leachable trivalent chromium. The method is integrated in that ferrous sulfate produced by oxidizing iron pyrite serves as a source of ferrous ions in the first contacting step.
Claims22
A method for reducing mobile hexavalent chromium to non-leachable trivalent chromium in alkaline chromium-contaminated particulate matter, the method comprising the steps of:
- contacting a source of hexavalent chromium with ferrous ions to produce ferric ions;
- oxidizing iron pyrite to produce ferrous sulfate and sulfuric acid;
- contacting the alkaline chromium-contaminated particulate matter with the ferrous sulfate and the sulfuric acid for a time sufficient to convert ferrous sulfate into ferric sulfate and to reduce mobile hexavalent chromium to trivalent chromium in the particulate matter,
- wherein ferrous sulfate produced by oxidizing iron pyrite is a source of ferrous ions in the first contacting step.
Dependencies are inferred from the claim text.