Process and apparatus for fixing, encapsulating, stabilizing and detoxifying heavy metals and the like in metal-containing sludges, soils, ash and similar materials
OwnerBradford H. Jonesinventor
Life of this patent
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Abstract
Heavy metals and compounds thereof and other toxic materials in industrial wastes, sludges, soils, incinerated ashes and the like are fixed and stablized in a char residue, obtained by critical region pyrolyzing techniques and appropriate proportions of cabonaceous materials intimately mixed with the sludge, to encapsulate the heavy metals with carbon bonded thereto which effectively detoxifies the residue and renders it immune to any substantial leaching out or later exposure to the toxic metals, such that the same is environmentally safe for such uses as landfill and the like.
Claims15
A process for fixing and stabilizing heavy metals in a metal-containing sludge, soil, or ash feed material that comprises, heating the metal containing material with intimately contacting carbon-containing material to a temperature sufficient to drive off volatile organics and solvents, but below the temperatures for complete volatilization of most heavy metals and while inhibiting the formation of oxides of nitrogen and sulfur, and in a substantially oxygen-free environment;
- continuing the heating for a period of time sufficient to produce a char residue with carbon bonded to the metal, the heating being continued until the weight of the residue expressed as a percentage of the weight of the metal containing material is a minimum and until substantially all volatile organics and solvents are driven off;
- cooling the char residue in the absence of air to a temperature of about 250.degree. F. to ensure that the residue will no longer combust if exposed to air;
- and thereafter cooling the residue further to ambient temperature to provide a non-leachable residue.
A process for fixing and stabilizing heavy metals in a metal-containing sludge, soil, or ash feed material, that comprises, heating the metal containing material with intimately contacting carbon-containing material including an added solvent to a temperature sufficient to drive off volatile organics and solvents, but below the temperatures for complete volatilization of most heavy metals and while inhibiting the formation of oxides of nitrogen and sulfur, and in a substantially oxygen-free environment;
- continuing the heating for a period of time sufficient to produce a char residue with carbon bonded to the metal, the heating being continued until the weight of the residue expressed as a percentage of the weight of the metal containing material is a minimum and until substantially all volatile organics and solvents are driven off;
- cooling the char residue in the absence of air to a temperature low enough to ensure that the residue will no longer combust if exposed to air;
- and thereafter cooling the residue further to ambient temperature to provide a non-leachable residue.
Dependencies are inferred from the claim text.