US 5,284,503 AGranted

Process for remediation of lead-contaminated soil and waste battery

AssigneeExide Corporation

InventorsJohn A. Bitler, John P. Baranski

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Abstract

Lead-contaminated soil and battery casings are remediated using a plasma arc furnace which pyrolyzes the soil and waste battery casings so as to form a vitrified slag and a combustible gas, respectively. The combustible gas along with volatilized lead (and other heavy metals which may be present) are transferred to, and used as a primary fuel by, a conventional smelting furnace. The volatilized lead that is entrained in the combustible gas is thus transferred to the recovery and environmental protection/control equipment associated with the smelting furnace. The soil, on the other hand, is converted into a non-toxic (i.e., according to the Toxicity Characteristic Leaching Procedure) vitrified slag by the plasma arc which may be crushed and used as a commercial material (e.g., roadway aggregate, asphalt filler material and the like) or simply transferred to a landfill where it poses no environmental threat.

Claims17

Dependent claims

A process for the remediation of lead-contaminated soil and waste lead-acid battery casings comprising the steps of:

(a) feeding a mixture of lead-contaminated soil and waste lead-acid battery casings into a plasma arc furnace;
(b) pyrolyzing the mixture in the plasma arc furnace by bringing the mixture into contact with a plasma arc torch at a temperature between about 4,000.degree. to about 8,000.degree. C. for a time sufficient to (i) convert the battery casings into a combustible gas, (ii) volatilize substantially all lead contaminants which are present in said mixture and entrain said volatilized lead contaminants as a vapor in said combustible gas, and (iii) vitrify the soil, whereby lead contaminants that were present in said mixture are substantially removed therefrom;
(c) transferring the combustible gas and vaporized lead contaminants entrained therewithin from the plasma arc furnace to a combustion/lead-recovery apparatus, and then
(d) combusting the combustible gas in the combustion apparatus and recovering the lead contaminants entrained therewithin.

1 more element

Dependencies are inferred from the claim text.