The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1993
Filed:
Jul. 23, 1991
Dhiraj Pal, Chicago Heights, IL (US);
Karl Yost, Crete, IL (US);
MAECORP Incorporated, Chicago, IL (US);
Abstract
A two-step treatment process is disclosed for application of lead-toxic wastes to fixate and stabilize leachable lead contained therein. The process employs the use of a sulfate compound, such as gypsum, in a first step; and a phosphate reagent, such as phosphoric acid, in a second step. After thorough mixing and curing, a substantially solid end product is formed in which the lead is chemically fixed and remains in stabilized form for indefinite geologic periods. The process reduces Toxicity Characteristic Leaching Procedure lead levels below the regulatory threshold of 5 mg/l as required by the U.S. Environmental Protection Agency. The waste also beneficially undergoes volume reduction in a short curing time, and is applicable in a variety of situations.