The Recovery of Pure Chromium Metal From Hazardous Plating SludgeEPA Contract Number: 68D99039
Title: The Recovery of Pure Chromium Metal From Hazardous Plating Sludge
Investigators: Whelan, Edward P.
Small Business: Climax Research Services
EPA Contact: Richards, April
Project Period: September 1, 1999 through March 1, 2000
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (1999) RFA Text | Recipients Lists
Research Category: Hazardous Waste/Remediation , SBIR - Waste , Small Business Innovation Research (SBIR)
Description:Chromium-containing sludge waste from electrolytic chromium plating, leather tanning, and wood preservation operations is classified as a hazardous waste. Its disposal is a major environmental concern. In Phase I, this sludge will be converted into a purified chromic oxide by using an innovative combination of pyrometallurgical, hydrometallurgical, and mineral processing techniques. The sludge cannot be converted directly to a metallurgically usable product due to the relatively high concentration of metallic and nonmetallic impurities that it contains. The proposed innovative procedure removes these impurities from the sludge waste and generates a purified chromium oxide. The procedure involves chemical reaction in heated fluidized beds and subsequent chemical processing treatment. The purified chromic oxide that is formed is converted by conventional aluminothermic reaction to pure chromium metal. Wastes generated throughout the processing will be converted in an environmentally acceptable manner into a vitrified product. The composition of the pure metal will meet the American Society for Testing and Materials' specification for aluminothermic chromium metal.
The proposed project will result in the conversion of hazardous chromium plating sludge into pure aluminothermic chromium metal. The U.S. metallurgical foundry industry imports 100 percent of the aluminothermic chromium that it consumes. The recovery of chromium metal values from hazardous sludge waste by the proposed process will offset chromium metal imports. Metallurgical applications for the pure metal include all nickel and cobalt base alloys for high-temperature gas turbine engine components, all nickel and iron base oxidation-resistant alloys for use in electrical resistance heating, most corrosion-resistant nickel base alloys for the chemical and oil industries, and hardfacing alloys for wear and corrosion resistance.