Record Display for the EPA National Library Catalog


Main Title Metal Recovery/Removal Using Non-Electrolytic Metal Recovery.
Author Leak, V. G. ;
CORP Author Minnesota Univ.-Duluth. Natural Resources Research Inst. ;Minnesota Technical Assistance Program, Minneapolis. ;Minnesota Waste Management Board, St. Paul.;Environmental Protection Agency, Cincinnati, OH. Risk Reduction Engineering Lab.
Publisher Jul 90
Year Published 1990
Report Number EPA/600/2-90/035;
Stock Number PB90-250150
Additional Subjects Materials recovery ; Water pollution control ; Sludge disposal ; Waste treatment ; Heat radiators ; Hazardous materials ; Repair shops ; Process charting ; Performance evaluation ; Waste water ; Precipitation(Chemistry) ; Motor vehicles ; Copper ; Lead(Metal) ; Leaching ; Cleaning agents ; Oxidation reduction reactions ; Alkalies ; Metal complexes ; Heavy metals ; Waste utilization ; Waste recycling ; Ammonium carbonates ; Case studies ; Sodium sulfides ; Liquid wastes
Library Call Number Additional Info Location Last
NTIS  PB90-250150 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 36p
Radiator repair shops most commonly use hot caustic solutions to clean radiator sections prior to resoldering. The hot caustic, or 'boil-out' solutions as they are called in the trade, become contaminated with dirt, rust flakes, paint flakes and miscellaneous particulate debris. In addition, the 'boil-out' solutions dissolve lead, copper, zinc, and tin from the brass radiator components and the solder used for assembly. A portion of the dissolved heavy metals are in true solution whereas an important percentage precipitates as metal hydroxide, 'quasi-colloids'. Cooling the solutions and allowing the dissolved metals to precipitate and settle enables the operator to recycle up to 80 percent of the solution. Preliminary test work has shown that sodium sulfide added to the caustic 'enhanced sludge' solution will precipitate the metal hydroxides. The precipitates are coarse enough to settle out of the solution and leave a stripped, clarified liquid. This means that it should be feasible to design a precipitation and clarification system that could be used by any small radiator repair shop and eliminate this hazardous waste stream from the environment. The work was performed between May 15, 1987, and June 30, 1988, at the University of Minnesota, Duluth.