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Increasing the Leaching Rate of Bulk Superalloy Scrap by Melting With Aluminum.
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The Bureau of Mines investigated a method for increasing the leaching rate of bulk superalloy scrap to facilitate recycling and recovery of critical metals such as ni, CO, and cr. Three superalloys were investigated, the cast-nickel-base superalloy in- 738, the wrought-nickel-base superalloy rene-41, and the cast-cobalt- base superalloy mar-m-509. Superalloys melted with 20,30,40, and 50 pct al metal to form intermetallic compounds were easily crushed to a convenient particle size and reacted rapidly with acid solutions which dissolved the metals. For example, leaching 1/2-in pieces of unalloyed in-738 with excess 6n hcl at 95 deg c for 2 h dissolved about 0.5 pct, while leaching 10 g of minus 20-mesh 30 pct al-70 pct in-738 with excess 6n hcl at 95 deg c for 2 h dissolved 96.2 pct.
Page last reviewed: November 12, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division