Abstract
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. Superalloys were melted with 20%, 30%, 40%, and 50% al to form intermetallic compounds. The melts were easily crushed to a convenient particle size and leached rapidly with hydrochloric and sulfuric acid solutions. Leaching 1/2-in pieces of scrap in-738 with excess 6n hcl at 95 deg c for 2 h resulted in only 0.5% Dissolution, whereas leaching 10 g of minus 20 mesh 30% al-70% in-738 with excess 6n hcl at 95 deg c for 2 h achieved a 96.2% Dissolution.
