摘要 |
A substantially iron-free copper nitrate solution is made by dissolving a copper-containing solid catalyst composition such as a used copper-zinc oxide-alumina methanol synthesis catalyst in nitric acid and controlling the acid concentration at a level such that any iron oxide present in the composition remains substantially undissolved. The acid concentration during dissolution is preferably under 4 molar. Alternatively or additionally the terminal pH is greater than 1.0. The resulting solution is pure enough for reconversion to catalyst by co-precipitation. |