| 摘要 |
<p>1371107 Recovery of zinc from ferrites ASTURIANA DE ZINC SA 11 Nov 1971 [14 Nov 1970] 52373/71 Addition to 1127223 Heading C1A In a modification of the process claimed in claim 1 of Specification 1,127,223 the residues are leached in at least two stages, the residues being attacked in the first stage with a weak acid concentration such that acid concentration at the end of the first stage is not less than 5 g./litre, whereafter the first stage residues are attacked in a second stage with acid having a concentration of approximately 300 g./litre, the weak acid in the first stage being the solution resulting from the second stage. Preferably the solution resulting from treatment of the residues and partial neutralization, when containing a high percentage of copper, is treated with cemented lead to cement the copper.</p> |
