| 摘要 |
<p>Nickel and cobalt are recovered from nickeliferous laterites by (a) crushing and/or grinding the ore to particles of below 3 mm; (b) heat treating at at least 380 deg.C to transform all hydrated iron oxides present into haematite; (c) leaching with aq. sulphuric acid at atmospheric pressure and at a temp. between ambient and the normal boiling point of the soln., (d) decanting and/or filtering in countercurrent if necessary (e) discarding the solid residue and (f) treating the enriched soln. so as to recover all the metals present by any known method, esp. pptn. using hydrogensulphide and neutralisation in stages with a base, or liquid-liquid extraction. Used esp. in recovery from limonitic laterite. Working at lower temperature and pressure than prior art leaching (230-260 deg.C) saves the expense of an autoclave. The working conditions are easier to operate.</p> |
