| 摘要 |
<p>1295325 Leaching nickel-bearing ores SHERRITT GORDON MINES Ltd 2 Nov 1970 [23 Dec 1969] 52094/70 Heading C1A The magnesium content of nickel and cobaltbearing lateritic ores is separated from the Ni and Co values by quenching the reduction-roasted ore with ammoniacal ammonium carbonate, leaching with admission of free oxygen-bearing gas and prolonging the leaching beyond the time required for maximum extraction of Ni and Co so as to precipitate the dissolved Mg. The resultant slurry is thickened and the solution recycled as quench solution. In an embodiment, laterite ore is roasted and the resulting calcine which leaves the furnace at 1300‹F. is cooled to 410‹F.; the cooled calcine is quenched with recycle ammoniacal ammonium carbonate at 115‹F. to give a quench slurry at about 132‹F. This slurry is cooled, and optionally, a portion of the air required for the leaching is passed into the slurry. The cooled slurry is then passed to the leach vessel where it is leached at a temperature below 115‹F.; as the leaching is exothermic further cooling may be carried out in the leach vessel. Alternatively the quenched slurry at 132‹F. may be passed directly to the leach vessel, and all the cooling carried out in the leach vessel. The time spent in the leach vessel should be sufficient to obtain maximum dissolution of nickel and cobalt, and to reduce the dissolved magnesium content below 0À05 g./l. The leached slurry is then passed to a thickener where an overflow containing dissolved nickel and cobalt is obtained. A portion of this stream is mixed with fresh ammoniacal ammonium carbonate and recycled to the quench, and the remainder is sent forward as product for Ni and Co recovery. The residual slurry is sent for a second leaching and further processing.</p> |
