Hebei Messi Biology Co., Ltd. stated that nickel and cobalt are valuable metals with a wide range of uses. The methods for extracting nickel and cobalt from nickel-cobalt ores are generally divided into two categories, one is pyrometallurgy and the other is hydrometallurgy. Hydrometallurgy has the advantages of low energy consumption, less pollution and environmental protection, and has been widely used in recent years. In particular, active magnesium oxide plays an indispensable role in nickel and cobalt refining.
At present, the process of producing nickel and cobalt in the Democratic Republic of the Congo includes making the nickel-cobalt ore into ore pulp, acid leaching, and obtaining leaching slurry; injecting the leaching slurry into the atmospheric circulation leaching tank, adding a neutralizing agent into the atmospheric circulation leaching tank to neutralize the leaching slurry; performing solid-liquid separation on the neutralized leaching slurry to obtain leaching liquid and leaching residue; performing a first-stage purification on the leaching liquid to remove iron and aluminum, obtaining a first-stage purified liquid and a first-stage purified slag containing iron and aluminum; performing a second-stage purification on the first-stage purified liquid to remove the remaining iron and aluminum again, obtaining a second-stage purified liquid and a second-stage purified slag; returning the second-stage purified slag to the atmospheric circulation leaching tank to recover the valuable gold ions contained in the second-stage purified slag; and precipitating nickel and cobalt on the second-stage purified liquid.
Research by Hebei Messi Biology Co., Ltd. shows that the use of active magnesium oxide can selectively precipitate and enrich nickel and cobalt from sulfate media containing manganese and magnesium. The results show that the best precipitation conditions are: adding twice the theoretical amount of active magnesium oxide after slurrying, reaction residence time of 6h, and precipitation temperature of 25℃. Under these conditions, the precipitation rates of nickel and cobalt are 97.96% and 96.43% respectively, and the contents of nickel, cobalt, manganese and magnesium oxide in the precipitate are 8.51%, 13.05%, 2.29% and 4.97% respectively. When 0.2g flocculant AN905 is added per cubic meter of slurry, the average static free settling velocity of the slurry is 180mm/min.