The ocean poly-metallic nodule was leached by using slurry electrolysis process in HCl-NaCl medium.The leaching rates of Mn,Co,Cu and Ni in the ocean poly-metallic nodule are all above 97%.Meanwhile,the high purity of electrolytic MnO2 is also obtained as an anode product.The effects of electrolysis electric quantity,acidity,temperature,slurry density,grain size and iron ions concentration were studied.The results show that the ocean poly-metallic nodule can be treated economically in the slurry electrolysis process.
Nickel and cobalt were extracted from low-grade nickeliferous laterite ore using a reduction roasting-ammonia leaching method.The reduction roasting-ammonia leaching experimental tests were chiefly introduced,by which fine coal was used as a reductant.The results show that the optimum process conditions are confirmed as follows:in reduction roasting process,the mass fraction of reductant in the ore is 10%,roasting time is 120 min,roasting temperature is 1 023-1 073 K;in ammonia leaching process,the liquid-to-solid ratio is 4:1(mL/g),leaching temperature is 313 K,leaching time is 120 min,and concentration ratio of NH3 to CO2 is 90 g/L:60 g/L.Under the optimum conditions,leaching efficiencies of nickel and cobalt are 86.25% and 60.84%,respectively.Therefore,nickel and cobalt can be effectively reclaimed,and the leaching agent can be also recycled at room temperature and normal pressure.
