Preparation Of Nickel Compounds, Recovered From The Nickel-molybdenum Ore Smelting Slag

Residue of metalliferous black shale was a residue of extracting molybdenum from metalliferous black shale. The residue contained many heavy metals and rare metals can be used as a raw material for extraction of nickel.In this paper, extracting nickel from molybdenum leach residue of metalliferous black shale by the process of "reduction roasting-sulfuric acid leaching-purification-solvent extraction" was investigated. Moreover, the mechanism and parameters of reduction roasting, sulfuric acid leaching and solvent extraction on nickel recovery were studied. In addition, the method of preparation of high-purity nickel monoxide was also studied.The results show that activated carbon was the most effective reductive agent for reduction roasting of the residue among activated carbon, pulverized coal and graphite. When the temperature of reduction roasting is 850℃; the time of reduction roasting is 2 h; the activated carbon dosage is mactivated carbon:mdry residue=1:2.5; as well as sulfuric acid leaching; when the concentration of sulfuric acid is 4.5 mol/L; liquid-solid ratio of 6:1; leaching time of 5 h; leaching temperature:80℃; adding amount 30% H2O20.6mi for 1g dry residue; the leaching rate of nickel is up to 90.5%. Oxidation and hydrolysis was used to reject iron; sulfide precipitation was chosen to remove copper; fluoride precipitation was adopted to remove calcium and magnesium and solvent extraction was used to remove zinc from leach liquor. Then, purged liquor was obtained. Optimum parameters of extraction and stripping were established as follows:adding PC-88A of 30%(Vpc-88A:Vorganic phase); pH value of feed solution of 6.7; organic phase to aqueous phase ratio of 1:3; phase contact time:3 min; extraction temperature:30℃; hydrochloric acid concentration:2 mol/L, organic phase to aqueous phase ratio of 3:1; phase contact time:3 min; under these experimental conditions, nickel extraction rate of is up to 99.6% under two step cross-current extraction and the extent of nickel stripping is up to 99.3% under one step stripping. A new process was carried out to deal with the residue, so that the leaching rate of nickel and the recovery rate of nickel had been significantly improved. The process shows a new way of recovery nickel from the residue.