|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,900,000 (Direct Cost: ¥2,900,000)
Gamierite is an oxide mineral and the main resource for Ni recovery in the industry. The purpose of this research is to improve wettability and leachability of the gamierite by selectively producing sulfide or sulfate using a mechanochemical treatment with sulfur addition in order to concentrate Ni before the smelting or refining processes.
(1)Three kinds of Gamierite ores with different sources were characterized as initial samples. They contained from 2.19 to 2.57mass% of Ni and exhibited XRD peaks of (Ni, Mg)3Si205(OH)4 and SiO2. Specific surface areas were from 80 to 100m2/g determined by gas absorption method.
(2)Mechanochemical treatments with the planetary ball mill were conducted. The samples were characterized and also leached with sulfuric acid solution. After the milling for 60 minutes, only the peak of SiO2 was detected. With the sulfur addition, the peaks of S and SiO2 were detected but not the sulfide peaks were confirmed. The specific surface area became 10m2/g. Leaching with 0.5mol/L H2SO4 for 60 minutes extracted 85% of Mg and Ni, 15% of Fe and Si. The sulfur addition of 2.5mass% and more decreased the extraction rates except Ni and hence the selectivity of Ni extraction increased.
(3)Considering the practical operation, treatments with mixer ball mill were conducted for the treatment time for 30 minutes with the sulfur additions of 0 and 0.625mass%. The extraction rates of the initial sample of Montagnat were Ni 10.7%, Mg 2.93%, Fe 2.48%, Si 0.40%. After the treatment without sulfur addition, extraction rates became higher as Ni 58.1%, Mg 56.5%, Fe 17.4%, Si 0.60%. Sulfur addition did not change the extraction rates : In comparison with the treatment with the planetary ball mill, the extraction rates were lower after the treatment with the mixer ball mill.