从红土镍矿镍铁渣中分离浸取镍铬工艺

将镍铁渣破碎、球磨后磁选富集Ni于精矿中，富集Cr于尾矿中. 磁选后Ni从0.26%富集至2.57%(w)，Cr从4.55%富集至4.61%(w). 考察了H2SO4常压酸浸精矿时Ni的浸出规律. 结果表明，在酸浸温度110℃、酸浓度220 g/L、酸浸时间2 h、液固质量比5的优化酸浸条件下，Ni浸出率为91.5%. 在80~120℃内，Ni浸出反应活化能为19.6 kJ/mol. Ni浸出反应主要受扩散控制. 用Na2CO3碱熔焙烧尾矿，在温度1000℃、Na2CO3/渣质量比0.65、时间1 h、镍铁渣尾矿粒度<74 mm的优化条件下，Cr浸出率为94.1%.

Separation and Recovery of Ni and Cr from Ferronickel Slag of Nickel Laterite

Magnetic separation was used to treat the ferronickel slag derived from pyrometallurgy of nickel laterite. After magnetic separation, Ni was enriched in magnetic concentrate. The content of Ni in magnetic concentrate increased from 0.26% to 2.57%, and the content of Cr in non-magnetic tailing from 4.55% to 4.61%, respectively. Then, Ni was leached from the magnetic concentrate with H2SO4 at atmospheric pressure. Under the optimum leaching conditions of sulfuric acid concentration of 220 g/L, leaching temperature of 110℃, leaching time of 2 h, and mass ratio of liquid to solid of 5, 91.5% of Ni was leached out from the magnetic concentrate of ferronickel slag. The acid leaching kinetics of Ni from magnetic concentrate revealed that the apparent activation energy from 80 to 120℃ was 19.6 kJ/mol, which corresponds to a diffusion controlled process. The leaching of Cr from the non-magnetic tailing was carried out by alkali-roasting with Na2CO3 and then leaching with water, the optimum conditions were as follows: temperature of 1000℃, mass ratio of alkali to slag of 0.65, time of 1 h, and particle size of <74 mm. Under the optimum conditions, 94.1% of Cr was leached out from the non-magnetic tailing of ferronickel slag.