Low-Temperature Carbothermic Reduction of Indonesia Nickel Lateritic Ore with Sub-Bituminous Coal
In this work, the experiment was conducted to investigate the effect of temperature and sub-bituminous coal on upgrading nickel laterites ores by carbothermic reduction. The reduction was carried out in the muffle furnace at a temperature ranging of 800-1100 °C. The produced calcine from reduction step was grounded in vibrating mill, mixed with water and passed on a magnetic separator to separate nickel concentrates from the tailing. The experimental results showed that the concentrate with highest nickel grade was produced at temperature 1000 °C. The nickel grade on concentrate was 5.0 %, with the recovery of nickel was 80.6 %.
Beneficiation of nickeliferous laterite by reduction roasting in the presence of sodium sulfate
Abstract In this paper, the reduction roasting of laterite ore in the absence or presence of sodium sulfate was carried out for nickel beneficiation by wet magnetic separation. Sodium sulfate is found to be capable of enhancing the reduction of laterite ore through liberating iron and nickel from Ni/Fe substituted-lizardite, as well as increasing the size of ferronickel particles considerably. When the laterite pellets were reduced at 1100 °C for 60 min, the average particle size of ferronickel grains was approximately 50 μm in the presence of sodium sulfate, which far exceeded the size of 5–10 μm in the absence of sodium sulfate. Compared with those reduced without sodium sulfate, the Ni grade of ferronickel concentrate increased from 2.33% to 9.48%, and the magnetic separation recovery of Ni increased from 56.97% to 83.01% with the addition of 20 wt.% sodium sulfate. Experimental evidence showed that troilite (FeS) serves as an activating agent to accelerate melt phase formation via a low melting point (985 °C) Fe–FeS eutectic. This markedly facilitated the aggregation of ferronickel particles during reduction, along with the selective enrichment of Ni by suppressing the complete metallization of Fe.
Numerical Simulation of Induction Heating Process of Continuous Casting Slab
Compared with traditional blazing furnace, the Continuous Casting-Direct Rolling is an advanced manufacturing steel technology, which can reduce energy waste, decrease pollution and enhance efficiency. The characteristics of steels during induction heating are complex, the change of material properties with temperature makes exact analysis methods very difficult to implement. Therefore, a powerful computer aided numerical tool (i.e., finite difference analysis) is selected to numerically model the induction heating process in this paper. The mathematic model coupling with electromagnetic field and thermal field was established, and it was solved by finite difference method (FDM), thus the slab temperature distribution and its variation with time were obtained, and the characteristics in whole induction heating process were studied. To validate the program feasible, the results were evaluated and compared with experiment results, which showed that the simulation results are reliable and effective. The skin effect in heating process from the two results was studied and demonstrated, the temperature change caused by different parameters such as the induced power intensity and the corner radian were also presented, which indicate that the slab temperature can be heated uniformly through adjusting these parameters, thus the continuous casting slab can meet the rolling requirement.