Effect of CaF2 on the aggregation and growth of ferronickel particles in the self-reduction of Nickel laterite ore

2021 ◽  
Vol 118 (4) ◽  
pp. 407
Author(s):  
Guihua Hang ◽  
Zhengliang Xue ◽  
Ying Jiang Wu ◽  
Bo Zhang
Keyword(s):  
Magnetic Separation ◽  
Average Particle Size ◽  
Reduction Process ◽  
Separation Process ◽  
The Self ◽  
Particle Aggregation ◽  
Average Particle ◽  
Nickel Laterite ◽  
Nickel Laterite Ore ◽  
Laterite Ore

Increasing attention is being paid to the self-reduction and magnetic separation of nickel laterite ore because of economic and efficiency advantages. The aggregation and growth of ferronickel particles during the reduction process is an important factor for subsequent magnetic separation. In this study, the effect of CaF2 on ferronickel particle aggregation and growth during the self-reduction of nickel laterite ore was investigated by visual data analysis of ferronickel particles. The recovery and grade of Ni and Fe from the self-reduction, fine grinding, and magnetic separation of nickel laterite ore under the strengthening action of CaF2 were measured. Increasing CaF2 addition yielded a significant increase in the average particle size of ferronickel particles and an increased recovery of a higher grade of Ni. A ferronickel concentrate with 7.1 wt% Ni and 68.5 wt% Fe was obtained at a Ni recovery of 84.14% in the presence of 8 wt% CaF2. CaF2 accelerates the aggregation and growth of ferronickel particles, which promotes the separation of the ferronickel alloy from the gangue in the magnetic separation process.

scholarly journals Mechanism of Calcium Sulphate on the Aggregation and Growth of Ferronickel Particles in the self-Reduction of Saprolitic Nickel Laterite Ore

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 423
Author(s):  
Guihua Hang ◽  
Zhengliang Xue ◽  
Jinghui Wang ◽  
Yingjiang Wu
Keyword(s):  
Magnetic Separation ◽  
Calcium Oxide ◽  
Reduction Process ◽  
Calcium Sulphate ◽  
The Self ◽  
Nickel Laterite ◽  
Fine Grinding ◽  
Nickel Laterite Ore ◽  
Mineral Structure ◽  
Laterite Ore

Saprolitic nickel laterite is characterized by relatively low iron and nickel contents. Iron and nickel oxides are reduced to form fine ferronickel particles that disperse and embed in silicates in the reduction process, limiting the application of magnetic separation to extract ferronickel. Additives are applied to promote the aggregation and growth of ferronickel particles, then the large ferronickel particles will be separated by fine grinding and recovered via magnetic separation. Calcium sulphate is considered to be capable of increasing the size of ferronickel particles considerably. Due to the decomposition of calcium sulphate in the reduction process, the mechanism of calcium sulphate on the aggregation and growth of ferronickel particles should be conducted studied in-depth. The current work explores the effects of calcium sulphate, elemental sulphur, and calcium oxide on the formation of ferronickel particles in a saprolitic nickel laterite ore. The results showed that the formation of an Fe-FeS eutectic and the mineral structure transformation contributed by calcium oxide were all conducive to the mass transfer of ferronickel particles in gangue, ferronickel particles aggregated and grew up at the boundary between the hole and the gangue. The self-reduction, fine grinding, and magnetic separation of nickel laterite ore in the presence of three types of additive were examined. Nickel laterite ore with 7.88 wt% coal, 12 wt% calcium sulphate reduced at 1200 °C for 30 min, a ferronickel concentrate of Ni 8.08 wt%, and Fe 79.98 wt% was obtained at a nickel and iron recovery of 92.6% and 79.9%, respectively.

scholarly journals Production of Ferronickel Concentrate from Low-Grade Nickel Laterite Ore by Non-Melting Reduction Magnetic Separation Process

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1340
Author(s):  
Guorui Qu ◽  
Shiwei Zhou ◽  
Huiyao Wang ◽  
Bo Li ◽  
Yonggang Wei
Keyword(s):  
Magnetic Separation ◽  
Separation Process ◽  
Phase Changes ◽  
Low Grade ◽  
Nickel Laterite ◽  
Nickel Laterite Ore ◽  
Roasting Temperature ◽  
Grinding Time ◽  
Optimal Reduction ◽  
Laterite Ore

The production of ferronickel concentrate from low-grade nickel laterite ore containing 1.31% nickel (Ni) was studied by the non-melting reduction magnetic separation process. The sodium chloride was used as additive and coal as a reductant. The effects of roasting temperature, roasting duration, reductant dosage, additive dosage, and grinding time on the grade and recovery were investigated. The optimal reduction conditions are a roasting temperature of 1250 °C, roasting duration of 80 min, reductant dosage of 10%, additive dosage of 5%, and a grinding time of 12 min. The grades of nickel and iron are improved from 2.13% and 51.12% to 8.15% and 64.28%, and the recovery of nickel is improved from 75.40% to 97.76%. The research results show that the additive in favor of the phase changes from lizardite phase to forsterite phase. The additive promotes agglomeration and separation of nickel and iron.

The effect of sodium sulphate on the hydrogen reduction process of nickel laterite ore

2013 ◽  
Vol 49 ◽  
pp. 154-164 ◽  
Author(s):  
Jie Lu ◽  
Shoujun Liu ◽  
Ju Shangguan ◽  
Wenguang Du ◽  
Feng Pan ◽  
...  
Keyword(s):  
Hydrogen Reduction ◽  
Reduction Process ◽  
Sodium Sulphate ◽  
Nickel Laterite ◽  
Nickel Laterite Ore ◽  
Laterite Ore

Ferronickel enrichment by fine particle reduction and magnetic separation from nickel laterite ore

2014 ◽  
Vol 21 (10) ◽  
pp. 955-961 ◽  
Author(s):  
Xiao-hui Tang ◽  
Run-zao Liu ◽  
Li Yao ◽  
Zhi-jun Ji ◽  
Yan-ting Zhang ◽  
...  
Keyword(s):  
Magnetic Separation ◽  
Fine Particle ◽  
Nickel Laterite ◽  
Nickel Laterite Ore ◽  
Laterite Ore

Kinetics of synthesizing process for obtaining iron nanopowder by chemical-metallurgical method under isothermal conditions

2021 ◽  
pp. 72-77
Author(s):  
Tien Hiep Nguyen ◽  
◽  
Van Minh Nguyen ◽  
Keyword(s):  
Hydrogen Reduction ◽  
Average Particle Size ◽  
Chemical Deposition ◽  
Reduction Process ◽  
Nitrogen Adsorption ◽  
Specific Rate ◽  
Average Particle ◽  
Isothermal Conditions ◽  
Electron Microscopes ◽  
Kinetics Of

In this work the kinetics of synthesizing process of metallic iron nanopowder by hydrogen reduction from α-FeOOH hydroxide under isothermal conditions were studied. α-FeOOH nanopowder was prepared in advance by chemical deposition from aqueous solutions of iron nitrate Fe(NO3)3 (10 wt. %) and alkali NaOH (10 wt. %) at room temperature, pH = 11, under the condition of continuous stirring. The hydrogen reduction process of α-FeOOH nanopowder under isothermal conditions was carried out in a tube furnace in the temperature range from 390 to 470 °C. The study of the crystal structure and composition of the powders was performed by X-ray phase analysis. The specific surface area S of the samples was measured using BET method by low-temperature nitrogen adsorption. The average particle size D of powders was determined via the measured S value. The size characteristics and morphology of the particles were investigated by transmission and scanning electron microscopes. The calculation of the kinetic parameters of the hydrogen reduction process of α-FeOOH under isothermal conditions was carried out by the Gray-Weddington model and Arrhenius equation. It is shown that the rate constant of reduction at 470 °C is approximately 2.2 times higher than in the case at 390 °C. The effective activation energy of synthesizing process of iron nanopowder by hydrogen reduction from α-FeOOH was ~38 kJ/mol, which indicates a mixed reaction mode. In this case, the kinetics overall process is limited by both the kinetics of the chemical reaction and the kinetics of diffusion, respectively, an expedient way to accelerate the process by increasing the temperature or eliminate the diffusion layer of the reduction product by intensive mixing. It is show that Fe nanoparticles obtained by hydrogen reduction of its hydroxide at 410 °C, corresponding to the maximum specific rate of the reduction process, are mainly irregular in shape, evenly distributed, the size of which ranges from several dozens to 100 nm with an average value of 75 nm.

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