Viscosity and structure evolution of the SiO2-MgO-FeO-CaO-Al2O3 slag in ferronickel smelting process from laterite

The effect of ZnO/PbO and FeO X /SiO 2 on the viscosity of the PbO-ZnO-Fe 3 O 4-SiO 2-CaO slag was measured using the rotating spindle method. The slag viscosity decreased with decreasing ZnO/PbO mass ratio because of the depolymerization of the silicate structures. The viscosity decreased with increasing FeO X /SiO 2 mass ratio as the experimental temperature was above 1623 K, while the viscosity increased significantly with the increase of FeO X /SiO 2 as the experimental temperature below 1623 K because of the phase transition and the change of slag melting point. According to XRD analysis of as-quenched slag, the spinel and the zincite phase increased with increasing FeO X /SiO 2. Increasing ZnO/PbO and FeO X /SiO 2 could enhance the crystallization capacity of the slag. FTIR analysis revealed that the degree of polymerization of the as-quenched slags decreased with decreasing ZnO/PbO and increasing FeO X /SiO 2. The temperature dependencies of the viscosity on ZnO/PbO and FeO X /SiO 2 were investigated, and the apparent activation energies of each system were found to be between 169.5 to 227.4 KJ/mol, and 151.1 to 676.4 KJ/mol, respectively.

Section: Effect Of Zno/pbo On Slag Viscositysupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effect of ZnO/PbO and FeOX/SiO2 ratio on the viscosity of lead smelting slags

Ouyang

Zhang

et al. 2020

“…In relation to the viscosity of laterite smelting slags, the readers are referred to the paper which was published by X.M. Lv et al [19]. The authors of the present work thought that use of colemanite could be a solution to decrease physical losses.…”

Section: Introductionmentioning

confidence: 80%

Use of colemanite in ferronickel smelting

Keskinkilic

Pournaderi

Geveci

et al. 2019

Use of colemanite in metal-slag systems aims primarily to decrease the viscosity of slag and, therefore, achieve better metal-slag separation. Enhanced metal-slag separation is helpful to decrease the number of suspended metal/alloy droplets in slag, i.e. the physical losses. In the literature, successful use of colemanite was reported both in steelmaking and copper matte smelting processes. Ferronickel smelting slags contain nickel in the range of 0.1-0.2% and correspondingly, metal-slag distribution ratio values of nickel are reported even above 200. On the contrary, nickel recoveries are hard to exceed 95%. This can be mostly attributed to the physical losses of nickel due to very high slag volume in ferronickel smelters; for 1 ton of ferronickel, 10-15 tonnes of slag are generated regardless of the type of the laterite, which contains significant quantity of gangue components. The authors thought that use of colemanite could be a solution to decrease physical losses. Therefore, the use of colemanite in ferronickel smelting was investigated in the present work. Laboratory-scale smelting experiments were conducted using calcined and prereduced laterites in a vertical tube furnace under different gas atmospheres. The amount of colemanite added was in the range of 0-2.5% of the total charge. The experiments were also performed using ferronickel and slag samples obtained from a ferronickel smelter.

“…A previous study on calcium additives in garnierite was conducted, but the valuable metals in the minerals could not be comprehensively utilized [26][27][28][29][30][31]. The purpose of this work is to explore a new process and provide a highly efficient and energy saving method, named the vacuum carbothermal reduction-magnetic separation method, to comprehensively utilize the garnierite.…”

Section: Introductionmentioning

confidence: 99%

The effect of CaO on the recovery of Fe and Ni in a vacuum carbothermal reduction of garnierite

Wang

X.-P.

et al. 2019

The effects of adding CaO during a vacuum carbothermal reduction on Fe and Ni recovery yields were examined. In addition, magnetic separation was investigated. Experiments were conducted under pressures ranging from 10 to 50 Pa with different proportions of CaO at different temperatures. The results indicated that at 1723 K, the mass ratio of ore/C was 100:65.5; when the amount of CaO was 22.64% (the mole ratio of CaO/Si was 1:1), the recovery of Fe and Ni reached 84.33% and 97.00% in the vacuum carbothermal reduction-magnetic separation process, and the enrichment ratios of Fe and Ni were maximized, reaching 6.32 and 6.72, respectively. In addition, the recovery of Mg in the reduction process reached 99.35%. An analysis of the experimental results also indicated that the addition of CaO could cause the Fe-Si alloy to transform into the Fe-Ni alloy in the nickel-rich residue, which increased the content of Fe-Ni in the magnetic separation material from 13.34% to 73.17%. In addition, the concentration in reduced ore of Si from 45.43% increased to 83.68%, which could reduce the evaporation of Si in the form of SiO at high temperatures. If Si volatilized in the form of SiO during the condensation process, SiO would disproportionate to form Si and SiO 2 contaminated condensed magnesium. In summary, the valuable metals in the minerals were comprehensively utilized with the addition of CaO. Jou rn al of Min in g an d Metallu rgy, S ection B: Metallu rgyhttps://doi.org/10.2298/JMMB190213035W