Waste Valorization Process: Sulfur Removal and Hematite Recovery from High Pressure Acid Leach Residue for Steelmaking

Ang, Cheen Aik; Feixiong, Zhang; Azimi, Gisele

doi:10.1021/acssuschemeng.7b02245

Cited by 11 publications

(4 citation statements)

References 17 publications

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“…The main phase in the residue was found to be hematite (Fe 2 O 3 ), with small intensities of quartz (SiO 2 ) and alunite (KAl 3 (SO 4 ) 2 (OH) 6 ) also observed. This result is similar to the phases of HPAL residue from Vale’s nickel plant located near the Goro mine in the south of New Caledonia reported by Ang et al Furthermore, Lei et al reported that the main phases of HPAL residue from Indonesian limonite laterite are hematite, chromite, alunite, and aluminosilicate.…”

Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

“…The residue generated from the HPAL process contains significant amounts of iron (up to 50%), which can be further processed and recovered to become a raw material for iron and steelmaking. 24 Recently, the HPAL residue was successfully converted into blast furnace charge for ironmaking. It was reported that the briquettes were preheated at 975 °C for 12 min and roasted at 1225 °C for 15 min; this resulted in roasted briquettes with a strength of 2815 N/pellet, with an iron concentration of 59.27 wt %, and sulfur effectively removed.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue

Setiawan,

Harjanto,

Kawigraha

et al. 2023

ACS Omega

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This paper describes the microstructure evolution and phase transformation of residue from the lateritic nickel ore high-pressure acid leaching (HPAL) during carbothermic reduction using palm kernel shell (PKS) charcoal as a reductant. The study consisted of thermodynamic calculations combined with analysis of reduction experiments. The thermodynamic assessment predicted that the main phases formed during the reduction process were γ-Fe metal, liquid metal, slag, and spinel, with abundance of reducing gas (CO and H2) at the temperature range of 750–1500 °C. The experimental study shows that the resulting product upon cooling was sponge iron or direct reduced iron when HPAL residue-PKS charcoal composites were reacted up to 1400 °C for 45 min. The sponge iron had an average apparent density of 5.8 ± 0.1 g/cm3 and a 90.8 ± 0.4% metallization degree. The microstructure analysis revealed that as the reduction time was increased, small iron nuggets began forming on the surface of the reduced product. By addition of Na2CO3, the separation of iron nuggets from slag appeared to be improved, hence enhancing the overall reduction process. Furthermore, iron nuggets’ highest apparent density and metallization degree were obtained at 7 ± 0.1 g/cm3 and 98 ± 0.5%, respectively, when adding Na2CO3 of 6 wt %. The phase and microstructure analyses also revealed that the iron nuggets comprised coarse pearlite, eutectic cementite, ledeburite, and sulfides. Thus, this study offers alternative sustainable process conditions for simultaneously handling the HPAL residue using PKS waste to produce metallic iron.

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue

Setiawan,

Harjanto,

Kawigraha

et al. 2023

ACS Omega

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“…Nickel resources are primarily divided into nickel oxide minerals and nickel sulfide minerals. From a worldwide perspective, nickel in oxidized ore accounts for 65%–70% of the total land-based nickel reserves. − At present, the resources of nickel sulfide ore in the world are gradually being exhausted, and the global nickel demand will continue to grow at a high rate. The trend in the nickel industry is to obtain nickel from nickel laterite ore to fulfil market demand.…”

Section: Introductionmentioning

confidence: 99%

Effective Separation and Beneficiation of Iron and Chromium from Laterite Sulfuric Acid Leach Residue

Lei

Chen

et al. 2020

ACS Sustainable Chem. Eng.

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The utilization of laterite sulfuric acid leach residue has always been a challenge in the metallurgical industry. The current treatment involves deep-sea landfills, which leads to considerable environmental pollution and resource wastage. In this work, an effective method is proposed to recover iron and chromium from sulfuric acid leach residue. The effects of roasting temperature, reducing agent dosage, and reaction duration on the recovery of iron and chromium were investigated. The optimum conditions were as follows: roasting temperature of 1200 °C, reducing agent dosage of 30%, and reaction duration of 60 min. Results show that the concentrate contains 87% Fe and that only 0.7% S can be obtained with an iron recovery of 82%, indicating suitability for ironmaking. Meanwhile, 85% of chromium can be beneficiated in tailings at a chromium content of 3.5%. The microstructure and composition of reduction products were analyzed by XRD, SEM, and EDS to understand the phase transformation and the aggregation of the reduction products. Hematite in the leach residue is first reduced to FeS and Fe3O4 at low temperature and then reduced to metallic iron with increased temperature. Sulfur is combined with alunite to form FeS at a low temperature, and the decomposition of chromite at high temperature leads to the formation of chromium oxide. In a high temperature and reducing atmosphere, Cr2O3 reacts with FeS to transform Fe and CrS. Through the reduction roasting–magnetic separation process, most of the iron is beneficiated in the concentrate, and nonmagnetic minerals such as FeS and CrS remain in the tailings. Consequently, the separation and beneficiation of iron and chromium occur. The process is economically feasible and environmentally friendly and thus has great potential for the industrial-scale recycling of laterite sulfuric acid leach residue.

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Sulfur Removal and Iron Recovery from High-Pressure Acid Leaching Residue of Nickel Laterite Ore

Wu,

Ma,

Chen

et al. 2024

J. Sustain. Metall.

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Waste Valorization Process: Sulfur Removal and Hematite Recovery from High Pressure Acid Leach Residue for Steelmaking

Cited by 11 publications

References 17 publications

Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue

Microstructure Evolution and Phase Transformation of Iron Produced from the Sustainable Carbothermic Reduction Process of High-Pressure Acid Leaching Residue

Effective Separation and Beneficiation of Iron and Chromium from Laterite Sulfuric Acid Leach Residue

Sulfur Removal and Iron Recovery from High-Pressure Acid Leaching Residue of Nickel Laterite Ore

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