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| Direct reduction ironmaking process for nitric acid pressure leaching residue from laterite nickel ore |
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Received:October 22, 2025
Revised:November 20, 2025
Accepted:December 16, 2025
Published Online:April 30, 2026
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| DOI：10.3969/j.issn.1005-7854.2026.02.020 |
| KeyWord:laterite nickel ore;leaching residue;hematite;biomass reduction;iron and chromium;resource utilization |
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| School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China |
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| Abstract: |
| Laterite nickel ore, accounting for over 70% of global nickel resources, is crucial for the production of new energy power batteries and stainless steel. Although the current mainstream high-pressure acid leaching (HPAL) process can achieve a nickel-cobalt recovery rate of over 95%, it generates 100–200 tons of leach residue per ton of metallic nickel. The residue contains 2%–5% sulfur, and its long-term stockpiling not only occupies land but also poses a risk of heavy metal leakage. Existing recovery technologies such as magnetization roasting-magnetic separation and reduction smelting are difficult to popularize due to high sulfur content and high process costs. Our research team has innovatively developed a pressure leaching process with nitric acid, which has been verified to operate stably through pilot-scale tests. Under the conditions of 180–210 ℃ and 1.5–2 MPa, the leaching rate of nickel and cobalt exceeds 95%, while the iron leaching rate is less than 1%. The produced leach residue has an iron content of over 55% and is sulfur-free. To realize the resource utilization of the laterite nickel ore nitric acid pressure leaching residue and alleviate the shortage of iron and steel raw materials in China, this study conducted research on the biomass direct reduction ironmaking process using peanut shells as the reducing agent. Experiments investigated the effects of roasting temperature, mass ratio of peanut shells to leach residue, and reaction time on the recovery efficiency of iron and chromium. The phase transformation laws during the reduction process were analyzed by means of ICP-OES, XRD, and SEM-EDS. The results show that the optimal process conditions are: roasting temperature of 1 500 ℃, peanut shell ratio of 0.75 g·g?1 (peanut shell : leaching residue), and reaction time of 120 min. Under these conditions, the recovery rates of iron and chromium from the leach residue reach 92.35% and 81.23%, respectively, and the contents of iron and chromium in the obtained alloy product are 91.85% and 1.98%, respectively. It was found that increasing the temperature promotes the migration, enrichment, and growth of metallic iron, reducing the entrainment loss of slag phase. An appropriate dosage of peanut shells can enhance chromite decomposition and iron-chromium eutectic formation. This study provides a new pathway for the resource utilization of laterite nickel ore smelting solid waste and the low-carbon raw material supply for the iron and steel industry. |
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