Abstract
The recovery of valuable metals from spent refractories, particularly in the nickel industry, is essential for enhancing resource efficiency and promoting sustainable practices in metallurgy. This study investigates the hydrometallurgical recycling of spent refractories from a nickel flash smelter (NiFS), focusing on optimizing nickel recovery through a two-step treatment process involving pyrometallurgical pretreatment and hydrometallurgical extraction.
The experimental setup commenced with the preparation of refractory materials, where the NiFS underwent pre-crushing and milling to achieve a particle size conducive to effective leaching. The milling process is crucial for enhancing the efficiency of subsequent leaching operations. The pyrometallurgical pretreatment was conducted at 1000°C in a muffle furnace to remove sulfur impurities via roasting, rendering the material suitable for nickel recovery.
After pretreatment, various leaching experiments examined parameters such as time, temperature, solid-to-liquid (S/L) ratio, pH, and oxidizing agents. The experiments, spanning 60 to 240 minutes with a focus on 120 minutes, were conducted at temperatures ranging from 60°C to 90°C, typically maintaining an S/L ratio of 1:10, with variations of 1:15 and 1:20 and pH values between 0.3 and 1.
The findings demonstrate that roasting followed by leaching can effectively recover nickel from spent refractories, with optimal extraction conditions identified as 90°C, 240 minutes leaching time, an S/L ratio of 1:10, and pH of 0.3, achieving a recovery of around 77%. The use of aggressive acid leaching with HCl, combined with high temperature and extended leaching time, proved most effective for nickel dissolution. Incorporating H₂O₂ in the final leaching stages enhanced nickel recovery through oxidation.
The results underscore the importance of refining leaching conditions and balancing effective extraction with operational feasibility. Maintaining optimal operational conditions while balancing efficiency and cost-effectiveness is crucial for industrial-scale applications.
The experimental setup commenced with the preparation of refractory materials, where the NiFS underwent pre-crushing and milling to achieve a particle size conducive to effective leaching. The milling process is crucial for enhancing the efficiency of subsequent leaching operations. The pyrometallurgical pretreatment was conducted at 1000°C in a muffle furnace to remove sulfur impurities via roasting, rendering the material suitable for nickel recovery.
After pretreatment, various leaching experiments examined parameters such as time, temperature, solid-to-liquid (S/L) ratio, pH, and oxidizing agents. The experiments, spanning 60 to 240 minutes with a focus on 120 minutes, were conducted at temperatures ranging from 60°C to 90°C, typically maintaining an S/L ratio of 1:10, with variations of 1:15 and 1:20 and pH values between 0.3 and 1.
The findings demonstrate that roasting followed by leaching can effectively recover nickel from spent refractories, with optimal extraction conditions identified as 90°C, 240 minutes leaching time, an S/L ratio of 1:10, and pH of 0.3, achieving a recovery of around 77%. The use of aggressive acid leaching with HCl, combined with high temperature and extended leaching time, proved most effective for nickel dissolution. Incorporating H₂O₂ in the final leaching stages enhanced nickel recovery through oxidation.
The results underscore the importance of refining leaching conditions and balancing effective extraction with operational feasibility. Maintaining optimal operational conditions while balancing efficiency and cost-effectiveness is crucial for industrial-scale applications.
| Translated title of the contribution | Hydrometallurgisches Recycling von feuerfesten Abfallmaterialien aus einer Nickel-Flash-Schmelze |
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| Original language | English |
| Qualification | Dipl.-Ing. |
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| Supervisors/Advisors |
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| Award date | 11 Apr 2025 |
| Publication status | Published - 2025 |
Bibliographical note
no embargoKeywords
- recycling
- nickel flash smelter
