Periodic Reporting for period 2 - ENICON (Sustainable processing of Europe's low-grade sulphidic and lateritic nickel/cobalt ores and tailings into battery-grade metals)
Période du rapport: 2023-12-01 au 2025-05-31
The cobalt (Co) and nickel (Ni) demand is expected to be about 20 times higher in 2040 than in 2020. Given that Europe plays only a minor role in the global Ni/Co supply chains, which are concentrated in the DRC, Indonesia and China, we face a serious problem in securing a reliable, affordable and sustainable supply of battery-grade Ni/Co, vital for Europe’s aims to be climate-neutral by 2050. In view of a “domestic and foreign sourcing” procurement model, ENICON exploits the potential of (low-grade) Ni/Co resources within Europe – i.e. sulphidic Ni/Co ores and derived Ni/Co-bearing pyrite and silicate tailings, and limonitic/saprolitic laterite Ni(/Co) ores – while improving and developing the Ni/Co-refining capacity that can process imported ores, concentrates and intermediates. ENICON comprises both major improvements to existing Ni/Co metallurgical unit operations in Europe as well as the development of a new HCl-based route for both Ni/Co sulphide concentrates and laterites. ENICON’s HCl-route dispenses with the old-school hydro approach of continuously precipitating and redissolving metals that requires lots of chemicals and creates problematic waste streams. The HCl-based route can be extended to the downstream processing of FeNi (Class-II Ni) obtained from laterites; (2) Mixed (Ni/Co) Sulphide/Hydroxide Precipitate (MSP/MHP) from the bioleaching of Co-rich pyrite tailings; and Ni/Co-containing silicate tailings. ENICON targets a “forensic geometallurgy” protocol, making it possible to identify and mitigate the mineralogical and textural reasons for processing losses along existing and new flowsheets. To make the transition to (near) zero-waste processing and to further reduce CO2-footprints, ENICON develops enhanced mineral-matrix valorisation processes. The outputs from ENICON’s group of European Ni/Co mining, processing and refining companies will all be benchmarked in terms of positive environmental and techno-economic impacts against current methods.
The HCl leaching process showed mixed results for the sulpidic materials. The process was highly effective in extracting Ni and Co from sulphide tailings yet the efficiency of the leaching was lower in Ni concentrates. The mineralogy of the laterites varied widely. A non-neglegible amount of Co is found to be contained in chromite, a poorly leachable mineral.
The bioleaching/oxidative leaching and precipitation processes were successfully designed and operated.
A mineral carbonation pre-treatment process was successfully developed for the Ni/Co-silicate tailings together with a subsequent CO2 sequestration investigation. As to leaching behaviour with HCl, carbonated materials from a hydrothermal treatment route yielded high Ni extraction efficiency and selectivity.
The use of biochar was investigated for nickel slag cleaning, and results revealed that biochar consistently outperformed coke in reducing residual concentrations of Ni and Co in the slag, achieving higher matte-to-slag distribution coefficients for both metals, and higher metal recoveries.
Flowsheets have been developed for 5 ENICON materials: limonitic laterite, saprolitic laterite, MHP, MSP and ferronickel (FeNi). The model that has been developed for leaching, solvent extraction, etc. has already shown to be predictive and valid against experimental results and were used to guide process design decisions.
As to the adaptation of the existing leaching/SX/EW route to the ENICON imtermediates (MHP/MSP), Mn removal plays a critical role and it became evident that Mn could be precipitated quantitatively, together with Fe. However, there was a considerable loss of Ni and Co, being co-precipitated with Mn and Fe. Washing of the precipitate did not sufficiently recover Ni and Co.
In terms of the mineral-matrix valorisation, a scientific breakthrough was achieved with the invention of akermanitic clinckers, which proved to provide CO2-lean construction materials with high compressive strength. This was the subject of 2 patent applications and 2 journal publications. Furthermore, alkali-activation of ENICON residues was successful. The leaching residues obtained from HCl leaching of laterites showed great potential to be used as supplementary cementitious material, due to their reactivity.
As to the LCA, the carbon-neutral smelting showed significant improvements in all but 3 studied impact categories. The higher infrastructure and land requirements associated with the use of H2 for reduction are the main drawbacks. Overall, the results support the viability of H2 as a more sustainable reductant, but its successful implementation will depend critically on upstream energy sourcing (i.e. the production of green H2) and resource efficiency. The environmental profile of the ENICON HCl-based process for the upgrading of ferronickel (FeNi) shows overall low environmental impacts. It combines efficient resource utilisation with reduced emissions and freshwater use, supporting the sustainability and scalability of battery-grade Ni-Co production. The environmental performance of alkali-activated mortar production showed many advantages over conventional Ordinary Portland Cement (OPC) production. The ENICON technology reduced the environmental impacts in all categories, but one (photochemical ozone creation potential).
As to the TEA for the processing of FeNi and limonitic laterites to produce battery-grade Ni and Co, it became evident that HPAL exhibits a higher profitability compared to the ENICON processes. The ENICON process for the limonitic laterite has the most chance of becoming profitable, through reduction of CAPEX costs.
The bioleaching/oxidative leaching and precipitation processes were successfully designed and operated.
A mineral carbonation pre-treatment process was successfully developed for the Ni/Co-silicate tailings together with a subsequent CO2 sequestration investigation. As to leaching behaviour with HCl, carbonated materials from a hydrothermal treatment route yielded high Ni extraction efficiency and selectivity.
The use of biochar was investigated for nickel slag cleaning, and results revealed that biochar consistently outperformed coke in reducing residual concentrations of Ni and Co in the slag, achieving higher matte-to-slag distribution coefficients for both metals, and higher metal recoveries.
Flowsheets have been developed for 5 ENICON materials: limonitic laterite, saprolitic laterite, MHP, MSP and ferronickel (FeNi). The model that has been developed for leaching, solvent extraction, etc. has already shown to be predictive and valid against experimental results and were used to guide process design decisions.
As to the adaptation of the existing leaching/SX/EW route to the ENICON imtermediates (MHP/MSP), Mn removal plays a critical role and it became evident that Mn could be precipitated quantitatively, together with Fe. However, there was a considerable loss of Ni and Co, being co-precipitated with Mn and Fe. Washing of the precipitate did not sufficiently recover Ni and Co.
In terms of the mineral-matrix valorisation, a scientific breakthrough was achieved with the invention of akermanitic clinckers, which proved to provide CO2-lean construction materials with high compressive strength. This was the subject of 2 patent applications and 2 journal publications. Furthermore, alkali-activation of ENICON residues was successful. The leaching residues obtained from HCl leaching of laterites showed great potential to be used as supplementary cementitious material, due to their reactivity.
As to the LCA, the carbon-neutral smelting showed significant improvements in all but 3 studied impact categories. The higher infrastructure and land requirements associated with the use of H2 for reduction are the main drawbacks. Overall, the results support the viability of H2 as a more sustainable reductant, but its successful implementation will depend critically on upstream energy sourcing (i.e. the production of green H2) and resource efficiency. The environmental profile of the ENICON HCl-based process for the upgrading of ferronickel (FeNi) shows overall low environmental impacts. It combines efficient resource utilisation with reduced emissions and freshwater use, supporting the sustainability and scalability of battery-grade Ni-Co production. The environmental performance of alkali-activated mortar production showed many advantages over conventional Ordinary Portland Cement (OPC) production. The ENICON technology reduced the environmental impacts in all categories, but one (photochemical ozone creation potential).
As to the TEA for the processing of FeNi and limonitic laterites to produce battery-grade Ni and Co, it became evident that HPAL exhibits a higher profitability compared to the ENICON processes. The ENICON process for the limonitic laterite has the most chance of becoming profitable, through reduction of CAPEX costs.
The impact expected by the results of the project is still in line with the impact as described in the grant agreement. A forensic-geometallurgical protocol (FGP) is established for the processing of sulphidic and lateritic materials, and can be replicated with similar ore materials to tailor leaching processes and mineral-matrix valorisation. Treatment of stream (2) using state-of-the art technology has proven to be feasible. Furthermore, the invention of akermanitic clinkers, which proved to provide CO2-lean construction materials with high compressive strength starting from slags and HCl-leach residues, is a scientific breakthrough. This is the subject of 2 patent applications and 2 journal publications. More elaborate TRL4 experimentation is ongoing and TRL5 prototype development has been started. At this point, no major bottlenecks have been identified in obtaining the results to be expected as described in the GA. Uptake of results is guaranteed as major industrial players drive the consortium. The strategy for exploitation has been described in the draft communication, dissemination & exploitation plan.