Jervois Mining says it plans to integrate a pressure oxidation leach (POX) circuit into the São Miguel Paulista nickel-cobalt refinery in Brazil.
Jervois paid the first tranche towards its acquisition of SMP refinery in December after announcing plans to acquire the refinery in September 2020. The acquisition aims to complement its 100%-owned Idaho Cobalt Operations (ICO) in the US, transforming Jervois into a vertically integrated producer capable of refining cobalt and nickel.
The company appointed Australia-based Elemental Engineering to commence sysCAD modelling of the SMP refinery flowsheet for optimisation of product integration, including hydroxides and carbonate products, oxides and sulphide concentrates as part of a feasibility study (FS) for SMP’s restart.
As a result of Elemental’s work, Jervois has determined it shall integrate a POX leach circuit at the refinery.
“The inclusion of the POX autoclave offers a number of advantages compared to roasting concentrates, namely high metal recovery, low overall operating costs, enhanced ESG metrics due to lower emissions and energy usage, improved refined product purity and compact installation footprint on site,” the company said. “Preliminary POX sighter testwork at SGS Perth Western Australia, in conjunction with Elemental’s work, returned satisfactory results.”
While POX comes with a higher capital expense than roasting alternatives, it is a commercially demonstrated technology with low technical risk, allowing Jervois to leverage its recently appointed commercial team, Jervois said. A POX autoclave better compliments the refinery flowsheet, unlocks sunk capital by debottlenecking the existing leach capacity and adds significant flexibility to future refinery feed options, it added.
Jervois will process sulphide concentrate produced from ICO via this integrated POX leach circuit, with Jervois’ commercial team actively pursuing supply contracts for nickel and cobalt intermediate products. The introduction of a POX autoclave opens up greater capacity to leach other hydroxide and carbonate feed products to maximise existing refinery capacity, the company said.
Third-party concentrates can also be potentially introduced into the POX to process with Jervois’s ICO concentrates. Early discussions with potential third-party suppliers of sulphide-based concentrates have been positive, with the company now openly engaging with suppliers to optimise the sizing and economics of front-end pre-treatment.
As part of this, a decision has been made to reserve the maximum amount of copper capacity at SMP refinery for third parties. A consequence is that ICO construction is being advanced on the basis of the production of separated cobalt and copper concentrates. Jervois’s engineering advisers, DRA Global and M3 Engineering, completed the ICO BFS on both bulk and separated concentrate flowsheets, with construction plans being implemented based on the production of cobalt concentrate (containing gold and low in copper) and a copper concentrate. Commercial terms were obtained for both separated products as part of the BFS.
Jervois says it and Companhia Brasileira de Alumínio (CBA), the current owner of the SMP refinery, continue to work expeditiously towards closing Jervois’ acquisition of SMP.
Jervois plans a measured and staged approach to the refinery facility restart. Initial refurbishment works will be completed to progress the processing of intermediate hydroxide and carbonate products followed by the integration of the POX leach circuit to align with ICO commissioning, it said.
Jervois is in discussions with suitably qualified engineering contractors that have the appropriate nickel and cobalt refining experience, have a significant presence in Brazil, and have recently completed a POX and metals plant installation, to award the BFS for the refinery restart. This formal tender process is underway.