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Potential Reduction of Environmental Liabilities
There are many potential environmental benefits envisaged from a successful integration of the ExtrEL process in an operating pilot (EPP) or extraction plant. Some of these benefits are listed below:
- Low energy requirements, especially when compared with smelter, expensive mill crushing and flotation system inputs, and rail/road/sea shipment of ore to a central mill site;
- Recovery of H2S(g) with conversion to elemental sulphur (S) or sulphuric acid (H2SO4 ), all potentially marketable materials. The technologies are available from the oil and gas industries for integration into an EPP;
- Conversion of FeCl3 in hydrochloric acid matrix to a high purity hematite, a saleable product, through pyrohydrolysis;
- Possibility of co-extraction of occluded PGE's as Cl- complexes if in waste stream initially. Discussions with former industry chemists indicates, for example, that rhodium may be also more highly concentrated in the pyrrhotite tailings than in the modern smelter feeds in the Sudbury Basin;
- Use of current industry wastes as feedstock for the ExtrEL extraction process which, if metal recovery efficiency is improved to over 90%, could produce a benign secondary tailings or paste backfill material. Such 'clean' tailings materials are currently being 'remined' from surface deposits for use as backfill of underground stopes;
- Could produce a clean road or construction material feedstock, or potentially a siliceous sand for use in the glass industry;
- Small plant footprint, possibly of modular construction in easily transportable segments;
- Modular plant could be developed to run on remote mill sites, or abandoned pyrrhotite-rich TMA's, using renewable energy resources such as Wind-Power for operations, with expensive green-house gas emitting diesel generation systems as plant back-up only. There would thus be no need for expensive connection to the regional grid, and even a potential to sell any surplus energy to local remote community. This could create a unique synergy for the mining industry;
- Potential low water requirement for process, with high probability of in-plant recycling and reuse; and
- Recovery of significant quantities of process acids (HCl in the current development stage of ExtrEL) in the ion exchange module of the EPP. This is also a major cost-saving advantage of the ExtrEL process integration into an operational EPP.
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