Phytomining and hyper-accumulators.
An electric or hybrid car needs a rechargeable battery to power the electric motors of the vehicle. The batteries make use of oxides of lithium nickel manganese & cobalt. The battery of such vehicles makes up a significant portion of
- the cost and
- environmental impact
of an electric vehicle.
Growth in this market has created issues in securing ethical battery supply chains. The future supply of nickel, cobalt and lithium is problematical, presenting challenges both in environmental and geopolitical terms. Much of the battery production is centred on China. Mining of a metal such as Nickel generates significant quantities of carbon dioxide, which contributes to global warming. The demand for Nickel is forecast to double.
An alternative to traditional mining techniques for metallic ores is phyto-mining. This is possible where there is a significant quantity of the metal in the soil, and there is a plant that can take up and accumulate the metal. The absorption and accumulation of metals like Nickel, Cadmium and Copper is perhaps more problematic as they are toxic to many plants. Worldwide some 450 different species can absorb and accumulate ‘toxic’ metals, growing in ‘poisoned’ or toxic soils, such as former mine workings. Some of these plants are hyper-accumulators – noted for their ability to take up a metal to many times the level in the soil.
In Albania, a project is underway to use a plant to ‘mine’ nickel. The plant is a perennial herb with yellow flowers - Odontarrhena decipiens. It is a member of the Brassica / cabbage family and is a hyperaccumulator. It can take up into its stems and leaves about 2% of its dry weight as nickel. The plant is being ‘farmed’ in Albania, where there are nickel-rich soils derived in part from the mineral Olivine. Though olivine contains too little nickel for conventional mining, it has enough for hyper-accumulators to absorb and concentrate it. When the olivine is ground up and spread on the field, it not only replenishes the soil with nickel [that the plants absorb] but it also reacts with carbon dioxide in the atmosphere locking the CO2 away. This project is being developed by ‘Metalplant’ . Whether phytomining using this plant will prove to be a useful way of augmenting Nickel supplies remains to be seen.
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