Science: Ya know the one that gets a big brownie points for...

Science: Ya know the one that gets a big brownie points for research if ya publish in this journal


https://www.nature.com/articles/s43017-022-00387-5

Environmental impact of direct lithium extraction from brines

In this Review, we discuss the environmental impact of lithium mining from continental brines, outline the challenges in the nascent field of lithium mining from geothermal brines and assess the proposed DLE technologies in the framework of an overall mining and processing technology.

The scope of the Review includes an assessment of DLE in terms of input of chemicals, production and fate of spent brines, energy and freshwater requirements and the potential for exploiting the by-products produced. These are factors that need to be considered in a discussion of the potential environmental impact of DLE. We also discuss the potential of DLE for scaling up to industrial levels.

Key points

Fresh water consumption of direct lithium extraction (DLE) needs to be urgently quantified. Many DLE technologies might require larger freshwater volumes than current evaporative practices, compromising their applicability in arid locations.

Chemical processing is not completed until a pure solid product is obtained. Energy consumption of DLE should be estimated for the overall process, including potential water extraction or evaporation from pure but dilute LiCl solutions, as is the case with many DLE technologies.

Lithium ions are only a minor component in continental, geothermal and oilfield brines. Thus, from a circular economy perspective, there is potential for extraction of more than one valuable mineral, notably, borates, magnesium, potassium and sodium salts.

Knowledge of the precise number, distribution and depths of brine and fresh water wells is vital for hydrogeological modelling of lithium brine deposits. The distinct hydrogeology of each salar means that each deposit should be modelled independently, and results from one exploitation cannot be directly extrapolated to another.

Environmental monitoring should be permanent and precede the start of the exploitation as environmental impacts might only be observable in the long term. Water monitoring requires gathering precipitation data, river flows and a sufficient number of observation wells to follow water tables at different locations.

Environmental monitoring guidelines have been drafted with evaporitic technology in mind, but they should also be applied to the implementation of any DLE technology, which still consumes brine, uses fresh water and produces residues, the latter two hopefully at considerably lower volumes.