The U.S. Offer a Green Method of Producing Lithium from Brine

Dec 5th, 2017

A group of scientists from Oak Ridge National Laboratory (ORNL) as a part of the US Department of Energy has created a sorbent to enhance selectivity for lithium. Lithium is the lightest metal highly demanded by the growing industries of electric vehicles, cell phones and other products that use lithium-ion batteries. Experts doubt if the supply of lithium can meet the increasing demand.

A new sorbent can be used for lithium extraction from brines that are released by geothermal power stations in abundant amounts.  The use of an improved sorbent is an eco-friendly way to get lithium from brine.

Geothermal power stations like that near the Salton Sea, California pump water for electricity generation from geothermic deposits. A by-product of this process is a salty solution which contains huge amounts of lithium ppm.

The testing showed that the improved sorbent had trapped over 90% of lithium from the brine solution which also contained boron, calcium, potassium, manganese and sodium.  To release lithium from sorbent the scientists used a dilute solution of lithium chloride. On an industrial scale, the process of lithium capturing from wasted brine takes two hours.  By contrast, it takes a year to harvest lithium from evaporation ponds.  The extraction of lithium from spodumene also consumes much time and effort as spodumene has to be mined, heated and treated with acid. Therefore, the sorbents are a good alternative for producing lithium from brines.

The selectivity of this method is hundred times higher for lithium, potassium and sodium. The sorbents containing hydrogen titanates (H4O4Ti) and delithiated manganese oxides (Li2MnO3) can absorb more lithium parts. However, the extraction of lithium from these sorbents requires acid treatment which is not friendly to the environment.

To produce impurity-free lithium chloride on a commercial scale, the U.S. plans to build an extraction plant near the Salton Sea where a new sorbent will be used. Here lithium chloride can be turned into lithium carbonate for batteries production. The expected annual capacity of the plant is 15,000 tons of lithium carbonate.