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Lithium recycling still 'too expensive'

By Myles McCormick
Published: Friday, 23 December 2016

Despite recent price increases, the recovery of lithium chemicals from lithium-ion batteries remains uneconomical.

The lithium-ion (Li-ion) battery has been thrust into the limelight in recent years.

Driven most recently by the growing popularity of electric vehicles (EVs), its usage has risen sharply, pushing up demand for its constituent minerals and metals.

This phenomenon is perhaps best illustrated by the rocketing price of lithium, the mineral that lends its name to the battery category, and a market caught off guard by the sudden growth in demand, with supply struggling to keep pace.

On the China spot market the price of lithium rose from $7.7/kg in June 2015 to a peak of $26.8/kg in June 2016. In the rest of the world, meanwhile, contract prices for 2017 have doubled from 2016 levels, according to IM’s market assessments.

Experts now speak of the need for another full project to come online each year for the next few years in order to satisfy the growing demand.

The current supply tightness has led some in industry to ask – why not recycle lithium from Li-ion batteries and reuse it?

The answer is simple. For now at least, the quantities and processes involved make this uneconomical.

Doesn’t pay

The core of the issue is the relatively small proportion of the cost of the battery which lithium makes up.

"The price of lithium would have to go way up before it seriously impacted the cost of the battery," Linda Gaines, transportation system analyst at the Argonne National Laboratory in Illinois, US told IM.

While materials make up the largest part of the cost of the battery and the cathode accounts for the majority of materials cost, the part of this attributable to lithium is relatively small.

The cost of other cathode materials, such as cobalt, is more of a worry to cathode producers than the cost of lithium. For cobalt in particular, cathode makers are seeking alternative raw material options driven partly by its cost, said Gaines.

But this is not the case for lithium.

On top of this, primary production of lithium is not energy intensive, Gaines explained, particularly for lithium production from brines, where solar evaporation is used to extract the mineral from salt flats.

"[The process] is not energy intensive and it’s not expensive. Lithium carbonate is not an expensive material," she said.

As a result, the expense of separating out a small quantity of lithium from recycled batteries, while possible in some situations, is not justified by the value of what can be gained.

"It may not pay to get lithium back," said Gaines.

Pyrometallurgy and hydrometallurgy

There are two methods of recycling Li-ion batteries – pyrometallurgical and hydrometallurgical processing. The former involves putting batteries in a furnace and treating them thermally, while the latter involves treating them chemically to separate the materials.

The only large scale Li-ion recycling facility currently in operation is Umicore’s plant in Hoboken, Belgium, where the company employs both methods to break down batteries.

According to Umicore, it uses a form of pyrometallurgy, employing its own ultra-high temperature (UHT) technology, to separate batteries into three parts – an alloy (containing the valuable metals – cobalt, nickel and copper); a slag fraction, which can be used in the construction industry; and clean air.

The alloy can be further broken down using hydrometallurgy, while the slag element has the potential for lithium recovery.

Full hydrometallurgical processing involves chopping up the battery to recover aluminium and copper foils, as well as a black mass of active materials, before screening out big pieces of metal – the foils that had held the anode and cathode.

At this point, lithium ions dissolve out into a solution and metal oxides and carbon (graphite) are filtered out.

The graphite is usually then burned off in the pyrometallurgical recovery of the metal oxides. It is in theory possible to recover the graphite, if instead the metals were recovered as salts, this is not currently a method employed by any company. And, as IM explained in a recent feature, graphite is not in short supply at present.

Primary lithium batteries

While lithium extraction from Li-ion remains problematic, it is possible to extract it from primary lithium batteries.

One company that does this is Retriev Technologies, which operates a facility in Ohio, US.

Retriev makes use of a proprietary cryogenic process to treat the highly reactive batteries, before crushing them into metal solids and a "lithium-enriched solution". The lithium sulphate in the solution is then converted to lithium carbonate.

Cost makes this process unfeasible for Li-ion, however.

"The filtrate solution from processing primary lithium batteries can be used to create lithium carbonate, but the recyclers don’t generally do this with lithium-ion because it’s just too expensive. There’s less lithium per battery," said Gaines.

The world is becoming more reliant on the mineral to power the growing use of Li-ion technology.

But given that the recent lithium price spike did not justify recycling of Li-ion, unless technology makes the cost of the process significantly lower, the process is unlikely to become large scale in the near future. 



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