Lepidico’s L-Max technology maximises mica’s lithium potential

Lepidico is making waves in the lithium industry with its L-Max technology, which can extract valuable battery-grade lithium chemicals from previously ignored mica sources.

Publicly-listed, Perth-based company Lepidico has been turning heads in the lithium industry since it unveiled its proprietary L-Max lithium extraction system in 2016. L-Max allows for the extraction of valuable lithium chemical from mica and phosphate mineral concentrates, a process that was until recently considered too complicated or costly to pursue at a commercial scale. 

The project grew from the efforts of a team of metallurgists from Strategic Metallurgy, which began working on the process around 2014. They eventually developed a method whereby the concentrate is saturated with sulphuric acid, which leaches the elements of interest into a solution prior to a series of impurity removal precipitated steps at different pH ranges, generating lithium chemicals and a fleet of by-products, including valuable sources of sodium silicate and sulphate of potash.

This method is more ecologically sound than other tailings-heavy processes, leaving behind a residue of benign white powder that is comprised of around 50 per cent gypsum. It also maxes out at about 100 degrees Celsius and is conducted at atmospheric pressure, making for a low-energy intensive extraction process.

Managing director Joe Walsh and his team at Lepidico have within the last couple of years identified the city of Sudbury, Ontario as a prime location for the development of the company’s first L-Max chemical plant, in part due to its proximity to two large nickel smelters that can provide sufficient quantities of sulphuric acid for commercial-scale L-Max extraction. 

Speaking from Toronto, Walsh explains why lithium-rich micas have until recently been neglected by the industry at large.

“Until about five years ago or so, the lithium price was $5000-6000/t and annual lithium demand growth was in the single digits, allowing the existing lithium chemical producers to satisfy market requirements,” he tells Australian Mining.

“There wasn’t a need for any significant new supply, so while lithium micas were known about, they were of largely academic interest. 

“The lithium chemical market now has strong double digit demand growth annually, with an incentive price well over $10,000/t for lithium carbonate; new sources of lithium are now being sought including the lithium micas which while not mainstream are no longer being overlooked.”

Lepidico is coming into the lithium market at a buoyant time, encouraged by rising electric vehicle (EV) demand, which has seen government incentives across the world to expedite adoption; for example, Norway and the Netherlands have pledged to ban sales of new petrol and diesel cars by 2020 and the United Kingdom and France have pledged the same by 2040 (2032 in Scotland). 

China is also aggressively pursuing a petrol-free future, having set targets of at least 10 per cent of new car sales being zero-emission cars by 2019, and 12 per cent by 2020.

And there has also been interest from academia too. Since heading to Canada, Lepidico has entered into talks with Sudbury-based Laurentian University to evaluate whether or not the residue left over from the L-Max production process can be converted into valuable materials for landfill encapsulation via biomass mixing. 

“If we are successful with this body of work, we’ll have a perfect chemical process in the sense that the feed and reagents combine to produce a suite of valuable products with zero waste,” says Walsh. “We will end up with a process that has no waste products and whose only emission is steam.”

In addition to the L-Max process for which it is most known, Lepidico recently announced a new, patented hydrometallurgical process dubbed S-Max that can serve as a second process technology arm for the company. 

S-Max allows for the production of marketable amorphous silica — a key material in areas such as chromatography (chemical separation) and microelectronics — sourced from the leach residue of the aforementioned sulphuric acid leach. The process has been in development in collaboration between the company and Strategic Metallurgy P/L for over a year.

“Compared to existing processes, S-Max should be an extremely low-cost way of producing amorphous silica when combined with L-Max process,” says Walsh. “It’s effectively a second process limb to L-Max; the two start off with a similar feed, but then downstream from that, S-Max allows for further refinement in the production process on the initial L-Max reside stream.”

Lepidico’s planned phase one plant in Sudbury is the subject of a feasibility study that is evaluating a concentrate processing capacity of 30,000 tonnes a year (t/y) — producing 2500–3000t/y of nominal battery-grade lithium carbonate equivalent (LCE) — with an overall capital expenditure in the region of $US40–45 million ($53–60 million). 

The company hopes to achieve operational status by 2020, and by the early 2020s upgrade to a full-scale plant capable of over 20,000t/y LCE, nearly 10 per cent of the current lithium market. Lepidico is entering at an exciting time, embracing the next step on the ladder to becoming a low-cost lithium producer of international renown.  

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