Thursday, 10 December 2020

Cutting edge lithium technology for Cornwall

There is a lot going on at Cornish Lithium Ltd. In September I reported that the company had found “globally significant” lithium grades in geothermal waters and is preparing to extract lithium in a zero-carbon operation.  These geothermal waters are rapidly becoming recognised as the ultimate ethical source of lithium, as Direct Lithium Extraction (DLE) technology will be used to extract dissolved lithium compounds from the water using ionic adsorbents and/or ion exchange membranes, with the residual water being returned to depth via a borehole. Using DLE technology Cornish Lithium aims to maximise product recovery from the geothermal waters in a small footprint, energy efficient extraction plant, which will be powered by an on-site geothermal power plant. Lithium will be extracted from the water from the geothermal power plant's 5.2km deep borehole and the water will then be reinjected into the rock.

Cornish Lithium announced this week that, following its maiden hard rock lithium drilling programme earlier this year it is to accelerate this project within an existing china clay pit near St Austell in east Cornwall, following the successful production of nominal battery-grade lithium hydroxide, achieved using Australian Stock-Exchange listed Lepidico Ltd's technologies on lithium mica samples. 

Cornish Lithium said it had acquired a technology licence from Lepidico, which provided it with a metallurgical processing solution for the Trelavour Downs project. The company will now proceed towards bulk metallurgical testing and the construction of a pilot plant using Lepidico’s proprietary L-Max® and LOH-Max technologies. Work so far has indicated the potential of this technology to produce battery-grade lithium in Cornwall without the need for further refining, thus offering a complete on-site solution.

The Lepidico pilot plant in action July 2019
Source: Lepidico Ltd

Unlike other hard rock lithium extraction processes, the L-Max® process does not require costly pyrometallurgical processing routes in order to extract and recover the valuable lithium. The hydrometallurgical L-Max® process involves direct atmospheric leaching of lithium mica and impurity removal stages with subsequent lithium carbonate precipitation. It differs considerably from the processing of spodumene, which requires high temperature decrepitation and sulphate roasting prior to lithium recovery. This novel process is simpler, and is expected to have lower energy requirements than existing lithium recovery processes. 

LOH-Max produces lithium hydroxide, which currently attracts a premium price compared with lithium carbonate and is in strong demand

The licence to these technologies would allow development of the low-carbon extraction of lithium from zinnwaldite and polylithionite mica ores in the St Austell region. The Company believes that this work will accelerate domestic production of battery quality lithium chemicals for the UK automotive and battery industry as well as generating a significant number of skilled jobs in the St Austell area of Cornwall.

“The next phase of work, which will shortly commence at Trelavour, will run in parallel with studies which continue to advance the company’s lithium in geothermal waters projects across Cornwall. In particular, the forthcoming construction of the lithium pilot plant at United Downs, will enable the company to trial direct lithium extraction technology at the United Downs Deep Geothermal Project together with partners Geothermal Engineering,” commented founder and CEO Jeremy Wrathall

@barrywills

5 comments:

  1. This is a positive step towards protecting “Mother Earth” and Brines may be future targets for Lithium and this technology is great step towards extracting Lithium for use in modern Science and Technology.
    Thanks Prof Barry for posting .

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  2. This one and your earlier Blog are very informative and it reiterates that "recovery of certain element" require multidisciplinary approach.
    Next major breakthrough required is how to extract these elements when they are at ppm levels in some other parent rock with major mineral being recovered by pyrometallurgical route-- where do these elements end up-- in the metal itself or in the slag? Hope geochemists, geologists. processing people make strong linkages with metallurgists to ensure recoveries of these elements.
    Now one question I have is, if it is from "geothermal waters" which one is the parent rock? Nature must have done a lot of work to bring this lithium from some source into a solution form.
    NATURE IS GREAT--done so much to create minerals and we are finding it very challenging to recover--more of philosophical note--

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  3. For many years during my employment in the Minerals Engineering Dept at Leeds University we often ran Final Year BEng design projects to recover lithium from samples of china clay residues kindly provided by ECC. These studies involved test work on various approaches including flotation and acid or alkaline leaching. The usual conclusions were that recovery by hydrometallurgy was technically feasible but that the world demand for lithium chemicals was such that for a plant to be large enough to perhaps be economic the scale production would depress the price of Li to a level that would then make it unprofitable. This was before the advent of lithium batteries and the need for electric vehicles.

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    Replies
    1. The lightest metal in the periodic table- the limit of my knowledge of lithium when I was at CSM

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