Lepidico Ltd (ASX:LPD) claims new testing has confirmed its trade-marked LOH-Max technology as a new process for the production of high purity lithium hydroxide to meet battery grade specifications.
The company said assay results from the recent pilot plant lithium hydroxide monohydrate batch trials have been received, with a purity of >56.5% LiOH achieved.
Managing Director Joe Walsh said this is consistent with a nominal battery grade reference purity of 56.5% LiOH.
Mr Walsh added that importantly, impurity levels of the deleterious elements for battery grade specifications were below required levels and often below detection limits.
He said these results confirm the viability of LOH-Max at pilot plant scale as a new process for the production of high purity lithium hydroxide from a lithium sulphate intermediate, importantly without the production of potentially problematic sodium sulphate as a by-product.
Production of a high purity lithium hydroxide monohydrate with very low levels of deleterious elements is a clear endorsement of the LOH- Max process.
“In addition to being compatible with Lepidico’s L-Max process technology, LOH- Max also represents an alternative final process step in the conventional conversion of spodumene concentrates, without the generation of costly and potentially problematic sodium sulphate. Lepidico is now focused on generating samples of all products from the Phase 1 Project for qualification purposes.”
Stockpiled lithium sulphate liquor from Campaign 1 of the continuous L-Max pilot plant were used as feed to the LOH-Max pilot. The trial was conducted in a series of large-scale batch operations, performed in sequence to match the process flowsheet.
Key recycle streams were introduced back into the LOH-Max process in order to properly account for any build-up of impurities. Given the relatively benign nature of the materials in the process, no exotic materials of construction were required and the major equipment employed was sourced from the existing L- Max pilot plant.
The process involves generation of an initial crude lithium hydroxide followed by refining into a high purity lithium hydroxide monohydrate product. Optimisation testing, conducted in parallel to the LOH-Max pilot identified a number of improvements to the process that have led to modifications to the previous design for the Phase 1 Plant.
Carbon dioxide represents a challenge in the refining and sampling of high purity lithium hydroxide monohydrate due to its affinity to absorb CO2 from the air. A method for sampling high purity LiOH.H2O immediately after production was developed by Strategic Metallurgy and successfully trialled in early January 2020.
Work has now started on refining a larger sample of high purity lithium hydroxide monohydrate, which is planned to be used to start the product qualification process with prospective customers.