Core Lithium Limited has produced battery-grade lithium hydroxide monohydrate (LH) from spodumene mineral concentrate from the Finniss Lithium Project in the Northern Territory.
Core Lithium’s Managing Director, Stephen Biggins, said it has been confirmed that battery-grade lithium hydroxide suitable for high-end uses in the lithium battery, renewable energy and electric vehicle industries, can be produced from Core’s lithium concentrate produced from the Finniss Project.
“This successful proof-of-concept test work provides Core, and our customers, the confidence in utilising Finniss lithium concentrates in the global lithium battery supply chain,” Mr Biggins said.
“Together with the recent award of Major Project Status from the Federal Government, this program lays a foundation for Core to explore the potential of adding downstream processing infrastructure to our portfolio, incorporating the strong synergies with the infrastructure at the nearby Middle-Arm Industrial Precinct at Darwin Port and aligning with Australia’s national Modern Manufacturing Strategy and expansion of the Global lithium battery supply chain.”
Core remains focused on completing the Finniss Lithium Project concentrate Definitive Feasibility Study and finalising current live off-take negotiations ahead of reaching a Final Investment Decision in the third quarter of 2021.
Testwork Program
The scoping level test work program demonstrated that the conventional ‘direct’ flowsheet can be applied to the processing of the mineral concentrate sample to produce battery-grade lithium hydroxide monohydrate.
The test work program was completed by the Minerals Business Unit of the Australian Nuclear Science and Technology Organisation (ANSTO). ANSTO is one of Australia’s largest public research organisations and its Minerals personnel have extensive lithium processing experience with hard rock and brine feedstocks, to produce high purity chemical concentrates required for the manufacture of lithium-ion batteries.
The main objective of the test work program was to demonstrate the production of ‘battery grade’ LH using a sample of the Finniss Project spodumene mineral concentrate composited from previous Grants and BP33 gravity concentrate test work (see Core’s ASX announcements on 17/04/19, 10/03/20 and 15/4/20).
Scoping level test work was conducted on the major unit processes of the ‘direct’ conversion approach. The ‘direct’ conversion flowsheet involves decrepitation, sulfation baking/water leaching, purification, Glauber salt crystallisation and lithium hydroxide crystallisations.
The test work program was specifically designed to confirm the suitability of the major unit processes and provide an increased level of confidence in the process modelling.
According to Core, without optimisation of the decrepitation, sulfation baking or water leaching conditions, excellent extraction of lithium (greater than 95 per cent) was achieved in two separate tests on 2 kg samples of blended concentrate.
The company outlined that conventional impurity removal steps, as well as three stages of crystallisation, afforded excellent rejection of the key impurities, potassium, sodium and sulphur as well as minor impurities such as rubidium and caesium.
The most critical factor to the successful extraction of lithium from spodumene mineral concentrates is the decrepitation step and the complete conversion of α- to β-spodumene.
This was achieved for the samples of the initial Finniss spodumene mineral concentrate, with additional mineralogical data, increasing confidence in the processibility of the mineral concentrate.
Following decrepitation to β-spodumene, the major unit processes of a conventional ‘direct’ process flowsheet can be applied to convert the contained lithium to lithium hydroxide monohydrate, which satisfies the commonly referenced Livent battery-grade LH specification.
The knowledge of the process chemistry associated with all the major unit processes, especially each stage of LH crystallisation, gained from this program has allowed the development of a preliminary process model.