Development of a Large Scale Silica Leach Pilot Plant For Lithium Production

Andrew Skalski

Lithium Australia NL

Lithium Australia NL (ASX:LIT) has been actively looking to exploit the lithium bearing micas (phyllosilicates), spodumene (pyroxene / chain silicates) and clays (hectorites) contained within its deposit portfolio, and as part of strategic joint ventures and agreements. These deposits and interests are located across the globe in Australia, Germany, Mexico and Canada.
Since 2015, LIT has worked with ANSTO Minerals Group (ANSTO) and CPC Project Design (CPC) to develop the SiLeach® process for extraction of lithium from mica ores and mineral concentrates, as well as spodumene mineral concentrates. The associated laboratory and small-scale pilot plant development of the SiLeach process by LIT and ANSTO has been described in a previous paper. There is a comprehensive understanding of the SiLeach technology and the associated purification circuits, recycle streams and by-product production circuits. Moreover, the potential lithium-loss mechanisms and impurity deportment are also well understood.
In 2017 LIT engaged CPC to provide engineering and process development support for a Large Scale Pilot Plant (LSPP) to a level of accuracy that would support an investment decision. Further process development and improvement of the flowsheet occurred and culminated in a design for a fully integrated facility processing 3.7t/h of lithium mica concentrate and producing up to 2,500t/y of lithium carbonate equivalent.
To continue development of the SiLeach process, LIT plans to complete extended continuous pilot plant testing in the LSPP. This facility will demonstrate on a steady state continuous basis the SiLeach process with full internal recycles, allowing confirmation of the overall lithium recoveries, impurity management, reagent consumptions and lithium chemical and by-product quality. Ultimately the LSPP will allow LIT to readily apply the SiLeach technology to a full scale commercial development.
This paper provides an overview of the development of the SiLeach LSPP, including key aspects of the engineering design and techno-economic analyses completed to date. Assessment of the pilot plant scale performance and some equipment selection for the LSPP is also discussed, providing a summary of the development pathway that has been taken.

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