Impact Minerals (ASX: IPT) is considering the integration of membrane technology into the flowsheet of the Lake Hope project in Western Australia to accelerate the commercialisation of its patented low-cost, low-carbon process for producing high purity alumina (HPA).
The company has been exploring the option under a $2.87 million Cooperative Research Centres Projects (CRC-P) programme in partnership with CPC Engineering and the Mineral Recovery Research Centre (MRRC) at Perth's Edith Cowan University (ECU).
The MRRC has advanced capabilities in the application of membrane technologies, which are widely-used in the water treatment industry and are now being introduced to mining and critical mineral applications.
Membrane platforms
Impact plans to integrate the technology into Lake Hope’s flowsheet to reduce the project’s water footprint and environmental impact; enhance the recovery of high-value by-products including sulphate of potash (SOP) and magnesium potash; and promote the production of HPA precursor ACH (aluminium chloride hexahydrate).
Membrane platforms will include established micro-, ultra-, and nano-filtration and reverse osmosis, alongside emerging distillation and crystallisation systems and more specialised ion- and compound-selective options.
CAPEX and OPEX savings
Impact believes that membrane technology could lead to significant capital and operating expenditure savings in the proposed production of 10,000 tonnes per annum of HPA at Lake Hope, as outlined in the project’s pre-feasibility study.
The study demonstrated strong economic prospects for the project including one of the world’s lowest operating costs per tonne of HPA.
The introduction of membranes to the flowsheet may also facilitate modular HPA production, which could be a key factor in expediting entry into the HPA marketplace.
Boosting Lake Hope’s value
Impact managing director Dr Mike Jones said solid technical progress in the first year of the CRC-P work had significantly boosted the value of Lake Hope.
“Our teams at ECU and CPC Engineering are demonstrating clear pathways to lowering operating costs, enhancing water efficiency and producing high-value fertiliser by-products such as high-purity SOP and magnesium potash,” he said.
“These outcomes, based around elegant membrane technologies, strongly support the benefits of our patented process for producing low-carbon, low-waste HPA and highlight the potential to fully realise the commercial opportunities at Lake Hope.”
Potash production flowsheet
Impact has identified the potential for a separate metallurgical flowsheet (minus evaporation ponds) for the direct production of potash from the clays at Lake Hope and surrounding lakes.
A valuable acid by-product would also be generated using the work already completed under the CRC-P for potash crystallisation.
Initial economic assessment suggests that the process could present an opportunity to develop a large-scale mining project alongside the HPA operation, producing key commodities in high demand by the agricultural and chemical sectors.
Results from preliminary test work on the new process are due next month and are expected to provide a better understanding of the potential for potash and acid production.
