Anson purifies Green River lithium to near-perfection as polishing process proves its worth

Anson Resources (ASX: ASN) is edging closer to battery-grade lithium production from its Green River project in Utah, with its polishing process delivering exceptional results in removing impurities from lithium chloride eluate.

The company announced it has successfully completed the “polishing” stage of its direct lithium extraction flowsheet. This critical downstream step removes residual contaminants from the lithium-rich solution produced by Koch Technology Services’ pilot plant.

According to Anson, the polishing process achieved rejection rates of up to 100 percent for contaminants including barium, magnesium, copper and zinc. Calcium and boron were reduced by more than 95 percent. These unwanted elements, if left untreated, could compromise the purity of the final lithium carbonate product. Their removal at this stage improves both the efficiency and economics of the subsequent refining process.

The polishing flowsheet, developed and tested at Anson’s Lithium Innovation Center in the US, uses a combination of nanofiltration, reverse osmosis and ion exchange systems. The system is now in continuous operation, processing 43,000 gallons of eluate produced by the direct lithium extraction (DLE) unit.

Anson’s executive chairman and CEO Bruce Richardson said the company was on track to deliver a high-purity product.

“We have now proven that our polishing circuit can deliver exceptionally clean lithium chloride, ready for final processing. This is a critical milestone for our Green River development and a strong indicator of our ability to produce battery-grade material,” he said.

The eluate is now undergoing final concentration and will proceed to evaporation and carbonation steps. These final stages will precipitate out any remaining impurities and crystallise lithium carbonate suitable for electric vehicle batteries.

Green River sits alongside Anson’s flagship Paradox project in Utah, and the company has ambitions to turn both into commercial lithium operations. The Green River project has access to significant brine volumes, which the company believes could support a long-life production hub in the western US.

The success of the polishing process adds to Anson’s credibility as it aims to move into the ranks of lithium producers. The company is leveraging its US-based team and infrastructure to refine its processing technology, which is increasingly viewed as a key differentiator in a crowded lithium space.

While production timelines have not been detailed in this announcement, the results from polishing give investors a glimpse into the company’s technical progress. High rejection rates for impurities and reliable processing at scale are vital hurdles on the path to commercial supply.

If Anson can maintain this trajectory through to full-scale lithium carbonate production, Green River could emerge as an important domestic source of battery materials in the United States. With geopolitical attention focused on securing critical minerals supply chains, the company is positioning itself at the right time and place.