Namibia Critical Metals issues test results for Lofdal heavy rare earth project
Namibia Critical Metals has made significant strides in optimizing its hydrometallurgical process for the Lofdal 2B-4 heavy rare earth project in Namibia.
Their latest optimization tests, conducted on a 93 kg concentrate sample produced by a flotation pilot plant at SGS Lakefield, have provided critical insights into improving REE extraction efficiency and managing reagent consumption.
Darrin Campbell, President of Namibia Critical Metals, expressed satisfaction with the results, highlighting the pioneering nature of the beneficiation steps due to the unique primary xenotime mineralization at Lofdal. The successful optimization efforts indicate a promising path forward for reducing operational costs and improving REE extraction efficiency.
Results
Tests were performed on flotation concentrate samples with varying iron levels. Results indicated that the sulphation process could effectively manage different iron concentrations in the feed material. Confirmatory tests at high temperature sulphation using flotation pilot plant concentrate demonstrated improved REE dissolution coupled with reduced iron dissolution, reinforcing the potential for further OPEX reductions.
A finding of low temperature sulphation (~300°C) resulted in higher REE dissolution but also caused increased iron dissolution. The high iron dissolution necessitates substantial reagent use to remove iron from the leach solution.
On the other hand high temperature sulphation (~600°C) condition significantly reduced iron dissolution from approximately 60% to 30%. This reduction in iron dissolution correlates with a decrease in magnesium carbonate (MgCO3) consumption required for iron precipitation in the impurity removal process.
The ongoing test-work program will inform the scale-up of acid sulphation and water leach unit operations planned for Q2 2024. Following this, further optimization of downstream REE recovery steps will be undertaken to produce a mixed rare earth oxide product. These advancements are crucial as Namibia Critical Metals prepares for the next phase of its Lofdal 2B-4 project, ensuring a robust and cost-effective production process for heavy rare earth elements.
