• Impurity removal is a key step in rare earths processing, and the tests showed minimal formation of problematic by-products
• Magnesium oxide (MgO) was selected as the optimal neutralizing reagent, enabling effective removal of iron, silica, thorium, and other deleterious elements
• The results de-risk a material technical and economic hurdle in processing allanite-based rare earths

American Rare Earths (ASX: ARR) has successfully completed a critical stage in its mineral processing program, the first phase of impurity removal testing, with highly encouraging results. This milestone confirms that key contaminants like iron, aluminum, silica and others can be effectively removed from Halleck Creek ore, paving the way for efficient rare earths extraction. Importantly, the tests showed minimal formation of problematic by-products like gypsum and silica gel, a common challenge in processing allanite-based rare earths elements. Six potential neutralizing agents were tested, and magnesium oxide (MgO) was selected as the optimal reagent, enabling effective removal of iron, silica, thorium, and other deleterious elements while minimizing rare earth element losses. The primary neutralization using 15% MgO removed over 99% of iron, silica, thorium, and titanium, with an average rare earth element loss of less than 1%. The secondary neutralization further removed over 99% of the remaining iron, aluminum, silica, thorium, and titanium. These results de-risk what has historically been a material technical and economic hurdle in the processing of allanite-based rare earths elements and represent a major milestone in unlocking Halleck Creek's vast rare earth supply potential.

The company expects to complete the remaining hydrometallurgical testing, including the creation of a mixed rare earth oxide, before the end of the year. In parallel, bulk samples are being tested for comminution optimization, with the results to be reported to the market once complete.