Brannerite, UTi₂O₆, is the most common of the refractory uranium minerals and requires leaching under intense conditions to effectively extract the uranium contained within. Brannerite is often found together with apatite in metasomatic uranium deposits. Apatite and other phosphate gangue minerals can inhibit uranium leaching by generating phosphate ions which interfere with the reactions between acidic ferric sulphate and uranium minerals. As part of a detailed fundamental study on the leaching reaction mechanisms for brannerite, tests under a range of selected leach conditions were carried out with the addition of 10 g/L fluorapatite with the goal of identifying conditions where the negative effects of phosphate are reduced. Leaching was carried out for 5 hours with 0.05 mol/L Fe³⁺ as Fe₂(SO₄)₃ with 0.25–1.00 mol/L H₂SO₄ and at temperatures between 25 and 96 °C. A single test was performed with 0.05 mol/L Fe³⁺ as FeCl₃ and 1.00 mol/L HCl. In the sulphate system, the effect of phosphate was weakest at the highest acid concentration (1.00 mol/L H₂SO₄). In the chloride system, phosphate did not suppress uranium extraction, suggesting that HCl leaching could be a viable alternative for the leaching of high-phosphate refractory uranium ores.

褐铁矿UTi ₂ O ₆是最难熔的铀矿物质，需要在强烈条件下进行浸出才能有效地提取其中所含的铀。褐铁矿经常与磷灰石一起在交代铀矿床中发现。磷灰石和其他磷酸盐脉石矿物可以通过产生磷酸根离子来抑制铀的浸出，这些离子干扰酸性硫酸铁和铀矿物之间的反应。作为对褐铁矿浸出反应机理的详细基础研究的一部分，在一系列选定的浸出条件下进行了测试，并添加了10 g / L氟磷灰石，目的是确定减少磷酸盐负面影响的条件。在0.05 mol / L的铁中浸出5小时³⁺作为Fe ₂（SO ₄）₃，浓度为0.25–1.00 mol / LH ₂ SO ₄，温度在25至96°C之间。使用0.05 mol / L的Fe ³⁺作为FeCl ₃和1.00 mol / L HCl进行了一次测试。在硫酸盐体系中，在最高酸浓度（1.00 mol / LH ₂ SO ₄）下，磷酸盐的作用最弱。在氯化物系统中，磷酸盐不能抑制铀的萃取，这表明HCl浸出可以替代高磷酸盐难处理铀矿的浸出。