Rare earth elements (REEs) can be extracted from monazite under aggressive decomposition and leaching conditions. Much of the waste rocks are removed prior to the extraction process to minimize the costs and waste generation, which is difficult with coal byproducts. The possibility of extracting REEs from low-grade monazite concentrates under relatively mild conditions has been explored to simulate the extraction of REEs from coal byproducts.

It has been found that monazite can be decomposed in 10 to 50 % NaOH solutions at 80 °C, with the resulting hydrous oxide being subjected to the ammonium sulfate leaching at pH 4. The ς-potential measurements conducted in the presence of the lixiviant suggest that the NH₄⁺ ions displace the hydrated Ln³⁺ ions from the surface of Ln(OH)₃(s) by an ion-exchange mechanism, which may be driven by the large differences in the hydration enthalpies between the charged species involved. This approach may be advantageous over acid leaching, including the regeneration of spent lixiviant, lower chemical consumption, and leaching at higher pH.

稀土元素 (REE) 可以在剧烈分解和浸出条件下从独居石中提取。大部分废石在提取过程之前被去除，以最大限度地减少成本和废物产生，这对于煤炭副产品来说是困难的。已经探索了在相对温和的条件下从低品位独居石精矿中提取 REE 的可能性，以模拟从煤副产品中提取 REE。

已经发现，在 80 °C 下，独居石可以在 10% 到 50% 的 NaOH 溶液中分解，生成的水合氧化物在 pH 值为 4 时经受硫酸铵的浸出。在浸出剂存在下进行的 ς 电位测量表明NH ₄ ⁺离子通过离子交换机制从 Ln(OH) ₃ (s) 表面置换了水合 Ln ³⁺离子，这可能是由所涉及的带电物质之间水合焓的巨大差异驱动的。这种方法可能优于酸浸，包括废浸出剂的再生、较低的化学品消耗和在较高 pH 值下的浸出。