有色金属(选矿部分)

锂、铷、铯是重要的战略性关键金属，在新能源、航空航天等前沿领域具有不可替代的作用。锂云母作为主要的锂资源原料，同时富集高价值的铷、铯资源。现有锂云母硫酸盐焙烧工艺存在能耗高、渣量大及铷铯回收率低等问题，因此，开发锂、铷、铯经济高效的提取工艺已成为研究热点。本文以锂云母为原料，提出了复盐焙烧—水浸提取法对矿物中的锂、铷、铯多金属进行综合提取，并探究了其反应机制。系统考察了添加剂类型、配比、温度、时间等对锂铷铯浸出行为的影响，结合热力学计算、X射线衍射和扫描电镜分析等研究了锂云母提取过程中的反应机理。研究结果表明，当锂云母与CaCl₂、Na_2SO₄、CaO质量比为1∶0.4∶0.05∶0.05，在925℃下焙烧1 h后，于液固比为3∶1条件下水浸2 h，锂、铷、铯浸出率分别为92.05%、92.43%和99.81%。热力学分析表明，在研究温度范围内，CaCl₂与铷铯反应的吉布斯自由能变为-350～-480 kJ/mol且远低于其他反应，Na_2SO₄与锂反应的?G在SiO₂/Al_2O₃存在后由131 kJ/mol降至-255 kJ/mol。X射线衍射和扫描电镜分析表明，复盐焙烧破坏了锂云母的层状结构，促进了置换反应生成可溶性盐，同时形成钙铝硅酸盐等稳定新相。通过CaCl₂提铷铯、Na_2SO₄催化提锂与CaO固氟促分解的协同机制，显著提升了锂、铷、铯的浸出效率，实现了有价金属的综合回收，为锂云母资源绿色高效综合利用及共伴生稀有金属的高效提取提供了重要的理论依据和技术路径。

Lithium,rubidium and cesium are strategically critical metals with irreplaceable roles in cuttingedge fields such as new energy and aerospace. As a primary source of lithium,lepidolite is also enriched with highvalue rubidium and cesium resources. However,the conventional sulfate roasting process for lepidolite suffers from high energy consumption,large slag volumes,and low leaching rates of rubidium and cesium. Therefore,developing an economically efficient extraction process for lithium,rubidium and cesium has become a research focus. This study proposed a composite salt roasting-water leaching method for the comprehensive extraction of lithium,rubidium and cesium from lepidolite and investigated the underlying reaction mechanisms. The effects of additive type,ratio,temperature,and time on the leaching behavior of lithium,rubidium and cesium were systematically examined. The reaction mechanisms during the extraction process were studied by using thermodynamic calculations,X-ray diffraction(XRD),and scanning electron microscopy(SEM). The results indicated that when lepidolite was roasted with CaCl₂,Na₂ SO₄ and CaO at a mass ratio of 1∶0. 4∶0. 05∶0. 05 at 925 ℃ for 1 hour,followed by water leaching at a liquid-to-solid ratio of 3∶1 for 2 hours,the leaching rates of lithium,rubidium,and cesium reached 92. 05%,92. 43% and 99. 81%,respectively. Thermodynamic analysis revealed that,within the studied temperature range,the Gibbs free energy change for the reaction between CaCl₂ and rubidium/cesium ranged from-350 kJ/mol to-480 kJ/mol,significantly lower than that of other reactions. The ΔG for the reaction between Na₂ SO₄ and lithium decreased from 131 kJ/mol to-255 kJ/mol in the presence of SiO₂/Al_2O₃. XRD and SEM analyses indicated that roasting with composite salts disrupted the layered structure of lithium mica,promoted displacement reactions to produce soluble salts,and simultaneously formed stable new phases such as calcium aluminum silicate. By leveraging the synergistic mechanisms of CaCl₂ for rubidium and cesium extraction,Na₂ SO₄ for catalyzing lithium extraction,and CaO for fluorine fixation and decomposition promotion,this study significantly enhanced the leaching efficiency of lithium,rubidium and cesium,enabling the comprehensive recovery of valuable metals. The findings provide an important theoretical basis and technical pathway for the green,efficient,and comprehensive utilization of lepidolite resources and the efficient extraction of associated rare metals.