有色金属(冶炼部分)

深海富稀土沉积物作为全球稀土资源战略接替的新载体，在太平洋、印度洋部分深海区域呈现超常富集特性，富含关键中-重稀土元素，且其储量潜力达到陆地资源的千倍级，同时放射性元素(Th/U)含量仅为陆地矿床的1/100～1/10，兼具资源与环境优势。为揭示海底沉积物中稀土赋存状态及选冶性能，对某深海富稀土沉积物进行矿物学表征与选冶试验。结果表明：稀土元素主要赋存于磷灰石中，少部分以微晶态铁锰氧化物(与黏土胶结共生)、独立矿物独居石或离子吸附形式存在；极细嵌布粒度(90%稀土矿物<0.005 mm，磷灰石<0.010 mm粒级占50%)与严重泥化效应导致传统选矿效率低下——磁选几乎无效，浮选磷未能实现富集，可见开发微细粒稀土载体的靶向捕收剂，突破微细粒矿物分选极限是提高稀土富集回收的关键。高浓度无机酸(H_2SO₄/HNO₃/HCl)对钇(Y)浸出率可达87%～93%，铈(Ce)为45%～60%；采用低盐酸-氯盐协同体系可提高Ce/Y浸出率，Cl~–具有促进含铈/钇矿物的溶解作用。未来需深化沉海沉积物中微细粒稀土载体的非常规捕集以及协同浸出-矿物界面反应机制研究，开发原位富集-浸出技术，推动深海稀土资源商业化进程，为我国构建"深海稀土资源大国"地位、破解陆地稀土供给与地缘风险提供核心支撑。

Rare earth elements(REEs), prized for their unique optical, electrical, and magnetic properties, serve as indispensable components not only in traditional sectors like glass manufacturing, metallurgy, ceramics, and petrochemicals but also in cutting-edge material technologies including permanent magnets, hydrogen storage systems, catalysts, and high-temperature superconductors, thus holding profound strategic significance; widely acclaimed as the "Industrial vitamin" and "Industrial seasoning, " they have evolved into critical mineral resources essential for sustaining global economic development and societal progress. Deep-sea REY(rare-earth elements and yttrium)-rich sediments, as a new strategic global alternative to terrestrial rare-earth resources, exhibit extraordinary enrichment in critical medium-to-heavy REY within specific abyssal regions of the Pacific and Indian Oceans, with reserve potential estimated at 1 000 times that of terrestrial deposits and radioactive elements(Th/U) concentrations merely 1/100–1/10 of land-based ores, highlighting dual resource and environmental advantages. Mineralogical characterization and metallurgical experiments reveal that REY predominantly occur in apatite, with minor occurrences in cryptocrystalline Fe-Mn oxides(cemented with clay), discrete monazite grains, or ion-adsorbed forms; ultrafine grain sizes(90% REY minerals<5 μm; apatite<10 μm in 50% of particles) and severe argillization effects render conventional beneficiation inefficient— magnetic separation proves ineffective, and phosphate flotation fails to achieve enrichment— therefore, developing targeted collectors for ultrafine REY carriers and advancing micro-particle separation limits are critical for REY recovery. High-concentration inorganic acids(H₂ SO₄/HNO₃/HCl) achieve leaching rates of up to 87%–93% for yttrium(Y) and 45%–60% for cerium(Ce). The low HClchloride salt synergistic system selectively enhances Ce/Y leaching rates, where Cl~– plays a role in facilitating the dissolution of Ce/Y-bearing minerals. Future research must prioritize unconventional capture mechanisms for ultrafine REY carriers, synergistic leaching-mineral interface reactions, and in-situ enrichment-leaching technologies to accelerate commercial exploitation, thereby consolidating China's position as a "Deep-Sea REY Resource Powerhouse" and mitigating geopolitical risks in terrestrial REY supply chains.