【摘要】 随着高科技产业对镓需求的增加，铝土矿中镓的高效提取成为研究热点。因其低熔点、高沸点和优异的导电性能，镓广泛应用于半导体、航空航天和医药领域。镓在铝土矿中主要以类质同象或离子吸附形式存在，与铝或铁等金属元素共存。由于镓与铝的化学性质相似（如+3价氧化态和两性行为），镓常嵌入铝矿物的晶格中，增加了其回收的难度。沉淀法尽管成本低，但因步骤复杂且回收效果较差而限制了应用；电化学方法虽不改变溶液组成，但电解效率低且汞含量高；溶剂萃取法操作简便，却受限于镓浓度低导致的分离难度；相比之下，离子交换法因其操作简便、回收效率高、污染小等优势，已成为从拜耳法生产液中回收镓的主流技术。随着对镓需求的持续增长，提高回收效率与减少环境污染已成为工艺优化的核心目标。本文综述了铝土矿中镓的赋存状态及其对提取工艺的影响，重点讨论了沉淀法、电化学法、萃取法及离子交换法的原理和特点，并展望了未来的发展方向，为相关产业的可持续发展提供了参考。更多还原

【Abstract】 Gallium,a critical rare metal,has become increasingly significant due to its wide range of applications in advanced technologies,particularly in semiconductors,solar cells,and light emitting diode （LED） technologies.Its unique properties,such as low melting point,high electrical conductivity,and excellent alloying capabilities,make it indispensable for various electronic and optoelectronic devices.Despite the growing demand for gallium in emerging technologies,its natural abundance is relatively low,primarily in trace amounts within bauxite,a key material used in the aluminum industry.This presents a considerable challenge,as gallium extraction from bauxite remains complex,inefficient,and costly.This paper reviewed gallium′s occurrence in bauxite and the challenges in its extraction methods,emphasizing recent advancements.Gallium was found in various forms within bauxite,including ionexchangeable gallium,lattice-substituted gallium,and surface-adsorbed gallium,and each of these forms presented distinct challenges for extraction.For example,ion-exchangeable gallium,which was loosely bound,couldbe readily extracted through solvent extraction,while lattice-substituted gallium,which was incorporated into the crystal structure of the mineral,required high-temperature treatments or the use of specialized solvents to disrupt the mineral lattice.Surface-adsorbed gallium,which was weakly bound to the surface of bauxite particles,could be recovered through adsorption techniques.For instance,solvent extraction was effective for ion-exchangeable gallium,whereas lattice-bound gallium required high-temperature treatments or specialized solvents to disrupt the mineral structure.Understanding these forms and their interactions was crucial for enhancing extraction efficiency.The predominant method for extracting gallium from bauxite was Bayer process,which was originally developed for aluminum recovery.In this process,bauxite was treated with a sodium hydroxide solution to form a sodium aluminate solution,dissolving aluminum while leaving behind most impurities,including gallium.The challenge was selectively separating gallium from the sodium aluminate solution,due to its low concentrations （0.1%～0.3%）.In this process,bauxite was treated with sodium hydroxide,forming a sodium aluminate solution that dissolves trace amounts of gallium,which must then be selectively separated.Currently,approximately 90%of gallium production relied on this method,utilizing techniques such as precipitation,electrochemical processes,solvent extraction,and ion-exchange adsorption.Precipitation and electrochemical methods were the most established for gallium recovery.Precipitation techniques,including lime milk-electrolysis and carbonationelectrolysis,involved adding lime milk or carbon dioxide （CO₂） to precipitate gallium from solution.Electrochemical methods,which applied an electric current to enhance separation,were also widely used,both face significant challenges,such as low efficiency at the trace gallium concentrations in Bayer process liquor.Additionally,high energy consumption in electrochemical processes and CO₂emissions from carbonation-electrolysis limited their industrial scalability.Solvent extraction,utilizing organic solvents such as carboxylic and phosphonic acids,had been developed to recover gallium from bauxite-derived liquor due to its high affinity for the metal.Synergistic reagents further enhanced selectivity and efficiency,enabling effective separation of gallium from other metal ions.However,challenges remained,including high reagent costs,environmental concerns related to solvent disposal,and difficulties in scaling for industrial applications due to complex chemistry.Ion-exchange adsorption,particularly using chelating resins,had emerged as a promising technique for gallium recovery.This method selectively adsorbed gallium ions onto a resin,which could then be eluted for recovery.Compared to other techniques,ion-exchange offered higher selectivity,sustainability,and compatibility with Bayer process,achieving high recovery rates with minimal environmental impact.Its simplicity,resin renderability,and seamless integration into Bayer cycle made it an attractive option for large-scale applications.Despite the potential advantages of existing recovery methods,significant challenges persisted,including lowgallium concentrations in bauxite-derived liquor,complex interactions with other metal ions,and the high costs and environmental impacts of certain techniques.Recent advancements in materials science had introduced novel chelating resins and hybrid extraction techniques that combine multiple methods to enhance recovery efficiency.These innovations,alongside improvements in electrochemical processes and solvent extraction,were expected to address the rising demand for gallium in high-tech sectors.Future research should focus on developing advanced materials,hybrid methods,and more sustainable processes to improve gallium recovery and minimize the environmental impact of extraction activities.The continued advancement of these technologies would be critical to securing a stable supply of gallium for emerging industries and meeting global technological needs.更多还原