【摘要】 为了减轻硫的危害，提高一水硬铝石型脱硫精矿中有价元素的富集效率，研究了CaO添加量、苛性碱浓度、反应温度和时间对氧化铝、硫和镓溶出行为的影响，并揭示了反应热力学和机理。在高温拜耳法溶出过程中，氧化铝和镓协同溶出，黄铁矿以S^2-和SO₄^2-的形式溶出。适量CaO有利于氧化铝和镓的提取，并促进硫以水合硫铝酸钙的形式析出，有效地去除溶液中的硫。但过量的CaO会导致水化石榴石生成，部分Ga³⁺会取代Al³⁺并进入晶格，降低镓的溶出率。在最佳条件下（CaO添加量3%，反应温度260℃，时间60 min，苛性碱浓度260 g/L），氧化铝和镓的溶出率分别达到90.82%和77.58%，溶液中总硫浓度降低到1.32 g/L。本研究基于拜耳法溶出工艺为脱硫精矿中氧化铝和镓的高效溶出提供了理论指导。更多还原

【Abstract】 To mitigate the detrimental effects of sulfur and enhance the enrichment efficiency of valuable elements in desulfurized diasporic bauxite, the effects of CaO dosage, caustic alkali concentration, reaction temperature and time on the digestion behavior of alumina, sulfur and gallium were illustrated, and the digestion thermodynamics and mechanism were also revealed. During the high-temperature Bayer process, alumina and gallium were digested synergistically, while pyrite was digested to S^2- and SO₄^2-. Appropriate CaO dosage promotes the digestion of alumina and gallium, and facilitates the precipitation of sulfur as calcium sulfoaluminate hydrate, effectively removing sulfur from the solution. Excess CaO leads to the formation of hydrogarnet, wherein Ga³⁺ incorporates into the crystal lattice by substituting for Al³⁺, reducing the digestion efficiency of gallium. Under the optimum conditions（CaO dosage of 3%, reaction temperature of 260 ℃, reaction time of 60 min, caustic alkali concentration of 260 g/L）, the corresponding alumina and gallium digestion efficiencies reach 90.82% and 77.58%, respectively, with a significantly reduced sulfur concentration of 1.32 g/L in the solution. This work provides theoretical guidance for the efficient co-extraction of alumina and gallium from high-sulfur bauxite via the Bayer process.更多还原