研究采用双氧水催化二氧化硫还原六价硒获得单质硒的新方法.通过对催化还原过程中的溶液电位、离子浓度、产物形貌及晶型变化规律的研究,揭示催化还原过程中硒单质晶型转变机理.结果表明:在反应温度小于60℃时硒还原率可达到98%以上,六价硒还原产物为无晶型红硒单质;反应温度高于60℃时还原产物为斜方晶型的黑硒单质,其还原反应历程为SeO42-还原产生红硒,红硒进一步被二氧化硫过还原为Se2-离子,Se2-离子与还原中间产物SeO32-发生归中反应最终生成斜方晶型的黑硒单质.%In the present paper, the hydrogen peroxide catalytic reduction of selenate by sulfur dioxide was reported for the first time, by which the reduction rates of selenate reached 99.8%, proving a new way to recycle Se6+. A series of experiments were carried out by monitoring the change of solution potential, selenium concentration, the change of morphology and crystal. In addition, intermittent sampling during the reaction process was carried out to analyze the morphology transformation mechanism of catalytic reduction process. It was found that selenate could be directly catalytic reduced into red selenium below 60 ℃. The trigonal crystal selenium was formed by reaction between Se2- and Se4+ when reaction temperature was above 60 ℃, where the Se2- was produced by further reduction of red selenium.
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