(中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083)
摘 要: 研究采用雙氧水催化二氧化硫還原六價硒獲得單質(zhì)硒的新方法。通過對催化還原過程中的溶液電位、離子濃度、產(chǎn)物形貌及晶型變化規(guī)律的研究，揭示催化還原過程中硒單質(zhì)晶型轉(zhuǎn)變機理。結(jié)果表明：在反應(yīng)溫度小于60 ℃時硒還原率可達(dá)到98%以上，六價硒還原產(chǎn)物為無晶型紅硒單質(zhì)；反應(yīng)溫度高于60 ℃時還原產(chǎn)物為斜方晶型的黑硒單質(zhì)，其還原反應(yīng)歷程為SeO42-還原產(chǎn)生紅硒，紅硒進一步被二氧化硫過還原為Se2-離子，Se2-離子與還原中間產(chǎn)物SeO32-發(fā)生歸中反應(yīng)最終生成斜方晶型的黑硒單質(zhì)。
關(guān)鍵字: 六價硒；催化還原；二氧化硫；雙氧水
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract: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.
Key words: hexavalent selenium; catalyze reduction; sulfur dioxide; hydrogen peroxide
