不同温度下Se-H_(2)O系电位-pH图的研究  

The Research of Potential-pH Diagram of Se-H_(2)O System at Different Temperatures

作　　者：姚浩 杨四齐 白希为 张利华 YAO Hao;YANG Siqi;BAI Xiwei;ZHANG Lihua(Key Laboratory of Unconventional Metallurgy,Ministry of Education,Kunming University of Science and Technology,Kunming 650093,China;Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China;State Key Laboratory of Complex Non-ferrous Metal Resources Clean Utilization,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学非常规冶金教育部重点实验室,昆明650093 [2]昆明理工大学冶金与能源工程学院,昆明650093 [3]昆明理工大学省部共建复杂有色金属资源清洁利用国家重点实验室,昆明650093

出　　处：《有色金属工程》2024年第2期49-56,共8页Nonferrous Metals Engineering

基　　金：国家自然科学基金资助项目(52164040);云南省基础研究计划面上项目(202101AT070121);“兴滇英才支持计划”青年人才项目(YNWR-QNBJ-2019-150)。

摘　　要：针对Se-H_(2)O体系中重要的单核配合物进行计算分析,通过查询热力学手册,获得了各反应物质298 K标准态下的S0、ΔfG0、ΔfH0和CP的数据,计算得到298~573 K下Se(-Ⅱ)-H_(2)O、Se(+Ⅳ)-H_(2)O和Se(+Ⅵ)-H_(2)O体系中各溶解组分在不同pH下的优势区域图。在此基础上,结合不同温度下各含Se物质参与氧化、还原反应的平衡热力学数据,分别构建298、373、473、573 K温度下的Se-H_(2)O系电位-pH图。结果表明:H_(2)Se和H_(2)SeO_(3)均可稳定存在于强酸性溶液中,而H_(2)SeO4仅能存在高温强酸性和溶液中。在298~573 K,单质Se能稳定存在于水溶液中。在298~473 K之间,H_(2)SeO_(3)、HSeO^(-)_(3)、SeO_(3)^(2-)全部可以直接还原成Se。因此,控制一定的pH值和电位,可以使Se以单质形式沉淀从溶液中净化除去。随着温度的升高,H_(2)O的优势区域减少,以固相存在的单质Se的优势区域也在逐渐减少,液相区以Se(+Ⅳ)存在的H_(2)SeO_(3)、HSeO^(-)_(3)及SeO_(3)^(2-)的稳定区域不断扩大。且随着温度的升高,将硒单质氧化为Se(Ⅳ)且进一步氧化为Se(Ⅵ)的氧化电位略有降低,氧化反应更易进行。This paper presents the calculation and analysis of the important mononuclear complexes in the Se-H_(2)O system.Based on the thermodynamic data of S 0、Δf G 0、Δf H 0 and C P of each reaction substance at standard state,the dominant region distribution of the dissolved species in Se(-Ⅱ)-H_(2)O,Se(Ⅳ)-H_(2)O and Se(Ⅵ)-H_(2)O systems were calculated at different pH values under the temperature range of 298~573 K.Combined with the equilibrium thermodynamic data of the oxidation and reduction reactions of Se containing substances at different temperatures,the potential-pH diagrams of the Se-H_(2)O system at 298,373,473 and 573 K were constructed.It was found that both H_(2)Se and H_(2)SeO_(3)could exist stably in high acid content solution,while H_(2)SeO 4 could only exist in high-temperature and high acid content solution.At 298~573 K,Se could exist stably in aqueous solution.In the range of 298~473 K,H_(2)SeO_(3),HSeO^(-)_(3)and SeO^(2-)_(3)could be directly reduced to elemental Se.Therefore,by controlling a certain pH value and potential,Se could be removed from the solution by precipitation in the form of elemental Se.With the increase of temperature,the stable region of H_(2)O decreased,and the region of Se,which existed in the solid phase,also gradually decreased.I n the liquid phase,the stable regions of H_(2)SeO_(3),HSeO^(-)_(3)and SeO^(2-)_(3)with Se(+Ⅳ)continued to increase.With the increase of temperature,the oxidation potential of elemental selenium oxidized to Se(Ⅳ)and further to Se(Ⅵ)decreased slightly,and the oxidation reaction could be easier to carry out.

关 键 词：Se-H_(2)O系 热力学 电位-PH图 优势区域 氧化-还原反应 

分 类 号：TF843[冶金工程—有色金属冶金]