NaNO_3、KNO_3和NaNO_2熔盐的Raman光谱测定与计算

采用Raman光谱法,结合量子化学计算,进行不同温度下NaNO_3、KNO_3和NaNO_2熔盐的结构研究,发现这3种物质Raman特征峰的半高宽随温度的增高而增大;得到3种熔体中N-O离子团的v_1特征峰Raman频移随N-O键长的变化关系方程;同时研究还发现,NaNO_3和KNO_3熔化后,NO_3~-的v_1特征峰红移,而NaNO_2熔化后,NO_2~-的v_1特征峰蓝移,且随着温度的升高,熔融态的3种物质中N-O离子团的N-O键长增加。研究结果有助于进一步开展二元和三元混合熔盐的结构变化研究。     

Study on spinel-based inert anode for aluminium electrolysis

1 IntroductionSince the Hall-Heroult process was applied in aluminium production,an inert anode was al ways thetarget that the aluminiumindustry is seeking for in the newtechnology field. The greenhouse gases CO2and the fluoride CFnemittedfromthe present carbon anodes ,give a huge pressure onthe environment .Theapplication of inert anodes will help us go through this trouble :a cell with inert anodes emits oxygen in-stead of CO2and other nocuous gases ;the newtype of cell with inert anodes …     

基于Raman光谱表征的NaOH亚熔盐浸出铝电解废旧阴极固体产物中碳材料石墨化度研究

本文利用Raman光谱法检测NaOH亚熔盐浸出铝电解废阴极固体产物中碳材料，以此考察不同浸出条件对碳材料石墨化程度的影响。结果表明，浸出过程有助于提高废阴极中碳材料的石墨化程度。NaOH亚熔盐质量分数和温度对碳材料石墨化程度影响不显著，搅拌速率和浸出时间的增加可以有效提高碳材料石墨化程度，而随着搅拌时间延长，碳材料石墨化程度提高的速率逐渐放缓。     

Density and ionic structure of NdF3-LiF melts

NdF3-LiF melts are commonly used in the electrolysis process of metallic neodymium production. Research on the density and ionic structure of the electrolyte is important for its close connection with the electrolysis mechanism and process. In this paper, the density of LiF-NdF3 melts was studied by the Archimedes method. The results showed that the density decreased with increasing temperature and LiF contents. The changing law was discussed and explained in terms of the micro ionic structure of the melts....     

酸性NaF-AlF3熔盐离子结构的Raman光谱

采用紫外激光Raman光谱,在封闭样品池中研究不同分子比的酸性NaF-AlF3熔盐的离子结构。结果表明：当电解质分子比为1时,熔盐中的铝氟离子团只以AlF4-的形式存在,而对于分子比大于1的酸性电解质,熔盐中有AlF4-和AlF63-两种铝氟离子团形式;随着温度的增加,AlF63-离子团的”寿命“越来越短,而且AlF63-特征波段峰的峰位随分子比的增加而发生红移,温度对AlF4-的”寿命“影响不大。Raman光谱的定量分析表明,在测量的熔盐配重分数区间内,温度对于熔盐中各离子摩尔分数的影响不大,而且F-含量很小,当NaF的配重摩尔分数为0.60时,AlF4-的摩尔分数在0.75左右,AlF63-的摩尔分数仅约为0.25;当NaF的配重摩尔分数增至0.71时,AlF4-的摩尔分数降为0.25左右,AlF63-增为约0.75。     

Equivalent conductivity and its activation energy of NaF-AlF3 melts

Electrical conductivity of NaF-AlF3 melts was measured by continuously varying cell constant(CVCC) technique. Relationships between equivalent conductivity at 990-1 030 ℃ and temperature and composition, and relationship between equivalent conductivity activation energy and composition of the melts were then studied on the basis of two-step decomposition mechanism of AlF63-. According to the changes of molar fractions of different anions in NaF-AlF3 melts, courses of dependence of equivalent conductivity and its activation energy on composition were analyzed. The results show that the influence of temperature on equivalent conductivity of the melts is small in the researched temperature range, and equivalent conductivity increases with increasing the molar fraction of AlF3; there is a minimum point in the activation energy-composition curve when molar fraction of AlF3 is 0.29.     

Identification of structural entities in NdF3-LiF melts with cryoscopic method

Nd-F species in NdF3-LiF melts were studied using cryoscopic method.Liquidus temperatures of melts of various compositions were determined by differential thermal analysis(DTA).Based on the different model calculations,NdF4- was identified as the most likely Nd-F entity in the melts in which the mole fraction of NdF3 was lower than 20%,considering only one single Nd species in the melt,and which was formed in accordance with Temkin model or Flood model.Then,activities of different components in the melts were researched.The results show that activity of LiF decreases,and that of NdF3 increases with increasing the mole fraction of NdF3.The value of activity coefficient of NdF3 is higher than 1,and that of LiF is lower than 1.     

氧化镁直接电解制备Al-Mg合金的研究

以氧化镁为原料,BaF2,MgF2,L iF做电解质体系,直接电解制备Al-Mg合金.研究表明,该电解质体系密度比Al液密度大,采用了上浮式阴极.电流效率在80%以上,最高可达到87.7%,每隔一定时间,加入一定量MgO,电解能够稳定进行.Mg在Al-Mg合金中的含量可逐步增加,最高可达到18.8%.同时,添加一定量的KCl,可以改善电解质的物理化学性质.     

酸性NaF-AIF3熔盐离子结构的Raman光谱

采用紫外激光Raman光谱,在封闭样品池中研究不同分子比的酸性NaF-AIF3熔盐的离子结构.结果表明:当电解质分了比为1时,熔盐中的铝氟离子团只以AlF4的形式存在,而对于分子比大于1的酸性电解质,熔盐中有AlF4和AlF6两种钳氟离子团形式;随着温度的增加,A1F6离子团的"寿命"越来越短,而且AlF6特征波段峰的峰位随分子比的增加而发生红移,温度对AlF4的"寿命"影响不大.Raman光谱的定量分析表明,在测量的熔盐配重分数区间内,温度对于熔盐中各离子摩尔分数的影响不大,而且F含量很小,当NaF的配重摩尔分数为0.60时,AlF4的摩尔分数在0.75左右,AIF6的摩尔分数仅约为0.25;当NaF的配重摩尔分数增至0.71时,AlF4的摩尔分数降为0.25左右,AlF6增为约0.75.     

NaF·AlF3-Al2O3-CaF2-ZrO2熔盐体系的电导率

采用改进的固定电导池常数法研究 NaF-AlF3-CaF2-Al2O3-ZrO2熔盐体系的电导率。结果表明, NaF-AlF3-3%Al2O3-3%CaF2-ZrO2熔盐体系的电导率随着ZrO2含量（0~5%）的增加呈降低趋势。每增加1%氧化锆,电导率相应地降低约0.02 S/cm。温度每增加1°C时电导率相应降低约0.004 S/cm。随着NaF与AlF3摩尔比的增加,体系的电导率随之增加。最后采用二次回归正交设计方法,建立分子比相同时电解质的电导率与温度和氧化锆浓度关系的回归方程。