熔盐预电解脱水与电解时间对溶盐电解TiO2脱氧行为的影响

摘要

以无水氯化钙作为熔盐，采用熔盐电解法对TiO2阴极片进行脱氧，通过X射线衍射(XRD)和扫描电镜(SEM)对TiO2电解产物的相组成、电极表面形貌与元素组成进行观察与分析，研究熔盐的预电解脱水与熔盐电解时间对TiO2电解脱氧行为的影响。结果表明，熔盐未经预电解时，TiO2阴极片不发生脱氧反应，电解产物只有 CaTiO3相；熔盐经预电解脱水后，TiO2电解产物部分或全部为低价钛氧化物，预电解时间达到15 h即可有效去除熔盐中的水分，从而获得较佳的熔盐电解脱氧效果，电解产物为氧含量较低的Ti2O。TiO2电解脱氧是分步进行的，随电解进行，先后出现Ti2O3、TiO、Ti2O，由于钛的化合价逐渐降低，所需分解压升高，导致脱氧效率逐渐降低。TiO2阴极的脱氧反应是由表面到心部进行，电解后的阴极片明显分层，表层为氧含量较低的 Ti2O，中间层为 CaTiO3和钛的低价氧化物，心部为CaTiO3。%The effects of pre-electrolysis dehydration and electrolysis time on the TiO2 deoxidation during molten salt electrolysis were studied. The results showed that the electrolytic product was only CaTiO3 phase in the molten salt without pre-electrolysis. When pre-electrolysis time of 5h, 15h, 26h were applied, the electrolytic products were partial or complete suboxide of titanium. Pre-electrolysis of 15h can remove moisture and deoxidize effectively. During the deoxidization process, the electrolytic products of Ti2O3, TiO, Ti2O were formed successively. With the decrease of titanium valence, the decomposition voltage increased and led to the low deoxidation efficiency. The deoxidation reaction occurred from surface to inner of the TiO2 cathode. The electrolytic product showed layered structure with stable surface layer of Ti2O, interlayer of CaTiO3and low titanium oxide, inner layer of CaTiO3.