Effect of electrolysis voltage on electrochemical reduction of titanium oxide to titanium in molten calcium chloride

The electrochemical reduction of solid TiO2 directly to solid metal is a promising alternative to the current Kroll process. The present work is aimed at studying the effect of electrolysis voltage on the rate of electrochemical reduction. The products of electrochemical reduction of TiO2 and Ti2O were examined using the scanning electron microscopy （SEM） and X-ray diffraction （XRD） techniques. The results show that Ti2O was reduced to low valent titanium oxide at 1.5 -1.7 V, which was the result of ionization of oxygen. TiO2 and Ti20 were reduced to titanium metal at 2.1-3.1 V, which was the co-action of ionization of oxygen and calciothermic reduction. The oxygen content decreased rapidly with voltage increasing from 2.1 to 2.6 V, while it changed little from 2.6 to 3.1 V. The optimized cell voltage was 2.6-3.1 V.

Electrochemical Reduction of Niobium lons in Molten NaF-CaF_2

The mechanism of the electrochemical reduction of niobium ions in molten NaF-CaF_2 (2 : 1 mol) wasinvestigated by means of cyclic voltammetry and chronoamperometry. It is found that the reduction ofNb ( V ) proceedsintwosteps : Nb ( V)→ Nb (Ⅳ)→Nb ( 0 ) . Theelectrochmical reaction Nb ( Ⅳ) + 4e →Nb( 0 ) is a reversible and diffusion-controlled process.

Cathodic Process of Ti(Ⅳ) in Molten LiF-NaF

The mechanism of the cathode reduction of Ti(Ⅳ) at platinum electrode in molten LiF-NaF containingvarious concentrations of K_2TiF_6 has been investigated by means of cyclic voltamrnetry and convolutiontechnique. The transfered electron number of each reduction step has been determined. It is found that thereduction of Ti(Ⅳ) proceeds in three steps: Ti(Ⅳ)→Ti(Ⅲ)→Ti(Ⅱ)→Ti(0). The first step is accompanied bythe chemical disproportionation reaction: ZTi(Ⅲ)→Ti(Ⅳ)+Ti(Ⅱ). The cathodic product is soluble and prob-ably forrns alloy with the platinurn electrode.

Study on Mechanism of Electrodeposition of Y(Ⅲ) in Molten LiF-YF_3-Y_2O_3 by Cyclic Voltammetry

The mechanism of the cathodic process of Y(Ⅲ) on platinum and molybdenum electrode in molten LiF YF 3 Y 2O 3 was investigated by means of cyclic voltammetry. The number of electron transferred was calculated. The results show that the electrochemical reduction of Y(Ⅲ) is a reversible one step three electrons reaction and the cathodic process is diffusion controlled. The reductive product easily forms the intermetallic compounds with the platinum electrode, but it is pure yttrium on the molybdenum electrode.

氟化物熔体中电解共沉积硼化钛的阴极过程

采用循环伏安法首次研究了ＬｉＦ－ＮａＦ－Ｋ２ＴｉＦ６－ＫＢＦ４熔盐体系中钛离子和硼离子在铂、钼电极上电化学还原及电合成硼化钛的阴极过程机理。对恒电位电解的沉积物进行了Ｘ射线衍射分析。结果表明，当体系中硼钛摩尔比Ｂ／Ｔｉ大于２时，钛与硼可在同一电位下实现电解共沉积并反应生成硼化钛。

LiF─NaF─K2TiF6熔盐中Ti（Ⅳ）的电化学还原

用循环伏安法和卷积技术研究了ＬｉＦ－ＮａＦ低共熔体中，以Ｋ２ＴｉＦ６形式加入的Ｔｉ（Ⅳ）在铂电极上阴极还原机理，计算了各还原步骤所传递的电子数。结果表明，Ｔｉ（Ⅳ）的电化学还原机理为耦联均相歧化反应的三步骤电荷传递反应。

LiF-NaF-KF-K_2TiF_6熔盐中Ti(IV)的电化学还原及电结晶过程(英文)

采用循环伏安法和计时电流法研究了700℃时LiF-NaF-KF-K2TiF6熔盐中Ti(IV)在铂电极上阴极电化学还原机理以及电结晶过程。结果表明:Ti(IV)的电化学还原机理为三步骤电荷传递反应:Ti(IV)+e→Ti(III);Ti(III)+2e→Ti(I);Ti(I)+e→Ti(0),且阴极过程可逆;电结晶过程为瞬时形核。

熔盐体系中电沉积制备TiB_2镀层的研究现状

介绍了熔盐体系中电沉积制备TiB2镀层技术中熔盐的选择、电镀工艺和参数的选择,概述了不同熔盐体系中B离子、Ti离子在阴极沉积的电化学机理以及TiB2的合成机理,论述了TiB2惰性阴极在铝电解工业中的研究现状,最后分析了熔盐体系中石墨电极上制备TiB2镀层的可行性。

LiF-NaF-KF-K_2TiF_6-KBF_4熔体中电沉积TiB_2的阴极过程

采用循环伏安法研究了700℃时46.5LiF-11.5NaF-42KF(摩尔分数,%)熔盐中Ti(Ⅳ)(c(K2TiF6)=0.2 mol/L)和B(Ⅲ)(c(KBF4)=0.4 mol/L)在铂电极上的电化学还原机理,计算了各还原步骤传递的电子数。研究了LiF-NaF-KF-K2TiF6-KBF4(c(K2TiF4)=0.3 mol/L,c(KBF4)=0.3,0.6,0.9 mol/L)熔盐中电化学合成TiB2的阴极过程机理。结果表明:Ti(Ⅳ)的电化学还原为三步电荷传递反应,且阴极过程近似可逆;B(Ⅲ)在铂电极上的电化学反应机理为简单的三电子一步反应,阴极过程近似可逆;Ti(Ⅳ)和B(Ⅲ)可在同一电位下发生共沉积并反应生成TiB2。

Ti(Ⅳ)在氯化物熔体中的电化学还原

研究了ＫＣｌＬｉＣｌ熔体中Ｔｉ（Ⅳ）的电化学还原机理和钛沉积及沉积动力学，计算了各还原步骤传递的电子数。结果表明，Ｔｉ（Ⅳ）的电化学还原为三步电荷传递反应，即：Ｔｉ４＋→Ｔｉ３＋→Ｔｉ２＋→Ｔｉ。Ｔｉ（Ⅳ）的电化学还原速度由离子扩散速度来控制。在一定熔体组成及温度下，沉积物的性质依赖于电解时间及电解电位。在ＫＣｌＬｉＣｌ熔体中阴极电位为５００ｍＶ（相对钼电极），电解时间为４ｈ时，可获得粘附性能好的钛沉积物，并观察到沉积物为细小结晶堆积起来的多孔体。钛的纯度可达９９．９％。