Ir-Ta氧化物涂层阳极在硫酸盐电解溶液中的电化学行为

采用测量极化曲线等电化学方法研究了钛基Ir-Ta氧化物涂层阳极在酸性硫酸盐溶液中的电化学行为。结果表明:酸性硫酸盐溶液中Ir-Ta氧化物涂层阳极上的析氧反应发生电化学极化,但超电势远低于Pb阳极和Pb-Ag阳极而电催化活性好,可以显著降低电解能耗。溶液pH和电解温度升高,Ir-Ta氧化物涂层阳极上析氧反应的超电势降低;溶液中含有不同金属离子时析氧反应的超电势略有不同,但金属离子浓度不影响其超电势。Ir-Ta氧化物涂层阳极在1 mol/L H2SO4溶液和电流密度40000A/m2的条件下的强化寿命可达55天。     

无硒氯化物体系电解金属锰消减氯气的实验研究

为了减少氯化物体系电解金属锰中氯气的溢出量,通过电化学测试及电解实验探究了阳极电流密度、锰离子以及氯化铵浓度对氯气溢出量的影响。阳极极化曲线测试表明,在氯化锰、氯化铵溶液中,阳极过程按电流密度分成两个区域:低电流区域,以Mn2+和Cl-的氧化为主要反应;高电流区域,以氧的析出反应为主要过程。电解实验证实上述结果,电流密度越高,氯气的溢出量越少;溶液中氯离子浓度越高,氯气的产生量也越多;纯氯化物体系电解金属锰在接近工业生产条件时,阳极过程难以完全抑制氯气的溢出,采用混合电解质为1 mol/L NH4Cl+0.5 mol/L(NH4)2SO4时,氯气溢出量低于检出限,无硒电解条件下,Mn沉积效率可达到72.81%。     

Cl~-对Pb-0.1%Ca-1.5%Sn阳极在硫酸锌溶液中电化学性能的影响

采用失重法、恒电流极化、EIS、CV和CP等方式研究了不同Cl~-浓度下Pb-0.1%Ca-1.5%Sn阳极的析氧行为和腐蚀行为。研究表明,在电解过程中引入Cl~-,多出现了一个氧化峰(Cl~-→Cl_2)。随着Cl-的加入,阳极的析氧过电位先升高后降低,自腐蚀电流先升高后降低,腐蚀速率也先增大后降低。恒电流极化12h后,阳极表面主要由PbO_2、PbSO_4和PbO·PbSO_4组成。Cl-也可以抑制恒电流极化条件下PbO·PbSO_4的生成,促进PbO_2和PbSO_4的生成,加速阳极的腐蚀。     

氧化物夹杂对Al-Zn-In-Si牺牲阳极电化学性能的影响

以不同铁含量的Al-Zn-In-si牺牲阳极为研究对象,考察了精炼前后阳极微观组织的变化.采用恒电流测试、动电位极化曲线、电化学阻抗等测试手段,对阳极的电化学性能进行了研究.结果表明:氧化物夹杂的存在使阳极的开路电位和工作电位正移,阳极的极化程度增大,同时还造成了阳极电流效率在一定程度上的损失.     

熔盐电解制备铝锂合金中阳极过程动力学参数的分析与计算

680℃下,在LiCl-LiF-KF体系中分别以LiCl和Li2CO3为原料电解制备铝锂合金,采用连续脉冲-计算机法测量阳极过电压并研究极化曲线的变化,根据电极过程动力学的理论计算并分析了CO2-3放电机理和反应速度控制步骤.研究表明：在电流密度为0.1-0.3 A·cm-2的Tafel区内,LiCl电解电极反应受电化学极化控制,Li2CO3电解电极反应受化学极化控制;电解Li2CO3时整个电极反应速率是由炭阳极上配合氧离子的缓慢放电引起的电化学控制步骤决定的.     

用离子膜电解槽无硒电沉积金属锰

研究了用阴离子膜电解槽在硫酸盐体系中无硒电解金属锰,采用循环伏安法研究了阴极电化学机制。单因素条件试验确定的最佳电解条件为:锰离子质量浓度30g/L,硫酸铵质量浓度135g/L,电解温度35℃,阴极液pH=7.7,电流密度450A/m2,SO2添加量为0.4g/L。最佳条件下,电解效率达到82%,直流电耗为4 985kWh·t-1,电解产品为α-Mn,质量符合国家标准。阴离子交换膜可以减弱阴极浓差极化,有效区分锰沉积峰和析氢还原峰;SO2添加剂可显著抑制析氢反应,降低锰沉积电流,减小直流电耗。     

栅栏型铝基铅合金复合阳极板在电解锌中的应用

采用连续挤压拉拔技术在铝芯上包覆铅合金制备了一种铝棒铅合金复合阳极。通过万能试验机、低电阻测试仪、电子密度计及电化学强化腐蚀研究了该阳极的抗拉强度、导电性、密度和腐蚀速率,并组装成栅栏型铝基铅合金复合阳极板用于电解锌。结果表明:对比轧制Pb-0.06%Ca-0.3%Ag合金阳极,铝基Pb-0.06%Ca-0.3%Ag复合阳极的抗拉强度提高8.07%,延伸率降低10.7%,导电性提高3.39倍,质量相对减轻22.83%,腐蚀速率降低28.4%;在电解锌过程中,槽电压降低40 mV,电流效率提高2.97%,能耗降低3.08%。栅栏型铝基铅合金复合阳极质量轻,导电性好,耐腐蚀,有较广泛的开发应用前景。     

900℃下合成Ti-C-O固溶体的电化学行为研究

以TiC和TiO_2为原料在900℃烧结得到了与USTB钛电解工艺所用阳极原料类似的Ti-C-O固溶体,并对该固溶体在750℃NaCl-KCl熔盐体系中的电化学行为进行了研究。结果显示,该固溶体可以发生电化学溶解,钛元素以离子的形式进入熔盐中,碳元素和氧元素则以CO为主、CO_2为辅的气体形式析出。以该固溶体为阳极进行恒电流电解,最终在阴极得到了金属钛。     

全国电解金属锰第五届厂长会议和第二届学术研讨会会议纪要

全国电解金属锰第五届厂长会议和第二届学术研讨会于 2 0 0 0年 12月 5日至 7日在广西桂林市召开 ,参加会议的共有 54个单位 ,71名代表。其中电解金属锰生产厂家 2 4家 ,广西壮族自治区锰矿公司党委书记刘忠林同志参加了会议。会上全国锰业技术委员会副主任、全国电解金属锰自律领导小组组长谭柱中同志作了“中国电解金属锰的现状及发展趋势”的报告 ,中南大学冶金系梅光贵教授作了“电解金属锰的阴、阳极过程 ,电化学行为及电流效率”的学术报告 ;刘忠林书记作了“广西锰矿资源分布情况及开发”的报告 ,曾湘波同志作了“电解金属锰行业加入…     

石墨基二氧化铅作阳极从MnCl2体系制备电解金属锰

介绍了可用于ＭｎＣｌ２体系制备电解金属锰的石墨基二氧化铅电极的制备方法。用该电极代替石墨作阳极在２７５Ｌ隔膜电解槽中成功地制备出优质电解金属锰，并具有电流效率高（８０％～８２％）、槽压低（３６～３８Ｖ）、能耗少（４３１～４５５ｋＷｈ／ｋｇ）、可使用高阳极电流密度（７００Ａ／ｍ２）和阳极放氯量少的优点。     

The effect of quality of anodes on the process of electrolytic of manganese dioxide

During the electrosynthesis of manganese dioxide, the anode material and anode current density (i _a) exert the largest influence on the characteristics of electrolysis and the quality of the obtained material. The activation of anodes, which consists of the deposition of the titanium-manganese alloy on the titanium base of the electrode by the thermal-diffusion method, prevents passivation at i _a = 100 and 200 A/m². The electrochemical characteristics of electrolysis for NTMA (a built-up titanium-manganese activated anode) and ATDP (an experimental activated anode with thermodiffusion coating) anodes at i _a = 100 and 200 A/m² have close values. The voltage across the bath does not exceed 2.2–3.0 V, the current efficiency is 95–98%, and electrical power consumption is 1.33–1.80 (kW h)/kg. The chemical composition and the crystalline modification of electrical manganese dioxide corresponds to the requirements of GOST (State Standard) 25823-83. The activated ATDP anodes behave similarly to the known HTMA anodes. After electrolysis, no variations in the surface layer are found on them.     

Electrorefining of a gold-bearing antimony alloy in alkaline xylitol solution

The electrochemical dissolution and electro-deposition of a gold and silver bearing antimony alloy obtained from the smelting of antimony concentrate were investigated in alkaline NaOH/xylitol electrolyte. The results show that the electrochemical antimony dissolution increases with higher temperature, but the relationship between antimony dissolution and NaOH/xylitol/antimony concentration is uncertain. The antimony electro-deposition becomes faster with increasing antimony concentration and temperature，but decreasing xylitol concentration. The effects of NaOH/xylitol/antimony concentration, current density, electrode distance, and electrolyte temperature on the electro-refining of antimony process were studied. Under optimal conditions, the current efficiency was 98.3% and energy consumption was 436.7 kwh/t-Sb. The purity of electrolytic antimony was 99.4% and gold and silver were enriched 8–9 times in the anode slime, therefore providing an effective separation of precious metals from antimony by electrolysis.     

Surface Modification of a MCFC Anode by Electrochemical Alloying

Considering the properties of the valve metal alloys with specific corrosion resistance and electrocatalytic ac tivity, an investigation was made to examine if nickel-niobium alloy could serve as the anode material for molten carbo nate fuel cell (MCFC). An attempt was made to produce nickel-niobium surface alloy by an electrochemical process in the molten fluorides and to testify its performance required by the MCFC anode. Experimental results indicated that the corrosion resistance as well as polarization performance of the nickel electrode was improved by the surface alloying.As far as the corrosion resistance and polarization performance is concerned, the nickel-niobium surface alloy can be considered as a candidate material for the anode of MCFC.     

Ir_(1-x)Ru_xO_2/Ti析氧阳极的电催化活性研究

以氯铱酸为主要的前驱体,采用加热分解法制备了不同Ru含量的Ir1-xRuxO2/Ti析氧阳极,并采用扫描电镜,循环伏安,恒电流电解,线性极化等测试手段对电极进行表征和测试。电化学测试结果表明当Ir,Ru的摩尔比为3∶2时,500mA.cm-2恒电流水解电位最低,为1.4V(vs.SCE);循环伏安测试表明,Ir0.6Ru0.4O2/Ti的伏安电量亦达到最高,达到1271mC.cm-2,析氧电催化活性点最多。SEM表面形貌进一步证实了Ru的加入使得电极的表面的多孔结构更加明显,当Ir,Ru摩尔比为3∶2时,电极表面颗粒最小,孔隙率最高,亦表明该电极的电化学活性表面积最大,电催化活性最高。     

电解二氧化锰用钛基钛锰合金全浸没板状阳极的研制

电解二氧化锰生产中采用铸铝横担钛基钛锰合金全浸没板状阳极代替传统阳极或条状钛基钛锰合金阳极，能显著地提高电解二氧化锰（ＥＭＤ）质量，有明显的节能效果。其设计合理，整体强度高，几何形状稳定，电解电流分配均匀，便于装卸和剥离产品，大大减轻了工人劳动强度，提高了设备利用率，有显著的经济效益和社会效益。     

Preparation of CeNi2 intermetallic compound by direct electroreduction of solid CeO2-2NiO in molten LiCl

Electrochemical reduction of solid CeO 2 -2NiO to produce CeNi 2 was conducted in molten LiCl at 650 oC. The electrochemical reduction behaviors of NiO, CeO 2 and their mixture were investigated by cyclic voltammetric measurements. Moreover, a series of electrolysis experiments of different electrolysis cell voltages and electrolysis duration were performed to evaluate the reduction mechanism of the mixed oxides pellet cathode as well as the energy efficiency of the process. Homogeneous CeNi 2 was prepared by electrolysis at the constant cell voltage of 3.5 V with a graphite anode. The results demonstrated that the NiO was preferentially reduced to Ni and it subsequently promoted the reduction of CeO 2 . The electrolysis energy consumption for preparation of the CeNi 2 could be as low as 6.5 kWh/kg-CeNi 2 .     

Electroreduction of Ho~(3 ) on Nickel Cathode in Molten KCl-HoCl_3

The holmium metal can be prepared bymolten salt electrolysis with high consumptionof electric energy and low recovery of holmiumat the high electrolytic temperature. As weknow, the electrolytic temperature would bedecreased, provided rare earth alloy was prepared by electrolysis. We are interested in investigating the preparation of Ho-Fe, Ho-Co,Ho-Ni and Ho-Cu alloys by molten salt electrolysis on consumahle transition metal cathodes and the mechanism of forming alloys so asto provide scie…