Study of Back Electromotive Force in the Preparation of Al-Ca Alloy by Molten Salt Electrolysis Method

2011 ◽  
Vol 233-235 ◽  
pp. 2765-2768
Author(s):  
Yi Yong Wang ◽  
Hui Jin ◽  
Fa Yu Wu ◽  
Ji Dong Li ◽  
Zhi Ying Wang

Al-Ca master alloy was prepared by molten salt electrolysis method, using a mixed molten salt system of CaCl2-CaF2and feeding CaO as electrolysis material. The technological parameters such as back electromotive force (BEMF), cell voltage, and current were measured by testing device of molten salt electrolysis. The effects of current density, CaO addition, electrolysis time and feeding period on the back electromotive force in the electrolysis process are studied. The results indicate that back electromotive force increases with current density increasing, the feeding period is 30min measured by potential control method. Finally, the Al-Ca alloy with the Ca content of 11.6wt% can be obtained by electrolyzing for 1h at the current of 7A and at 740.

Author(s):  
Jinglong Liang ◽  
Jing Wang ◽  
Hui Li ◽  
Chenxiao Li ◽  
Hongyan Yan ◽  
...  

AbstractMassive deployment of lithium-ion battery inevitably causes a large amount of solid waste. To be sustainably implemented, technologies capable of reducing environmental impacts and recovering resources from spent lithium-ion battery have been an urgent task. The electrochemical reduction of LiNiO2 to metallic nickel has been reported, which is a typical cathode material of lithium-ion battery. In this paper, the electrochemical reduction behavior of LiNiO2 is studied at 750 °C in the eutectic NaCl-CaCl2 molten salt, and the constant cell voltage electrolysis of LiNiO2 is carried out. The results show that Ni(III) is reduced to metallic nickel by a two-step process, Ni(III) → Ni(II) → Ni, which is quasi-reversible controlled by diffusion and electron transfer. After electrolysis for 6 h at 1.4 V, the surface of LiNiO2 cathode is reduced to metallic nickel, with NiO and a small amount of Li0.4Ni1.6O2 detected inside the partially reduced cathode. After prolonging the electrolysis time to 12 h, LiNiO2 is fully electroreduced to metallic nickel, achieving a high current efficiency of 98.60%. The present work highlights that molten salt electrolysis could be an effective protocol for reclamation of spent lithium-ion battery.


2011 ◽  
Vol 675-677 ◽  
pp. 1125-1128 ◽  
Author(s):  
Rui Guo ◽  
Xiu Jing Zhai ◽  
Ting An Zhang

The paper studied the preparation of Al-Sc alloy by molten salt electrolysis. LiF-ScF3-ScCl3 as the electrolyte, Sc2O3 as raw material, liquid Al as cathode and graphite as anode. The process condition of preparating Al-Sc alloy includes the influence of current density, electrolysis time, temperature of electrolysis, Back EMF, content of Sc in alloy and current efficiency.The content of Sc in alloy prepared by this method has reached to the maximum of 3.437%. The components of alloys showed by SEM were uniform, it is applicable for commercial purposes. Preparation of Al-Sc alloys with scandium oxide as raw materials, it not only reduce environment pollution, but also decease the cost of production. It is reported in many documents, preparing aluminum base alloy by the method of molten salt electrolysis[1-3], people could make many alloys such as Al-Ce、Al-La、Al-RE、Al-Ti、Al-Si-Ti in the aluminum cell, also the method to prepare some rare earth alloys such as Al-Sr、Nd-Fe、La-Ni was reported[4,5]. Use the method of electrolysis to produce some aluminum base alloy with high-melting-point , difficult to restore , high-priced element is a good method because it is technological process is brief, economy is rational, the technology is feasible, this viewpoint is broadly approved in the world[6]. It isn’t necessary to use high-priced Sc as raw material in preparing Al-Sc alloy with molten salt electrolysis, it could control the Sc amounts in the alloy through the different current efficiency and electrolysis time, production in this method could be continuous or semi-continuous, so it is easy to be automatic controlled. A new molten salt system is used in this paper, we use molten salt electrolysis to produce Al-Sc alloy, take scandium oxide as raw material, through the study of the effect of the current intensity,electrolysis time and the electrolysis temperature , Back EMF and cell voltage, the final production Al-Sc alloy contains Sc 2~6%.


2011 ◽  
Vol 284-286 ◽  
pp. 1477-1482 ◽  
Author(s):  
Tie Chui Yuan ◽  
Qi Gang Weng ◽  
Zhi Hui Zhou ◽  
Jian Li ◽  
Yue Hui He

Titanium sponge is used as anode, titanium plate as cathode and NaCl-KCl-TiClx molten salt as electrolyte, to prepare high purity titanium by molten-salt electrolysis at 900~980°C. The effects of feeding TiCl4 temperature, electrolytic temperature, soluble titanium concentration and cathode current density on the content of impurities of cathode products have been studied. The results show that the impurities in product can be controlled when the temperature of feeding and electrolyte is higher. The final product with different morphology and degree of purity can be prepared by controlling the soluble titanium concentration and cathode current density.


2013 ◽  
Vol 873 ◽  
pp. 72-76
Author(s):  
Guang Qiang Ma ◽  
Ming Zou ◽  
Qi Ling Wang

This paper systematically analyzes the various factors that affect the current efficiency in the process of sponge titanium production by vacuum molten salt electrolysis method. The research result shows that firstly, when electrolysis is undertaken in CaCl2 molten salt system under the condition that the pressure is under 101Pa, temperature is at 850°C, space between electrodes is 5 cm, cathodic current density is 1.05 A.cm-2 and anodic current density is 0.8A.cm-2 , the reoxidation of sponge titanium can be effectively avoided, the loss of electric current can be reduced and current efficiency can be greatly improved. Secondly, current efficiency can be greatly improved when mix molten salt system CaCl2+A is adopted, which can greatly reduce the electrolysis temperature and the resistance of molten salt. Thirdly, current efficiency can be greatly improved through selecting appropriate vacuum degree, appropriate molten salt system, appropriate space between electrodes, appropriate current density; in addition, keeping tidy reduction cell inside and adopting high-purity molten salt and raw material TiO2 are another ways for current efficiency improvement.


2012 ◽  
Vol 78 ◽  
pp. 95-98
Author(s):  
Haiyang Ding ◽  
Shigang Lu ◽  
Juanyu Yang ◽  
Surong Kan ◽  
Xiangjun Zhang

2005 ◽  
Vol 178 (7) ◽  
pp. 2401
Author(s):  
Junfeng Wang ◽  
Rui Xiong ◽  
Fan Yi ◽  
Di Yin ◽  
Manzhu Ke ◽  
...  

2020 ◽  
Vol 10 (2) ◽  
pp. 111-126
Author(s):  
Nebojša D. Nikolić

In this study, comprehensive survey of formation of disperse forms by the electrolysis from aqueous electrolytes and molten salt electrolysis has been presented. The shape of electrolitically formed disperse forms primarily depends on the nature of metals, determined by the exchange current density (j0) and overpotential for hydrogen evolution reaction as a parallel reaction to metal electrolysis. The decrease of the j0 value leads to a change of shape of dendrites from the needle-like and the 2D fern-like dendrites (metals characterized by high j0 values) to the 3D pine-like dendrites (metals characterized by medium j0 values). The appearing of a strong hydrogen evolution leads to formation of cauliflower-like and spongy-like forms (metals characterized by medium and low j0 values). The other disperse forms, such as regular and irregular crystals, granules, cobweb-like, filaments, mossy and boulders, usually feature metals characterized by the high j0 values. The globules and the carrot-like forms are a characteristic of metals with the medium j0 values. The very long needles were a product of molten salt electrolysis of magnesium nitrate hexahydrate. Depending on the shape of the disperse forms, i.e. whether they are formed without and with vigorous hydrogen evolution, formation of all disperse forms can be explained by either application of the general theory of disperse deposits formation or the concept of "effective overpotential". With the decrease of j0 value, the preferred orientation of the disperse forms changed from the strong (111) in the needle-like and the fern-like dendrites to randomly oriented crystallites in the 3D pine-like dendrites and the cauliflower-like and the spongy-like forms.


2012 ◽  
Vol 42 (9) ◽  
pp. 1328-1336 ◽  
Author(s):  
XiuShen YE ◽  
ShiDong WANG ◽  
Min GUO ◽  
Quan LI ◽  
HaiNing LIU ◽  
...  

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