Electrical Conductivity of Low-Temperature Potassium Cryolite Electrolytes Suitable for Innovation of Aluminum Preparation

2018 ◽  
Vol 165 (7) ◽  
pp. E274-E278 ◽  
Author(s):  
Emília Kubiňáková ◽  
Vladimír Danielik ◽  
Ján Híveš
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Potassium Cryolite

Electrical conductivity of low-temperature carbons as a function of frequency

1978 ◽  
Vol 30 (1) ◽  
pp. 87-98 ◽  
Author(s):  
J.C. Giuntini ◽  
D. Jullien ◽  
J.V. Zanchetta ◽  
F. Carmona ◽  
P. Delhaes
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature

LOW TEMPERATURE THERMOELECTRIC PROPERTIES AND AGING PHENOMENA OF NANOSTRUCTURED p-TYPE Bi2-XSbXTe3 (x = 1.46, 1.48, 1.52 AND 1.55)

2013 ◽  
Vol 06 (05) ◽  
pp. 1340008 ◽  
Author(s):  
DALE HITCHCOCK ◽  
YEN-LIANG LIU ◽  
YUFEI LIU ◽  
TERRY M. TRITT ◽  
JIAN HE ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Thermoelectric Properties ◽  
Optimal Composition ◽  
Ambient Conditions ◽  
Bulk Materials ◽  
The Past ◽  
Aging Phenomena ◽  
P Type ◽  
Cold Pressed

Over the past decade the widely used p-type ( Bi 2-x Sb x) Te 3 bulk thermoelectric materials have been subject to various nanostructuring processes for higher thermoelectric performance. However, these nanostructuring processing were conducted on compositions optimized for bulk materials (x ~ 1.52–1.55). This leads to the question of whether the optimal composition for bulk materials is the same for their nanoscale counterparts. In this work we hydrothermally grew Bi 2-x Sb x Te 3 nanopowders (nominally, x = 1.46, 1.48, 1.52 and 1.55) and measured their thermoelectric properties on cold-pressed vacuum-sintered pellets (74–78% of the theoretical density) below 300 K. The measurements were conducted 18 months apart to probe the aging phenomena, with the samples stored in ambient conditions. We have found that (i) the peak of thermopower shifts to lower temperatures upon nanostructuring but it shifts back to higher temperatures upon aging; (ii) the electrical conductivity degrades by a factor of 1.5–2.3 upon aging while the temperature dependence is largely retained; and (iii) the ZT of freshly made samples is sensitive to the x value, a maximum ZT ~ 1.25(~ 0.62) at ~ 270 K (~ 255 K) was attained in the freshly made sample x = 1.55(x = 1.46), respectively; while the ZT of aged samples is significantly lowered by a factor of 2–4 but lesser x-dependent. These observations have been discussed in the context of charge buildup and compensation at grain boundaries.

Efficient Assessment of Physico-Chemical Properties of the Cryolite Melts for Research on the Improvement of Low-Temperature Aluminum Electrolysis

2018 ◽  
Vol 284 ◽  
pp. 839-844 ◽  
Author(s):  
V.A. Lebedev ◽  
Andrey A. Shoppert
Keyword(s):  
Low Temperature ◽  
Chemical Properties ◽  
Aluminum Electrolysis ◽  
Total Power ◽  
Potassium Cryolite ◽  
High Magnitude ◽  
Rate Of Dissolution ◽  
Physico Chemical ◽  
Hazardous Production ◽  
High Level

Modern aluminum electrolysis in cryolite-alumina melts is energy-intensive, inefficient and environmentally hazardous production. Addressing these significant shortcomings, the technology of low-temperature electrolyte is directed. The basis of low-temperature electrolysis is potassium cryolite, which results in high magnitude and rate of dissolution of alumina. Additive of sodium and lithium fluorides provide the necessary conductivity. Experimental investigation of these properties is extremely time consuming. In this work, as a parameter, which will allow to characterize effectively and rapidly the complexing ability of cryolite melts, the ratio of cationic ion power of Al3+ to the total power of the other cations of the melt is proposed. Regression analyses of the known experimental data establish the existence with a high level of reliability (R2=0.966-0.995) of a directly proportional dependence of this parameter on solubility of alumina and electrical conductivity of cryolite melts.

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