Electrical conductivity of the (KF-AlF3)-NaF-LiF Molten System with Al2O3 additions at Low Cryolite Ratio

Abstract

The electrical conductivity of low temperature electrolytes for aluminum electrolysis has been measured. The potassium cryolite was the basic melt. Additions of LiF and NaF increased the conductivity of (KF +AlF3) molten mixtures but Al2O3 decreased it.

Electrical Conductivity of Molten Fluoride–Chloride Electrolytes Containing K2SiF6 and SiO2

“…The most aggressive part of the electrolyte is the fluoride salt. Over the last 20 years, pyrolytic boron nitride has primarily been used for fluoride melt measurements. , A detailed description of the conductivity measurements can be found in our previous publications. , …”

Electrical conductivity of low-temperature sodium-potassium cryolite melts

“…However, KF-AlF 3 electrolytes in the industrial process will never be pure potassium mixtures. Sodium oxide is always present in alumina as an impurity and regular additions of alumina into the electrolyte cause accumulation of sodium in the system (Dedyukhin et al, 2009). From an industrial point of view, NaF-KF-AlF 3 systems are more suitable as low temperature electrolytes for aluminium electrolysis.…”

“…Basic three-component melts were measured in capillary cell and multicomponent melts were measured in a cell with two parallel molybdenum electrodes. Apisarov et al (2010) described the electrical conductivity of the KF-NaF-AlF 3 system at the same MRs, temperature ranges, measuring technique as in the previously mentioned paper (Dedyukhin et al, 2009). The last publication by this research group (Dedyukhin et al, 2011) studied the infl uence of CaF 2 on the electrical conductivity of a mixture of cryolite-based electrolytes with MR = 1.3 and 1.5.…”

“…However, the composition of measured electrolytes before the melting, types of fractions (mol % or wt %) and molar ration (MR), are not listed. Dedyukhin et al (2009) studied KF-NaF-AlF 3 melts with an addition of LiF and/or Al 2 O 3 with MR = 1.3 (and 1.5 for three-component melts). The systems were measured from their temperature of primary crystallization (TPC) up to 800 °C.…”

Temperatures of Primary Crystallization and Density of the KF + AlF3 + LiF + Al2O3 Molten System

“…In the last 20 years many authors have carried out investigations of the physicochemical properties of various molten systems containing mixed Na/K cryolite or pure K cryolite. Investigation has mostly focused on liquidus temperatures, − alumina solubility, ,,,− and conductivity. ,,,,− Information on the density of potassium-based cryolite systems is very scarce. ,, …”