Novel Molten Salts Media For Production of Functional Materials

Olga Tkacheva,Alexander Kataev,Yuriy Zaikov,Alexander Dedyukhin,Alexey Rudenko,Alexander Redkin,M Jawaid,El-R Kenawy

doi:10.1051/matecconf/20166706044

Olga Tkacheva, Alexander Kataev + Show 6 more

Open Access

https://doi.org/10.1051/matecconf/20166706044

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Abstract

Physical-chemical properties of molten salt media based on potassium cryolite with additions of boron or scandium oxides have been considered from the point of view of their feasibility in production of functional materials, such as aluminum alloys. Liquidus temperature in the quasi-binary systems: [KF–AlF 3 ]-B 2 O 3 , [KF–AlF 3 ]-Sc 2 O 3 , [KF–NaF–AlF 3 ]-B 2 O 3 , and [KF–NaF–AlF 3 ]-Sc 2 O 3 has been measured by thermal analysis. Solubility of Al 2 O 3 , B 2 O 3 , and Sc 2 O 3 in potassium and potassium-sodium cryolites has been determined. The potassium-cryolite-based melts were found to have an enhance protective function due to a low melting point, and an effective refining ability due to a good alumina solubility. It has been assumed that for aluminum alloys production the potassium-cryolite-based melts can be used as fluxes with improved properties as well as electrolytes for low-temperature electrolysis.

Highlights

A modern industry is closely connected with a development of functional materials, to which the aluminum alloys belong
A density of molten flux has to be much less than the molten aluminum density to the effect that the layer of liquid flux could be settled on the aluminum surface
Scandium-containing (Sc2O3) additions to the molten KF-AlF3 and KF-NaF(10 wt%)-AlF3 mixtures with cryolite ratio (CR)=1.3-1.5 on the key electrolyte properties: liquidus temperature and solubility of alumina and alloying additions, in order to identify a feasibility of the potassium-cryolite-based melts as fluxes or as electrolytes-solvents in production of aluminum alloys

Summary

Introduction

A modern industry is closely connected with a development of functional materials, to which the aluminum alloys belong. It is known that the alkali fluorides are capable to dissolve alumina They act as surface-active additives, enhance wetability and conduce to separation of oxides, flux and molten aluminum. With low cryolite ratio (CR), which is determined as CR = NKF/NAlF3 (mol/mol) for the KF-AlF3 or as CR = (NKF + NNaF)/NAlF3 (mol/mol) for the KF-NaF-AlF3 mixture, are worth to be tested as basic components of flux. Scandium-containing (Sc2O3) additions to the molten KF-AlF3 and KF-NaF(10 wt%)-AlF3 mixtures with CR=1.3-1.5 on the key electrolyte properties: liquidus temperature and solubility of alumina and alloying additions, in order to identify a feasibility of the potassium-cryolite-based melts as fluxes or as electrolytes-solvents in production of aluminum alloys

Experimental

System “potassium-cryolite-based melt – B2O3”

System “potassium-cryolite-based melt – Sc2O3”

Findings

Conclusions