Synthesis of Al-Zr Master Alloys via the Electrolysis of KF-NaF-AlF₃-ZrO₂Melts

Abstract

Effects of the KF-NaF-AlF 3 melt composition, ZrO 2 concentration and aluminothermic synthesis parameters on the conversion rate of zirconium to aluminum were investigated. The kinetics of zirconium electroreduction on glassy-carbon obtained from KF-AlF 3 -ZrO 2 melts at a temperature of 750 • C was studied via the cyclic voltammetry method. Parameters of the electrolysis of KF-NaF-AlF 3 -ZrO 2 melts were derived on the basis of obtained results, and the theoretical possibility for the electrolytic production of Al-Zr master alloys (having up to 15 wt% zirconium content) was demonstrated.

Electrowinning of Aluminum and Scandium from KF-AlF3-Sc2O3 Melts for the Synthesis of Al-Sc Master Alloys

“…Significant prospects are related to the production of alloys and composite materials based on aluminum. [1][2][3] One of the highly-demanded products are the aluminum-scandium master alloys (Al-Sc master alloys) used for the production of the multi-functional aluminum alloys and composites. 4,5 However, the high prime cost of the produced Al-Sc master alloys does not allow them to be used in significant volumes in the automotive industry.…”

Review—Synthesis of Aluminum Master Alloys in Oxide-Fluoride Melts: A Review

“…Electrowinning of Zr and Al from the KF-AlF 3 melts.-The kinetics of the electrowinning of zirconium and aluminum from melts on tungsten is investigated in the works. 56,107 potential of about 0.05 V. With similarly thermodynamic probability of electrolytic decomposition of Al 2 O 3 and ZrO 2 oxides in the studied system, the discharge of zirconium at a more positive potential can be explained by the lowest resistance of zirconiumcontaining complexes. 78 When the potential is shifted to the anode region, a wide wave of dissolution of aluminum, zirconium and its compounds is observed.…”

“…3). 56 To determine the parameters of the electrical deposition of aluminum with silicon, zirconium, scandium, and boron a base KF-AlF 3 (CR = 1.3, 1.5) melt was used. Oxides were loaded into the melt according to its solubility values.…”

“…Synthesis of master alloys.-Master alloys was obtained in the corundum or graphite reactor in air by two ways: chemical (aluminum-thermal) and electrolytic. 56 For electrolysis graphite anode and liquid metal aluminum cathode (99.998 wt% grade) were used. The cathode with steel current-lead was also stirred with the rate of 0-100 rpm.…”

“…The peculiarity of aluminum alloys obtaining in KF-AlF 3 -based melts is that in the presence of liquid aluminum in the melt, one of the mechanisms of transition of the alloying element from oxides into alloy is aluminum-thermal reduction. [19][20][21]56,91 In this case, the maximum extraction of the alloying element from the oxide, as well as the possibility of continuous production of the master alloy is provided by the removal of products from the front of the aluminumthermal reaction (Fig. 16).…”