Kinetics of Zinc Evaporation from Aluminium Alloys Melted Using VIM and ISM Technologies.

Albert Smalcerz,Maciej Jodkowski,Jerzy Labaj,Adrian Smagor,Bartosz Wecki,Leszek Blacha

doi:10.3390/ma14216641

Albert Smalcerz, Maciej Jodkowski

Open Access

https://doi.org/10.3390/ma14216641

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Abstract

Using a vacuum during the smelting and refining of alloys removes dissolved gasses, as well as impurities with high vapour pressure. When smelting is carried out in vacuum induction furnaces, the intensification of the discussed processes is achieved by intensive mixing of the bath, as well as an enhanced mass exchange surface (liquid metal surface) due to the formation of a meniscus. This is due to the electromagnetic field applied to the liquid metal. This study reports the removal of zinc from the Al-Zn alloy containing 6.3 wt.%. Zn. The experiments were carried out with the use of two types of metallurgical devices: the VIM and ISM furnaces. For the experiments carried out in the crucible induction furnace, reduction in the operating pressure in the furnace from 1000 Pa to 10 Pa, together with the increase in temperature from 953 K to 1103 K, is accompanied by a decrease in zinc content in the alloy from 6 to 96%, compared with the initial value. Simultaneously, the overall mass transfer coefficient kZn increases from 5.15 × 10−6 to −1.49 × 10−4 ms−1. For the experiments carried out in the furnace with a cold crucible (T = 953 K), a reduction in the operating pressure in the furnace from 1000 Pa to 10 Pa resulted in a decrease in zinc content in the alloy from 18 to 80%, compared with the initial value. For comparison, the experiments carried out in the crucible induction furnace at 953 K showed a reduction in zinc content in the alloy from 6 to 50%, which means that more intense zinc evaporation is seen in the furnace with a cold crucible. Comparison of ISM and VIM technologies in the removal efficiency of the Al-Zn alloy indicates a higher removal efficiency using the first technology, which, using the same conditions, achieves 80% of the removal efficiency of the component.

Highlights

The dynamic development of the world economy requires the supply of more and more materials that meet high-quality requirements
The emerging of secondary materials the exhausting of natural resourcesbase of that secondary rawfor materials and thehave exhausting existing resources natural resources mean the search solutions that the potential in the area ofofprocessing and meanrecovery that the search for solutions that have the potential in the area of processing selective of materials with complex chemical compositions are ofand selective materials complex chemical are interest
We observe a significant increase in the bath surface due to the formation of a meniscus, which is an effect of the electromagnetic field acting on the liquid metal

Summary

Introduction

The dynamic development of the world economy requires the supply of more and more materials that meet high-quality requirements. Metals belong to the group of strategic construction materials, but the basic issue of their use in advanced solutions is their purity. The emerging solutions based on scientific studies and the increasing technical possibilities of building advanced metallurgical structures create new possibilities, especially in the area of selective metal preparation and purification. In the literature on the subject, one can find a well-documented database of results concerning metal refining processes with the use of melting aggregates based on inductive. The emerging of secondary materials the exhausting of natural resourcesbase of that secondary rawfor materials and thehave exhausting existing resources natural resources mean the search solutions that the potential in the area ofofprocessing and meanrecovery that the search for solutions that have the potential in the area of processing selective of materials with complex chemical compositions are ofand selective materials complex chemical are interest

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