Physical Modeling of the Impeller Construction Impact on the Aluminum Refining Process.

Mariola Saternus,Tomasz Merder

doi:10.3390/ma15020575

Mariola Saternus, Tomasz Merder

Open Access

https://doi.org/10.3390/ma15020575

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Abstract

Obtaining high-quality aluminum is associated with the use of an effective method of refining, which is argon-purging, in which gas bubbles are introduced into the liquid metal by means of rotary impellers. Various rotary impellers are used in the industry; however, if a newly designed impeller is constructed, it should be tested prior to industrial use. For this purpose, physical modeling is used, which enables the investigation of the phenomena occurring during refining and the selection of optimal processing parameters without costly research carried out in the industry. The newly designed rotary impeller was tested on the physical model of a URO-200 batch reactor. The flow rate of refining gas was: 10, 15 and 20 dm3·min−1, whereas rotary impeller speed was 300, 400 and 500 rpm. The research consists of a visualization test showing the schemes of the gas bubbles’ dispersion level in the liquid metal and experiments for removing oxygen from water, which is an analogue of removing hydrogen from aluminum.

Highlights

There is a steady increase in aluminum production due to the growing demand for aluminum products
The main goal of refining is to remove unwanted hydrogen from liquid metal, which is the main reason for the porosity, leading to a deterioration of the strength properties of finished aluminum products [1,2,3,4,5]
Physical modeling is a good and helpful tool to better understand phenomena occurring during the refining process of aluminum and its alloys by purging them with argon

Summary

Introduction

There is a steady increase in aluminum production due to the growing demand for aluminum products. Obtaining a high purity of aluminum and its alloys became a basic technological steps. It is used both in the production of primary aluminum (from bauxite) and secondary aluminum (from scrap). Contaminating elements such as hydrogen, alkali metals, alkaline earth metals and inclusions like oxides, borides, carbides and chlorides can be introduced into the liquid metal from a raw alumina feed, electrolyte cell, anode, refractory cells and furnaces and the atmosphere causing serious defects if they exceed the assumed safe level. Impellers are generally classified into two types: pump type and propeller type

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