Papers by Keyword: Aluminium Refining

Abstract: Today physical modelling is a commonly used tool in modelling metallurgical processes. It can be applied both in steel metallurgy and non-ferrous metals metallurgy processes. It gives the opportunity to determine the hydrodynamic conditions of the processes. Although, the flow of mass and gas is not totally presented by such modelling, this kind of research is very often and willingly used. That is because it is really difficult to conduct experimental research in industrial conditions. Typically water is used as a modelling agent, so the physical modelling is not as expensive as the one carried out in industrial conditions. To obtain representative research from physical modelling the physical models have to be built according to the strict rules coming from the theory of similarity. The results obtained from the experimental test on the physical model, after verification, can be transferred to the real conditions. The article shows the obatined results coming from physical modelling of the steel production process. In the Institute of Metals Technologies of Silesian University of Technology the appropriate test stand was built to simulate the steel flow and mixing in the ladle. The visualization results have been presented. To simulate processing condition during aluminium refining additional test stand was also built. The exemplary results have been shown for different flow rate of gas, rotary impeller speed and different shapes of impellers. All presented results have been discussed and presented for the perspectives of further research.

Abstract: Today aluminium obtained from ores (primary) and from scrap (secondary) need to be refined. During this process harmful impurities such as hydrogen, sodium, lithium, oxides, borides or carbides can be removed. There are many different ways of aluminium refining process. The most popular seem to be barbotage that means blowing through aluminium many tiny gas bubbles of refining gas. Reactors applying this methods have been working all over the word. They are of different types: bath and continuous, using ceramic porous plugs, special kinds of nozzles or rotary impeller for generating small gas bubbles. At present reactors for continuous refining have become the most popular. In Poland typical representative of such reactors is URC-7000 reactor. The phenomena occurring during this process are rather complicated. Therefore to know them better the modelling research is applied, especially physical modelling. The paper presents the results of such a research. The tests were carried out in the test stand for modelling the babotage process in the URC-7000 reactor. The different modelling agents were tested (water, glycerin and mixture of water and glycerine). The density and viscosity of water and glycerin mixture were determined. Modelling tests were conducted for four different flow rates of refining gas: 6, 10, 15 and 20 dm3/min. Results were registered by digital camera. Pictures for different modelling agents were juxtaposed and discussed.

Abstract: At present both primary and secondary aluminium needs to be refined before further treatment. This can be done by barbotage process, so blowing small bubbles of inert gas into liquid metal. This way harmful impurities especially hydrogen can be removed. Barbotage is very complex taking into consideration hydrodynamics of this process. Therefore modelling research is carried out to get to know the phenomena that take place during the process better. Two different modelling research can be applied: physical and numerical. Physical modelling gives possibility to determine the level of gas dispersion in the liquid metal. Whereas, numerical modelling shows the velocity field distribution, turbulent intensity and volume fraction of gas. The paper presents results of physical and numerical modelling of the refining process taking place in the bath reactor URO-200. Physical modelling was carried out for three different flow rate of refining gas: 5, 10 and 15 dm3/min and three different rotary impeller speeds: 0, 300, 500 rpm Commercial program in Computational Fluid Dynamics was used for numerical calculation. Model VOF (Volume of Fluid) was applied for modelling the multiphase flow. Obtained results were compared in order to verify the numerical settings and correctness of the choice.

Abstract: Today the barbotage process is commonly used for refining aluminium and its alloys. There are many refining reactors available all over the world. The refining gas can be introduced to the liquid metal by nozzles, ceramic porous plugs and rotary impellers. The last ones become the most popular. The shape of impellers is different and influences the level of gas dispersion in the liquid metal. Physical modelling is quite often used for modelling the aluminium barbotage process. In this way it is possible to observe the phenomena that take place in the whole process. Results obtained from this kind of research can be representative and transformed to real conditions if the test stand is built according to the theory of similarity. The test stand was built for modelling the refining process in the URO-200 reactor. Three different shapes of impellers were tested. The processing parameters like the flow rate of refining gas and the impeller rotary speed changed in the range from 5 to 15 dm³/min and from 0 to 500 rpm respectively. Additionally the research of oxygen removal from water was carried out as an analogy of hydrogen removal from liquid aluminium. The level of oxygen was measured by means of oxygen meter Elmetron CO-401. The obtained results were discussed and graphically presented.

Abstract: Today the aluminium refining process, especially barbotage is one of the most essential necessary technological stages in obtaining aluminium. It gives possibility to remove undesirable hydrogen and non-metallic and metallic inclusions from aluminium. Phenomena that take place during the barbotage process are rather complicated, but the knowledge about their character enables to optimize and control this process. Modelling research is used to outline these phenomena. Physical and mathematical modelling can be applied in carrying out aluminium barbotage process. Mathematical modelling uses numerical methods to solve the system of differential equations. The paper presents results of physical and numerical modelling of the refining process taking place in the continuous reactor URC-7000. Physical modelling was carried out for the different flow rate of refining gas (argon). It was in the range between 2 to 25 dm3/min. Numerical calculation was done using commercial program in Computational Fluid Dynamics (CFD). Model Volume of Fluid (VOF) was applied in modelling the multiphase flow. Obtained results were compared in order to verify the numerical settings and correctness of the choice.