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- Chen, Chao, 1989-, et al.
(författare)
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Mathematical modelling of molten alloy mixing in a continuous casting tundish - A hydrodynamic study
- 2015
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Ingår i: Proceedings of the 6th International Congress on the Science and Technology of Steelmaking, ICS 2015. - : Chinese Society for Metals. ; , s. 407-411
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Konferensbidrag (refereegranskat)abstract
- The emergence of the nozzle clogging have inspired steelmakers to optimize the alloying routine from alloying in ladle to alloying in tundish or in continuous casting mould. Meanwhile, wire injection in tundish has been shown to be successful for postalloying and tundish temperature adjustment. However, there is limited information on the continuous feeding of alloy in tundishes. There are three aspects to be considered: a) "alloy melting", b) "alloy particle dispersion" and c) "liquid alloy mixing". In the present paper, the "liquid alloy mixing" process is studied using CFD (Computational Fluid Dynamics) from a hydrodynamic perspective. In the simulation, the molten alloy is described by the density coupled mixed composition fluid model, which has been verified and validated by water modelling experiments using black ink and KCl tracer mixing in water as a priori. In the present model, the density of the liquid alloy is assumed to be 1.15 or 0.85 times of that of the liquid steel. Thereafter, the denser alloy injection at two positions has been studied, i.e. near the inlet (L1) and at the centre of the tundish (L2). The results indicate that the breakthrough time for the mass fraction of alloy at the outlet are about 100s for both locations. The difference is when the alloy was injected at the center (L2), there is a bypassing flow above the dam. As a result, the mass fraction of alloy at the outlet increases rapidly but the homogeneity in the tundish bath is reduced. Moreover, the denser alloy injection with different velocities was studied. The result shows that the mixing is slightly enhanced during the initial injection stage for the big velocity case. Besides, a test simulation on the mixing of a lighter alloy indicates that the alloy is floating to the top surface.
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| 2. |
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| 3. |
- Kasedde, Hillary, et al.
(författare)
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Mineral recovery from Lake Katwe brines using isothermal evaporation
- 2013
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Ingår i: International Mine Water Association Annual Conference 2013. - : IMWA International Mine Water Association. - 9780615793856 ; , s. 855-860
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Konferensbidrag (refereegranskat)abstract
- Lake Katwe is a saline lake within the East African Rift system in Western Uganda, with a rich source of mineral salts. The present work aims at evaluating possibilities of future salt extraction from the lake deposit. An isothermal evaporation experiment was conducted on the lake brines. The precipitated salts were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. Various economic salts such as thenardite, gypsum, mirabilite, burkeite, hanksite, anhydrite, trona, halite, nahcolite, thermonatrite, and soda ash precipitate from the lake brines. The experiments also reveal the sequence of mineral salt precipitation in the order sulfates→chlorides→carbonates.
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