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- Björkman, Bo, et al.
(författare)
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Waste reduction through process optimization and development
- 1996
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Ingår i: JOM. - 1047-4838 .- 1543-1851. ; 48:3, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- In this article, the possibilities of optimizing metallurgical processes based on minimization for waste reduction and application requirements for the reuse of waste products are discussed together with the possibilities of treating existing waste in direct connection with the process involved. Some results from ongoing projects on controlled dust generation and an outline of an ongoing research program are also described.
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- Nedar, Lotta
(författare)
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Dust formation in a BOF converter
- 1996
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Ingår i: Steel research. - : Wiley. - 0177-4832. ; 67:8, s. 320-327
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Tidskriftsartikel (refereegranskat)abstract
- Four dust forming mechanisms can be considered in a BOF converter: ejection of metal, ejection of slag, entrainment of charged material and vaporization. In order to determine the importance of the four dust forming mechanisms and to characterise dust, with special emphasis to zinc, the off-gas from a 100-t BOF was sampled during twenty seven heats. The sampling equipment allows the sampling of both solid dust particles and vaporized elements. Samples from the first and the second part of blowing show significant differences both in chemical composition and in the origin of formation. The major dust formation mechanism is the ejection of metal and slag, respectively. Entrainment of solids plays an important role only during the first part of blowing. Vaporization of elements from the bath is most important during the end of blowing. The formation of dust is influenced by process operation control, especially lance position, silica contents and time of charging of slag formers. Zinc is mostly found on the rim of ejected particles where a gradual transition of zinc oxide to zinc ferrite to iron oxide is found. At sampling temperatures of 800-1000°C most of the zinc had already condensed. (
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4. |
- Nedar, Lotta, et al.
(författare)
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Mechanisms of dust formation in LD-converter : conclusions from characterization of dust and thermodynamic modelling of condensed compounds in the gas duct
- 1996
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Ingår i: 79th Steelmaking Conference proceedings. - Pittsburgh, Pa : Iron and Steel Society. - 1886362114 - 1886362122 ; , s. 755-762
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Konferensbidrag (refereegranskat)abstract
- To investigate the importance of the vaporization in the BOF process the vaporization from a steel bath was simulated together with the condensation of the resultant gas phase. An additional calculation was also made to simulate the condensation when the actual BOF dust composition was used. The course of condensation was investigated to determine the final products. The results from the calculation was compared with the results from hot gas sampling in the off gas system of a 100-t BOF. Four gas atmospheres were used to study the influence of the different oxygen potentials on the condensation reactions. Special emphasis was put on the condensation reactions of zinc. The results show the importance of the vaporization in the hot spot from which especially the elements having low vapour pressure will be vaporized. The increased oxygen potential will mostly influence the course of condensation but not very much the final products. The calculated condensation temperatures indicate a possible temperature span suitable for separation of zinc, alkali and chlorine gas from dust by gas treatment at high temperature in BOF. Dust are characterized by a complex mineralogical composition and especially the surface of the ejected metal and slag particles seem to be the nucleus for condensation and perhaps subsequent oxidation reactions
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