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Luleå, Sweden

Lindvall M.,Swerea MEFOS | Rutqvist E.,LKAB Technology and Business Development | Ye G.,Swerea MEFOS | Bjorkvall J.,Swerea MEFOS | Sichen D.,KTH Royal Institute of Technology
Steel Research International | Year: 2010

Experiments on a vanadium recovery method from vanadium containing BOF-slag using both a Tamman furnace (3 kg scale) and an induction furnace (150 kg scale) were conducted. The vanadium was extracted into the slag phase by bubbling oxidation gas into a metal bath consisting mainly of V (1-10 mass%), Si (less than 1 mass%) and P (about 1 mass%). The first experiments revealed that the slag formed during oxidation reaction had considerably high phosphate capacity. High phosphorus content would rule out the possibility of using the slag as a raw material for the production of ferrovanadium of high quality. In order to reduce the P-content in the slag, addition of slag former to reduce phosphate capacity was necessary. A suitable slag system (having the initial composition 40 mass% Al2O3 - 25 mass% CaO - 35 mass% SiO2) and a suitable atmosphere, by using CO2, that enhanced the oxidation of vanadium, but limit the oxidation of iron and phosphorus was found. However, more efforts should be put forward, e.g. study of the phase diagram, the viscosity of the slag and even oxide activities to gain more insight into the slag formed by selective oxidation. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Lindvall M.,Swerea MEFOS | Gran J.,Swerea MEFOS | Sichen D.,KTH Royal Institute of Technology
Calphad: Computer Coupling of Phase Diagrams and Thermochemistry | Year: 2014

Vanadium (V) solubility in the Al2O3-CaO (25 mass%)-SiO2 system was determined experimentally at 1873 K and at a fixed oxygen potential of 9.37×10-11 bar. EPMA microanalyses were employed to identify the phases and their compositions in the quenched samples. It showed that the solubility of V-oxide increased slightly with decreasing Al2O3-content in the interval from 3 mass% to 53 mass%. The maximum V-solubility was up to 7 mass% (as V). A solid solution rich in V-oxide was detected. The Al2O3 solubility in this solid solution was found to increase with increasing Al2O 3-content in the liquid. © 2014 Elsevier Ltd. Source


Zetterholm J.,Lulea University of Technology | Ji X.,Lulea University of Technology | Sundelin B.,SSAB | Martin P.M.,Siemens AG | Wang C.,Swerea MEFOS
Applied Energy | Year: 2016

A large amount of energy is required in the production of steel where the preheating of blast in the hot blast stoves for iron-making is one of the most energy-intensive processes. To improve the energy efficiency of the steelmaking it is necessary to investigate how to improve the hot blast stove operation.In this work a mathematic model for evaluating the performance of the hot blast stove was developed using a finite difference approximation for the heat transfer inside the stove during operation. The developed model was calibrated and validated by using the process data from hot blast stove V26 at SSABs plant in Oxelösund, Sweden. The investigation shows a good agreement between the measured and modelled data.As a case study, the developed model was used to simulate the effect of a new concept of OxyFuel technique to hot blast stoves. The investigation shows that, by using this OxyFuel technique, it is possible to maintain the blast temperature while removing the usage of coke oven gas (COG). The saved COG can be used to replace some fossil fuel, such as oil and LPG.Furthermore, the effect of the cycle time on the single stove was studied. As expected, both the hot blast and flue gas temperatures are increased when increasing the cycle time. This shows that it is a good strategy for the hot blast stove to increase the blast temperature if the stove is currently not operated with the maximum allowed flue-gas temperature. © 2016 Elsevier Ltd. Source


Millman M.S.,Tata Research Development And Design Center | Overbosch A.,Tata Research Development And Design Center | Kapilashrami A.,Tata Research Development And Design Center | Malmberg D.,Swerea MEFOS | Bramming M.,SSAB
Ironmaking and Steelmaking | Year: 2011

A unique in blow sampling system has been applied to a blowing converter to retrieve simultaneously representative bulk metal bath and slag/metal emulsion samples from seven specified positions and every 2 min from start of blow. Full sample datasets from 20 heats have been grouped according to differences in the bulk bath phosphorus removal profiles and analysed with respect to relative refining ability of the slag/metal emulsion and the bulk metal bath. The complexity of the thermokinetic relationships behind the removal of carbon and the transfer of silicon, phosphorus, manganese and sulphur between the metal and slag is highlighted and the metal circulation rate in the emulsion is derived. © 2011 Institute of Materials, Minerals and Mining. Source


Karlberg M.,Swerea MEFOS
ISIJ International | Year: 2011

It has always been of greatest importance to control the temperature distribution in the products throughout the hot strip rolling process including the final coiling operation. A computational model of the latter has been developed and validated, which is presented in this paper. Furthermore, the influences of the different parameters on the transient thermal distribution are evaluated. The formulated model as accounts for twodimensional heat conduction is assuming axi-symmetric conditions. Temperature dependent properties are accounted for results in a nonlinear heat conduction problem that is solved by use of the Finite Element Method (FEM). The calculations have been validated by two full scale measurement campaigns and show a good agreement with measurements. © 2011 ISIJ. Source

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