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Papers by Jan van der Stel

Matériaux et techniques, Dec 31, 2022

Ironmaking & Steelmaking, Oct 1, 2013

$Research paper thumbnail of Effect of binding system on the compressive behaviour of refractory mortars$

Journal of The European Ceramic Society, Nov 1, 2014

For many decades use of infrared equipment has been common practice at Hoogovens, both in process... more For many decades use of infrared equipment has been common practice at Hoogovens, both in process control and research. The development of modern thermal imagers gives new opportunities for the steel and aluminium industries. Thermal imaging has been used in applications for cokemaking, iron making and steelmaking, web handling, annealing and high pressure die casting of aluminium. This paper presents some results of these industrial measurements.

Revue de métallurgie, 1996

Ti-stabilized ultra-low carbon steel grades have extremely good deep drawing properties. These gr... more Ti-stabilized ultra-low carbon steel grades have extremely good deep drawing properties. These grades, however, are sensitive to surface defects in the cold rolled product. Optical inspection techniques are extensively used, both manual and automated ; by these methods, only the surface can be inspected. Defects below the surface have to be made visible by the use of other techniques.Ultrasonic and magnetic techniques, which can be used for the detection of small defects, are described. Sheet material having non visible defects in hot rolled and cold rolled condition has been inspected. Results are presented and discussed.

Revue de métallurgie, Mar 1, 1992

The tundish is an effective metallurgical reactor for the improvement of steel cleanliness. Durin... more The tundish is an effective metallurgical reactor for the improvement of steel cleanliness. During the last two years, in a joint research program, Hoogovens and Irsid have examined several aspects of tundish metallurgy. Different advanced techniques have been studied : –basic powders, as a metallurgical active slag ;–dams and weirs, for flow control; an optimization of fluid flow has been assessed with the use of modern numerical calculation techniques ;– filtering, argon bubbling and control of the atmosphere in the tundish are aids to decrease the oxidic level in the steel.To assess steel cleanliness, total oxygen measurements combined with sophisticated inclusion count methods have been applied.

Physica status solidi, Mar 16, 1989

Ironmaking & Steelmaking, Jul 27, 2018

Melting and reduction of fine iron ore particles in the gas environment of a HIsarna smelting cyc... more Melting and reduction of fine iron ore particles in the gas environment of a HIsarna smelting cyclone is a critically important topic, but very limited information is currently available except for some experimental data from high temperature drop tube furnace (HTDF). This work discusses the equilibrium state of reacting iron ore in the HTDF environment by thermodynamic calculations to strengthen the understanding of the HIsarna process. The limit of reduction termination of the ore particles was estimated in the calculation for the thermal decomposition and topochemical gas reduction. The theoretical calculation results are compared with the experimental data from the previous studies. Furthermore, variation of slag composition and iron valence states were estimated theoretically to understand the effects of post combustion ratio value and hydrogen/carbon ratio on the equilibrium state of the ore particles in the reducing gas.

Aiche Journal, Feb 10, 2022

Magnetic particle tracking (MPT) was employed to study a rotating drum filled with cork particles... more Magnetic particle tracking (MPT) was employed to study a rotating drum filled with cork particles, using both air and water as interstitial medium. This noninvasive monitoring technique allows for the tracking of both particle translation and rotation in dry granular and liquid–solid systems. Measurements on the dry and floating bed rotating drum were compared and detailed analysis of the bed shape and velocity profiles was performed. It was found that the change of particle–wall and particle–particle interaction caused by the presence of water significantly affects the bed behavior. The decreased friction leads to slipping of the particles with respect to the wall, rendering the circulation rate largely insensitive to increased drum speed. It was also found that the liquid–particle interaction is determining for the behavior of the flowing layer. The well‐defined experiments and in‐depth characterization performed in this study provide an excellent validation case for multiphase flow models.

International Journal of Multiphase Flow, Nov 1, 2020

Liquid-solid systems are frequently encountered in industrial processes and it is broadly recogni... more Liquid-solid systems are frequently encountered in industrial processes and it is broadly recognised that numerical simulations are a useful tool for gaining insight in these processes. In this study, the unresolved CFD-DEM approach is extended with a complete momentum coupling for liquid-solid flows. Established correlations are used for the drag and lift forces, while new implementations are introduced for the unsteady interaction forces. A virtual mass force model based on the work of Felderhof (Felderhof 1991) is introduced, which accounts for the local particle volume fraction and the liquid-solid density ratio. The Basset history force, which is usually neglected due to computational difficulties related to its implementation, is evaluated according to the approach proposed by Parmar et al. A liquid fluidised bed is used as a demonstration case for the extended model. In this work, it is shown that with appropriate stabilisation measures, the Basset history force is approximated accurately (within 5%), while computational efficiency is maintained (< 30% increase in computational time). Furthermore, the relevance of the complete momentum coupling is demonstrated by analysis of the solids mixing in the liquid fluidised bed. It is shown that when accounting for the complete interaction force, solids mixing is up to 20% slower compared to simulations with the drag-only approach.

Journal of Iron and Steel Research International, Apr 13, 2019

HIsarna is a promising ironmaking technology to reduce CO 2 emission. Information of phase transf... more HIsarna is a promising ironmaking technology to reduce CO 2 emission. Information of phase transformation is essential for reaction analysis of the cyclone reactor of the HIsarna process. In addition, data of density and volume of the ore particles are necessary for estimation of the residence time of the particles in the cyclone reactor. Phase transformation of iron ore particles was experimentally studied in a drop-tube furnace under simulated cyclone conditions and compared with thermodynamic calculation. During the pre-reduction process inside the reactor, the mineralogy of iron ore particles transforms sequentially from hematite to sub-oxides. The density changes of the particles during the melting and reduction can be predicted based on the phase composition and temperature. Therefore, density models in the studies were evaluated with reported experimental data of slag. As a result, a more reliable density model was developed to calculate the density of the formed slag containing mainly FeO-Fe 2 O 3. The density and volume of the partially reduced ore particles or melt droplets were estimated based on this model. The results show that the density of the ore particles decreases by 15.1% at most along the progressive reduction process. Furthermore, the model results also indicate that heating, melting and reduction of the ore could lead to 6.63-9.37% swelling of the particles, which is mostly contributed by thermal expansion. It would result in corresponding variation in velocity of the ore particles or melt droplets during the flight inside the reactor.

Ironmaking & Steelmaking, Mar 21, 2019

High-temperature reduction processes of iron oxide particles suspension are promising in carbon e... more High-temperature reduction processes of iron oxide particles suspension are promising in carbon emission abatement. Recently, researchers have contributed abundant knowledge of the reaction mechanism and kinetics of iron oxide particles above 1473 K, while there was very limited information 10 years ago. Although the understanding of the high-temperature reduction of iron oxide particles is still not comprehensive, a brief review of the academic reports is helpful for the future work on this topic. The high-temperature reduction of iron oxide suspension is characterized by having: rapid reaction, obvious thermal decomposition and melting process. Evaluation of the kinetic data shows that the reduction process of single particles is not rate-determined by the diffusion process at the studied temperatures. The reaction rate constant is within 10 −2-10 s −1 in these studies. Furthermore, comparing previous studies in iron oxide reduction field, the phase transformation and effect of gangue minerals to the reduction of iron oxide particles above 1473 K requires more input and research.