Graduated from "Ecole Centrale Paris" in 1985
PhD. studies at "Ecole Centrale Paris" (1986-1989)
ALTRAN Technologies (1989-1991)
PECHINEY → ALCAN → RIO TINTO (1991-2009)
In this paper, we will present some recent examples of models and simulations that were developed to study and optimize metallurgical processes at ERAMET.
ERAMET is a world leader in alloying metals, particularly manganese and nickel. ERAMET also designs and develops high-performance steels, tool steels, parts and products in high-speed steels, superalloys, aluminum and titanium alloys, using advanced foundry and forming processes (e.g. vacuum-induction melting, atomization and hot isostatic pressing, rolling, forging…). The materials and products designed are then used to supply high-technology markets such as aerospace, energy, nuclear, medical, automotive, etc. In addition, ERAMET has major research and development projects in new business lines with high growth potential, such as titanium dioxide, zircon, lithium, niobium and the rare earths, as well as recycling.
In this context, ERAMET Research, the corporate research center, is developing its expertise in the fields of mineralogy, hydrometallurgy and pyrometallurgy, as well as in the fields of physical characterization, chemical analysis and modeling. It essentially works for the plants and the Group's projects. Involved in the projects since their beginning, ERAMET Research then sets up pilot programs for the innovations it has developed and supports their roll-out on an industrial scale
In the first part of the paper, we will give an overview of the main characteristics of the metallurgical processes under investigation, and specifically the difficulties that researchers have to deal with, especially when they want to develop models to understand and improve these processes. The keyword here is "complexity", to be considered at different levels that will be covered in the paper.
In the next part, we will also detail the methodology and the modeling tools necessary to tackle these kinds of studies. Starting from the central concept of "metallurgical reactor", we will see the different approaches that can/should be followed to provide relevant information.
In the last part, we will then illustrate these concepts by showing several examples. The 1st one deals with the pre-reduction of manganese ore which is introduced in Submerged Arc Furnaces (SAF) to produce ferro-manganese alloys. Before reaching the deeper reduction region in the furnace, the ore is pre-reduced by the gases generated in the reduction zone. The promotion of a more complete pre-reduction could lead to an increase of the furnace efficiency. Different models to predict the pre-reduction mechanisms within the so-called burden have been developed in the past years to determine the impact of the ore characteristics on the pre-reduction levels. These models are based on ANSYS Fluent and include a set of user-defined functions to take into account the specific chemical reactions that represent the pre-reduction phenomenon.
The second example illustrates the development of a "reactor model". The studied reactor is a converter blowing gases into a 1200°C Ni-Fe-S melt for several hours to obtain the required composition at the end of the operation. Thus, the aim of the model is to simulate the chemical evolution of the different species, phases and temperature in the reactor as a function of time and for a given set of operating conditions. This work has been performed using MTDATA, a thermodynamic software package designed to compute the equilibrium state of a system as a function of temperature and elemental composition. A standard SCILAB script is used in parallel to deal with the coupling of the other transport phenomena (heat and mass transfer). The chosen approach is based on the construction of a meta-model taking into account the thermodynamic information. It is then fully embedded in SCILAB, making it possible to incorporate easily the thermodynamic data u sing the meta-model. Furthermore, this model is independent of the large thermodynamic database and can be more easily used for industrial process control.
The last example shows how numerical models can help the setup of industrial operations. The initial objective of this study was to determine the power of a burner required for the pre-heating of the ladles to be used as liquid metal receivers during a pilot campaign (manganese SAF). A 1st CFD ANSYS Fluent model has been developed to simulate the heating of the ladle walls due to the combustion gases inside the ladle cavity generated by a burner positioned above. A 2nd model describing the cooling phase (when the ladle is emptied) has been also setup. Knowing the heating target temperature at the inner surface of the ladle to prevent metal freezing, and the maximum admissible temperature for an operator to clean the inner surface when the ladle is emptied, it was possible to define the whole operating sequence and to know if it was necessary to use 2 or 3 ladles during the campaign.