Numerical model of electrolytic pickling for the stainless steel industry

Aperam is a listed multinational company in stainless steel. The company has 6 production facilities located in Belgium (2), France (3) and Brazil (1). Aperam employs 9500 people. 1100 of them are based in Genk which makes the Aperam Genk plant one of the largest and most important employers in the region. The current production capacity of Aperam is 2.5 million tons of flat stainless steel. Approximately 40% is produced in the Genk plant. The production of stainless steel holds a series of well defined productions steps. One of the most important production steps is the pickling process which removes the surface oxide layer (a.k.a. scale) formed during previous steps. This pickling process is executed in two subsequent stages: electrolytic pickling and chemical pickling. Electrolytic pickling is commonly used in the industry to remove the out-most oxide layer, followed by chemical pickling to remove the chromium-depleted layer. Unfortunately the current electrolytic pickling efficiency is low (down to 30%) and the process itself is poorly understood. Indeed, electrolytic pickling is a complex process involving two-phase fluid flow, electrochemical reactions and a varying current distribution. To be able to increase the efficiency and to access and optimize the different pickling configurations a numerical model is needed. This PhD proposal involves the development of such a numerical model to simulate the current density through the electrodes, electrolyte and the moving steel strip. With this model we should be able to access the influence of the pickling cell geometry, the material properties of the steel strip and the electrodes (anode, cathode), the electrolyte conductivity and temperature and the strip speed.