Program > Browse abstracts by speaker > Gaborieau Marion

Stone wool, commonly used for building insulation, is obtained by fiberizing a silicate melt produced by melting various raw materials in furnaces such as E-melters. The raw materials are continuously fed into the furnace, where they react with the stone wool melt already present. To ensure that the fibering process, which takes place under the action of centrifugal force, runs smoothly, the melt leaving the furnace must contain as few impurities and unmelted pieces of raw materials as possible. This is why it is essential to constrain the raw material behavior once in contact with stone wool melt, in particular the time required to fully dissolve the most refractory raw materials depending on their particle size. Numerous studies have been carried out to determine the dissolution rates of oxides and minerals (e.g., Al2O3, MgO, spinel) in various industries (ladle, continuous casting, glass impurities). A few studies have also been carried out to understand the dissolution of limestone, but available data on more complex raw materials as dolomite are scarce.
In this study, we used an experimental approach to simulate the interactions between stone wool melt and complex raw materials such as dolomite and bauxite. Raw material cylinders of different diameters were heated for durations ranging from a few minutes to two hours, at 1500°C and 1 atmosphere in a stone wool melt. The experimental samples were characterized by X-ray tomography, scanning electron microscopy and electron probe microanalysis. The results obtained show that dissolution of dolomite and bauxite is complex, involving the interplay between several processes: degassing, thermal decomposition of primary minerals, partial melting, chemical interdiffusion between stone wool melts and raw material melts, and the formation of secondary refractory phases. The dissolution of these secondary phases controls the time scale of total dissolution of the raw materials.