Regeneration des sables de fonderie par le procede gaz-contact

In this work incineration of solid wastes is performed in a co-current gas-solid reactor. The proposed co-current gas-solid reactor is very attractive due to the direct contact of the solid waste with a high temperature flame produced by a counter-rotation burner. The burner is fitted at the top of the vertical cylindrical furnace where the falling used sand is incinerated by a co-current flow of hot gas.

The main objectives of this study are: (1) characterization of resin coating sand by thermal analysis, (2) development of an appropriate kinetic model from thermogravimetric data, (3) generalization of the optimal model developed for different foundry sands by making use of the hydrodynamics and heat transfer models that have been previously developed.

The thermal analysis method allows us to determine the initial temperature of resin decomposition along with the heat of combustion of combustible matter covering sand particles.

In order to be able to design and operate such gas solid reactor for the reclamation of foundry sand, a model previously developed by Mao was used for the prediction of the hydrodynamics and heat transfer. Although many models based on different controlling steps have been investigated, an optimum model of the gas-contact process for the treatment of the used sand is proposed. This model can predict satisfactorily the temperature profiles of both gas and solid particles as well as the degree of advancement of the incineration of combustible materials; in this model the incineration process is limited by chemical reaction. (Abstract shortened by UMI.)