Preparation and Characterization of Some Particulate Materials in the Aluminum Industry

Preparation and characterization techniques for the following particulate materials are reviewed: micromineralogical samples of bauxite, alumina and its trihydroxide, as well as sedimentary and respirable particles. Scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDS) and image analysis were used to characterize the microminerals of bauxite. Comparisons were made among micromineralogical samples with various grain size fractions and the degree of weathering could be quantified. Programs were developed for characterization of the sandy and floury types of aluminum trihydroxide and alumina. We have used backscattered electron SEM images to characterize the size and shape of various aluminum trihydroxides. Comparison could be made between sandy and floury types of aluminum trihydroxide/alumina samples and the effects of technological changes could be quantified. The shape and composition of respirable particles in alumina plants were studied from the point of view of environmental protection

PREPARATION OF RAW MATERIALS FOR FINE CERAMICS IN PLASMAS

Les matériaux céramiques sont indispensables dans la technologie au température élevée dues à leurs qualités mécaniques, électriques, magnétiques et optiques. Par celle présentation nous voulons donner les détails des différentes types des équipements de plasma et des technologies qui ont été développées pour préparer des poudres céramiques.Ceramic materials as silicon nitride, aluminium oxide, titanium nitride are promising materials for the high temperature technology due to their good mechanical, electrical, magnetic and optical properties. For preparation of these materials plasma technique represents a very important field, because ceramic powders have been successfully synthetized in thermal plasma reactors. Different types of plasma equipments were developed and some technologies were evaluated in this work for preparation of the above mentioned ceramic raw materials