Estudo comparativo de dispersantes químicos na distribuição granulométrica a laser de argilas.

Abstract

Due to the high surface energies of the ceramic powders, when in liquid medium, the van der Waals forces act in the direction of the destabilization of the suspensions by the formation of agglomerates. In order to eliminate these effects, substances that neutralize this reactivity among the particles, called deflocculants, are used. The efficiency of the deflocculants is investigated through deflocculation curves, which determine the least amount of deflocculant required to drive the suspensions to their lowest apparent viscosity values. Thus, the objective of this work was to investigate the influence of the concentration and type of deflocculant on the physical properties, through the laser granulometric analysis of bentonite and kaolinite clays, from the State of Paraíba and industry. The clays were characterized physically, chemically and mineralogically by the following techniques: granulometric analysis by laser diffraction, X-ray diffraction, chemical analysis by X-ray fluorescence, thermal analysis and cation exchange capacity. The clays were dispersed at 4% solids concentration with sodium silicate, sodium hexametaphosphate, sodium carbonate, sodium hexametaphosphate + sodium carbonate, sodium carbonate + sodium hexametaphosphate and sodium silicate + sodium hexametaphosphate, in order to to obtain their respective deflocculation curves. The results confirm that the best deflocculant for bentonite clays was sodium hexametaphosphate + sodium carbonate and for the kaolinite clays was sodium hexametaphosphate, as they presented a higher percentage of accumulated volume with a diameter of less than 2 μm and a smaller average diameter, the granulometric analysis. The Cillas 1064 equipment presented greater potential to be used in the study of particle size distribution analysis of the clays of Paraíba State.