Estudo reológico de argilas utilizadas em indústria de revestimento cerâmico do Cabo de Santo Agostinho – PE

Abstract

Clays are essential components for the production of ceramic coatings, and when they are combined for this purpose, they present different rheological characteristics according to particle size, mineralogical and chemical composition. The present work aims to study the structural, morphological characteristics and the influence of two de-flocculants, sound silicate and sound tripolyphosphate, on the rheology of clay mixtures used in coating coatings. Four clay mixtures were studied with a composition of 50% of four raw materials donated by the coating industryin Cabo de Santo Agostinho – Pernambuco combined with 50% clay also donated by another industry in the sector located in the Northeast region. The clay powders were processed and characterized by X-ray diffraction (XRD) and particle size distribution by laser diffraction. Next, rheology was evaluated by determining deflocculation curves as a function of flow time for clay mixtures in wet suspensions (50% solids). Based on the results, the presence of kaolinite, quartz and mica phases was identified. The morphology of the samples presented different particle size ranges ranging from 0.1 μm to 100 μm. The rheology of the suspensions produced three more viscous samples, with plasticity indices, different from the remaining sample, which presented characteristics of a fluid suspension. None of the clay mixtures indicate thixotropic characteristics. The sodium tripolyphosphate deflocculant promoted the best deflocculation results for all clay mixtures, while the sodium silicate provides overdeflocculation at lower rates.