Rheological properties of the raw material used in the Santa Gertrudes Ceramic Cluster proceeding from the Corumbatai Formation located in the Rio Claro, SP area

Abstract

Silstones and mudstones from the Corumbatai Formation are exploted as raw material for the ceramic industries of Santa Gertrudes'Cluster Lithotypes from three quarries (Granusso, Tute and Cruzeiro), located in the Rio Claro region -SP- Brazil, were characterized)rheologically (deflocculation curve, solid critic content and aging time), representing the entire stratigraphic column of this formation. The results obtained were correlated with the mineralogical composition. The lithotypes in the lower part of the formation deflocculated very well, with small doses of deflocculant, and were generally composed of illite, feldspar, quartz, hemotite, chlorite, and interstratified (chlorite together with expansive clay minerals or illite together with expansive clay minerals). The majority of the lithotypes found at the top of the formation deflocculated. However, for this to occur, a greater amount of deflocculant was necessary, in comparison to the amount used for the bottom samples. The lithotypes found at the upper part contained the same minerals as the bottom, but in addition, corbonates were found. One of the samples, collected at the top Tute quarry showed evidences of wathering and did not deflocculate. The corbonates of the top strata and the supergenic alteration damaged the deflocculation. The maximum amount of solids in the suspension was 66% in weight for the the lithotypes from the top. The test samples presented characteristics of suspension aging, however after 120 hours their viscosity was similar t0 that used in the file industry.