Coloidhymic and reological characterization of aqueous suspensions of coral mud

Abstract

In this work the chemical and granulometric compositions, the colloidal characteristics, as well as the rheological behavior of the coral mud that is used in the High Pressure Acid Leach (HPAL) process were determined. Three suspensions were analyzed, one industrial and two prepared in the laboratory, with different dispersing media (process water and distilled water). It was determined that all samples have an average content of 89% by weight of Calcium Carbonate and that 70% of the particles have sizes smaller than 53 microns, with a particle size cumulative distribution that can be described by the model obtained by Pérez García [7], for lateritic suspensions. The aqueous coral mud exhibits colloidal properties, which are typical of the polidisperse aqueous systems where govern the superficial properties caused by the small crystalline particles. It was found that the magnitudes of the zero charge points (p.z.c) depend on the nature of the solid phase and the ionic composition of the dispersing medium, since in the suspensions prepared with distilled water the magnitude of the p.z.c is equal to 7,75 and in those suspensions prepared in the laboratory with process water the value of the p.z.c is 7,45. In all cases the rheological behavior of these suspensions is typical of the systems which exhibit plasticity, and could be described by the Bulkley-Herschel model with high regression coefficients.