Estudo da estabilidade e secagem de polpas de hidróxido de magnésio

Abstract

Magnesia is a magnesium oxide (MgO) and is obtained by the processing of the mineral Magnesita. Among Magnesium derivatives, it is possible to highlight the Magnesium Hydroxide (HM), obtained by the hydration of magnesia in water and which has a growing demand in several industrial segments. Due to the use in several industrial sectors, the study of new routes becomes important since diversified characteristics must be assumed by the final product, in this sense the study of dispersed HM pulps from two different sources (HM-A and HM-B ), obtained by a process of reaction-fragmentation, in terms of its stabilization in a stationary system (sedimentation) and by means of acting shear forces (rheology) comparing both with a commercial product (HM-R). The results demonstrate that the dispersed HM pulps prepared by hydration have similarities of stabilizing behaviors to those obtained using an HM already available on the market. Due to the tendency of the particles of these pulps to agglomerate to form systems difficult to be resuspended (called by some authors as clusters), the use of the addition of anionic sodium polyacrylate dispersant in the pulps obtained with the objective the maintenance of the suspended particles during the processing of the product. The feasibility of using the spray drying technique in the drying of HM-R dispersed pulps was studied aiming at the future commercialization of the powdered product. The obtained results allow positive and unpublished conclusions that corroborate with the few works found in the literature in the study of the stabilization of HM pulps and in the drying in spray drier that proved to be feasible to be applied in both laboratory scale and plant scale pilot