Effect of pyrophyllite on the properties of dinas

Abstract

This article contains the results of research into the effects of pyrophyllite on the properties of dinas refractories and is aimed at studying the possibility of extending the re~ serves of quartzite raw materials for their production.Pyrophyllite 3 AI203-4SiO='H20 [I] belongs to the micaceous group of materials~ Its chemical composition, %* is: A1203 28.3, Si02 66.7, H20 5.0. Impurities are en=ountered as MgO (up to 9%), FeO (up to 5%), Fe=O3, CaO, alkalies, and titania, Pyrophyllite normally consists of plate-rod accumulations or aggregates or cryptop!atelet, dense rocks, The mineral is white with yellow or pale green shades; it has a glassy shine with mother-of-pearl shades or pale-green shades; it is greasy to the touch, with a hardness of about i, Ng = 1.600, Np = 1.552, and N m = 1.588. The cleavage is excellent.The density is 2.66-2,90 g/cm 3.Pyrophyllite is encountered in association with quartz, carbonates, hematite, and other minerals formed as a result of the hydrothermal decomposition of ordinary acid~ igneous rocks; it is observed in metamorphic slates. During heat treatment pyrophyllite shows an endothermic effect at 710-800~ as a result of the dehydration [2] (according to data in [3] at 600-800~ and can be used as an independent refractory material.*Here and subsequently mass proportions are indicated.