Effect of andalusite rich schist grain size and the addition of metallic aluminum powder on the properties of silica–alumina refractory

Abstract

Refractory materials were elaborated from silica-alumina geomaterials related to granitoids and their direct surrounding rocks (kaolin clay and andalusite rich schist). The use of andalusite rich schist as aggregates (mean grain size: 1000-2000 m) could improve the mechanical properties of synthesized refractory. The flexural strength increased from 39.10 to 54.16 MPa. The pyroscopic temperature increased from 1400 to 1450 • C. Thermal conductivity of the porous brick produced in this study (1.11 W/m K) showed 39% of reduction compared to initial brick of the same composition (1.83 W/m K). The thermal shock tests showed that the refractory samples have a good thermal shock resistance.

Analysis of tiles produced from a schist material and their ultraviolet, near-infrared, mid-infrared, longwave-infrared and far-infrared spectra

“…The CaO reacts with the amorphous phase, which is derived from the decomposition of mica at increasing firing temperatures. An increase in water absorption is observed due to the release of CO 2 , which increases porosity (Sadik et al , 2013).…”

Composition and Ceramic Characteristics of Cretaceous Clays from Morocco

“…The relatively high mechanical properties of ceramic products are essentially due to their structure which is mainly composed of crystalline phases [10]. Refractoriness of a material is strongly dependent on microstructural parameters such as grain size and shape, the relative volume of solid and vitreous phases, the viscosity of the vitreous phase and porosity [4]. Refractoriness can be evaluated by examining the evolution of the morphology of test samples with increasing temperature under their own weight (without any other load).Refractoriness in this paper is defined as the temperature corresponding to the moment when a material begins to lose its shape (melting point).…”

“…Worldwide clays are the main raw materials exploited in the fabrication of diversified ceramic products for building construction [4][5][6][7][8][9][10]. For this reason, particular attention should be given to the exploitation of raw materials in Morocco for ceramic applications.…”

“…Between 1000 and 1200 °C considerable decrease in the porosity occurs, coinciding with the beginning of vitrification. The densification behaviour of the Cretaceous red clay is influenced by the sources of flux materials such as K 2 O, Na 2 O and Fe 2 O 3 , which favour the formation of a vitreous phase[4]. At 1100 °C the porosity starts to reduce, when a liquid phase was present.…”

Review on the elaboration and characterization of ceramics refractories based on magnesite and dolomite

“…Generally, every refractory is composed of four major structural elements that are depicted in Fig. 1 as the following; (1) aggregates (mean grain size: 1000-2500 mm) [3,4]; (2) matrix or filler materials smaller than 150 m; (3) binder, bond, or cement; (4) pores.…”