Sintering of anorthite based ceramics prepared from kaolin DD2 and calcite

Abstract

In this work, the preparation of anorthite based ceramics using a modified milling system and 80 wt% kaolin (DD2 type) and 20 wt% calcium oxide extracted from CaCO3 is shown. The choice of these raw materials was dictated by their natural abundance. Previous studies have shown that a simple and vibratory multidirectional milling system using a bimodal distribution of highly resistant ceramics can be successfully used for obtaining fine powders. The prepared samples were sintered at different temperatures ranging between 800 and 1100 °C. It has been found that the relative density of samples sintered at 900 °C for 1 h with a heating rate of 5 °C/min was about 96% of the theoretical density of anorthite (2.75 g/cm3). Finally, the prepared samples were also characterized by scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

Mechanical properties of anorthite based ceramics prepared from kaolin DD2 and calcite

“…The main phase detected in samples fired at different temperatures was only anorthite (CaO.Al 2 O 3 .2SiO 2 , JCPDS 20-0020), as illustrated in Fig. 3, since sintering produces a series of reactions or phase transformations that may lead to the anorthite formation [5]. Furthermore, the decomposition reaction of CaCO 3 into CaO and CO 2 is also confirmed by XRD analysis [5,50].…”

“…3, since sintering produces a series of reactions or phase transformations that may lead to the anorthite formation [5]. Furthermore, the decomposition reaction of CaCO 3 into CaO and CO 2 is also confirmed by XRD analysis [5,50]. One of the main objectives in this subsection is to find out the appropriate amount of CaO composing the final mixture to obtain an anorthite phase alone.…”

“…2. Further details about the samples preparation, including the flowchart of main route used in this work for anorthite samples elaboration, can be found elsewhere [5].…”

“…For these reasons, several studies were carried out to improve these properties in the past few years [5][6][7][8].…”

“…This study is also focused on the effect of firing temperatures (800 to 1100 °C) on mechanical properties of anorthite based ceramics. [5,44]. The particle size distribution of this material was determined by the dynamic laser beam scattering (DLBS) technique; this method gave an average particle size of 2.2 μm [45].…”