The geopolymer behavior of metakaolin and spinel structures of different kaolins

The aim of this study is to examine the possibility of using different kaolins, which are used in the ceramic industry for the production of geopolymers as a source of Al2O3 and SiO2, in raw, sintered metakaolin and spinel form. Each of these three different forms of kaolin specimens, obtained by sintering them at 700°C for the metakaolin form and at 1000°C for the spinel form, were separately used to produce geopolymer products. Alongside with the chemical analysis of the kaolin specimen, one realized the mineralogical and phase analysis of the kaolins in spinel and metakaolin form, which were sintered at different temperatures.In order to enable the raw and heat-treated kaolins to produce geopolymer reaction, one mixed and milled them with NaOH. In order to increase the grain-to-grain contact during the completion of the reactions in geopolymerization, water was added according to the recipe and this blend was shaped by pressing. The shaped blends were cured at a fixed period of firing time and varying temperatures. Following the curing, one realized the phase, compressive strength, bulk density and micro structure analysis of the products. As a result; it has been determined that the geopolymer specimen obtained by using Iranian kaolin that was sintered at different temperatures and cured, revealed optimal compressive strength values. And it is also possible to use the oxides contained in kaolins for the production of geopolymer materials as cheap and suitable sources of silicate between an amount of 46-60% and as a source of SiO2 and alumina between an amount of 25-38%. However, it was determined that is necessary to examine the effects of the minerals, contained in the kaolin, during the geopolymerization reactions and to conduct further researches about the utilization of this material. One determined that in this sense not all kaolins are suitable and therefore it is merely possible to use them by examining the geopolymerization mechanisms of the kaolin specimens.