The utilization of Şaphane alunite in geopolymer production

The aim of this work is to research the usage of alunite from the alunite deposits of Şaphane-Kütahya (Turkey) as a raw material in the production of a geopolymer material. Alunite samples were characterized and prepared to use in body recipes. Manufacturing of geopolymer was conducted by mixing alumina silicate sources, silica fume, and sodium silicate solution. The geopolymer samples were cured at 60 °C for 24 h. Chemical and microstructural characterization of materials prepared from representative samples was carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD), 27 Al-magic angle spinning nuclear magnetic resonance ( 27 Al MAS-NMR), and scanning electron microscopy (SEM), techniques, respectively. The compressive strength of the geopolymer materials was obtained from the samples after 7 and 28 days. Compressive strength measurements show a maximum strength of almost 48 MPa after 28 days. As a result of this study, it has been shown that alunite minerals can be utilized as alternative raw materials for production of geopolymer mortars.