Incorporation of Bentonite Mining Waste in Ceramic Formulations for the Manufacturing of Porcelain Stoneware

Abstract

Mining processes produce a massive amount of waste which, if not treated properly, can cause significant environmental and social impacts. Recently, some studies have focused on the use of mining waste as an alternative raw material. This work developed new sustainable ceramic formulations based on bentonite mining waste (BMW) for applications in porcelain stoneware. The BMW was incorporated into the ceramic masses in different percentages (0, 2.5, 5, 10, 15, 20, 25, and 40 wt.%), in partial replacement to feldspar and total to quartz. X-ray diffraction (XRD), differential thermal calorimetry (DTA), and thermogravimetry analysis (TGA) techniques were used to characterize bentonite waste. Samples (50 mm × 20 mm × 5 mm) were obtained by uniaxial pressing. Such samples were dried and sintered at 1150, 1200, and 1250 °C. The physical–mechanical properties (apparent porosity, water absorption, linear shrinkage, apparent density, and flexural strength) were evaluated for sintered samples. The phases formed after sintering treatments were characterized by XDR and scanning electron microscopy (SEM). The BMW presented a mineralogical composition suitable for use as ceramic raw material. In summary, our results presented that the new sustainable ceramic formulations sintered at 1250 °C have the potential for use in stoneware and porcelain stoneware.

Assessment of the Levels of Potentially Toxic Elements Contained in Natural Bentonites Collected from Quarries in Turkey

“…7 Bentonite is usually exploited in open quarries by surface mining. 18 The bentonite production process involves ore mining, and if necessary, sodium activation by adding soda ash (Na 2 CO 3 ) to convert Ca bentonite to Na bentonite, drying to obtain the required moisture content, and grinding. 16 Moreover, bentonite mining generates a large amount of waste that has a significant environmental impact and has no commercial value.…”

“…Bentonite is usually exploited in open quarries by surface mining. 18 The bentonite production process involves ore mining, and if necessary, sodium activation by adding soda ash (Na 2 CO 3 ) to convert Ca bentonite to Na bentonite, drying to obtain the required moisture content, and grinding. 16 Moreover, bentonite mining generates a large amount of waste that has a significant environmental impact and has no commercial value.…”