a b s t r a c tFly ash contains metals such as cadmium, iron, lead, aluminum and zinc in its structure in appreciable amounts. These metals can leach out into surface and ground waters if fly ash is not properly disposed of. A similar problem also exists for acidic process waste waters discharged by numerous industries. The purpose of this study was to utilize such wastes as additives in the production of construction quality bricks for the purpose of waste elimination. The bricks produced were subjected to flexural strength and water retention capacity tests along with heavy metal leaching experiments in order to determine the applicability of the procedure and the best possible recipes. This paper summarizes the results obtained in these tests along with the possible mechanisms involved in stabilizing the two wastes in the brick structure.
Experimental compositions were prepared by the additions of ulexite concentrator waste to a standard wall tile body sintered at different temperatures. Tests of linear firing shrinkage, water absorption, and fired bending strength (eğilme mukavemeti) were done. XRD analyses were conducted to determine major crystalline phases in wall tile bodies. SEM-EDX analyses were performed to study the microstructural evolution of the standard and experimental wall tile bodies. Colorimetric analyses were also made. The wall tile body containing 5 weight percent ulexite concentrator waste fired at 925 o C for 6 minutes was determined to be the optimal composition with 0.60% of linear firing shrinkage, 17.66% of water absorption, and 208.60 of kg/cm 2 fired bending strength (eğilme mukavemeti). Sintering temperature was reduced from 1182 o C of industrial practice down to 925 o C. Utilization of ulexite concentrator waste in tile bodies will help reduce energy costs in favour of the environment and economy.
ÖzÜleksit konsantratör atığının standard duvar karosu bünyesine katılması ve değişik sıcaklıklarda sinterleşmesiyle deneysel numuneler hazırlanmıştır. Doğrusal pişme küçülmesi, su absorpsiyonu ve pişme bükülme testleri yapılmıştır. X-ışınları kırınım analizleri duvar karolarının kristal fazlarını tayin etmekte; SEM-EDX analizleri standard ve deneysel duvar karolarının mikro yapılarındaki değişimlerin anlaşılmasında kullanılmıştır. Renk analizleri de gerçekleştirilmiştir. 925°C de 6 dakika pişirilen %5 üleksit konsantratör atığı %0.6 doğrusal pişme küçülmesi, %17.66 su emme ve 208.6 kg/cm 2 pişme bükülmesi değerleriyle optimum konsantratör atık derişimi olarak belirlenmiştir. Endüstriyel üretimde 1182°C olan sinterleşme sıcaklığı 925°C'ye düşürülmüştür. Üleksit konsantratör atığının duvar karolarında kullanımı enerji maliyetlerini düşürmeye yardım ederek ekonomi ve çevreye yarar sağlayacaktır.
AB ST R ACT : The purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.
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