Incorporation of SCBA in Red Ceramics and Sintering in Microwave Oven

Abstract

The present study investigated the incorporation of sugarcane bagasse ash (SCBA) in red ceramics, sintered in conventional oven and microwave oven, aiming to provide an alternative product, and a sintering process with higher energy efficiency in the production of red ceramics. The raw materials were characterized by XRF, XRD, thermogravimetry, particle size distribution and specific mass analyses. The specimens were shaped by extrusion in two different compositions, red clay and red clay with addition of 20 % SCBA and sintered at temperatures from 700 to 1100 ºC. The conventional sintering occurred for 60 min with heating rate of 10 ºC/min. In the microwave oven the sintering occurred in a hybrid way, with heating rate of 50 ºC/min for 5, 10 and 15 mins. After sintering the tests of linear shrinkage, compressive strength, water absorption, apparent porosity and apparent specific mass were performed. The addition of SCBA causes an increase in the values of water absorption and decreases the compressive strength and specific mass of the red ceramic. This occurs due to the creation of pores inside the material from the volatilization of organic matter present in the ashes. The sintering in microwave oven, when compared to conventional sintering, promotes an increase in the values of compressive strength and specific mass and reduction of water absorption values of ceramics, probably due to the refinement of the microstructure and the higher densification. Thus the incorporation of ashes can be partially compensated by a more efficient sintering. The use of SCBA and the sintering in microwave oven, showed to be viable alternatives in the development of a more sustainable and light material, promoting the management of waste, reduction in the consumption of raw materials and energy saving.