Foaming Control Of Polishing Ceramic Tile Waste During Firing And Its Application In Sound Absorption Ceramics

In the post treatment of ceramic production,it needs to be trimmed and polished with a polishing machine,which produces a large amount of polishing ceramic tile waste.When the polishing ceramic tile waste was directly recycled as a raw material,it caused severe foaming and deformation during firing.Therefore,controlling the foaming of polishing ceramic tile waste during sintering has an important scientific value and socio-economic significance.The purpose of this dissertation is to develop the resource utilization of polishing ceramic tile waste.The effects of three additives?Al powders,Al₂O₃ powders,and Si powders?on the foaming of polishing ceramic tile waste during sintering was studied in detail,and foaming control mechanism was systematically analyzed.At the same time,a sound absorbing ceramic was prepared by polishing ceramic tile waste with Al powders,and the effects of raw material and experimental process were studied in detail.The result of this work indicates that the addition of Al powders can effectively control the foaming of polishing ceramic tile waste during sintering.For example,when firing at1200°C and the Al powders content reaches 12 wt%,the bulk density of the sample increases from 1.02 g/cm³ to 2.17 g/cm³.The control mechanism of Al powders:on the one hand,after the Al powders melted,it easily reacts with O₂ inside the body and consumes part of O₂,thereby reducing the amount of CO and CO₂ generated from the reaction of SiC and O₂,and thus lowering the foaming rate in the sample.On the other hand,Al₂O₃ increases the viscosity of the high temperature liquid phase and controls the growth of bubbles in the high temperature liquid phase.The addition of Al₂O₃ powders can also effectively control the foaming of polishing ceramic tile waste during sintering,but under the same condition,its effect is weaker than that of Al powders.The reason is that Al₂O₃ can only inhibit the bubble growth in the high temperature liquid phase by increasing the viscosity of the high temperature liquid phase,but it cannot consume O₂ inside the green body.So it may be speculated that O₂ in the internal gap of the green body is the major factor of oxidative foaming of SiC in the polishing ceramic tile waste during sintering.The addition of Si powders can also effectively control the foaming of polishing ceramic tile waste during sintering,but under the same condition,its effect is between that of Al powders and Al₂O₃ powders.For example,when firing at 1200°C and the Si powders content reaches 12 wt%,the bulk density of the sample increases from 1.02 g/cm³ to 1.76 g/cm³.The control mechanism of Si powders:on the one hand,part of the Si powders react with O₂ in the internal gap of the sample and consume O₂.On the other hand,SiO₂ and another unreacted Si powders,both increase the viscosity of the high temperature liquid phase and inhibit bubble growth in the sample.On this basis,sound absorbing ceramics were prepared with polishing ceramic tile waste by polishing ceramic tile waste with Al powders.The results show that in the conditions of 88wt%polishing,12 wt%Al powders,firing temperature of 1050-1300°C,and holding time of1 hour,the samples with the bulk density of 0.44-0.78 g/cm³,the water absorption of75.94-149.95%,the open porosity of 59.36-76.26%,the compressive strength of 1-4.5 MPa,and it has excellent sound absorbing performance due to the average sound absorption coefficient in 200-2000 Hz of 0.34-0.64.In this paper,the foaming control of polishing ceramic tile waste during sintering and its application in sound absorption ceramics was examined innovatively.This work provides a certain theoretical basis and practical use for the direct resource utilization of polishing ceramic tile waste,which has a important social significance and economic value.