Preliminary Study On Environmental Protection Type Building Ceramics Of Barren Materials Prepared By Wet Cast Molding

With the rising attention of sustainable development and environmental protection rising, there is a great significance to turn waste into treasure by comprehensive utilization of waste. In the field of building ceramics, fly ash originated from solid waste of power plants has been used as main raw material instead of the traditional materials used for the production of the architectural ceramics and the total applying amount of fly ash accounts for 30%. This paper studied the composition, morphology, thermal properties and related process performance of the fly ash from Jingdezhen power plant. The building ceramics with good performance were prepared by using fly ash as main raw material, potassium feldspar, quartz, dolomite as auxiliary materials and adding a certain amount of additives. The amount of fly ash is up to 85% in the optimal formula. As a result, the fly ash can be used as alternatives to natural raw materials for the preparation of ceramics, and also it is a good way for us to realize resource utilization effectively. In the study, we prepared the building ceramic products with high content of fly ash, which have innovativeness and broad application prospects.Due to the high content of fly ash and all raw materials are barren materials, it is difficult for body molding during the producing process. Although the formula contains much barren material, we innovatively introduced the in-situ solidification molding method into the production of traditional architectural ceramic. By using wet cast molding, we effectively improve the green body strength of the barren material to meet the demand of mass production.The results showed that the infrared emissivity of the green body decreased with the rising of sintering temperature. In the firing range, the infrared emission rate gradually increased with the amount of fly ash, as well as the firing shrinkage of products. Also, the density of the products after burning was higher, while the porosity decreased with the more amount of fly ash, leading to the increasing of flexural strength. Introduction of bentonite is beneficial for enhancing the strength of green body. The gelatinization temperature of potato modified starch was about 70-80℃, and due to its containing a hydrophilic group which can increase the affinity of starch molecules and water, the modified starch can also improve the strength of the green body. As to products with the addition of 4% potato modified starch, the time required for mold release gradually decreased with the rising of holding temperature. Also, the strength of green body gradually increased, while water absorption decreased with the rising of holding temperature, leading to the increasing of the firing shrinkage, as well as the flexural strength of products. When the amounts of adding cassava starch、 acetate starch, cassava modified starch、potato modified starch and the Jilin starch、corn modified starch were 2%、3%、4% respectively, the strength of the produced green body were all up to 1MPa which meet the demand of mass production.