Drying and firing properties of green body
(1)The drying properties of green body need to adjust the drying shrinkage and drying strength of green body by adjusting the type and proportion of plasticity raw materials and controlling the fineness of mud.
(2)Firing properties of green body In the course of firing-A series of physical and chemical changes. What is more concerned about production is:The volume change of the green body during heating and cooling, the phase composition of the sintered green body and the corresponding physical properties.
Drying processEquipment and equipment
Ceramic granulating spray dryerThe design and selection must be subject to the requirements of the drying process, and the drying process or drying system is part of the overall production process.;For sanitary ceramics, different production scale, different raw materials, different sintering equipment will affect the green body molding process, of course, will also affect the drying system and drying equipment selection.
Drying meaning and principle
Significance of drying
At present, almost all the sanitary ceramics are produced by grouting. As long as the sanitary ceramic body is formed by grouting, the moisture content of the body after demolding is generally greater than that of the body.19%Some even reach as high as23%Above. The strength of wet billet is low, it is not easy to transport, and it can not be glazed or fired. Therefore, it must be dried to less moisture content.2%.
(1)Drying heat consumption of billet Drying and dehydration heat consumption can be achieved under the traditional molding drying process.6720kj / kgAbove, the heat consumption in the molding workshop is about the whole plant.40%Therefore, improving drying efficiency is of great economic value.
(2)It is difficult to dry and produce defects. Shrinkage rate at least2%If the dehydration rate of each part of the green body and the inner and outer layers of the green body are not uniform, the drying shrinkage will not be uniform, which will cause the internal stress in the green body and lead to the cracking of the green body. Therefore, it is the central task of drying technology to ensure the rapid and uniform drying of green body, reduce the loss of green body drying, and improve the thermal efficiency. Due to the large volume, complex structure and great difference in thickness of various parts of sanitary ceramics, it is difficult to dry any part of the green body uniformly and quickly.
(3) Drying process link up and down Drying technology and equipment not only reflect the above value, but also affect the working environment and production continuity of upper and lower processes and the effective use of production sites.
Principle of drying
Water in green body Sanitary ceramics can be divided into three categories according to their combination status.
①The structural water in the chemical composition of mineral water can not be removed by drying.
②Less than absorbed water materialφ104mmThe physical and chemical conjugates adsorbed by capillary, colloidal particles and fibrous skin. This part of water content is balanced with the temperature and humidity in the drying medium.
③Other free water in the green body can be removed by drying.
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