After the preliminary grinding of the raw materials is completed, the raw materials still contain a lot of air, and the structure of the mud cake obtained through the filter press is not uniform. If the mud cake with uneven structure is directly used for production, it will cause uneven shrinkage of the green body during subsequent drying and firing, resulting in deformation and cracks. After rough training, the vacuum degree of the mud section is generally required to reach between 0.095-0.1. Another advantage of the rough mud cake is that the mud cake is made into a certain size of mud section, which is convenient for transportation and storage. It also provides convenience for subsequent production.
Putting the rough mud section in a certain temperature and humid environment for a period of time, this process is called staleness. The main functions of staleness are: make the water in the mud more evenly distributed through the action of the capillary; increase the content of humic acid, improve the viscosity of the mud, and improve the molding performance; some oxidation and reduction reactions occur to make the mud loose and uniform. After aging, the strength of the green body can be improved and the chance of deformation during firing can be reduced. Usually it takes 5-7 days for the stale, and there are 3 days for the fast ones. After a long period of aging, the product is not easily deformed due to uneven moisture and air bubbles, which better guarantees product quality.
Post time: Apr-26-2021