The case of crockery

The processes using a wet method for forming parts are still widespread. The duration of the drying proves to be an obstacle for the development of production lines continuously functioning. The recent progress made in the field of infrared and microwave drying should allow a rapid evolution. Indeed, it has been shown that it is possible to dry a cup containing more than 22% mass of water in less than 30 minutes [CUB 93]. 

New grinding technologies have modified the methods of preparing coloring and the enamel. The use of fine powders considerably improves the covering effect and the brilliance of the enamel, as well as the quality and reproducibility of the decorations. 

All these processes, the availabihty of new types of kilns and a better rmderstanding of the phenomena have made it possible to reduce by up to 5 to 10 times the duration of the production cycle of certain types of crockery while guaranteeing better reproducibility of the parts. 

Silicate ceramics are very old materials that are very widely used in society thanks to their undeniable assets, namely their high mechanical strength, excellent chemical inertia and esthetic qualities. A common feature is that they are obtained 

Currently, the defects responsible for the downgrading of certain parts are primarily spots due to impurities contained in the raw materials. High magnetic field purification helps reduce by two the number of these scraps. Non-magnetic coloring impurities still cause uncertainties in quality. A few ppm of certain elements are enough to make 10% of the parts non-compliant with the standard. To aehieve the zero defect objective, great effort must be made, in order to master the purification and the selection of raw materials and the constancy of their properties. 

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