The process most used worldwide in the manufacture of porcelain stoneware, whether enamelled or unglazed, is the so-called "wet way" with single firing. This manufacturing process is associated with an important consumption of
energy and natural resources, among which is water. The average consumption of water per square meter produced oscillates around 20 liters, while energy consumption is around 32 kWh per meter
square produced.
Around 60% of the water consumed corresponds to that used in the grinding of the composition of the support. Although an important part of the water consumed is recycled, for some types of support the situation is different because the solids that contain the water to be recycled can modify some characteristics of the finished product, such as color and function, which limits recycling.
With regard to energy consumption, the highest proportion of energy consumed (90%) is of thermal origin, so energy improvements should be directed mainly towards the reduction of this type of energy. The two stages that consume more than 90% of thermal energy are the drying by atomization of the support suspensions and the cooking. Although some energy saving measures are being implemented in single-layer kilns, it is not currently foreseen that alternative technologies will arise in the short-medium term to the firing of tiles that suppose a significantly lower energy consumption than the current one. Therefore, in the present work an alternative technology is studied to the current system of preparation of the composition of the support, in order to reduce the environmental burdens associated with the tile manufacturing process.
This involves significantly reducing water consumption during this stage to make the drying phase of the suspension unnecessary. The process that is studied in the present work is the one consisting in the dry milling in pendular mill and
in the subsequent granulation (to obtain a press powder with fluidity similar to that of atomized powders).
Continue reading at: http://www.qualicer.org/recopilatorio/ponencias/pdf/2012002.pdf
