Respuesta :
Answer:
Answer is option D.
The terms vitrification, oxidation, water smoking, and flashing are all associated with firing bricks in a kiln.
Explanation:
Brick is one of the building materials made from the clay. The manufacturing process of brick include;
1) Winning - It is the process of mining of clay and its transportation to the manufacturing site.
2) Preparation - It includes the crushing and grinding of clay and later mixing them into a uniform raw material.
3) Forming/Molding - It is the process of mixing water with the clay mix and mold it into the desired shape. The plasticity of the clay depends on the amount of water used.
4) Drying - The process of removing the moisture from wet clay by drying it through evaporation.
5) Firing and Cooling - Firing is the process of burning the clay in a kiln and it usually requires 40 - 150 hours. The different stages in firing are;
- Water smoking or dehydration stage - It is a process in which free water retained in the pores of the clay after drying gets evaporated under a high temperature of 400-650°C and the clay loses its plasticity. Some of the carbonate minerals are eliminated.
- Oxidation - This process occurs at a very high temperature of 650-900°C in which the ferrous iron is oxidized to the ferric form and the remaining carbon is eliminated.
- Vitrification- This process occurs at a very high temperature of 900- 1100°C for low melting clay and 1000-1250°C for high melting clay, where the clay is transformed into a soft molten mass as a result of an increase in temperature. It gradually loses the shape and transforms into a glassy structure after cooling.
- Flashing - In this process, the fire in the kiln is regulated in such a way that it causes a reduction in the kiln temperature and the cooling process begins which produces color variations in bricks.
6) Drawing - It is the process involving the unloading of the kiln after cooling and packing of the bricks for further shipment.
