1. Mix all raw materials evenly according to the designed mixing list. The main raw materials of glass bottles are: quartz sand, limestone, feldspar, soda ash, boric acid, etc.
2. Glass bottle forming refers to the transformation of molten glass into solid products with fixed shape. Forming must be carried out within a certain temperature range. This is a cooling process. The glass bottle first changes from viscous liquid to plastic state, and then into brittle solid state. Forming methods can be divided into manual forming and mechanical forming.
3. Melting: the prepared raw materials are heated at high temperature to form a uniform bubble free liquid glass. This is a very complex physical and chemical reaction process. The melting of glass bottles is carried out in the furnace. There are mainly two types of melting furnaces: one is crucible kiln, in which glass frit is contained in the crucible and heated outside the crucible. Only one crucible can be placed in a small crucible kiln, and up to 20 crucibles can be placed in a large crucible kiln. Crucible kiln is gap production. Now only optical glass and color glass are produced in crucible kiln. The other is the tank kiln, in which the glass frit is melted in the kiln tank and heated by open fire on the upper part of the glass liquid level. The melting temperature of glass bottles is mostly 1300 ~ 1600 ゜ C. Most of them are heated by flame, and some are heated by electric current, which is called electric melting furnace. Now, tank kilns are produced continuously. Small tank kilns can be several meters and large ones can be as large as more than 400 meters 2.
4. After annealing, the glass bottle undergoes intense temperature change and shape change during forming, which leaves thermal stress in the glass bottle. This thermal stress will reduce the strength and thermal stability of the glass bottle. If it is cooled directly, it is likely to break during cooling or later storage, transportation and use (commonly known as the cold explosion of glass bottles). In order to eliminate cold explosion, glass bottles must be annealed after forming. Annealing is to keep heat in a certain temperature range or slowly cool down for a period of time to eliminate or reduce the thermal stress in the glass to the allowable value.
Post time: Apr-14-2022