The forming process of float glass production is completed in a tin bath with protective gas.
The molten glass flows into the kiln and floats on the surface of the tin liquid with relatively high density. Under the action of gravity and surface tension, the molten glass spreads on the tin liquid surface and spreads out to form the upper and lower surfaces. On the transition roller table. The roller of the roller table rotates to pull the glass ribbon out of the tin bath and enter the annealing kiln. After annealing and cutting, the flat glass product is obtained.
Advantages of float glass: good flatness, no ripples, used for mirror making and automotive glass; the product is pure, white, good in transparency, compact in structure, smooth in hand, easy to cut, and not easy to break.
1. Mixing of raw materials
The main raw materials of float glass include silica sand, soda ash, limestone, dolomite, feldspar, Glauber's salt and carbon powder. The ingredients are: 73% silicon dioxide (SiO2), 13% sodium carbonate, 9% calcium oxide and 4 % of magnesium, etc. These raw materials are mixed according to the proportion, and then small particles of recycled cullet are added.
2. Melting of raw materials
The prepared raw materials pass through a mixing chamber and then enter a kiln with 5 chambers for heating, and become glass melt at about 1550 degrees Celsius.
3. Forming of glass
The glass melt flows into the tin bath and floats on the molten metal tin liquid, and the temperature is about 1000 degrees Celsius at this time. The molten glass on the molten tin forms a glass ribbon with a width of 3.66 meters and a thickness of 3mm to 19mm. Because glass and tin have very different viscosities, the glass melt floating above and the tin liquid below do not mix together and form a very flat contact surface.
4. Cooling of molten glass
The temperature of the glass ribbon is about 600 degrees Celsius when it leaves the tin bath, and then enters an annealing chamber or a continuous slow cooling kiln to gradually reduce the temperature of the glass to 50 degrees Celsius. Glass produced by this slow cooling method is also called annealed glass.
5. Cutting and storage of glass
After annealing, the glass undergoes several stages of quality inspection before being cut into different sizes for packaging, storage or transportation.
