There are various production processes for color flat glass. For body-colored flat glass, float method and flat drawing process and casting calendering process are mainly used at present.

Float and levelling

Float and flat glass are the main production processes of flat glass, and they are also the main production methods of color flat glass. We mix the colorant and glass raw materials evenly, and then send them to the glass tank kiln through a feeder for melting, clarification, molding, etc. The process obtains colored flat glass. Since colored glass is different from ordinary flat glass, the melting system and annealing process should be different from ordinary flat glass. In addition, some transition glass will be produced during the production and conversion of colored glass.

Color change in glass production

In the flat glass production line, the conversion production of colored glass mainly adopts the "production process refueling method". The method is: according to the color uniformity and quality requirements of good products, without affecting production, put the newly composed batch into the original glass liquid, so as to gradually replace and change the color of the glass in the shortest possible time. Convert to another color. Generally, it takes 6-14 days for all the molten glass in the whole kiln to be converted into the newly composed molten glass. The time is related to the time that the molten glass stays in the kiln, that is, the ratio of the total capacity of the molten glass in the kiln to the production certificate; it is also related to the amount of colorant added. Practice has proved that the speed of glass coloring conversion is not only related to the unique glass flow of each kiln, but also depends on the coefficient of blending excess colorant, which is generally 2-3 times the amount of standard colorant. Since changing the addition amount of the colorant has little effect on the composition of the base glass, the blending excess coefficient of the colorant can be adjusted within a wide range. The greater the amount of colorant added, the faster the colorant content in the finished glass rises, and the faster the glass is colored. The colorant content Cx in the glass is expressed by the following formula.

Cx=T×Co/R(B)/Tr

In the formula, T is the coloring time, hours; C. is the design content of colorant in the finished glass; R(B) is the coefficient related to the blending excess coefficient B; Tr is the ratio of the production capacity of the kiln to the off-duty output. According to production experience, the relationship between B and R(B) is as follows. If B is too large, it will cause difficulty in melting at the front end of the glass melting furnace, so B is usually not greater than 5:

B=l,R(B)=2;

B=2,R(B)=0.1;

B=3,R(B)=0.4;

B=4, R(B)=0.3.

Among them, T, is a ratio, which is equivalent to the average time that the molten glass stays in the kiln. For a 400t/d float glass production line, if the total volume of molten glass in the kiln is 2400t, Tr=2400/400=6 days. In addition, if starting coloring with the blending excess coefficient B, the entire glass kiln already contains the same glass colorant components uniformly, and the colorant-related components in the finished glass have reached Cy, then Cx=T×Co/R( The formula B)/Tr+Cy is the estimation formula for the coloring rate of float glass.