In the study of glass bubbles, the source of the gas in the bubbles, the interaction between the gas and the glass liquid, and the influence of the physical and chemical properties of the glass liquid on the formation or disappearance of the bubbles are analyzed.
The gas in glass bubbles usually comes from the following aspects:
Gas in the material particle gap and gas adsorbed on the material surface
At the initial stage of the mixing material melting, such gases will continuously volatilize or evaporate. In the process of rising, large bubbles will be formed to float upwards and escape the glass liquid, which will not directly lead to visible bubbles in the glass products. Unless the particle size of the raw material is not properly controlled, the coalescence of the mixed material is not fully melted and the gas cannot be discharged.
A gas released by the decomposition of salts
Mixtures in the presence of large amounts of carbonate, sulfate and nitrate, these salts thermal decomposition, produce a large number of tiny air bubbles, the gas generated in the salt decomposition quantity, accounts for about 20% of the weight of the batch of 15 a, and the formation of the glass liquid ratio, large size out many times, the release of gases and moving, promoting the improvement of the heat exchange efficiency, accelerate the melting of the batch, improved the uniformity of glass composition and temperature uniformity, but, this kind of gas bubbles not promptly eliminate will form glass bubbles.
Gas produced by external factors
The gas precipitated from refractory materials, the gas produced by the action of harmful impurities and the glass liquid, the glass bubbles formed by these gases disappear for a long time in normal production, which is difficult to disappear, but this kind of situation is relatively rare.
The temperature of glass liquid drops too fast or fluctuates too much, or the REDOX state of glass changes too much due to various reasons. These factors are combined to make the solubility of various gases in glass liquid fluctuate and release a large number of small secondary bubbles. This bubble is characterized by a small diameter and a large number of bubbles.
Sometimes, due to the wrong calculation of the material side or the wrong addition of the material side, the glass composition in the pool kiln fluctuates greatly, and the gas solubility in the glass fluctuates, causing a large number of glass bubbles.
There are two ways that glass bubbles can disappear in the process of clarification: one is that small bubbles grow into large bubbles, which float up due to the difference in density and eventually escape from the glass liquid. The other is a tiny air bubbles, with lower temperature, the gas solubility in the glass, because the surface tension, the bubble exists in several kinds of gas composition, due to the small air bubble diameter, high pressure, gas quickly absorbed by the glass, with the decrease of diameter, the bubble pressure rising, in the end all the gases in the air bubbles into the glass. The bubbles disappear completely.