Hey, If someone can help me to explain how does the kiln used to make glass slabs from recycled glass produc.?

Question

..es crackless slabs? any link or any book? thankyou very much.

Answer 1

When glass is melted, it is free from strain. As it cools, if it cools rapidly, the outer part becomes stiff before the inner part has cooled enough so the inner part keeps cooling and strinking and this put great strain on the glass and it shatters.
So a slab of glass is annealed - it is first brought to a temperature - the annealing point - where it is very stiff but will not sag - and held there for an time determined by the thickness, but usually a couple of hours. Then the temperature is lowered slowly so that it is as near uniform as possible through the thickness - with thick glass this may mean that it takes dozens of hours to get from about 900F to about 600F. It can then be let cool to room temperature in the kiln at its own rate.