Chalk detailed instructions

2012-10-27 21:20:11 本站 浏览量:

1 - chalk daily life widely used in stationery tool, generally used for writing on the blackboard. A component of the chalk is a white precipitate of calcium sulfate, is not easy to be decomposed, and particles smaller than dust. The ancient chalk usually made ​​of natural chalk, but today more than other substances used to replace. Now, the domestic use chalk ordinary chalk and chalk dust two main ingredients are calcium carbonate (limestone) and calcium sulfate (gypsum), or with a small amount of calcium oxide.

2 - chalk dust is a the ordinary chalk improvement products, aimed at destroying the the classroom chalk dust pollution. It is only in the ordinary chalk added fats and oils or poly-alcohols as a binder, then add a large proportion of filler, such as clay, marl, cement, etc. This enables to increase the specific gravity and the volume of chalk dust and difficult to scattering, but in practical applications, it chalk dust pollution reduction effect is not very clear

3 - ordinary chalk about two inches long, a coarse and a fine round shape, very well-balanced, very hard and very brittle. Commonly white. Now, China domestic use chalk ordinary chalk and chalk dust two main ingredients are calcium carbonate (limestone) and calcium sulfate (gypsum), or with a small amount of calcium oxide.