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What is the chalk dust, chalk dust definition

Come from：本站Click：Update Time：2012-10-27 21:21:11

Chalk chemical composition
The chalk is made from calcium sulfate dihydrate (commonly known as gypsum). Can be added to a variety of pigments made a nice color chalk. Gypsum is heated to a certain temperature in the production process, its partial dehydration becomes mature gypsum plaster then add water and stir into a paste, poured models solidified. The reaction → 2CaSO4 · 2H2O = 2CaSO4 · H2O 3H2O

Chalk dust is 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 obvious.
The main advantage of the chalk dust:
Addition to the production of white ① chalk dust can also produce red, yellow, green, blue, pink and other colors, and stored for a long time, will not fall chroma, always protect Xianyanduomu, clear colors.

② plus a small amount of smooth agent and binder, chalk finished and clothes, teachers left the class do not need to wash your hands, because the white marks on the finger.

③ adding a small amount of moisture agent, stored for a long time does not degenerate. Ordinary chalk prolonged storage extremely easy to absorb moisture, write brittle hardness decreased.

④ school blackboard cement board, wood, the hardness of the requirements chalk blackboard varying degrees of surface smoothness is not the same. I say a new generation of chalk dust can be arbitrarily changed its softness, slipping or easy-off phenomenon that does not occur in a variety of blackboard and feel, writing is fluent, and effort.

⑤ with traces Ingredients in chemical raw materials, increase the proportion of chalk to write on the blackboard, Environmental friendly flying phenomenon, Environmental friendly clean chalk Health, to avoid due to chalk foam through breathing into the visceral derived occupational diseases.

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Keywords：Chalk dust, Intelligent chalk, chalk dust definition