What is the material of chalk?

What is the material of chalk?

Chalk is a stationery widely used in daily life, usually used for writing on the blackboard. The main component of chalk is calcium sulfate, a white precipitate that is not easily broken down and has larger particles than dust. Now the use of chalk mainly ordinary chalk and dust-free chalk, its main components are calcium carbonate (limestone) and calcium sulfate (gypsum), or containing a small amount of calcium oxide.

Dust-free chalk

Dust-free chalk is an improved product of ordinary chalk, designed to eliminate the classroom chalk dust pollution. It is just in the ordinary chalk to add oil or polyalcohol substances as a binder, and then add a large proportion of filler, such as clay, marl, cement, so that the proportion of chalk dust and volume are increased, not easy to fly, but in practical application, it is not very obvious to reduce the effect of chalk dust pollution.

1. Add trace chemical raw materials in the main material, increase the proportion, chalk written on the blackboard, dust free flying phenomenon, sanitation and clean, avoid occupational diseases caused by chalk foam into the viscera through breathing.
2. Add a small amount of smoothing agent and binder, the chalk will not touch the hands and clothes, the teacher has no white marks on the fingers after a class, there is no need to wash hands.
3. Add a small amount of moisture-proof agent, long time storage will not deteriorate. Ordinary chalk for a long time is very easy to absorb moisture, hardness decline, easy to write broken.
4. The blackboard used by the school has cement board, wood board and wool glass board, etc., because of the smoothness of the blackboard surface, the hardness of the chalk is not the same. The new generation of dust-free chalk can arbitrarily change its hardness, in a variety of blackboard use will not slip or easy to break phenomenon, and writing fluently, labor saving, feel very good.
5. Dust-free chalk is in addition to the production of cosmetics materials with the latest successful development of high-tech products. Environmental protection, non-toxic, dust-free, is the ideal teaching office supplies for modern teaching.

Non-toxic chalk

Non-toxic chalk is the healthiest chalk, made of pure gypsum and water solidified and dried, the use of edible gypsum. Most foreign schools use this kind of chalk from primary school.
1. Non-toxic chalk belongs to senior chalk. It is non-toxic in the dust pollution of classroom chalk. Even the water produced causes zero pollution to the river.
2. Non-toxic teacher chalk: The chalk used by teachers in teaching is designed for the teaching industry. It is pollution-free and pollution-free.
3. Non-toxic children's graffiti chalk: according to the children's use habits, eat into the mouth will not matter chalk.

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