school automatic blackboard chalk making machine

(1) Dustless chalk is mainly made of CaCO3 . Normal chalk with dust is made of CaSO4 .

(2)Dustless chalk has no dust when writing , so it’s environmental and healthy for people . Normal chalk will producing dust floating in the air .

(3)Dustless chalk is very durable and can use long time . Normal chalk is easy to wear , it’s used in short time .  

(4)Dustless chalk is heavier than normal chalk .

(5)Dustless chalk is much more expensive than normal chalk .

(6)Dustless chalk is difficult to dry and become hard ,  normal chalk can become hard within 5 minutes .

(7)Dustless chalk and normal chalk process are obviously different and use different machines .