Swept construction MTD-2
- Country of manufactureUkraine
Chalk — sedimentary rock of a white, soft and friable, insoluble in water, an organic (zoogene) origin.
Chalk — a necessary component swept the ovanny paper used in polygraphy for the printing of the qualitative illustrated editions. Ground chalk is widely applied as cheap material (pigment) to whitewashing, coloring of fences, walls, borders, to protection of trunks of trees against solar burns.
Chalk is used for the letter on big boards for the general review (for example, at schools) (the formed school piece of chalk for 40% consists of chalk (calcium carbonate) and for 60% from plaster (calcium sulfate). At a lack of calcium medical chalk can be registered as an additive to food. It should be noted that at x - ray researches of a digestive tract apply substance which is mistakenly taken sometimes for chalk. Actually it is a suspension of also insoluble barium sulfate in water.