Lime not extinguished

Lime — the knitting material received by high-temperature annealing (1000-1200 °C) in the mine or rotating furnaces of the sedimentary rocks consisting mainly of a CaCO3 calcium carbonate (limestones, chalk, dolomite). Under the influence of temperature there is the following chemical reaction
CaCO3 →CaO+CO2 ↑.

At the same time the carbonate of calcium loses up to 44% of the weight with carbon dioxide (CO2), becomes easy and porous. The product received in that case - lump not extinguished lime (finely porous pieces of 5-10 cm in size). Further lump not extinguished lime is subjected or to clearing with use of water or to additional grind with receiving not extinguished powdery lime.

Advantage of powdery lime before lump consists that at a zatvoreniye water she behaves like plaster knitting: at first forms plastic dough, and in 20-40 min. grabs. This results from the fact that the water to processing forming dough is partially spent for lime clearing. At the same time limy dough gets denser and loses plasticity. Thanks to smaller amount of free water materials on the basis of powdery lime less porous and stronger. Besides, lime when clearing is warmed that facilitates work with it in cold time. Depending on quality of lime, water, necessary for a zatvoreniya, makes 100-150% of the mass of lime (is defined by practical consideration).

Most the most important indicators of quality of not extinguished powdery lime is:

1. Activity — percentage of the oxides capable is extinguished;
   2. Amount of not extinguished grains (nedozhog or burned through)

- Nedozhog (not decayed SASO3), turning out at too low temperature of roasting, quality of lime since does not possess the knitting properties reduces.

- Perezhog it is formed at too high temperature of roasting. Grains of a perezhog are slowly extinguished and can cause cracking and destruction of already hardened material.

3. Clearing time:
   Depending on clearing time lime is subdivided into types

Technical characteristics

Technical indicators:

• - Active Cao+MgO, not less - 90%
• - Contents act. MGO, no more - 2,8%
• - The maintenance of SO-2, no more - 1,5%
• - The maximum temperature of clearing - 98 °C
• - Clearing time no more - 8 minutes
• - Not extinguished grains, no more - 4%