Civil Engineering - Building Materials - Discussion

Fat lime is true as it contains 95%CaO and it slakes vigorously, it has a high degree of plasticity and set slowly in the presence of air by absorbing CO2 from air.

Calcination is the heating of limestone to form quick lime.

@All.

The hydraulic lime is made from Kankdar, i.e. it is made up of clay containing impurities up to 5% to 30%. Poor lime is made of clay containing impurities more than 50 to 30%.

Fat lime when mixed with water, it volume increase by 2 to 3 times. And it is used for putty & whitewashing work.

Quick lime is purely obtained by calcification and slack with water.

@Jay, calcination is the process by which we can get quick lime(CaO) from its combined state (Ore) i.e. from CaCO3. If CaCO3 is burned( calcined) at a temperature of 900°c we will get.

CaCO3 ---> calcination@900°C-------> CaO + CO2.

Quicklime is correct.

Types of quicklime (CaO+impurities in the form of clay etc)-

1. Rich lime/fat lime/white lime- The quicklime in which 95% to 100% pure lime (CaO), 0-5% impurity.
2. Hydraulic lime- The quicklime in which 70 to 95% pure lime (CaO), 5-30% impurity.
3. Poor lime/Lean lime- the quicklime in which up to 70% (CaO), more than 30% impurity.

Calcination is process when cao react with water forms ca(oh2).

What is calcination?

What is the difference between fat and quick lime?

Behavior of slaking:.

Fat lime slakes rapidly when water is added giving out considerable heat and making hissing and cracking noise and increases 2 to 3 times its original volume. Fat lime if exposed to air, it absorbs moisture and CO2 from the atmosphere and becomes inert CaCO3 or chalk again and loses its cementing power. For developing the cementing power, quick lime must be slaked with water as early as possible, after it is obtained from the kiln.

Yes, Quick lime is correct Major part is calcium oxide which is quick to react with H2O and cause slacking.