Bouge's Compounds, Manufacturing of cement and manufacturing Process,

Bouge's Compounds:-

There are four bouge's Compounds.

1. Tri Calcium Silicate (Aelite) C3S:-

Formula = 3CaO.SiO2

Percentage = 40%

Functions:- 

 It provides hardness & strength in initial days.

More heat of hydration (500 KJ/Kg).

It considered as the best cementing material.

It provides more strength in less time.

2. Di Calcium Silicate (Belite) C2S:-

Formula = 2CaO.SiO2

Percentage = 32%

Functions:-

• It provides hardness and strength in final/later days.
• Less heat of hydration.
• Due to less heat of hydration , in initial days sulphate acid attack is less.
• More heat of hydration in later/final days (240 KJ/Kg).

3. Tri Calcium Aluminate (Celite) C3A:-

Formula = 3CaO.Al2O3 

Percentage = 10%

Function:-

• It provides quick hardening.
• Heat of hydration (864 KJ/Kg).
• Flash-set.
• It provides initial setting.

4. Tetra Calcium Alumina Ferrite (Felite) C4AF:-

Formula = 4CaOAl2O3Fe2O3      

Percentage = 8%

Function:-

• It provides quick setting.
• Heat of hydration (420KJ/Kg).

Trick:-    

                     A  B  C  Fraud आदम है l

                 A- Aelite

                 B- Belite

                 C- Celite

                 F- Felite

Flash-Set:- 

• Flash set is the stiffening of cement paste without strength development with heat evolution. It is caused by (C3A).
• Tri Calcium Aluminate reacts immediately with water & is responsible for flash set.

Water Requirement for hydration:-

Hydration of cement is exothermic process.

Bound Water = 23%

Gel Water = 15%

Total Minimum = 38%

Rate of Heat evolution ➝C3A>C3S>C4AF>C2S

Rate of Hydration →C4AF>C3A>C3S>C2S

Special Points:-

• It is found that OPC achieves 70% of its final strength in 28 days and about 90% in one year.
• Gypsum is added to cement to reduce flash setting.
• Gypsum is usually mixed with clinker before final grinding.
• Gypsum retards setting time of cement.
• Excess of gypsum makes cement unsound.
• So gypsum added to clinker should not be greater than (2.5-3%).

Manufacturing of cement:- 

There are two process of manufacturing of cement.

1. Dry Process
2. Wet Process

1. Dry Process:- In Dry process material is hard.

• In the dry process the calcareous and argillaceous materials are crushed and grinding separately and after grinding mixed in the mixing chamber with 4% amount of water.
• After mixing the calcareous and argillaceous materials the mixed proportin comes in the correction silos.
• In correction silos some materials added in the mixed powdered form of cement.
• And again in mixing chamber.
• After the mixing process the powdered form of cement comes in rotatory kiln for heating purpose at a temp. 1400°C.
• After the heating process the material comes in the correction silos. 
• In correction silos some materials are added and clinkers are formed. 
• Clinkers are the small pieces of mixed material. 
• Again clinkers are grinding and 2.5-3% of gypsum is added. 
• And the Portland cement is obtained by the dry process. 
• Packing and transporting is done of cement. 

Wet Process:- In wet process the materials are soft. 

• In the wet process the calcareous materials are directly crushed and the argillaceous materials are first washed and then crushed. 
• After crushing the materials the grinding is done in Ball Mill / Tube Mill. 
• Both grinded materials are mixed in the mixing chamber and raw slurry is added. 
• After that all the processes are same as the dry process. 
• And Portland cement is obtained by wet process. 

Difference b/w the Dry and Wet Process:-