AMMONIA GAS - CEMENT
 
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Laboratory preparation
 
In Laboratory Ammonia gas is prepared by heating a mixture of Ammonium chloride and calcium Hydroxide.
2NH4Cl + Ca(OH)2 è 2NH3 + CaCl2 + 2H2O
Industrial Preparation
 
On Industrial scale NH3 gas is prepared by HABER-BOSCH METHOD.
Details of Haber-Bosch Process
 
Raw materials
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1. Nitrogen gas.
2. Hydrogen gas.
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Composition of Raw materials  
Nitrogen one part of volume.
Hydrogen three part by volume
Suitable Conditions for maximum yeild of NH3  
Formation of Ammonia in a reversible and exothermic process therefore following conditions are necessary to produce maximum amount of NH3.
Temperature: The reaction is carried out at low temperature.
Optimum temperature: 400 OC to 450 OC.
Pressure : The reaction is carried out at high pressure.
Optimum pressure: 400 atmosphere to 1000 atmosphere.
Catalyst: To increase the rate of reaction a catalyst of iron oxide and aluminum sulphate with molybdenum (Mo2) is used.
The Process
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One part of N2 and three parts of H2-gas by volume are heated upto 400 OC to 450 OC in the presence of catalyst to produce Ammonia gas.
N2+3H2 è 2NH3
CEMENT
 
Raw material
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1. Lime stone (CaCO3)
2. Clay (Al2Si2O7)
3.Gypsum (CaSO4.2H2O)
Manufacturing of cement
 
First of all lime and clay are pulverized and then mixed in proper proportion. Now this mixture is fed into a revolving Kiln. The mixture in Kiln is heated to 1500 OC.
Chemical changes:
Limestone decomposes to CaO.
CaCO3 è CaO + CO2
7CaO + Al2Si2O7 è 2Ca2SiO4 (Cement)+ Ca3Al2O6
The cement mixture finally forms into small size clinkers. After cooling, clinkers are ground into fine powder along with gypsum to produce cement.
Setting of cement
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Gypsum (CaSO4.2H2O) is added to cement to increase the setting time of cement. When water is mixed, cement sets. The setting of cement is a complex chemical change. It involves bonding forces between calcium ions (Ca+2)and silicates ions (SiO4)-4and water molecules.
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