Before going into large scale production of any product, based on their R&D work and the results obtained from pilot scale production laboratory has to fix certain parameters (recipe of production for that product) and provide it to the production department which the latter will follow in order to meet the required specifications and quality of that product. Two such important parameters required for manufacturing any type of refractory bricks are the ‘Moisture content’ of the green mixture (powder) and ‘Green BD’. Here our focus will be on the practical aspects of these two parameters of refractory bricks particularly those containing various percentages of alumina (Al2O3%).
The amount of moisture or water present in the green mixture (powder) of alumina containing refractory bricks help in green binding and also add plasticity. But beyond a certain percentage, water or moisture present in the green mixture of refractory bricks would be harmful leading to an increase the rejection percentage mainly due to -
(i) Increase in porosity and
(ii) Development of radial cracks in refractory bricks.
Suggested Article: Effects of Compacting Pressure on Sintering and other Properties of Refractory Bricks
What should be the maximum percent of moisture, green BDs corresponding to the different values of burned BDs of refractory bricks having different Alumina content (Al2O3%) etc. are given in the following table:
Refractory Bricks (Al2O3%)
|
Moisture%
|
Burnt BD
|
Green BD
|
Factor (Gr.BD/Br.BD)
|
40.00
|
7.00
|
2.20
|
2.36
|
1.073
|
45.00
|
6.50
|
2.25
|
2.41
|
1.071
|
50.00
|
6.50
|
2.45
|
2.62
|
1.069
|
60.00
|
5.50
|
2.50
|
2.65
|
1.060
|
70.00
|
5.50
|
2.60
|
2.75
|
1.058
|
75.00
|
5.00
|
2.65
|
2.78
|
1.049
|
80.00
|
4.50
|
2.70
|
2.82
|
1.044
|
Related Article: Bulk Density of Refractory Samples