Q-1: What are the advantages of fly ash brick technology over other technologies?
Ans: Fly ash bricks have high compressive strength and low water absorption (6-12%). They are light in weight and have high strength to weight ratio. They are less porous and have a thermal conductivity of 0.90-1.05 W/m2°C. Bricks have uniform pleasing colour like cement. They are uniform in shape and smooth in finish. No plastering is required. They also have dense composition.
Q-2: What is the production capacity of a fly ash unit?
This technology is economical and environment friendly. There is no emission of greenhouse gases during production. Required operational area is smaller than any other brick producing unit.
Ans: A fly ash unit has a daily production capacity of 6000-8000 bricks per shift of 8 hours.
Q-3: Is it possible to produce good quality bricks using fly ash?
Ans: The fly ash bricks have high compressive strength. The strength of the bricks can be engineered by varying compositions of fly ash, additives and filler materials. The bricks have a metallic ring to it. The bricks have uniform pleasing colour like cement. They have low water absorption. They have uniform size and shape conforming to IS 12894:2002, Class 7.5.
Q-4: What type of ash is used in fly ash brick technology?
Ans: Fly ash collected from electrostatic precipitators (ESP) or silos of thermal power plants in dry state can be used for brick production.
Q-5: What type of additives can be used in fly ash technology?
Ans: Lime and gypsum are used as additives in fly ash technology. Even waste lime can be used in the production process. Lime can be obtained from chemical plants like oxygen plants. Gypsum can be obtained from fertilizer plant.
Q-6: Is it economically feasible?
Ans: Yes, this technology is economically feasible. The machines cost can be upto INR 12 lakhs (24,000 USD). The working capital is approximately INR 5 lakhs (10,000 USD). It’s payback period is 2 years.
Q-7: Are skilled manpower required to operate fly ash unit?
Ans: No, skilled manpower is not required to operate a fly ash unit. 10 people are required to run a fly ash brick production unit. They can be easily trained on the site itself.
Q-8: Is all fly ash suitable for making bricks?
Ans: The suitability of fly ash to be used for making bricks can be tested in the Material Testing Laboratory, Datia.
Q-9: What type of fuel can be used in fly ash unit?
Ans: Coal is not used at all in the production of fly ash bricks. However, electricity and diesel is used in the production process.