Composition for building material and a process for the preparation thereof

A process for producing building materials, comprising the steps of:

• (a) mixing 1 to 10% by weight of a chemical activator comprised of at least one hydroxide selected from the group consisting of aluminum hydroxide, sodium hydroxide and potassium hydroxide, at least one sulfate selected from the group consisting of aluminum sulfate, sodium sulfate and potassium sulfate, and at least one salt selected from the group consisting of calcium acetate, magnesium acetate, calcium chloride and magnesium chloride with 80 to 98% by weight of fly ash, 2 to 18% additive materials selected from the group consisting of particles of metallurgical slag, waste aluminous refractory, slag wool, building material debris, resin, plastic, red mud of Bayer's alumina process, aluminous and alumino-silicate clay and mining wastes and mixtures thereof, and is included as a mixture comprised of finer fractions of below 100 mesh size and coarse granular fractions of 2 mm and above, and water for a period of about 6 to 12 minutes to obtain a homogenized mixture having 8 to 28% moisture by weight;
• (b) casting or molding the homogenized mixture as obtained in step (a) in the form of brick or block by vibration or compaction;
• and
• (c) curing the brick or block as obtained in step (b) by exposing to atmospheric air having a temperature of about 20 to 35° C. for about 72 to 720 hours or in air at a temperature above 40° C. for about 4 to 10 hours to produce the building materials.