Utilization of burnt rice and cotton straws in producing lightweight - thermally characterized clay building units

Abstract EN

Utilization of Burnt Rice Straw BRS or Burnt Cotton Straw BCS in building clay bricks industry shares in the environmental protection against the pollution caused by the accumulation of such solid waste, in addition to saving energy consumed in cooling instruments.

One method of increasing the insulation ability of brick is generating porosity in clay body.

Combustible organic types of pore-forming additives are most frequently used for this purpose.

El-Saff clay, (Giza Governorate, Egypt) representative sample as well as BRS and BCS were investigated, from their physical, mineralogical and chemical composition.

El-Saff clay is silty and well sorted with a mineralogical composition of montmorillonite, kaolinite and illite clay minerals in addition to, quartz, feldspar, gypsum and calcite as the non-clay minerals.

BRS is mainly composed of feldspars; BCS is mainly composed of quartz and calcite in addition to some feldspar minerals.

Specimens fired at 800 ˚c of clay \ BRS with 5, 10, 15, 20, 25 and 30 % of BRS have a reduction of 22.22, 35.74, 39.73, 49.17, 50.5 and 56.2 % of the bulk density of a blank clay specimen, while they have a reduction of 68.2 75.1, 86.9, 88.7, 90.5, and 93.5 % of the thermal conductivity of a blank clay specimen. A mix of clay / 10 % BRS or clay / 5 % BCS at a lower firing temperature (800˚C) completely agree with the limits of the Egyptian Standard Specifications for building units made from clay No.

43 for year 1982, No.1756for year 1989 and No.

1524 for year 1993.

Increasing the firing temperature has little effect on the product obtained ; this saves on fuel used in firing process.