Preparation of eco-environmental protection bricks from lake sludge

Abstract

Eco-environmental protection hollow bricks manufactured from lake sludge collected from North Lake in Wuhan of China were investigated. At first, the recipes of round samples( diameter in 5 cm and thickness in 1 cm) prepared by pressing molding under a pressure of 8 MPa and firing system were optimized, and properties such as bending strength, compressive strength, total shrinkage rate, water adsorption rate, apparent porosity and bulk density of the fired samples were tested. The experimental results showed that water adsorption rate and apparent porosity decreased, while bulk density increased with firing temperature increasing. Addition of additive can result in the improvement of strength of fired samples. At the same time, fly ash and additive may also broaden the firing temperature range and reduce firing temperature. Toxic characteristic leaching procedure (TLCP) tests of samples also show that the metal leaching level is low. The conditions for manufacturing good quality sample include 80% sludge with 10% additive and 10% fly ash fired at 1000 °C for 60 min. Bending strength and compressive strength of samples prepared under the conditions are 24.64 MPa, 131.95 MPa, respectively,which are far beyond the requirements of clay solid bricks of CNS. Finally, according to the optimized recipe,the eco-environmental protection hollow bricks with the sizes of 40 mm×38 mm×25 mm were made and tested by extrusion molding. Compared with the Chinese National Standards (CNS: GB13545-2003), compressive strength, water adsorption and bulk denstiy of the hollow bricks are 11.55 MPa,14.5% and 986 kg/m³ when they were fired at 1040 °C, which are far beyond the require of of CNS. Especially, its water adsorption arrives to standard of high-class products(16.0%) and compressive strength is above the hightest class(MU10.0).

Keywords

lake sludge / eco-environmental protection bricks / strength / performance / microstructure

References

[1] Ding D.-jun. Re-discussion of Walls Innovation and Sustainable Development[J]. Journal of Architecture and Civil Engineering, 2005, 22(3): 1-15.

[2] He L.-M. Production of Brick and Tail from Soil Effects Crops Around: Pollution Factors Analysis and Judgment[J]. Journal of Hunnan Institute of Engineering, 2001, 11(1): 34-35.

[3] Shen R.-x., Xu L.-yi. Approach to Technical Way for Sustainable Development of Wall Materials in China[J]. Journal of Building Materials, 2001, 4(3): 203-210.

[4] Wang R.-xiang. The Development Trend of Energy Saving Wall in Civil Buildings[J]. ShanXi Architecture, 2003, 29(1): 33-34.

[5] Chih-Huang W., Deng-Fong L., Pen-Chi C. Utilization of Sludge as Brick Materials[J]. Advances in Environmental Research, 2003, 7: 679-685.

[6] Cheng-Fang L., Chung-Hsin W., Hsiu-Mai H. Recovery of Municipal Waste Incineration Bottom Ash and Water Treatment Sludge to Water Permeable Pavement Materials[ J]. Waste Management, 2006, 26: 970-978.

[7] Liaw C. T., Chang H. L., Hsu W. C., . A Novel Method to Reuse Paper Sludge and Co-generation Ashes from Paper Mill[J]. Journal of Hazardous Materials, 1998, 58: 93-102.

[8] Nishigaki M. Production Permeable Bricks and Pavement Bricks from Molten Slag[J]. Waste Management, 2000, 20: 185-192.

[9] Lin K. L. Feasibility Study of Using Brick Made from Municipal Solid Waste Incinerator Fly Ash Slag[J]. Journal of Hazardous Materials, 2006, 137: 1810-1816.

[10] Xu L., Guo W., Wang T., . Study on Fired Bricks with Replacing Clay by Fly Ash in High Volume Ratio[J]. Construction and Building Materials, 2005, 19: 243-247.

[11] M D., G G., M R., . Orimulsion Fly Ash in Clay Bricks—Part 2: Technological Behaviour of Clay/Ash Mixtures[J]. Journal of the European Ceramic Society, 2002, 22: 1737-1747.