Utilization of Red Mud and Pond Ash for Construction of Embankments

Abstract

One of the major challenges before the processing and manufacturing industries is disposal of the residual waste products. Pond ash and red mud are one of the major waste products of any aluminum industry. The pond ash and red mud sample are acquired form BALCO, Korba where they are disposed off using the Thick Slurry Disposal System, which enables quick consolidation of the slurry once disposed at the ash and red mud pond sites. The project work focuses on the suitability of pond ash and red mud obtained hereby to be used for construction of embankment.
The ash and red mud samples are characterized and analyzed for the various geotechnical properties. The various experimental works include in situ density test using core cutter method, Standard Proctor density test to obtain the maximum dry density and optimum moisture content, and specific gravity test. Using the OMC and MDD results, Direct Shear Box test and Triaxial tests of the samples were carried out in 2-D and 3-D load conditions to obtain the shear strength parameters, c and Ф. The samples were also tested for their permeability characteristics using both falling head and constant head permeameter to obtain the coefficient of permeability, κ.
After characterization of the ash and red mud samples for their individual geotechnical parameters, the samples were mixed in various proportions to get a mix having optimum characteristics. The samples were mixed in the proportions of 90%-10%, 80%-20%, 70%-30%, 60%-40%, 50%-50% of red mud and ash content respectively. All the above experiments were carried out on each mix to obtain an optimum mix. The results of the experiments are all compiled in graphical form to observe the trends in the various parameters. Out of the all, the optimum mix is found out taking into account the considerations for construction of an embankment.
To account for the experimental findings, the samples were also observed under SEM (Scanning Electron Microscope). The magnified photographs of the particles, their arrangements and the mineralogical constitution are observed under the SEM and analyzed to validate the geotechnical parameters found from experimental procedures. From the analysis of the mineralogical data, presence of some toxic elements is observed. The above analysis and results can help in solving the problem of ash and red mud disposal and to a great extent help in increasing the economic benefit of the alumina industries.