Research Journal of Engineering and Technology

Suchita Rai ¹, K. L. Wasewar ², M. J. Chaddha ¹, J. Mukhopadhyay ³

Affiliations
1 Jawaharlal Nehru Aluminium Research Development and Design Centre (JNARDDC), Wadi, Amravati Road, Nagpur, Maharashtra, 440023, IN
2 Advance Separation Processes and Analytical Laboratory (ASPAL), Department of Chemical Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur -440010, Maharashtra, IN
3 Indian Institute of Technology, Gandhinagar, Gujarat, IN

Abstract

'Red mud' or 'bauxite residue' is a highly alkaline waste generated from alumina refinery with a pH of 10.5-12.5. Red mud poses serious environmental problems such as alkali seepage in ground water and alkaline dust generation. Most of the environmental hazards related to disposal of red mud can be reduced by its safe treatment and efficient utilization. Sintering of red mud along with a silicate material at a very high temperature fixes nearly all the leachable soda and the mixture can be utilized as a building material. Fired and non-fired bricks can be developed by mixing red mud with fly ash and other materials. In this way, red mud can be utilized in bulk in building and construction industry. Review of utilization of red mud in manufacture of fired and non-fired bricks is presented in the paper.

Keywords

Bauxite Residue, Red Mud, Utilization, Bricks.

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Suchita Rai ¹, K. L. Wasewar ², D. H. Lataye ², Kalpana Singh ², M. J. Chaddha ¹, J. Mukhopadhyay ³

Affiliations
1 Jawaharlal Nehru Aluminium Research Development and Design Centre, Wadi, Amravati Road, Nagpur-440 023, IN
2 Visvesaraya National Institute of Technology (VNIT), Nagpur-440 010, IN
3 Indian Institute of Technology, Gandhinagar, Gujarat, IN

Abstract

'Red mud' or 'bauxite residue', a waste generated from alumina refinery is highly alkaline in nature with a pH of 10.5-12.5. Enormous quantity of red mud is generated worldwide every year posing a very serious and alarming environmental problem such as alkali seepage in ground water and alkaline dust generation. Seawater neutralization is one of the methods for treating it and making it non-hazardous. Reuse of seawater neutralized red mud after heat activating it for fluoride adsorption is studied in present paper. Increase in activation temperature of seawater neutralized red mud resulted in increase in adsorption of fluoride. Moreover low adsorption may be increased by acid treatment of heat activated seawater neutralized red mud.

Keywords

Red Mud, Seawater Neutralized Red Mud, Heat Activation, Adsorption, Fluoride.

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Suchita B. Rai ¹, Kailas L. Wasewar ², M. J. Chaddha ¹, R. S. Mishra ¹, J. Mukhopadhyay ¹

Affiliations
1 Jawaharlal Nehru Aluminium Research Development and Design Centre, Wadi, Amravati Road, Nagpur, IN
2 Visvesaraya Institute of Technology (VNIT), Nagpur, IN

Abstract

Bauxite Residue or Red mud is the waste generated during bauxite processing for production of alumina through Bayer process. Red mud is a highly alkaline material (pH about 10.5-12.5) because of digestion of bauxite ore in caustic soda solution at elevated temperatures. The high alkalinity also limits its use for various applications such as vegetation, construction material etc. Land disposal of these materials often has negative environmental impacts such as contamination of soil and groundwater, and consumes vast areas of land. Revegetation of dewatered red mud is not possible without addition of amendments because of the high pH, high salinity, and absence of nutrients and organic constituents. Red mud ponds can be rehabilitated and abandoned bauxite mine pits can be refilled by identifying suitable amenders to ameliorate the caustic properties of red mud so that vegetation cover can be developed. Red mud from an alumina refinery situated at the eastern coast of India has been modified by adding amenders/ modifiers/ neutralizers such as coal dust, superphosphate and gypsum and their effectiveness is studied by carrying out the pH studies. The effect of addition of these neutralizers has been very well seen as the pH of red mud slurry stabilizes to a value well below 8.5-9.0 as compared to the value of above 10.5 obtained without using them. Gypsum and a combination of superphosphate and coal dust are found to be very effective as amenders as they reduce the pH of red mud to a much lower value. To study the suitability of red mud for vegetation, shrubs have been planted in red mud mixed with amenders The survival of the plants in red mud mixed with neutralizers/ amenders and their proper growth in it show that bulk utilization of red mud can be carried out in the area of vegetation by growing suitable flora and fauna.

Keywords

Amenders, pH, Red Mud, Vegetation.

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