Aluminium is used excessively in the modern world with extremely diverse due to its several unusual combinations of attributes. No other metallic element can be used in so many ways across such a variety of domains like in the home, in transport, on land, sea and in air, and in industry and commerce. Aluminium's usages are not always as obvious as they may seem, with sizeable proportions of manufactured aluminium and aluminium oxide going into other separate processes, like the manufacture of glass, rather than towards the common consumer products that we most readily associate Aluminium with.
Over 95% of the Alumina manufactured globally is derived from Bauxite by the Bayer process. The Bauxite residue primarily consists of iron oxides, silicon oxide, titanium oxide and undissolved alumina together with a wide range of other oxides. This depends on the place of extracted bauxite and during refinery process, it leaves behind a residue known as Red Mud. It is composed of a mixture of solid and metallic oxides. The red colour arises from iron oxides, which comprise up to 40% of the mass. The mud is highly basic with a pH ranging from 11 to 13. With about 77 million tonnes of this unsafe material being produced annually, red mud poses a serious disposal challenge in the mining industry.
Vedanta’s Lanjigarh Alumina refinery is the first Alumina Refinery in the country to become a ‘Zero Discharge Refinery’
Red Mud Management at Lanjigarh:
The red mud stacking methodology plays a vital role in determining the life of the red mud pond. In the current scenario at Lanjigarh, the disposal and stacking methodology has been updated and revised in ensuring the sustenance of the plant operations in the years to come. Upon studies on available methods, the unit has adopted progressive rise or step deposition method which is generally used in areas where the deposition area is in a hilly area or is highly sloped. In this method, the mud is deposited in the shape of steps and gradually raising the deposition height spreading across the red mud pond area leaving a garland drain along the dyke side. This technique eliminates the risk of dyke wall failures due to hydraulic pressure or any overflow due to non-retention of water inside the dyke. The Red Mud Powder Plant is designed to separate water from red mud slurry and is the first ever such initiative by any alumina maker in the world.
The red mud pond in Lanjigarh has been designed and certified by the Indian Institute of Science, Bangalore
Red Mud Utilisation:
Innovation that builds on industrial ecology and collaboration across normal business boundaries is a key success factor for our license to operate. Across the world, wastes have always been a challenge with a potential to deliver values. With the help of technology and collaboration, we are converting this challenge into opportunities.Effective utilisation of red mud is necessary to avoid any mishaps and subject any adverse impact on the ecology in the region. Dyke construction, brick manufacturing, usages in fertiliser manufacturing and cement manufacturing, etc. can be thought of for utilising the red mud effectively. The adoption of the model of ‘Zero Discharge’ and ‘Zero Waste’ can only help in developing a better relationship with the society and greening the economy.
Vedanta’s Alumina Refinery in Lanjigarh became the first Mining & Metal Industry in India to get accreditation for its Energy Management System for ISO 50001:2011 from the British Standards Institution for efficiently managing the existing natural resources and mitigating the impact of climate change in Odisha.
Since its inception, Vedanta Limited, Lanjigarh has developed a road map for “Zero Waste Alumina Refinery”. Moving in this direction, the Red Mud Filtration Unit is playing a pivotal role in the conversion of red mud into value added products for utilisation in building materials, cement and fertiliser industries. The installation of the filtration unit has not only helped in making this refinery as the environmentally friendly refinery but also helped in conducting future field trials for magma technology to recover iron and titanium. The unit has commissioned this filtration unit describing it as first of its kind in alumina industry tackling major environmental hazards. This will have advantages like savings in caustic consumption by 10-15 kg per tonne of alumina, minimising land requirement by 50 to 60 percent, and doing away with wet red mud storage thereby eliminating environmental hazards.
Vedanta understands that the nature of its operations has a variety of implications for the environment – through our emissions, wastes generated in mining, refining and smelting processes, water consumption and changes in land use. We are committed to minimising our environmental footprint from the start of our operations through to closure and beyond.
Read our report on Sustainable Development 2015-16:
Lanjigarh business unit develops world’s first Red Mud Powder Plant:
- http://sustainabledevelopment.vedantaresources.com/sustainable-development/performance-and-reports/case-studies/responsible-stewardship/automatic-powdery-red-mud-plant-at-lanjigarh.html
- http://www.business-standard.com/article/companies/vedanta-commissions-first-ever-red-mud-powder-plant-113111800905_1.html
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