Zero Waste Management for Alumina extraction

Challenge Summary

Utilization of Bauxite residue (Red mud) and fly ash for by product generation.

Challenge Scenario

Bauxite is used to produce alumina, which is then used to produce aluminium. Wastes can be generated at several points in the production process, including during the mining of the bauxite ore, and during the refinery production process. The refinery processes used to produce aluminium generates about 2 - 2.5 tons of solid waste for every 1 ton of aluminium produced. This includes a small amount of waste rock, waste “muds” and a small amount of other scrap and solid wastes. The red mud waste dries to a very fine, powdery solid and contains significant amounts of iron, aluminium, calcium and sodium.

Profile of the End-User

Vedanta is India's largest producer of aluminium with 2.2 million tons per annum (MTPA) production capacity aluminium smelters in Jharsuguda and BALCO. The smelter waste produced from these major plants shall be utilised for the implementation of new-age management processes.

Functional Requirements of the End-User

  • Sustainable ways of disposal and utilisation of accumulated wastes and tailings to extract meaningful minerals
  • Processes and methods to extract maximum value out of the wastes generated during alumina/aluminium extraction like fly ash, red mud etc in a sustainable manner

Functional & Operational Capabilities

  • Efficient and profitable extraction of metals from red mud, fly ash and other wastes generated during bauxite processing
  • Ability to extract valuable materials from red mud water & landfills
  • Capture and processing of fly ash and other minor wastes through a series of technical and chemical processing to extract residual value
  • Creation of sustainable byproducts from the re-processing of the wastes

Operational constraints

  • Ensuring environment friendly by products at the end of the proposed methods
  • The proposed recovery mechanism used for the valuable metals and minerals is to be adaptable by similar smelter units following the Bayer's process of extraction
  • The process should be favourable to tweaking based on the proportions of waste generated from time to time or place to place based on the goals of the Vedanta Management
  • Less process, power and material intensive than existing method of disposal

Expected Tangible Benefits and Measurable Gains

  • Gains from the production and selling of additional minerals, metals and material by-products generated from the recovery process
  • Reduction in disposal, cleanup and maintenance costs (in the order of 100 million per plant)
  • Avoidance of risks to surrounding environmental conditions

Performance Metrics or Outcomes

  • Percentage efficiency of disposal in terms of environmental impact from previous to the proposed method
  • Amount of value captured per ton of waste processed
  • Efficiency in energy utilisation in carrying out the processing