Zero Waste Management for Zinc extraction



Challenge Summary

Recovery of valuable metals from waste products of zinc extraction process for efficient disposal and utilisation of currently stored waste resources or byproducts resources.

Challenge Scenario

Wastes generated by lead-zinc mining operations include materials such as waste rock, tailings, and refuse. Processing of these sources results in the production of residues containing metallurgical slags which are frequently stored in waste piles or landfills. Many of these materials may be disposed of onsite or offsite, while others may be used or recycled during the active life of the operation. Waste constituents may include base metals, sulfides, or other elements found in the ore, and any additives used in beneficiation operations. Zinc ferrite is one of the most abundant representatives of this class of compounds. From a chemical point of view, the constituents of red mud, one of the important wastes would be iron, aluminium, copper, silica and other rare earth metals contributing to a collective value of over $600 per ton when processed.

The other primary waste generated by mineral extraction in underground mines is mine development rock, which there is an increasing interest in the use of zinc slag-containing materials as partial substitutes for sand in road materials and also for mine back-filling.

Profile of the End-User

Zinc metal extraction units of Vedanta within India and International namely Hindustan Zinc Limited, South Africa (2), Namibia and Ireland

Functional Requirements of the End-User

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

Functional & Operational Capabilities

  • Efficient and profitable extraction of metals from tailings of zinc ore processing
  • Ability to process slurry, solid and liquid waste 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

  • The proposed method of recovery of valuable metals and minerals must be adaptable to all kinds of tailings - red mud, jarosite, and dross suiting to every location of Vedanta's zinc companies
  • Environment friendly by products at the end of the proposed methods

Expected Tangible Benefits and Measurable Gains

  • Reduction in disposal, cleanup and maintenance costs (in the 100's of millions per plant)
  • Avoidance of risks to surrounding environmental conditions
  • Avoidance of risks to surrounding environmental conditions

Performance Metrics or Outcomes

  • Amount of value captured per ton of waste processed
  • Percentage efficiency of disposal in terms of environmental impact from previous to the proposed method
  • Percentage efficiency of disposal in terms of environmental impact from previous to the proposed method

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