Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Sequential Extraction of metals from Printed Circuit Boards by hydrometallurgical route

Technology Category/Market

Technology: Extraction of Metals from PCB

Industry: E-waste management, Chemical  Applications: Chemical, e-waste management

Market: The global Printed Circuit Boards (PCB) E-scrap recycling market is projected to reach $230.3B by 2031, at a CAGR of 12.9% during the period (2022-2031)

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Problem Statement

  • Rapid developmens in electronic industry has resulted in accumulation of electronic material which have reached the end of life. This has resulted in accumulation of ewaste. which can lead to severe pollution of ground water sources.
  • A large fraction of metals (Cu, Sn, Pb, etc.) contributes to increase toxicity levels of ecosystem. Therefore, there is a need to recover the metals from e-waste.
  • It is estimated 5 MMTonnes of ewaste is generated annually. Current technologies for treating, managing & handling of e-waste, use highly toxic chemical reagents and cause acidification of soil. Hence, there is a need to address above issues.


  • Present invention describes a Sequential Extraction of metals from Printed Circuit Boards by hydrometallurgical route using a single acid.
  • The features of the present invention is disclosed hereinbelow:
  • Recovery of salts of tin, lead, & copper from scrap PCBs in a sequential manner by changing only the concentration of nitric acid.
  • Further said invention discussed a process for recovery of NOx emissions during the treatment of PCBs with concentrated nitric acid. A pilot plant to process 100 tonnes per annum of waste is set up at BHEL Trichy.

Key Features/Value Proposition

Technical Perspective:

  • The present invention talks about obtaining lead nitrate (crystal or power forms) & obtained tin precipitate from stannic acid solution & the copper nitrate from the copper nitrate solution.
  • Concentrating the dilute solution of lead nitrate & nitric acid by evaporating or distilling & cooling the concentrated solution to obtain lead nitrate.

Industrial Perspective:

  • Features are given as  safe, eco-friendly, sustainable, & cost-effective/economic process.

Questions about this Technology?

Contact for Licensing

Prof. Pushpavanam S,

Department of Chemical Engineering

Research Lab

Intellectual Property

  • IITM IDF Ref. 1758;
  • Patent Application No:201841032120;

Technology Readiness Level


 Proof of Concept ready & validated

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