PCB Metal Extraction Without Toxic Emissions
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Solution Overview
Problem
Existing methods for recovering precious and base metals from printed circuit boards (PCBs) are environmentally damaging, releasing toxic compounds and greenhouse gases, and are inefficient in separating metals from non-metallic components.
Innovation Solution
A process involving mechanical shredding, micronization, chemical leaching, and thermal oxidation to extract metals and non-metallic components from PCBs, using environmentally friendly chemicals and processes to minimize pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional pyrometallurgical methods are used to recover metals from PCBs, then metal recovery is achieved, but toxic emissions (dioxins, furans, halogenated compounds) and greenhouse gases are produced
Solution Approach 1:
The patent replaces the thermal/pyrometallurgical system with a mechanical system consisting of shredding, micronization, and magnetic separation processes. This substitution eliminates the need for high-temperature incineration that produces toxic emissions, while still achieving effective metal recovery through physical separation methods
Solution Approach 2:
The patent extracts and removes the harmful organic components (epoxy resin and plastic) from the PCB material through selective dissolution and filtration processes. This extraction eliminates the source of toxic emissions before any metal recovery operations, allowing subsequent processing to occur without generating dioxins, furans, or halogenated compounds
2Manufacturing precision
If PCBs are shredded and micronized, then metal separation efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent performs preliminary removal of epoxy resin and plastic components through selective chemical dissolution before the micronization step. This preliminary action reduces the energy required for subsequent shredding and micronization by eliminating bulky organic materials that would otherwise require extensive mechanical processing, while still achieving the necessary particle size reduction for effective metal separation
Solution Approach 2:
The patent segments the PCB processing into distinct stages: chemical dissolution of organics, filtration, magnetic separation of metals, and residue disposal. This segmentation allows each process to be optimized independently, reducing overall energy consumption compared to a single-stage high-energy micronization process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively recovers metals like Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, and Pd while eliminating toxic emissions, with high recovery rates and minimal environmental impact.
Implementation Method 1
treating the micronized powder with an oxidizing agent dissolving the epoxy resin and the plastic
Implementation Method 2
The ferromagnetic metals (Fe, Ni and Co) are separated from the non ferromagnetic materials in the micronized powder with a magnetic separator
Implementation Method 3
leaching the delaminated content comprising Cu producing a filtrate from which the Cu is precipitate
Implementation Method 4
from which the Cu is precipitate
Data Source
AI summary
It is provided an environmentally friendly process for recycling metals and nonmetallic components from printed circuit boards (PCBs), without using treatments considered damaging to the environment and minimizing emission of greenhouse gases comprising the steps of shredding the PCBs, micronizing the shredded PCBs producing a micronized powder, removing plastic and epoxy from the micronized powder, leaching, precipitating and recuperating the Al, Fe, Zn, Ni, Cr, Cu, Au, Ag, and Pd from the micronized powder, producing a filtrate from which the Cu is recovered. The solid product of the process is a concentrate of precious metals.