Electronic Board Metal Recovery Without Shredding
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Solution Overview
Problem
Existing methods for recycling base metals and precious metals from electronic waste, such as pyrometallurgical and hydrometallurgical processes, are inefficient, costly, and environmentally harmful, with low yield and purity, particularly due to the use of corrosive chemicals like nitric acid and the risk of fire from manganese dioxide.
Innovation Solution
A hydrometallurgical method using an acid solution of water, acetic acid, hydrochloric acid, and hydrogen peroxide for leaching, followed by selective recovery of metals like silver, gold, copper, tin, lead, nickel, platinum, and palladium through precipitation and case hardening, without shredding the electronic boards, and using mild conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If pyrometallurgical methods are used for metal recovery, then high temperature processing can be achieved, but operational costs increase and toxic fumes are emitted
Solution Approach 1:
The patent changes the fundamental parameter of processing temperature from high (pyrometallurgical) to low/ambient (hydrometallurgical with acetic acid and hydrogen peroxide). This parameter change eliminates the need for high-temperature furnaces and associated toxic fume emissions while achieving effective metal recovery through chemical leaching and reduction reactions
Solution Approach 2:
The patent replaces the thermal/mechanical pyrometallurgical system with a chemical hydrometallurgical system using acetic acid and hydrogen peroxide solutions. This substitution eliminates the need for high-temperature thermal processing and replaces it with controlled chemical reactions that occur at ambient or mild temperatures, thereby eliminating toxic fume generation
2Productivity
If manganese dioxide is used in hydrometallurgical processes, then copper recovery can be achieved, but fire hazard increases and operator safety is compromised
Solution Approach 1:
The patent replaces the dangerous, self-heating manganese dioxide with safe, stable acetic acid and hydrogen peroxide solutions. These reagents are non-flammable, easy to handle, and can be disposed of or regenerated without special safety precautions, thereby eliminating fire hazards while maintaining copper recovery effectiveness through alternative chemical mechanisms
Solution Approach 2:
The patent converts the potentially harmful self-heating property of manganese dioxide into a beneficial controlled chemical reaction system using acetic acid and hydrogen peroxide. The mild exothermic reactions of these reagents provide sufficient energy for copper dissolution and reduction without the dangerous uncontrolled self-heating that characterizes manganese dioxide, thereby transforming a safety hazard into a controlled, safe process
3Productivity
If nitric acid is used for leaching, then metal extraction can be performed, but corrosiveness increases and wastewater treatment becomes difficult
Solution Approach 1:
The patent replaces the highly corrosive, environmentally problematic nitric acid with safe, non-corrosive acetic acid and hydrogen peroxide. These reagents are mild, biodegradable, and do not require complex wastewater treatment infrastructure, thereby eliminating corrosion issues and simplifying environmental compliance while achieving effective metal extraction through alternative chemical pathways
Solution Approach 2:
The patent changes the chemical parameters of the leaching solution from strong oxidizing acids (nitric acid) to mild organic acid and peroxide systems (acetic acid and hydrogen peroxide). This parameter change reduces the corrosiveness from pH <1 to pH 2-4, eliminates nitrogen oxide emissions, and creates biodegradable wastewater that can be treated through simple neutralization and biological processes
4Ease of manufacture
If physical/mechanical procedures are used for metal separation, then pre-treatment can be performed, but complete separation of valued metals is not achieved
Solution Approach 1:
The patent merges the physical pre-treatment step with the chemical extraction step into a unified hydrometallurgical process. By applying acetic acid and hydrogen peroxide solutions directly to the electronic board components, the method simultaneously achieves dissolution of metal-containing materials and selective extraction of precious and base metals, eliminating the need for separate mechanical preprocessing stages and achieving complete separation in one operation
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 method achieves high yield and purity in recovering base and precious metals, reducing environmental impact and operational costs, with yields exceeding 70% and purities above 50% for most metals.
Implementation Method 1
Leaching the base metals and the precious metals from the surface of said waste material by means of immersion of the waste material, if necessary pre-treated, in an acid solution containing water, acetic acid, hydrochloric acid, hydrogen peroxide
Implementation Method 2
acid solution containing water, acetic acid, hydrochloric acid, hydrogen peroxide
Implementation Method 3
selective recovery of the base metals copper (Cu), tin (Sn), lead (Pb) and nickel (Ni) from the acid aqueous solution obtained from the stage II-A)
Data Source
Figure 1
AI summary
The present invention relates to a hydrometallurgical method for the recycling and recovery of base metals, such as copper, tin, lead and nickel, and precious metals, such as gold and silver, from electronic boards or printed circuits of electrical and electronic equipment. It also relates to the recovery of palladium and platinum from waste catalytic converters.