E-Waste Composite Materials Using Selective Leaching and Drying
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Solution Overview
Problem
Conventional methods for recycling electronic waste (E-waste) are inefficient, time-consuming, and pose environmental and health risks due to the use of toxic chemicals, and do not effectively recover precious metals and plastics, leading to incomplete recycling and potential contamination.
Innovation Solution
A process involving size reduction, chemical leaching to extract base and precious metals, and drying to produce an E-waste powder, which is then combined with binders or plastics to form composite articles or materials, thereby removing toxic elements and forming a stable composite.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional pyrometallurgical and hydrometallurgical processes are used to recover precious metals from e-waste, then precious metals can be extracted, but toxic chemicals are released into the environment causing pollution and health risks
Solution Approach 1:
The patent extracts and removes toxic elements (lead, mercury, cadmium, chromium) from e-waste through selective leaching processes using acids such as nitric acid, hydrochloric acid, and sulfuric acid. The toxic elements are separated from the matrix material and precious metals, allowing precious metals to be recovered while toxic substances are isolated and disposed of safely, thereby eliminating environmental pollution while maintaining metal recovery efficiency
Solution Approach 2:
The patent introduces intermediary substances including leaching acids (nitric acid, hydrochloric acid, sulfuric acid), complexing agents (ammonium thiocyanate, sodium cyanide), and reducing agents (sodium borohydride, zinc powder) to facilitate selective extraction. These intermediaries enable the separation of toxic elements from precious metals through controlled chemical reactions, allowing precious metals to be recovered in high purity while toxic substances are removed through precipitation and filtration processes
2Quantity of substance
If conventional e-waste recycling methods are used, then some materials can be recovered, but the process is time-consuming and inefficient
Solution Approach 1:
The patent segments the e-waste recycling process into distinct sequential stages: size reduction to produce fine particles, selective leaching of toxic elements using specific acids, precipitation of metal hydroxides, filtration to separate solids from liquids, and final drying to produce recovered materials. This segmentation allows each step to be optimized independently and enables parallel processing of different e-waste streams, significantly reducing overall processing time while improving recovery efficiency
Solution Approach 2:
The patent performs preliminary size reduction of e-waste into fine particles (0.5-2 mm diameter) before chemical processing. This preliminary action increases the surface area of the material, enabling faster and more efficient leaching of toxic elements and precious metals in subsequent steps. The pre-processing also facilitates better mixing and contact between the leaching solutions and e-waste particles, reducing the time required for complete extraction
3Quantity of substance
If e-waste is incinerated or burned to recover metals, then metal recovery can be achieved, but harmful toxins and carcinogens are released into the environment
Solution Approach 1:
The patent replaces the thermal/mechanical incineration process with chemical leaching processes. Instead of burning e-waste at high temperatures to recover metals, the invention uses selective chemical reactions with acids (nitric acid, hydrochloric acid, sulfuric acid) to dissolve and extract toxic elements and precious metals from the e-waste matrix. This substitution eliminates the release of toxic fumes and carcinogens associated with incineration while achieving complete metal recovery through controlled chemical dissolution and precipitation
4Productivity
If complete recycling of e-waste is attempted using conventional methods, then all materials can be recovered, but the process becomes complex and costly
Solution Approach 1:
The patent employs a universal multi-step chemical processing protocol that can handle various types of e-waste materials (circuit boards, cables, connectors, plastics) using the same fundamental leaching and precipitation techniques. The process uses a standardized sequence of acid treatments (nitric acid for oxidizing metals, hydrochloric acid for dissolving base metals, sulfuric acid for precipitating metal sulfides) that can be applied to diverse e-waste compositions without requiring separate specialized processes for each material type, thereby simplifying the overall system while achieving complete recycling
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
This process enables efficient recovery of precious metals and reduces environmental contamination by converting E-waste into valuable composite materials, providing a safer and more effective recycling method.
Implementation Method 1
extracting one or more base metal by chemical leaching, extracting one or more precious metal by chemical leaching
Implementation Method 2
drying the slurry to provide the E-waste powder
Data Source
AI summary
An electronic waste (E-waste) recycling process and composite article or material using the E-waste. E-waste, for example including printed circuit boards (PCBs) and/or electronic components (ECs) such as integrated circuit chips, is size reduced, processed with one or more chemicals to remove base metals, precious metals, and chemicals of concern, and dried to provide a E-waste powder. The E-waste powder, may be used to form an E-waste composite article or material.