Liquid-liquid redox extraction of elements from glass matrix
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Solution Overview
Problem
Current methods for extracting valuable chemical elements from fly ash and laterites are inefficient, as they fail to recover elements with high boiling temperatures and do not adequately address the toxicity and environmental risks associated with storage, particularly due to the complexity and high-pressure/temperature requirements of existing processes.
Innovation Solution
A process involving mixing the material with an oxide or precursor of a third chemical element to form a glass matrix, followed by contact with a reducing agent in a liquid phase, allowing the extraction of chemical elements by redox reaction, which reduces the boiling temperature dependency and simplifies the extraction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vitrification process is used to extract chemical elements from fly ash, then toxic elements are vaporized and confined in vitrified material, but elements with high boiling temperatures cannot be extracted
Solution Approach 1:
The invention changes the chemical environment by introducing a basic liquid phase (containing Ca(OH)2, NaOH, or KOH) that reacts with metal oxides to form soluble complexes. This chemical parameter change enables extraction of elements at lower temperatures, overcoming the limitation of vitrification which requires temperatures above 1300°C and cannot extract high-boiling-point elements effectively.
Solution Approach 2:
The basic liquid phase acts as an intermediary medium that facilitates the extraction of metal elements from fly ash. The basic substances (Ca(OH)2, NaOH, KOH) mediate the reaction between fly ash components and the extraction system, forming soluble complexes that can be separated, thereby enabling extraction of elements that would otherwise require high-temperature vaporization.
2Object-affected harmful factors
If high temperature heating is applied to vaporize heavy metals, then toxic elements are recovered, but the process requires complex high-pressure and high-temperature conditions
Solution Approach 1:
The invention replaces the mechanical/thermal system (high-temperature heating and vaporization) with a chemical system (basic liquid phase extraction). Instead of using complex high-temperature equipment to vaporize metals, the process uses chemical reactions in a liquid phase at much lower temperatures, significantly simplifying the equipment and operational complexity.
Solution Approach 2:
The process changes the temperature parameter from high (above 1300°C in vitrification) to relatively low temperatures by utilizing chemical reactions in a liquid basic phase. This parameter change eliminates the need for complex high-temperature equipment and simplifies the overall process while maintaining effective toxic element recovery.
3Productivity
If conventional extraction methods are used, then some chemical elements are recovered, but residual content in the glass matrix remains high
Solution Approach 1:
The invention changes the chemical parameters by using a basic liquid phase (Ca(OH)2, NaOH, or KOH) that forms soluble complexes with metal oxides. This enables more complete extraction of chemical elements from the fly ash, reducing the residual content in the glass matrix compared to conventional methods. The basic substances react with acidic metal oxides to form soluble salts that can be thoroughly removed.
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 effectively extracts a wider range of valuable chemical elements, reduces residual content in the glass matrix, and minimizes environmental risk by immobilizing toxic elements in a stable glass structure, while avoiding the need for high-pressure and high-temperature conditions.
Implementation Method 1
bringing said glass matrix into contact, in the molten state, with a liquid phase comprising a fourth chemical element E4, said fourth chemical element E4 being a reducing agent capable of reducing said first element chemical E1, whereby said first chemical element E1 migrates into said liquid phase
Data Source
AI summary
The invention relates to a process for extracting at least a first chemical element E1 from a material additionally comprising at least one oxide of a second chemical element E2 chosen from silicon, iron, aluminium and calcium. This process comprises: the mixing, in the melt state, of said material with at least one oxide of a third chemical element E3, and/or at least one precursor of such an oxide in order to form a glass matrix comprising said first chemical element E1, - bringing said glass matrix, in the melt state, into contact with a liquid phase comprising a fourth chemical element E4, said fourth chemical element E4 being a reducing agent capable of reducing said first chemical element E1, and - separating said liquid phase comprising said first chemical element E1 from said glass matrix.