Redox Active Materials for Cyanide-Free Precious Metal Extraction
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Solution Overview
Problem
Current precious metal extraction processes are costly and environmentally polluting, particularly due to the use of toxic chemicals like cyanide, and lack efficient methods for selectively reducing oxidized precious metals like Mn+ to their zero-oxidation state.
Innovation Solution
Development of redox active materials incorporating 2,5-dithio-7-azabicyclo[2.2.1]heptane units, which are synthesized by reacting functionalized solid phase carriers with 2,5-dihydroxy-1,4-dithiane, enabling the reduction of metals and subsequent adsorption of reduced metals, and can be used in various applications including gold mining and filtration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional precious metal extraction processes using cyanide are employed, then metal extraction capability is achieved, but environmental pollution and toxicity increase
Solution Approach 1:
The patent converts the harmful cyanide extraction process into a beneficial redox-based extraction process. The 2,5-dithio-7-azabicyclo[2.2.1]heptane units on the solid phase carrier selectively reduce oxidized precious metals (Mn+) to their zero-oxidation state and adsorb them, eliminating the need for toxic cyanide while maintaining effective metal extraction capability
Solution Approach 2:
The patent changes the chemical mechanism parameter from cyanide complexation to redox reaction and adsorption. By using 2,5-dithio-7-azabicyclo[2.2.1]heptane functional groups that exhibit redox properties, the process transforms oxidized metals Mn+ into reduced metal form M0, which is then adsorbed onto the solid phase carrier, providing a non-toxic alternative to cyanide extraction
2Reliability
If materials that bind metals through chelation or electrostatic attraction are used, then metal binding capability is achieved, but selective reduction of oxidized metals to zero-oxidation state is not accomplished
Solution Approach 1:
The solid phase carrier material performs multiple functions simultaneously: (1) it binds metals through chelation and electrostatic attraction, (2) it selectively reduces oxidized precious metals Mn+ to their zero-oxidation state M0 through redox-active 2,5-dithio-7-azabicyclo[2.2.1]heptane units, and (3) it adsorbs the reduced metals. This multi-functionality resolves the contradiction by integrating binding and selective reduction capabilities into a single material system
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
These materials effectively reduce and adsorb precious metals, offering a cost-effective and environmentally friendly alternative to traditional methods, with applications in gold mining, filtration, and other industrial processes, while also functioning as anion exchange materials and halogen scavengers.
Implementation Method 1
Materials that react selectively with metals such as precious metals in their oxidized form, Mn+ in aqueous solution, reducing them to the zero-oxidation state
Implementation Method 2
obtaining a reduced metal that is adsorbed to the redox active material
Data Source
AI summary
The present disclosure relates to redox active materials, such as the compound of formula (I), comprising at least one 2,5-dithio-7-azabicyclo(2.2.1)heptane unit connected to a surface thereof, as well as processes for making said redox active materials. The present disclosure relates to a method for recovering a metal, comprising reacting a metal in oxidized state with said redox active material. The present disclosure relates to uses of these redox active materials in sensors, electronic materials and for extracting metals.