Simultaneous Gold Leaching and Extraction via Sulfur-Based Ligand
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Solution Overview
Problem
Current gold recovery processes using cyanide leaching are inefficient, environmentally harmful, and costly due to high toxicity, long reaction times, and high reagent consumption, and the activated carbon adsorption method suffers from low selectivity and high temperatures.
Innovation Solution
A method involving a sulfur-based ligand extractant for simultaneous leaching and solvent extraction of gold, using a compound of Formula I in an aqueous phase with an acid and oxidizing agent, which forms a complex with gold to facilitate extraction at room temperature, reducing the need for cyanide and activated carbon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cyanide leaching is used for gold recovery, then gold dissolution efficiency is improved, but environmental safety deteriorates due to high toxicity
Solution Approach 1:
The patent replaces toxic cyanide with a biodegradable organic ligand system that can be used in small amounts and breaks down naturally. The ligand is designed to be environmentally benign while maintaining effective gold complexation, allowing the process to be disposed of safely without long-term environmental contamination.
Solution Approach 2:
The patent changes the chemical parameters of the leaching system by using a different class of compounds (organic ligands with specific functional groups) instead of cyanide. This parameter change maintains the ability to form soluble gold complexes while eliminating the toxic properties associated with cyanide.
2Productivity
If activated carbon adsorption is used for gold extraction, then gold recovery is improved, but process time increases due to long reaction times and high temperatures
Solution Approach 1:
The patent merges the leaching and extraction steps into a single simultaneous operation. The organic ligand system performs both gold dissolution from the ore and selective complexation into the organic phase in one step, eliminating the sequential nature of traditional cyanide leaching followed by activated carbon adsorption.
Solution Approach 2:
The patent establishes continuous useful action by having the ligand continuously extract gold from the aqueous phase as it is released from the ore. The system maintains active gold complexation throughout the process without idle periods between leaching and extraction steps.
3Productivity
If conventional leaching methods are used, then gold dissolution is achieved, but reagent consumption increases due to high cyanide usage
Solution Approach 1:
The patent changes the stoichiometric parameters of the leaching reaction by using organic ligands that form stable complexes with gold at lower concentrations. The ligand-to-gold ratio can be optimized to minimize reagent consumption while ensuring complete gold dissolution and extraction.
Solution Approach 2:
The patent employs small amounts of biodegradable organic ligand that can be used in limited quantities without creating long-term environmental problems. The ligand is designed to be effective at low concentrations and can be safely degraded after use, reducing both economic and environmental costs.
4Productivity
If cyanide leaching with activated carbon adsorption is used, then gold extraction is achieved, but selectivity deteriorates due to low selectivity and high impurity adsorption
Solution Approach 1:
The patent applies local quality by designing the organic ligand with specific functional groups and molecular structures that create selective binding sites for gold. The ligand's chemical properties are locally optimized to preferentially interact with gold over other metals, achieving high selectivity at the molecular level.
Solution Approach 2:
The patent changes the chemical parameters of the extraction system by using organic ligands with specific properties (solubility, complexation strength, selectivity) that differ from cyanide and activated carbon. These parameter changes enable selective gold extraction while leaving impurities in the aqueous phase.
Data Source
AI summary
The present application relates to methods for the simultaneous leaching and extraction of precious metals. For example, the present application relates to methods of leaching and extracting gold and/or palladium from a substance comprising gold and/or palladium such as a gold and/or palladium-containing ore in one step using a compound of Formula I: (I).