Copper Gold Leaching via Halogen Ion Control
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Solution Overview
Problem
Current methods for recovering copper and gold from sulfide ores in the wet process face inefficiencies in separation and recovery yield due to overlapping redox potentials, where gold leaches prematurely during copper leaching, leading to incomplete copper extraction and high additional processing costs.
Innovation Solution
A method involving two aqueous acidic solutions: one containing chlorine ions but no bromine for copper leaching, and another with both chlorine and bromine ions for gold leaching, controlling redox potentials to achieve high copper extraction while minimizing gold leaching, followed by solid-liquid separation and subsequent gold recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the redox potential is elevated to enhance copper leaching efficiency, then copper leaching is improved, but gold starts to leach prematurely
Solution Approach 1:
The invention changes the chemical composition parameters of the leaching solution by selectively adding chlorine ions while controlling bromine ion content. This parameter modification allows the system to achieve high copper leaching efficiency through enhanced complex formation with copper ions, while simultaneously suppressing gold leaching by maintaining specific halogen ion concentration ratios that favor copper-selective chemistry.
Solution Approach 2:
The invention creates locally optimized chemical environments by controlling the distribution and concentration of different halogen ions (chlorine and bromine) in the leaching solution. By establishing specific local chemical conditions with elevated chlorine ion concentrations and controlled bromine ion levels, the system achieves differential leaching behavior where copper is actively leached while gold remains in the solid phase.
2Object-affected harmful factors
If the redox potential is lowered to suppress gold leaching, then gold leaching is suppressed, but copper leaching becomes incomplete
Solution Approach 1:
The invention modifies the chemical parameters of the leaching solution by introducing specific halogen ion compositions (high chlorine, controlled bromine) that fundamentally change the leaching mechanism. This parameter change allows the system to maintain lower redox potentials that suppress gold oxidation while still achieving complete copper leaching through enhanced complex formation kinetics and thermodynamics driven by the specific halogen ion composition.
Solution Approach 2:
The invention introduces halogen ions (particularly chlorine and bromine in specific ratios) as intermediary substances that mediate the leaching process. These intermediary ions form stable complexes with copper ions, facilitating copper dissolution at lower redox potentials, while simultaneously acting as selective agents that prevent gold oxidation by controlling the electrochemical environment.
3Quantity of substance
If conventional leaching methods are used, then both copper and gold can be leached, but separation efficiency between copper and gold deteriorates
Solution Approach 1:
The invention applies local quality control by creating distinct chemical environments for copper and gold leaching through controlled halogen ion composition. By establishing specific local chemical conditions with elevated chlorine ion concentrations and controlled bromine ion levels, the system achieves differential interaction with copper and gold, enabling high separation efficiency while maintaining high extraction rates for both metals.
Solution Approach 2:
The invention changes the chemical composition parameters of the leaching solution by selectively controlling halogen ion concentrations. This parameter modification creates a chemical environment that favors copper leaching through stable complex formation while suppressing gold leaching, thereby achieving high separation efficiency. The specific parameter regime (high chlorine, controlled bromine) enables selective metal extraction without requiring separate leaching stages.
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 approach enhances the separation efficiency between copper and gold, achieving a copper leach rate of 90% or more with a gold leach rate of 10% or less, and allows for high recovery yield of gold with reduced additional processing costs.
Implementation Method 1
bringing a first aqueous acidic solution which contains chlorine ion, copper ion and iron ion, but no bromine ion, into contact with sulfide ores under supply of an oxidizing agent, so as to leach copper component contained in the sulfide ores
Implementation Method 2
the presence of copper ion and iron ion, which act as catalysts for the leaching reaction
Implementation Method 3
when the redox potential gradually elevates as the leaching of copper proceeds, gold starts to leach
Implementation Method 4
bringing a second aqueous acidic solution which contains chlorine ion, bromine ion, copper ion and iron ion, into contact with the leaching residue obtained in Process (2) under supply of an oxidizing agent, so as to leach gold contained in the leaching residue
Data Source
AI summary
Disclosed is a method of leaching copper and gold from sulfide ores, which includes Process (1) of bringing a first aqueous acidic solution which contains chlorine ion, copper ion and iron ion, but no bromine ion, into contact with sulfide ores under supply of an oxidizing agent, so as to leach copper component contained in the sulfide ores; Process (2) of separating, by solid-liquid separation, a leaching reaction liquid obtained in Process (1), into a leaching residue and a leachate; and Process (3) of bringing a second aqueous acidic solution which contains chlorine ion, bromine ion, copper ion and iron ion, into contact with the leaching residue obtained in Process (2) under supply of an oxidizing agent, so as to leach gold contained in the leaching residue.