Copper Ore Heap Resetting to Remove Leaching Passivation
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Solution Overview
Problem
Conventional leaching processes for copper recovery from refractory sulfide ores like chalcopyrite are inefficient, with copper recovery rates below 40% due to the formation of passivation layers such as elemental sulfur, jarosite, and EPS, which hinder further dissolution.
Innovation Solution
A method involving a reset step with a chelating agent and reducing agent, followed by a leaching step using a copper ore heap, to chemically remove passivation layers and enhance copper recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional leaching processes use acid solutions and catalysts to dissolve copper from oxide ores and convert sulfide ores into soluble copper sulfates, then copper extraction is enabled, but passivation layers form on the ore surface that hinder further dissolution and reduce copper recovery to less than 40%
Solution Approach 1:
The patent applies preliminary action by conducting a reset treatment before the main leaching process. The reset solution, containing specific chemicals, is applied to the ore heap to prevent passivation layer formation or to remove existing passivation layers. This preparatory step modifies the ore surface chemistry to enable subsequent effective leaching, thereby improving copper recovery rates beyond the conventional 40% limitation
Solution Approach 2:
The patent employs parameter changes by modifying the chemical composition and properties of the leaching solution. Specific parameters such as pH, redox potential, and chemical concentration are adjusted through the reset process to create optimal conditions for copper dissolution while preventing passivation. The reset solution contains chemicals that alter the electrochemical parameters of the ore surface, enabling sustained leaching efficiency
2Quantity of substance
If the leaching process is extended to achieve higher copper recovery, then more copper can be extracted, but the passivation layer thickens and the process becomes less efficient over time
Solution Approach 1:
The patent implements periodic action through cyclic reset and leaching operations. Instead of continuous leaching that leads to diminishing returns, the process periodically applies reset solution to remove passivation layers and restore ore reactivity. This cyclic approach maintains high leaching efficiency throughout extended operation, enabling sustained copper recovery without the efficiency decline that would otherwise occur
Solution Approach 2:
The patent ensures continuity of useful action by maintaining active copper dissolution through periodic reset treatments. The reset solution removes passivation layers that would otherwise terminate the useful leaching action, allowing the process to continue extracting copper at high efficiency rates over extended periods. This creates a continuous cycle of effective leaching rather than intermittent extraction
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
The method significantly increases copper recovery rates by effectively dissolving passivating species, achieving up to 65 mM copper concentration in the pregnant leaching solution.
Implementation Method 1
The reset solution is applied to the heap of previously leached copper ore to chemically remove passivation layers
Implementation Method 2
The reset solution comprises a chelating agent and a reducing agent
Implementation Method 3
facilitating the dissolution of the Cu2+ ions
Implementation Method 4
the aqueous chemical extraction of valuable metals from metal-containing ores
Data Source
AI summary
Methods, compositions and systems are provided that improve recovery of copper from previously leached copper ores. A reset solution comprising a chelating agent and a reducing agent is provided to a heap of previously leached and passivated ore to improve copper recovery kinetics in subsequent leaching stages.