Two-Stage Leaching for Gold Copper Ore Recovery
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Solution Overview
Problem
Existing methods for leaching gold and copper from gold/copper-containing ores face challenges in achieving efficient and cost-effective recovery, particularly due to the formation of passive films on copper minerals and the complexity of processing both metals simultaneously.
Innovation Solution
A two-stage leaching method is employed, where gold is leached from a gold/copper-containing material in one stage using a gold leach liquor, and copper is leached from the gold-depleted material in a separate stage using a copper leach liquor, optimizing conditions to minimize co-extraction of the other metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gold and copper are leached simultaneously from gold/copper-containing ores, then processing complexity is reduced, but metal recovery efficiency and downstream processing difficulty worsen due to co-extraction issues
Solution Approach 1:
The patent applies segmentation by dividing the leaching process into two distinct stages: a first leaching stage that selectively leaches gold while leaving copper in the ore, and a second leaching stage that leaches copper from the gold-depleted ore. This staged approach resolves the contradiction by separating the leaching operations to achieve both high metal recovery efficiency and simplified downstream processing, avoiding the co-extraction problems that would occur with simultaneous leaching.
2Ease of manufacture
If conventional leaching methods are used on chalcopyrite, then processing is simpler, but copper recovery is limited to 20-40 wt.% due to passive film formation
Solution Approach 1:
The patent applies preliminary action by conducting a first leaching stage that removes gold from the ore before the second stage leaches copper. This preliminary removal of gold creates gold-depleted ore that is then more amenable to efficient copper leaching in the second stage, overcoming the passive film limitation that restricts copper recovery to only 20-40 wt.% in conventional single-stage leaching.
3Productivity
If acid leaching is used to dissolve copper, then copper extraction is effective, but downstream processing complexity increases due to acidic solution management
Solution Approach 1:
The patent applies segmentation by separating the leaching of gold and copper into distinct stages, with the first stage leaching gold under conditions that minimize copper dissolution, and the second stage leaching copper from gold-depleted ore. This segmentation reduces downstream processing complexity by preventing co-extraction of both metals in the acidic solution, thereby simplifying solution management and recovery operations.
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 allows for efficient and cost-effective recovery of gold and copper, with up to 60% gold recovery under mild conditions, and enables the copper to remain in the ore until a subsequent leaching step, simplifying downstream processing.
Implementation Method 1
a gold leach stage leaching gold from the material with a gold leach liquor
Implementation Method 2
a copper leach stage leaching copper from the material with a copper leach liquor
Implementation Method 3
These leaching processes involve the application of an acid and an oxidant to dissolve copper into solution
Data Source
AI summary
A method of leaching a gold/copper-containing sulfidic mined material that includes two leach stages, with a gold leach stage leaching gold from the material with a gold leach liquor and a copper leach stage leaching copper from the material with a copper leach liquor.