Oxidative Leaching of Metal Sulfides with Ceramic Grinding Media
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Solution Overview
Problem
Current methods for above-atmospheric pressure oxidative leaching of metal sulfides, particularly copper sulfides like enargite, are inefficient and require excessive reagents, grinding, and heating, which increase costs and energy consumption.
Innovation Solution
The implementation of an oxidative leach circuit with shear tank reactors and ceramic grinding media in autoclaves, allowing for improved leach kinetics and recovery by disrupting crystal structures and oxidizing sulfides to sulfates at reduced temperatures and pressures, thereby minimizing the need for additional reagents and energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional oxidative leaching methods are used for metal sulfides, then metal recovery can be achieved, but excessive reagents, grinding, and heating are required which increase costs and energy consumption
Solution Approach 1:
The patent applies parameter changes by operating the oxidative leaching process at elevated temperatures (90-200°C) and pressures (1-10 bar) to enhance reaction kinetics and metal recovery efficiency while reducing the need for excessive reagents and energy input compared to conventional methods
Solution Approach 2:
The patent utilizes strong oxidants including oxygen, ozone, hydrogen peroxide, and ferric sulfate to accelerate the oxidation of metal sulfides to sulfates, thereby improving metal recovery efficiency while reducing the overall energy consumption and reagent requirements
2Productivity
If conventional oxidative leaching methods are used for metal sulfides, then metal recovery can be achieved, but excessive reagents are required which increase costs and may negatively impact downstream SX/EW systems
Solution Approach 1:
The patent implements self-service by using the metal sulfide ore itself as the source of ferric oxidant through in-situ oxidation, eliminating the need to purchase, ship, and dose external ferric sulfate reagents, thereby reducing costs and avoiding negative impacts on downstream SX/EW systems
Solution Approach 2:
The patent employs an intermediary approach by introducing a controlled amount of ferric sulfate as a catalyst to facilitate the oxidation reaction, which can be recovered and reused in the system, thereby reducing net reagent consumption while maintaining high metal recovery efficiency
3Productivity
If high solids densities are used for leaching copper sulfides, then processing efficiency can be improved, but excessive grinding and heating energies are required without adding superfluous catalysts
Solution Approach 1:
The patent applies parameter changes by optimizing temperature (90-200°C) and pressure (1-10 bar) conditions to enable efficient leaching at high solids densities without requiring excessive grinding and heating energies, thereby improving processing efficiency while reducing energy consumption
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 metal recovery efficiency, reduces energy consumption, and eliminates the need for excessive reagents, leading to cost savings and improved processing times for copper and other metal sulfides like cobalt and gold.
Implementation Method 1
The grinding media may be configured to disrupt a crystal lattice structure of metal sulfide particles in the metal sulfide concentrate
Implementation Method 2
leaching the produced metal sulfide concentrate in the presence of oxygen at a pressure and/or temperature above ambient
Implementation Method 3
oxidizing sulfides to sulfates
Data Source
AI summary
A system and method for improving leach kinetics and recovery during above-atmospheric leaching of a metal sulfide is disclosed. In some embodiments, the method may comprise the steps of: (a) producing a metal sulfide concentrate [34] via flotation; (b) moving the produced metal sulfide concentrate [34] to at least one chamber [22a] of at least one reactor such as an autoclave [20]; (c) leaching the produced metal sulfide concentrate in said at least one chamber [22a] in the presence of oxygen [82] at a pressure and/or temperature above ambient, and in the presence of partially-used [25] and/or or new [92] grinding media within the at least one chamber [22a]. Systems [10] and apparatus [20, 200] for practicing the aforementioned method are also disclosed.