Copper Sulphide Leaching in Closed Reactor with Oxygen Recirculation
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Solution Overview
Problem
Current methods for hydrometallurgical copper recovery from copper sulphide ores require fine grinding, leading to high energy costs and inefficient oxygen use in open reactors.
Innovation Solution
A method involving leaching copper sulphide ore in a closed reactor with coarser grain size, using a solution containing sulphuric acid and iron, where oxygen is used to oxidize ferrous iron to ferric iron in the same stage, enhancing oxygen efficiency and incorporating copper as a catalyst to promote leaching in atmospheric conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ore is ground very fine to enable successful leaching, then the leaching process can proceed, but the grinding energy consumption increases significantly
Solution Approach 1:
The patent changes the particle size parameter to coarser grain sizes (avoiding very fine grinding) while simultaneously adjusting other leaching parameters such as using atmospheric conditions instead of autoclave conditions, and optimizing the iron and copper catalyst concentrations in the leaching solution to compensate for the coarser particle size and maintain effective leaching
2Ease of manufacture
If oxidation of ferrous iron is performed in an open reactor, then the process can be carried out, but oxygen efficiency decreases due to excess oxygen requirement
Solution Approach 1:
The patent implements a feedback mechanism where the gas phase (containing oxygen and other gases) rising from the upper section of the closed reactor is circulated back into the suspension of solution, solids and gas. This recirculation allows the oxygen that would otherwise be wasted to be reused for oxidizing ferrous iron back to ferric iron, significantly improving oxygen efficiency while maintaining the feasibility of the oxidation process
Solution Approach 2:
The patent creates a continuous cycle where the gas phase is continuously recirculated from the upper section back to the suspension, ensuring that oxygen is continuously available for the oxidation reaction. This continuous recirculation eliminates the need for excess oxygen input and maintains high oxygen efficiency throughout the process
3Productivity
If copper is present in the leaching solution, then leaching is promoted due to catalytic action, but the solution composition becomes more complex
Solution Approach 1:
The patent utilizes the copper that is naturally present in the copper sulphide ore being processed. The copper dissolves during leaching and automatically serves as a catalyst to promote further leaching of the copper sulphide. This self-service approach eliminates the need to add external copper catalysts or complex catalytic systems, maintaining solution composition simplicity while achieving high leaching rates
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 reduces grinding costs and improves oxygen efficiency, allowing for effective copper recovery with minimal pyrite dissolution, resulting in a more economical and efficient process.
Implementation Method 1
the copper sulphide leaches out, the trivalent iron is reduced to divalent and is oxidised back to trivalent by means of oxygen during leaching
Implementation Method 2
oxygen is used to oxidize ferrous iron to ferric iron in the same stage
Implementation Method 3
incorporating copper as a catalyst to promote leaching
Data Source
AI summary
The invention relates to a method whereby copper is recovered from a copper sulphide ore containing pyrite. According to the method the ore is ground and leached into a solution containing sulfuric acid in atmospheric conditions by means of trivalent copper. As the copper sulphide leaches out, the trivalent iron is reduced to divalent and is oxidized back to trivalent by means of oxygen during leaching. Leaching is carried out in a closed reactor, where the undissolved gas rising from the solution in the supper section of the reactor is circulated back into the suspension of solution, solids and gas. leaching is performed in the presence of both divalent and trivalent iron and preferably with the dissolved copper acting as a catalyst to promote leaching. The conditions are adjusted to be such that the pyrite of the ore essentially does not dissolve.