Atmospheric Leaching of Chalcopyrite Concentrate
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Solution Overview
Problem
Conventional chalcopyrite leaching methods, such as pressure leaching and bioleaching, are expensive and slow, and fine grinding leads to passivation and sludge build-up, increasing operating expenses and complicating liquid-solids separation.
Innovation Solution
A two-stage countercurrent leaching method using an aqueous solution with sulphuric acid and oxygen at atmospheric pressure, where the chalcopyrite concentrate is leached with a particle size range of 80% below 60-100 µm and acid concentration of 20-90 g/l, eliminating the need for fine grinding and incorporating a short purification milling step to clean mineral surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fine grinding is performed to prevent passivation of chalcopyrite, then leaching efficiency is improved, but sludge build-up increases and liquid-solids separation becomes complicated
Solution Approach 1:
The patent changes the particle size parameter from fine grinding (P80 < 20 μm) to coarse grinding (P80 = 60-100 μm), which prevents passivation through different mechanisms while avoiding sludge build-up. This parameter change resolves the contradiction by finding an optimal intermediate state that achieves leaching efficiency without the harmful effects of fine grinding.
2Productivity
If fine grinding is performed to prevent passivation of chalcopyrite, then leaching efficiency is improved, but operating expenses increase
Solution Approach 1:
The patent changes the particle size parameter from fine grinding to coarse grinding, which significantly reduces energy consumption and operating expenses while maintaining leaching efficiency through optimized leaching conditions (acid concentration, temperature, oxygen supply). This resolves the contradiction by achieving the same productivity goal with much lower energy input.
3Productivity
If pressure leaching is used to leach chalcopyrite concentrate, then leaching speed is improved, but process cost increases
Solution Approach 1:
The patent changes the pressure parameter from high pressure (pressure leaching) to atmospheric pressure, which dramatically reduces equipment cost and operating expense. The leaching speed is maintained through optimization of other parameters including acid concentration (20-90 g/l), temperature (75°C to boiling point), and oxygen supply, resolving the contradiction between speed and cost.
4Ease of manufacture
If bioleaching is used to leach chalcopyrite concentrate, then process cost is reduced, but leaching speed decreases
Solution Approach 1:
The patent changes the leaching method from bioleaching to chemical leaching using sulphuric acid, which increases leaching speed while keeping process cost low through the use of inexpensive reagents and atmospheric pressure conditions. The optimized parameters (acid concentration, temperature, oxygen supply) achieve fast leaching without the high costs of pressure equipment, resolving the contradiction between cost and speed.
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 method achieves high copper and zinc dissolution yields of 95-98% without sludge build-up, reducing energy costs and simplifying liquid-solids separation, while maintaining high metal recovery efficiency.
Implementation Method 1
the concentrate is leached with an aqueous solution, the acid concentration of which is regulated to be in the region of 20 - 90 g/l
Implementation Method 2
by means of an aqueous solution containing sulphuric acid and oxygen feed
Implementation Method 3
at a temperature between 75°C and the boiling point of the solution
Data Source
Figure 1
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Figure 4
AI summary
The invention relates to a method for leaching bulk concentrate of chalcopyrite-type by means of an aqueous solution containing sulphuric acid and an oxygen feed at atmospheric pressure and at a temperature between 750C and the boiling point of the solution. It is typical of the method that the particle size of the concentrate to be fed into leaching is in the region of 80 % below 60 - 100 µm and that the concentrate is leached with an aqueous solution, the acid concentration of which is regulated to be around 20 - 90 g/l.