Halophilic Microbial Consortium for Copper Bioleaching
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Solution Overview
Problem
Bioleaching processes for metal recovery from sulphide minerals are inefficient under high chloride ion content conditions and at low temperatures due to toxicity of free copper to microorganisms, requiring large volumes of fresh water and reducing efficiency.
Innovation Solution
A consortium of iron oxidising and sulphur oxidising halophilic or halotolerant microorganisms, including Leptospirillum ferriphilum strain Sp-Cl and a halophilic or halotolerant sulphur oxidising microorganism, is used in a chloride ion solution with specific conditions (1500 ppm to 30000 ppm chloride, temperatures above 10°C, pH 1 to 3, and presence of aluminium, magnesium, or sodium) to enhance bioleaching efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional bioleaching is performed at low temperatures and low chloride ion content, then microorganisms can survive and perform leaching, but the leaching rate is slow and large volumes of fresh water are required
Solution Approach 1:
The patent applies parameter changes by using halophilic or halotolerant microorganisms that can tolerate high chloride ion concentrations (1500-30000 ppm), and by operating at temperatures above 10°C, fundamentally changing the environmental parameters from conventional low-chloride, low-temperature conditions to high-chloride, elevated-temperature conditions that enable faster leaching with reduced water requirements
Solution Approach 2:
The patent uses a specific consortium of microorganisms including Leptospirillum ferriphilum strain Sp-Cl that has been adapted to replicate the functional capabilities needed for efficient bioleaching under high chloride conditions, effectively copying the desired performance characteristics in a controlled microbial system
2Quantity of substance
If chloride ion concentration is increased to reduce fresh water requirements, then water usage is reduced, but conventional microorganisms cannot tolerate the high salt conditions
Solution Approach 1:
The patent fundamentally changes the biological parameter by selecting halophilic or halotolerant microorganisms that are naturally adapted to high chloride environments, allowing the system to operate reliably at chloride concentrations of 1500-30000 ppm without requiring large volumes of fresh water for dilution
Solution Approach 2:
The patent employs a readily available consortium of microorganisms including Leptospirillum ferriphilum strain Sp-Cl that can be easily cultured and applied, replacing the need for complex, expensive water treatment and dilution systems
3Productivity
If temperature is increased to improve leaching efficiency, then leaching rate increases, but energy consumption increases and microorganism survival becomes more difficult
Solution Approach 1:
The patent optimizes the temperature parameter by operating at moderately elevated temperatures above 10°C (typically 20-45°C), which is sufficient to enhance leaching kinetics and efficiency while remaining within the tolerable range for the selected halophilic microorganisms, avoiding the need for high-energy heating to extreme temperatures
4Productivity
If free copper accumulates during leaching, then metal recovery progresses, but copper toxicity inhibits microorganism activity and reduces leaching efficiency
Solution Approach 1:
The patent uses a robust consortium of microorganisms including Leptospirillum ferriphilum strain Sp-Cl and halophilic sulphur oxidising bacteria that possess inherent tolerance to copper toxicity, allowing continuous operation even as free copper concentrations build up during the leaching process
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 consortium improves bioleaching efficiency by maintaining high cell counts and tolerance to copper, allowing effective metal recovery from sulphide and oxide ores even at high chloride concentrations and temperatures, reducing the need for fresh water and enhancing leaching rates.
Implementation Method 1
the mixed culture consortium enhances the rate of ferrous iron oxidation
Implementation Method 2
as sulphur is converted to sulphuric acid it becomes possible to prevent a significant reduction in the leaching rate which is otherwise caused by sulphur coating surfaces
Data Source
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AI summary
A copper bioleaching process which makes use of a consortium which contains Leptospirillum ferriphilum and a sulphur oxidising microorganism which is halophilic or halotolerant.