Copper-Cobalt Sulfide Recovery Using Flotation and Bioleaching
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Solution Overview
Problem
Existing methods for recovering cobalt from low-grade sulfide ores are costly and inefficient, with high capital and operating expenses due to low cobalt tenor in the ore, leading to complex impurity issues and high acid neutralization costs.
Innovation Solution
A process involving flotation and bioleaching to separate copper and cobalt-containing minerals, followed by solvent extraction and ion exchange to purify a cobalt-rich solution, reducing acid consumption and improving recovery efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pyrometallurgical or hydrometallurgical processes are used to recover cobalt from low-grade sulfide ores, then cobalt recovery is achieved, but capital and operating costs become prohibitively high
Solution Approach 1:
The patent segments the ore processing into distinct flotation stages (rougher, cleaner, scavenger) followed by selective bioleaching. This segmentation allows low-grade ores to be processed efficiently by separating copper-bearing minerals first, then selectively leaching cobalt from the remaining material, avoiding the need for expensive conventional processing of the entire ore body.
Solution Approach 2:
The patent changes the chemical parameters by using bioleaching with bacteria (such as Acidithiobacillus ferrooxidans) to selectively oxidize and dissolve cobalt from sulfide minerals at controlled pH and temperature conditions. This biological parameter change enables efficient cobalt recovery from low-grade materials without the high capital costs of pyrometallurgical facilities.
2Quantity of substance
If conventional leaching processes are used on low-grade ores, then cobalt is extracted, but the resulting leach solution has low cobalt tenor making downstream recovery difficult and costly
Solution Approach 1:
The patent performs preliminary flotation to concentrate copper-bearing minerals before bioleaching. This preliminary action removes the majority of copper from the system, so that subsequent bioleaching produces a leach solution with higher cobalt tenor, making downstream recovery more efficient and economical.
Solution Approach 2:
The patent uses bacteria as an intermediary agent in the bioleaching process. These microorganisms facilitate the selective oxidation of cobalt sulfide minerals, converting insoluble cobalt sulfide into soluble cobalt sulfate in the leach solution, thereby achieving efficient cobalt extraction with improved tenor for downstream processing.
3Reliability
If sulfide oxidation processes are used to recover cobalt, then cobalt is liberated from sulfide minerals, but acid neutralization costs become high
Solution Approach 1:
The patent employs autoxidation of pyrite (FeS2) present in the ore during the bioleaching process. The pyrite oxidizes spontaneously in the presence of oxygen and water, generating sulfuric acid in situ. This self-service acid generation reduces or eliminates the need for external acid addition and subsequent neutralization, significantly lowering acid neutralization costs while effectively liberating cobalt from sulfide minerals.
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 process effectively recovers cobalt from low-grade ores by enhancing copper recovery and reducing operational costs, improving the overall efficiency and reducing impurity contamination.
Implementation Method 1
floating a feed material comprising mainly non-sulfide gangue minerals and copper-containing sulfidic minerals, cobalt-containing sulfidic minerals, and iron pyrite at a pH of no more than about pH 10.5 to form a first separated portion
Implementation Method 2
Biooxidation can also oxidize the sulfides by contacting the slurried material with bacteria and oxygen (air) in a stirred bioreactor
Implementation Method 3
Hydrometallurgical processes can involve the use of pressure oxidation whereby the sulfide material is slurried and subjected to high temperature and pressure under an oxidizing environment which oxidizes the sulfide mineral
Implementation Method 4
Sulfide minerals can also be oxidized in an acid heap leach environment by adding sulfide oxidizing microbes to the heap leach and providing air to the system
Implementation Method 5
initial concentration of the cobalt sulfate from the leach solution using solvent extraction (SX)
Implementation Method 6
initial concentration of the cobalt sulfate from the leach solution using ion exchange (IX)
Implementation Method 7
direct electrowinning of the cobalt sulfate from solution to produce cobalt metal
Data Source
AI summary
The present disclosure is directed to a process for recovering copper and cobalt from a copper and cobalt-containing sulfide ores and concentrates, particularly relatively low grade cobalt bearing sulfide ores and concentrates.