Chloride Heap Leaching for Ambient-Temperature Chalcopyrite Dissolution
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Solution Overview
Problem
Existing methods for leaching copper from chalcopyrite ores are inefficient and require high temperatures or fine milling, and the presence of impurities like sulfate concentration can hinder pyrite oxidation, leading to slower leaching rates.
Innovation Solution
A chloride heap leaching process that includes an agglomeration step with nitrate or nitrite and chloride, followed by a curing step to create a highly oxidizing environment, generating heat and increasing the heap temperature, thereby enhancing copper dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional leaching methods are used on chalcopyrite ores, then copper dissolution can be achieved, but the process requires high temperatures or fine milling which increases energy consumption and processing complexity
Solution Approach 1:
The invention changes the chemical parameters of the leaching solution by adding nitrate and chloride salts to create a highly oxidizing environment. This chemical parameter change enables efficient copper dissolution from chalcopyrite at ambient temperatures without requiring high temperature or fine milling, thus resolving the contradiction between temperature and productivity
Solution Approach 2:
The invention uses nitrate salts (such as sodium nitrate or ammonium nitrate) as strong oxidants in the leaching solution. The nitrate ions provide high oxidation potential that accelerates the oxidation and dissolution of chalcopyrite minerals, enabling fast copper recovery at ambient temperatures without the need for high temperature processing
2Productivity
If nitrate is added to increase oxidation potential, then copper dissolution is enhanced, but sulfate concentration from pyrite oxidation can hinder the process by reducing oxidation potential
Solution Approach 1:
The invention introduces chloride salts (such as sodium chloride or calcium chloride) as intermediary substances that form stable complexes with copper ions during leaching. The chloride ions act as mediators that facilitate copper dissolution while the形成的 complexes maintain stable oxidation potential in the presence of sulfate, resolving the contradiction between productivity and reliability
Solution Approach 2:
The invention creates a composite leaching solution system containing both nitrate salts and chloride salts working synergistically. The nitrate provides oxidation potential while the chloride stabilizes the system against sulfate interference, and together they enable reliable and efficient copper dissolution from chalcopyrite ores
3Productivity
If fine milling is performed to increase surface area for leaching, then copper recovery is improved, but processing time and energy consumption increase
Solution Approach 1:
The invention changes the chemical environment parameters by adding nitrate and chloride salts to create conditions where coarse particles can be effectively leached. This chemical parameter modification eliminates the need for fine milling while maintaining high copper recovery, thus resolving the contradiction between productivity and time loss
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 achieves faster copper dissolution rates at ambient temperatures, reducing leach cycle duration and improving copper recovery by maintaining high oxidation potentials and self-generating heat through pyrite oxidation.
Implementation Method 1
heat is generated by oxidation of pyrite in the curing step, thereby increasing the heap temperature
Implementation Method 2
heat is generated by oxidation of pyrite in the curing step
Implementation Method 3
The oxidative action of nitrate and nitrite salts in aqueous solutions of sulfuric acid
Implementation Method 4
chloride heap leaching process
Data Source
AI summary
A method of leaching copper from a heap of ore which includes an ore agglomeration step, an ore stacking step wherein agglomerated ore is stacked to form a heap, a curing step, a leach step, and a rinse step, wherein, during the ore agglomeration step the ore is contacted with an acidified solution, nitrates or nitrites, and chloride, to create an oxidative environment prior to the leach step.