Reductive Autocatalytic Leaching for Chalcopyrite Passivation
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Solution Overview
Problem
Current hydrometallurgical processes face challenges in cost-effectively solubilizing copper from primary sulfide minerals like chalcopyrite due to passivation issues, which limits the efficiency of leaching and increases energy consumption, especially as copper oxide and sulfide reserves deplete.
Innovation Solution
A reductive autocatalytic chemical process with solid-solid interaction under oversaturation conditions, involving a Reductive Activation Stage and an Autocatalytic Dry Reductive Transformation Stage, using sulfuric acid, iron (II) salts, and chloride salts to solubilize copper without the need for oxidative agents or air injection, effectively overcoming passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hydrometallurgical leaching processes are used to solubilize copper from primary sulfide minerals, then copper recovery is achieved, but passivation of the mineral surface occurs due to formation of sulfur films and insoluble complexes, reducing solubilization efficiency
Solution Approach 1:
The patent inverts the conventional oxidative leaching approach by implementing a reductive leaching process. Instead of oxidizing the sulfide mineral surface, the process uses reductive agents (Fe2+, Sn2+, Zn0) to reduce copper species, preventing passivation film formation and maintaining surface reactivity throughout the leaching process
Solution Approach 2:
The patent changes the redox parameters of the leaching system by introducing reducing agents and controlling redox potential. This parameter change transforms the chemical environment from oxidative to reductive, fundamentally altering the leaching mechanism to prevent passivation while enhancing copper solubilization
2Productivity
If pyrometallurgical processes are used to process sulfide concentrates, then copper production is achieved, but high energy consumption and sulfur dioxide generation occur
Solution Approach 1:
The patent replaces the thermal/chemical energy-intensive pyrometallurgical system with a chemical leaching system using reducing agents. This substitution eliminates the need for high-temperature heating while achieving copper solubilization through redox chemistry, significantly reducing energy consumption
Solution Approach 2:
The patent converts the harmful passivation effect (sulfur film formation) into a beneficial by utilizing reducing agents that prevent film formation and even dissolve existing films. The reducing environment transforms what would be a harmful barrier into a facilitator of continuous leaching
3Productivity
If pyrometallurgical processes are used to process sulfide concentrates, then copper production is achieved, but sulfur dioxide generation and tailings production occur
Solution Approach 1:
The patent converts the harmful sulfur dioxide emission issue into a beneficial outcome by using reductive leaching that produces soluble copper species without oxidizing sulfur. The reducing environment prevents sulfur oxidation, eliminating SO2 emissions while the leaching solution can be recycled or treated more easily
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 process enhances copper solubilization efficiency, reduces operational costs, and minimizes environmental impact by lowering water consumption and energy requirements, while effectively handling common impurities like arsenic.
Implementation Method 1
a reductive autocatalytic chemical process with solid-solid interaction under oversaturation conditions
Implementation Method 2
the presence of elemental sulfur or other insoluble substances containing sulfur and/or insoluble salt complexes such as cuprous chloride species, inhibits the interaction between the leaching solution and the mineral, blocking the oxidation-reduction processes necessary to continue the solubilization of copper
Implementation Method 3
A reductive autocatalytic chemical process with solid-solid interaction under oversaturation conditions
Implementation Method 4
using sulfuric acid, iron (II) salts, and chloride salts to solubilize copper
Data Source
AI summary
The present invention relates to an autocatalytic reductive chemical procedure with solid-solid interaction in conditions of supersaturation of salts, via the phenomenon of efflorescence in order to dissolve a copper metal, from a metallogenically primary ore or chalcopyrite concentrate that contains same. The method comprises two steps, referred to as “Reductive Activation Step” and “Dry Autocatalytic Reductive Transformation Step” or efflorescence, which can be repeated as many times as necessary to maximise the extraction of copper or base metal of interest. The invention can also be used for sulphurised base metals such as nickel, zinc, cobalt, lead and molybdenum, among others, regardless of the common impurities of sulphurised ores, as occurs with the presence of arsenic.