Electrokinetic Lixiviant Sequencing for Lower-Power In-Situ Mining
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Solution Overview
Problem
In-situ mining methods face challenges with high electric power and cost requirements due to the conductive nature of lixiviant, which lowers rock mass resistivity, and issues with short-circuiting in electrokinetic processes, particularly in hard, low permeability rock formations.
Innovation Solution
Implementing timing sequences that alternate lixiviant injection with electric current application, varying lixiviant composition and flow rate, and electric field strength and type over time, along with measurement and optimization of physical properties to enhance efficiency and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lixiviant is injected into the rock formation to dissolve target material, then metal extraction efficiency is improved, but electric power consumption increases due to lowered rock mass resistivity
Solution Approach 1:
The patent applies periodic action by alternating between lixiviant injection phases and electric current application phases. During lixiviant injection, the conductive solution distributes through the rock formation, and during subsequent electric current application, the electrokinetic force moves the pregnant lixiviant toward collection points. This periodic alternation prevents continuous high power consumption while maintaining effective metal extraction through the combined chemical and electrokinetic processes.
2Productivity
If electric field is continuously applied to move lixiviant through rock formation, then metal recovery effectiveness is improved, but operational cost increases due to high power requirements
Solution Approach 1:
The system implements periodic action by cycling between electric field application and lixiviant injection phases. The electric field is applied intermittently rather than continuously, reducing overall power consumption and operational costs. During electric field phases, electrokinetic forces move dissolved metals toward collection points, while during injection phases, fresh lixiviant replenishes the formation. This periodic operation maintains metal recovery effectiveness while significantly reducing continuous energy expenditure.
Solution Approach 2:
The patent ensures continuity of useful action by overlapping and alternating the two processes: chemical dissolution by lixiviant and electrokinetic transport by electric field. Rather than having idle periods where neither process occurs, the system maintains continuous metal extraction and transport through coordinated phasing. The pregnant lixiviant formed during injection phases is continuously moved during subsequent electric field phases, ensuring uninterrupted metal recovery operations.
3Speed
If lixiviant flow rate is increased to improve metal dissolution, then extraction speed is improved, but electric power consumption increases due to higher conductivity in the rock mass
Solution Approach 1:
The patent resolves this contradiction by applying periodic action that separates the high-flow dissolution phase from the high-power transport phase. During lixiviant injection phases, high flow rates dissolve metals efficiently without requiring electric power. During subsequent electric current application phases, the system moves the already-formed pregnant lixiviant using electrokinetic forces. This temporal separation allows high extraction speed during injection while limiting power consumption to intermittent periods, rather than requiring high power continuously proportional to flow rate.
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
Reduces electric power needs and operational costs while improving the effectiveness of in-situ mining by optimizing lixiviant distribution and electric field application, minimizing short-circuiting, and enhancing metal recovery.
Implementation Method 1
injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material
Implementation Method 2
applying an electric field to at least one of the lixiviant or the solution by the first well operating as a first electrode and a second well operating as a second electrode
Data Source
AI summary
A method for operating a system for in-situ mining in a rock formation in an area of interest includes: receiving a lixiviant at a first well extending downward, injecting the lixiviant into a permeable layer of the rock formation via the first well to dissolve a target material to form a solution containing the lixiviant and the target material, and applying an electric field to at least one of the lixiviant or the solution by the first well as a first electrode and a second well as a second electrode, receiving the solution via the second well extending downward, and pumping the solution, via the second well, to a processing plant to separate the target material from the lixiviant, wherein one or both of the injecting the lixiviant or the applying the electric field are changed according to a timing sequence during an operational period of the in-situ mining.