Countercurrent Leaching Circuit Reagent Control
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Solution Overview
Problem
Current methods for extracting copper, gold, and other valuable metals from waste materials, such as E-waste, are inefficient and costly, as they fail to effectively control the oxidizer reagent in the leaching circuit.
Innovation Solution
A method involving a leaching circuit with multiple vessels in series, where a countercurrent flow is established, and a controller determines the reagent consumption rate for each vessel to optimize metal recovery, using an ammonia-based lixiviant and copper (II) as an oxidizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional leaching methods are used without controlled reagent distribution, then the leaching process is simpler to operate, but metal recovery efficiency is low and reagent consumption is high
Solution Approach 1:
The leaching circuit is segmented into multiple series-connected leaching vessels (first, second, and third vessels) with distinct functions. The first vessel performs initial leaching, the second vessel optimizes metal recovery with controlled reagent consumption, and the third vessel completes the extraction. This segmentation allows each vessel to be optimized for specific recovery targets, thereby improving overall metal recovery efficiency while maintaining manageable operational complexity through modular design.
Solution Approach 2:
Different reagent consumption rates are applied to different vessels based on their specific functions. The controller determines and maintains distinct reagent consumption rates for each vessel, with the second vessel operating at an optimized consumption rate to maximize metal recovery. This local optimization of reagent distribution ensures that each vessel performs its specific function efficiently, improving overall productivity without requiring uniform complex control across the entire system.
2Productivity
If high reagent consumption rate is used to maximize metal recovery, then metal recovery is improved, but reagent cost and leftover reagent discharge increase
Solution Approach 1:
The controller dynamically adjusts and maintains specific reagent consumption rates in each vessel based on operational parameters. By optimizing the reagent consumption rate in the second vessel and controlling the third vessel's consumption, the system achieves high metal recovery while minimizing overall reagent usage. This parameter optimization allows the system to operate at peak efficiency without excessive reagent consumption or discharge.
Solution Approach 2:
The controller continuously monitors and adjusts reagent consumption rates in each vessel based on process conditions and recovery performance. This feedback control ensures that each vessel operates at its optimal reagent consumption level, maximizing metal recovery in the second vessel while preventing excessive reagent use and discharge across the entire circuit, thereby reducing both cost and environmental impact.
3Productivity
If countercurrent flow is implemented in the leaching circuit, then metal recovery efficiency is enhanced, but system complexity and operational difficulty increase
Solution Approach 1:
The countercurrent flow system is segmented into three distinct vessels with clearly defined flow directions and reagent consumption zones. The controller manages each vessel independently with specific reagent consumption rates, making the complex countercurrent operation more manageable. This segmentation allows operators to control and monitor each vessel separately, reducing operational difficulty while maintaining the efficiency benefits of countercurrent flow.
Solution Approach 2:
Different operational parameters including reagent consumption rates and flow characteristics are applied locally to each vessel based on its position in the countercurrent circuit. The controller optimizes each vessel's operation independently, allowing the complex countercurrent system to be managed through localized control strategies rather than requiring uniform complex operation across the entire circuit.
4Ease of operation
If reagent consumption rate is not controlled in each vessel, then the process is easier to manage, but leftover reagent discharge from the first vessel increases
Solution Approach 1:
The controller implements and maintains specific reagent consumption rates for each vessel based on process requirements. By controlling the reagent consumption rate in the first vessel and optimizing rates in subsequent vessels, the system minimizes leftover reagent discharge while maintaining ease of management through centralized automated control. This parameter control prevents reagent waste without requiring complex manual management of each vessel.
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 method enhances the recovery of copper and gold from waste materials by optimizing reagent consumption and metal recovery, achieving a more efficient and cost-effective process.
Implementation Method 1
contacting the feed material with a lixiviant adapted to leach the target metal from a feed material feed stream
Implementation Method 2
using copper (II) (Cu(II)) as an oxidizer
Data Source
AI summary
A method and apparatus are presented for recovering a target metal from a feed material. The method includes: contacting the feed material with a lixiviant adapted to leach target metal from a feed material feed stream in a leaching circuit having a plurality of leaching vessels V1, V2, Vn in series, establishing a countercurrent flow in the leaching circuit by delivering feed material feed stream to leaching vessel V1 and moving the feed material feed stream through the leaching circuit in a first direction toward leaching vessel Vn and delivering the lixiviant to the leaching vessel Vn and moving the lixiviant through the leaching circuit in a second direction toward leaching vessel V1, determining, by a controller, a reagent consumption rate for each of the leaching vessels V1, V2, Vn so as to validate performance, minimize left over reagent discharged from leaching vessel V1 and maximize target metal recovery from leaching vessel Vn and recovering the target metal from the lixiviant.