Molten Oxygen Partial Pressure Control for Valuable Metal Recovery
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Solution Overview
Problem
The pyrometallurgical process for recovering valuable metals from lithium ion batteries faces challenges in strictly controlling the degree of redox, leading to impurities like phosphorus and iron being mixed into the alloy, and the conventional methods are inefficient in preventing oxidation of valuable metals.
Innovation Solution
Directly measuring the oxygen partial pressure in the molten material using an oxygen analyzer during heating and melting, and controlling it within a specific range (10−12.5 to 10−8 atm) to accurately separate valuable metals from impurities, thereby preventing the incorporation of phosphorus and iron into the alloy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pyrometallurgical process is used to recover valuable metals, then valuable metals can be separated from low value-added metals, but impurities like phosphorus and iron are mixed into the alloy and valuable metals are oxidized
Solution Approach 1:
The patent applies parameter changes by precisely controlling the oxygen partial pressure (a critical chemical parameter) during the pyrometallurgical process. By maintaining oxygen partial pressure within the specific range of 10^-18 to 10^-14 atm, the process achieves selective oxidation where impurities like phosphorus and iron are oxidized and removed, while valuable metals remain in reduced state and are recovered in high purity form. This precise parameter control resolves the contradiction between metal separation and prevention of valuable metal oxidation.
Solution Approach 2:
The patent utilizes controlled oxidation by introducing oxygen (a strong oxidant) at precisely controlled partial pressures. The oxygen selectively oxidizes impurities such as phosphorus and iron which have higher oxygen affinity, while the controlled low oxygen partial pressure prevents oxidation of valuable metals like copper, nickel, and cobalt. This selective accelerated oxidation of impurities enables high-purity metal recovery while avoiding the harmful oxidation of target metals.
2Manufacturing precision
If oxygen is introduced to control redox degree, then impurities can be oxidized and separated, but valuable metals may also be oxidized and lost in slag
Solution Approach 1:
The patent resolves this contradiction through precise parameter control of oxygen partial pressure within the range of 10^-18 to 10^-14 atm. At this specific parameter range, the oxidation potential is sufficient to oxidize impurities like phosphorus and iron for effective separation, yet remains below the threshold that would cause significant oxidation of valuable metals. This creates an optimal window where impurity removal efficiency is maximized while valuable metal loss to slag is minimized.
Solution Approach 2:
The patent employs a controlled atmosphere approach where oxygen is present at precisely controlled partial pressures, creating a selective chemical environment. This controlled oxygen atmosphere acts as a selective agent that copies the desired behavior: oxidizing only the impurities with higher oxygen affinity while leaving valuable metals unaffected, thereby achieving separation without significant loss.
3Productivity
If strict control of oxygen partial pressure is implemented, then recovery ratio of valuable metals increases, but process complexity and measurement requirements increase
Solution Approach 1:
The patent implements feedback control by continuously monitoring the oxygen partial pressure in the molten material using an oxygen analyzer and adjusting the oxygen input accordingly. The system measures the actual oxygen partial pressure and uses this feedback information to maintain it within the target range of 10^-18 to 10^-14 atm, ensuring high recovery ratios of valuable metals while managing process complexity through automated control rather than manual intervention.
Solution Approach 2:
The patent replaces complex mechanical control systems with analytical instrumentation. Instead of using complex mechanical mechanisms to control oxygen partial pressure, the system uses an oxygen analyzer (analytical device) to measure oxygen partial pressure and a control system to adjust oxygen input, substituting mechanical complexity with analytical precision and automated control.
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 enables more efficient recovery of valuable metals by strictly controlling the oxygen partial pressure, achieving high recovery ratios of copper, nickel, and cobalt while minimizing phosphorus and iron content in the alloy.
Implementation Method 1
an oxygen partial pressure in the melt is directly measured using an oxygen analyzer during heating and melting of the raw material
Implementation Method 2
low value-added metals are oxidized as much as possible to form slag, while valuable metals are prevented as much as possible from being oxidized
Implementation Method 3
a step of heating and melting the raw material into a melt
Implementation Method 4
separating and recovering valuable metals to be recovered, such as cobalt (Co), nickel (Ni), and copper (Cu), from low value-added metals, such as iron (Fe) and aluminum (Al), using the difference in oxygen affinity between them
Data Source
AI summary
The present invention provides a method which is capable of more strictly controlling the oxygen partial pressure required during the melting of a starting material, thereby being capable of recovering a valuable metal more efficiently. A method for recovering valuable metals (Cu, Ni, Co), said method comprising the following steps: a step for preparing, as a starting material, a charge that contains at least phosphorus (P), iron (Fe) and valuable metals; a step for heating and melting the starting material into a melt, and subsequently forming the melt into a molten material that contains an alloy and slag; and a step for recovering the alloy that contains valuable metals by separating the slag from the molten material. With respect to this method for recovering valuable metals, the oxygen partial pressure in the melt is directly measured with use of an oxygen analyzer when the starting material is heated and melted.