Self-Doped Ferrous Molybdate Anode from Waste Catalyst Recycling
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Solution Overview
Problem
Existing methods for recycling waste hydrogenation catalysts are lengthy, consume large amounts of acid and alkali, and fail to realize high-value utilization of recycled products, particularly in the production of lithium-ion battery materials.
Innovation Solution
A method involving calcination and mechanical activation of molybdenum-containing waste catalysts to produce a molybdenum-based self-doped lithium-ion battery negative electrode material, utilizing sodium carbonate for thermal treatment, water leaching, and a hydrothermal reaction with a polyol solution to achieve high-purity ferrous molybdate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional methods are used to recycle waste hydrogenation catalysts, then the catalysts can be recovered and reused, but the process is lengthy and consumes large amounts of acid and alkali
Solution Approach 1:
The waste catalyst undergoes preliminary calcination to remove carbon and organic substances before the main recycling process. This preliminary action simplifies subsequent treatment steps and reduces the overall process duration by eliminating the need for extensive cleaning and purification operations later in the process
Solution Approach 2:
The invention changes the chemical parameters of the waste catalyst through controlled calcination at specific temperatures (400-600°C), transforming the catalyst structure to make it more suitable for direct reuse. This parameter change approach converts the complex multi-step traditional process into a more efficient streamlined process
2Ease of manufacture
If traditional recycling methods are used, then waste catalysts can be processed, but large amounts of acid and alkali are consumed
Solution Approach 1:
The invention converts the harmful acidic and basic substances present in the waste catalyst into beneficial components through controlled calcination. The organic contaminants and unwanted compounds are transformed into removable ash or volatile substances, while the valuable inorganic components are concentrated and purified, eliminating the need for large amounts of acid and alkali consumption
Solution Approach 2:
The invention replaces the chemical-intensive traditional recycling process (using large amounts of acid and alkali for dissolution and precipitation) with a thermal-based approach. Calcination uses heat to directly decompose and separate components, substituting chemical reagents with thermal energy and reducing substance loss
3Device complexity
If waste catalysts are recycled into low-value products, then the recycling process is simple, but high-value utilization is not achieved
Solution Approach 1:
The invention makes the waste catalyst serve multiple functions: it is simultaneously purified, activated, and transformed into a multi-functional material suitable for various applications including catalyst reuse, battery materials, and ceramic precursors. This multi-functionality approach increases product value without significantly increasing process complexity
Solution Approach 2:
The invention transforms the waste catalyst into composite materials with enhanced properties by combining it with other substances during the calcination process. The resulting composite products have improved performance characteristics that command higher market value while the process remains relatively simple
4Ease of manufacture
If graphite is used as lithium-ion battery negative electrode material, then the material is readily available, but the theoretical specific capacity is low
Solution Approach 1:
The invention changes the fundamental parameter of specific capacity by replacing graphite (372 mAh/g) with ferrous molybdate derived from waste catalyst (992 mAh/g). This parameter change is achieved through chemical transformation of the waste catalyst components into high-capacity battery materials, simultaneously improving availability and performance
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 results in a simple, efficient process with high recycling rates of valuable metals, producing lithium-ion battery materials with excellent properties and environmental benefits.
Implementation Method 1
subjecting a waste catalyst to extraction to remove oil and to calcination to remove to carbon
Implementation Method 2
mixing the waste catalyst powder with sodium carbonate, to obtain a mixture, and subjecting the mixture to thermal treatment to selectively convert molybdenum trioxide in the waste catalyst into sodium molybdate
Implementation Method 3
subjecting the thermal treatment product to leaching with water being used as a leaching agent
Implementation Method 4
mixing the leaching solution with a polyol solution containing a ferrous salt, subjecting the resulting mixture to a hydrothermal reaction, and collecting produced ferrous molybdate
Data Source
AI summary
A method for preparing molybdenum-based self-doped lithium-ion battery negative electrode material from molybdenum-containing waste catalyst includes: (1) calcinating and mechanically activating a waste hydrogenation catalyst containing molybdenum trioxide and aluminum oxide to obtain an oil-free and carbon-free micron-sized waste catalyst powder; (2) mixing the waste catalyst powder with sodium carbonate to obtain a mixture, and subjecting the mixture to thermal treatment to selectively convert molybdenum trioxide in the waste catalyst into sodium molybdate to obtain a clinker; (3) subjecting the clinker to leaching with water being used as a leaching agent, and collecting a leaching solution; and (4) mixing the leaching solution with a solution of a polyol containing a ferrous salt, subjecting the resulting mixture to a hydrothermal reaction, and collecting produced self-Al-doped ferrous molybdate to obtain the molybdenum-based self-doped lithium-ion battery negative electrode material.