Vanadium Oxide Recovery from Gasifier Slag via Alkali Roasting
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Solution Overview
Problem
Current methods fail to effectively extract vanadium in oxide form from gasification slag due to its unique composition and glassy structure, which differs significantly from conventional vanadium ore or spent catalyst, resulting in low purity and inefficient recovery processes.
Innovation Solution
A process involving pulverization of gasifier slag, blending with an alkali salt, roasting, leaching, magnetic separation, and subsequent chemical reactions to isolate vanadium oxide, achieving high purity through the formation of ammonium metavanadate and calcination, while also recovering iron and silica components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional extraction techniques are used on gasification slag, then the process can be performed with existing technology, but the product purity is severely hampered due to the low vanadium to silica ratio and glassy structure
Solution Approach 1:
The patent applies parameter changes by modifying the chemical environment through pH adjustment and selective reagent addition. The process transforms the refractory spinel structure into soluble forms through controlled chemical reactions, changing the solubility parameters of vanadium compounds while leaving silica unaffected, thereby achieving high purity extraction despite the challenging matrix composition
Solution Approach 2:
The patent uses intermediary substances such as ammonium salts and other chemical reagents that selectively interact with vanadium compounds in the slag. These intermediaries facilitate the separation by forming soluble complexes with vanadium that can be selectively leached, acting as mediators between the refractory slag matrix and the extraction process
2Quantity of substance
If the gasifier slag is processed to recover vanadium, then valuable by-product can be extracted, but the glassy structure with spinel form vanadium makes recovery difficult by conventional routes
Solution Approach 1:
The patent applies preliminary action by performing size reduction and classification of the slag before extraction. This preliminary mechanical treatment increases the surface area and accessibility of vanadium compounds, making subsequent chemical extraction more effective and simplifying the overall process despite the refractory nature of the material
Solution Approach 2:
The patent replaces mechanical extraction methods with chemical extraction methods. Instead of using physical or mechanical means to separate vanadium from the glassy matrix, the process uses selective chemical reactions and solubility differences to achieve separation, thereby simplifying the extraction mechanism
3Productivity
If roasting is performed at higher temperature to break the glassy structure, then vanadium extraction efficiency improves, but energy consumption increases and other metals may be lost
Solution Approach 1:
The patent applies parameter changes by optimizing the roasting temperature to a specific range that is sufficient to break the glassy structure and liberate vanadium compounds without excessive energy input. This controlled parameter adjustment achieves the necessary structural transformation while minimizing energy consumption and preventing loss of other valuable metals
Data Source
AI summary
A process for obtaining vanadium component in the form of vanadium oxide from gasifier slag is disclosed. The process comprises pulverizing the slag to obtain pulverized slag, which is blended with water and an alkali salt to obtain a slurry. The slurry is dried and then roasted in the presence of air to obtain a roasted slag. The roasted slag is leached to obtain a first filtrate comprising the vanadium component. The first filtrate is reacted with a magnesium salt to remove a silica component in the form of a precipitate. The silica free second filtrate is reacted with an ammonium salt to obtain ammonium metavanadate, which is further calcined to obtain the significant amount of vanadium pentoxide (V2O5).