Vanadium Oxide Extraction from Bayer Spent Liquor Using Polymers
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Solution Overview
Problem
The existing Bayer process for alumina recovery from bauxite has a low yield of vanadium oxide extraction, leading to undesirable accumulation and potential economic loss due to the inability to effectively recover vanadium compounds.
Innovation Solution
Incorporating a water-soluble polymer during the decantation of spent liquor in the Bayer process, specifically using a polymer such as dextran, to enhance vanadium oxide crystallization and sedimentation, followed by liquid-solid separation methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional decantation is used without polymer addition, then the process is simple and easy to operate, but the vanadium oxide extraction yield is low
Solution Approach 1:
A water-soluble polymer is introduced as an intermediary substance that mediates between the vanadium oxide particles and the liquid phase. The polymer adsorbs onto the vanadium oxide particles, modifying their surface properties and enhancing their settleability during decantation, thereby increasing extraction yield without requiring complex equipment changes
Solution Approach 2:
The addition of polymer changes the physical-chemical parameters of the spent liquor, specifically affecting the surface properties and zeta potential of vanadium oxide particles. This parameter modification enhances particle aggregation and settling characteristics, improving separation efficiency during the decantation process
2Productivity
If cooling is applied to promote vanadium oxide crystallization, then extraction yield improves, but energy consumption increases
Solution Approach 1:
The water-soluble polymer acts as a mediator that enables effective vanadium oxide recovery at moderate temperatures (20-80°C) by enhancing particle settleability through adsorption. This eliminates the need for extensive cooling operations while maintaining high extraction yields, thereby reducing energy consumption
Solution Approach 2:
The polymer modification changes the temperature dependence characteristics of the extraction process. Instead of relying on strong temperature-driven crystallization, the polymer-enhanced adsorption mechanism allows efficient recovery at warmer temperatures, reducing the energy input required for cooling operations
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
The process significantly increases the yield of vanadium oxide extraction, allowing for higher recovery and potential economic benefits from vanadium compounds.
Implementation Method 1
the addition of a water-soluble polymer helps the crystallization of vanadium oxides and sedimentation in spent liquor
Implementation Method 2
the addition of a water-soluble polymer helps the crystallization of vanadium oxides and sedimentation in spent liquor
Implementation Method 3
Sending the spent liquor SL to an evaporator, to separate condensate water from caustic soda concentrate CSC
Implementation Method 4
The condensate formed in the heaters is re-used in the process
Implementation Method 5
Recovering said vanadium oxide VO particles from the suspension S by a liquid-solid separation method
Implementation Method 6
The underflow can then be centrifuged to separate the spent liquor depleted in vanadium oxides from the solid composed of crystallized vanadium oxides
Data Source
AI summary
The invention concerns a process for increasing the extraction yield of vanadium oxides from the spent liquor generated in the Bayer process for the recovery of alumina from bauxite, with the use of a water-soluble polymer.