Electrodialysis Process for Sodium Sesquicarbonate Separation
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Solution Overview
Problem
The production of sodium bicarbonate from trona typically involves debicarbonation and recarbonation, which is costly and limits its applications due to higher prices compared to soda ash, making it less competitive with cheaper alternatives like lime or limestone in flue gas treatment.
Innovation Solution
A process that directly separates sodium sesquicarbonate into sodium carbonate and sodium bicarbonate using an electrodialyzer with cationic and bipolar membranes, eliminating the need for debicarbonation and recarbonation, and optimizing the production of both products simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If debicarbonation and recarbonation steps are used to produce sodium bicarbonate from trona, then sodium bicarbonate can be produced, but production costs increase and the process becomes less competitive
Solution Approach 1:
The patent segments the trona mineral into its two constituent components (sodium carbonate and sodium bicarbonate) through direct separation in the electrodialyser, eliminating the need for sequential debicarbonation and recarbonation steps. This segmentation approach allows simultaneous production of both products from the raw material without additional processing costs.
Solution Approach 2:
The patent performs preliminary separation of sodium carbonate and sodium bicarbonate from trona during the initial dissolution and electrodialysis process, rather than producing pure sodium carbonate first and then separately producing sodium bicarbonate through recarbonation. This preliminary action avoids subsequent processing steps and reduces overall production costs.
2Quantity of substance
If sodium bicarbonate is produced through carbonation of sodium carbonate, then sodium bicarbonate is obtained, but the price remains higher than soda ash, limiting its competition with cheaper alternatives
Solution Approach 1:
The patent merges the production processes for sodium carbonate and sodium bicarbonate into a single integrated electrodialysis system. Both products are produced simultaneously from trona, allowing the more expensive sodium bicarbonate to be manufactured at lower cost through shared processing infrastructure and eliminated sequential operations.
Solution Approach 2:
The patent changes the fundamental processing parameters by using electrodialysis with specific membrane configurations (cationic and bipolar membranes) to directly separate and produce both sodium carbonate and sodium bicarbonate, rather than using conventional carbonation processes that produce only sodium carbonate and require separate recarbonation steps.
3Quantity of substance
If conventional debicarbonation and recarbonation processes are used, then sodium bicarbonate can be produced, but the process complexity and number of steps increase
Solution Approach 1:
The electrodialyser system performs multiple functions simultaneously: it separates sodium carbonate from sodium bicarbonate, concentrates both products, and enables their independent extraction. This multi-functional approach replaces multiple separate process steps (debicarbonation, filtration, recarbonation, filtration) with a single integrated operation.
Solution Approach 2:
The patent uses ion exchange membranes (cationic and bipolar membranes) as intermediaries to facilitate the separation and concentration of sodium carbonate and sodium bicarbonate. These membranes act as selective barriers that enable direct separation without requiring intermediate chemical reactions or multiple processing stages.
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 process significantly reduces production costs for sodium bicarbonate and potentially soda ash, enabling new applications by efficiently producing high-purity sodium bicarbonate without the usual steps of debicarbonation and recarbonation.
Implementation Method 1
an electrodialyser comprising at least a less basic and a more basic adjacent compartments separated by a cationic ion exchange membrane, permeable to sodium ions
Implementation Method 2
subjecting the mother liquor to electrodialytic water splitting by circulating the mother liquor through a bare compartment of an electrodialytic water splitter
Data Source
AI summary
Process for the joint production of sodium carbonate and sodium bicarbonate out of sesquicarbonate, in which the sesquicarbonate is dissolved in water, in order to form a feed water solution comprising both sodium carbonate and sodium bicarbonate, in which at least part of the feed water solution is introduced into all the compartments of an electrodialyser and in which a sodium bicarbonate enriched solution and a sodium carbonate enriched solution are extracted from the compartments.