Closed-Loop Mineral Extraction from Saltern Bittern
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Solution Overview
Problem
Current methods for extracting magnesium and trace elements from seawater do not utilize exhausted brines from salterns efficiently, lack the use of renewable energy from salinity gradients, and generate waste products, with no closed-loop processes for minimizing environmental impact and costs.
Innovation Solution
A closed-loop process and plant that uses renewable energy sources to extract magnesium and trace elements from saltern brine, producing chemical reagents in-situ from waste brine, and utilizing electrodialysis with bipolar membranes to convert waste brine into electrical energy, with no external reagents or waste products, recycling all byproducts back into the saltern or sea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional seawater desalination procedures are used to extract magnesium and trace elements, then extraction can be performed, but exhausted brines from salterns are not utilized efficiently and waste products are generated
Solution Approach 1:
The patent recovers valuable minerals (magnesium, trace elements) from exhausted brines that would otherwise be discarded, transforming waste streams into valuable resources through selective precipitation and crystallization processes
Solution Approach 2:
The patent converts the harmful waste brine streams into beneficial mineral products, using the high salinity and specific ion composition of exhausted brines as feedstock for magnesium and trace element extraction, thereby eliminating waste while producing valuable materials
2Use of energy by moving object
If conventional extraction methods are used, then minerals can be extracted, but renewable energy from salinity gradients is not utilized
Solution Approach 1:
The system uses reverse electrodialysis to generate electrical energy from the salinity gradient between brine and seawater, allowing the extraction process to be self-powered or partially self-powered, reducing external energy requirements
Solution Approach 2:
The patent combines mineral extraction operations with energy generation operations in an integrated system, where the same brine stream serves dual purposes: as feedstock for magnesium extraction and as energy source through reverse electrodialysis
3Object-affected harmful factors
If conventional procedures are used for mineral extraction, then extraction can occur, but environmental impact and costs are not reduced
Solution Approach 1:
The patent implements a closed-loop system where all process streams are recovered and reused, eliminating discharge of harmful waste products into the environment and reducing the need for expensive waste treatment facilities
Solution Approach 2:
The system uses the generated electrical energy and recovered materials to feed back into the extraction process, creating a self-sustaining system that reduces both environmental impact and operational costs through internal resource circulation
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
Achieves high-purity magnesium recovery (>95%) and trace element extraction with reduced environmental impact and costs, utilizing renewable energy and internal reagents, with no waste products, enhancing the efficiency and sustainability of mineral extraction from saltern brines.
Implementation Method 1
a reverse electrodialysis (RED) unit. According to this process, wastewater streams are obtained featuring a salinity that exceeds the salinity of the feed water by not more than 10%
Implementation Method 2
This process uses a device for removing cations and a device for removing anions. These devices are suitable for electrodialysis. Also, these devices comprise membranes for separation.
Implementation Method 3
these devices comprise membranes for separation
Implementation Method 4
a calcium sulphate precipitating chamber
Implementation Method 5
a sodium sulphate crystallization chamber, a metal crystallization chamber for crystallizing metals in the form of salts, a crystallizing chamber for crystallizing a cation in the form of a salt
Data Source
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AI summary
The present invention discloses a procedure for extracting minerals from the waste brine of saltern plants , where said brine is also called "bittern", wherein said bittern comprises a quantity of sodium ions Na+ ranging from about 18 to about 78 g/l, a quantity of potassium ions K+ ranging from about 3 to about 17 g/l, a quantity of magnesium ions Mg2+ ranging from about 10 to about 60 g/l, a quantity of chlorine ions Cl- ranging from about 178 to about 292 g/l, a quantity of sulphate ions SO4- ranging from about 43 to about 114 g/l, a concentration of calcium ions Ca2+ less than 1 g/l, a concentration in trace elements ranging from 10-6 to 1 g/l, and is substantially inorganic carbon free, wherein said procedure comprises the following steps: a) obtaining said bittern from a saltern by way of a fractioned evaporation and crystallization of calcium and chlorine salts, such as for example sodium chloride; b) sending said bittern to a first reactive crystallizer for magnesium hydroxide; c) extracting magnesium hydroxide from said bittern by way of a reactive crystallization, wherein the reagent is alkaline solution of alkaline hydroxides, such as, for example, NaOH and KOH or mixtures thereof, and obtaining a magnesium-free waste brine; d) sending the magnesium-free waste brine to a trace element separation unit; e) separating a solution from the magnesium-free waste brine comprising at least one of the trace elements included in the group formed of alkaline, alkaline-earthy, transition, and post-transition metals, at a concentration ranging from 10-4 to 100 g/l, so as to obtain a waste brine deprived of one or several trace elements; f) sending the solution to a second reactive crystallizer; g) extracting at least one of the trace elements of a group including alkaline, alkaline-earthy, transition, and post-transition metals from the solution by way of a reactive crystallization, wherein the reagent is an acidic solution, formed of a mixture of HCI and H2SO4, and/or an alkaline solution, formed of a mixture of NaOH and KOH; h) sending the waste brine deprived of one or several trace elements to an electrodialysis with bipolar membranes unit; i) submitting the waste brine deprived of one or several trace elements to electrodialysis with bipolar membranes, so as to convert a part of the sodium, potassium, and chloride ions and the water of the solution into hydrochloric acid (HCI), sulphuric acid (H2SO4), and sodium/potassium hydroxides (NaOH/KOH) in solution, thus obtaining acidic solutions, alkaline solutions, and a salt-concentrated waste brine; j) diluting said salt-concentrated waste brine for obtaining a diluted waste brine and recycling it in the saltern or in the sea, wherein the electrical energy necessary for implementing steps b) thru j) of the procedure is generated starting from said waste brines jointly with and/or alternatively to the electrical energy produced by at least one renewable energy source , wherein said procedure for extracting minerals from said bittern is closed cycle one, wherein the waste product of each individual step of the procedure feeds another step of the procedure itself, and wherein the final waste product of the procedure is re-used in the saltern itself or in the sea. The present invention also describes a plant for extracting minerals from a bittern that uses the above-described procedure.