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US 12,584,230 B2Granted
Electrolytic recycling system of waste phosphogypsum and method
OwnerJoshua Jun-Ren Tang, Alex Wanginventors
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Abstract
A chemical process utilizing electrodialysis in a flow cell with cation and anion selective ion exchange membranes to produce sulfuric acid from phosphogypsum and gypsum, and centrifugal separation to reduce radioactive phosphogypsum into a liquid slurry (mainly calcium hydroxide) capable of sequestration. Reactants used are water, phosphogypsum or gypsum, and sodium carbonate.
Claims10
A system for recycling of phosphogypsum, the system comprising:
- an electrodialysis unit having:
- a neutral compartment including a slurry chamber and a central chamber disposed above the slurry chamber, the slurry chamber in fluid communication with the central chamber and having a filter disposed therebetween to limit calcium hydroxide flow;
- an anolyte chamber adjacent to the central chamber and separated therefrom by an anion-exchange membrane, the anolyte chamber including an anode configured to be connectable to an external electrical current source,
- a catholyte chamber adjacent to the central chamber and separated therefrom by a cation-exchange membrane, the catholyte chamber including a cathode configured to be connectable to an external electrical current source;
- a sulfuric acid flow unit in fluid communication with the anolyte chamber, configured to cause dilute sulfuric acid to flow through the anolyte chamber;
- a sodium sulfate flow unit in fluid communication with the central chamber, configured to cause sodium sulfate to flow through the central chamber;
- a sodium hydroxide flow unit in fluid communication with the catholyte chamber, configured to cause sodium hydroxide to flow through the catholyte chamber;
- a slurry reactor unit configured to react phosphogypsum with sodium hydroxide to produce a slurry of calcium hydroxide and sodium sulfate;
- and
- a slurry flow unit in fluid communication with the slurry chamber and slurry reactor unit, configured to cause the slurry to flow through the slurry chamber;
- whereby the filter permits sodium sulfate to flow from the slurry chamber into the central chamber and
- whereby, when an electrical current is applied to the anode and cathode, the electrodialysis unit is configured to cause an ion flow through the anion-exchange membrane to produce sulfuric acid and oxygen in the anolyte chamber and an ion flow through the cation-exchange membrane to produce sodium hydroxide and hydrogen in the catholyte chamber.
9 more elements
Dependencies are inferred from the claim text.