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US 10,773,969 B1Granted
Method for producing potassium sulfate and sodium chloride from wastewater
AssigneeVeolia Water Technologies, Inc.
InventorsSebastien Bessenet, Jinhai Feng, James F. Rieke, Timothy F. Rittoff
Life of this patent
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Abstract
A method of producing potassium sulfate by employing sodium sulfate and potassium chloride sources is disclosed. The method includes a crystallization process that yields a mother liquor containing sulfate, sodium and chloride. The mother liquor is directed to an anion segregation unit that produces a reject or retentate rich in sulfate which is recycled and employed in the production of the potassium sulfate. Further, the anion segregation unit produces a permeate that is depleted in sulfate but includes sodium and chloride and is directed to a sodium chloride crystallizer for producing sodium chloride.
Claims25
A method of producing potassium sulfate comprising:
- directing a sodium sulfate source to a glaserite crystallizer;
- directing a liquor containing potassium sulfate from a downstream potassium sulfate reactor to the glaserite crystallizer and mixing the liquor containing the potassium sulfate with the sodium sulfate source;
- crystallizing glaserite in the glaserite crystallizer to form glaserite crystals and a mother liquor;
- separating the glaserite crystals from the mother liquor;
- directing the glaserite crystals to the downstream potassium sulfate reactor;
- directing a potassium chloride source to the potassium sulfate reactor and mixing the potassium chloride source with the glaserite crystals and precipitating potassium sulfate crystals;
- separating the potassium sulfate crystals from the liquor containing potassium sulfate;
- directing the mother liquor from the glaserite crystallizer to a nanofiltration unit and producing a reject or retentate stream rich in sulfate and a filtrate or permeate stream depleted in sulfate;
- recycling the reject or retentate stream to the glaserite crystallizer and combining the reject or retentate stream with the sodium sulfate source and the liquor containing the potassium sulfate in the glaserite crystallizer;
- and
- directing the filtrate or permeate stream to a sodium chloride crystallizer and producing sodium chloride crystals.
8 more elements
A method for producing potassium sulfate from a waste stream, comprising:
- concentrating the waste stream to form a brine or a slurry;
- crystallizing mirabilite from the brine or slurry in a mirabilite crystallizer to form mirabilite crystals and a mirabilite crystallizer liquor;
- separating the mirabilite crystals from the mirabilite crystallizer liquor;
- mixing the mirabilite crystals with a potassium liquor;
- producing or forming glaserite crystals from the mirabilite crystals and potassium liquor in a glaserite reactor or a glaserite crystallizer;
- separating the glaserite crystals from the potassium liquor;
- directing the glaserite crystals to a potassium sulfate reactor;
- mixing a potassium source with the glaserite crystals in the potassium sulfate reactor to form potassium sulfate crystals and the potassium liquor;
- recycling the potassium liquor from the potassium sulfate reactor to the glaserite reactor or glaserite crystallizer;
- filtering the mirabilite crystallizer liquor to form a filtrate or permeate depleted in sulfate and a retentate or reject rich in sulfate;
- recycling the retentate or reject stream to the mirabilite crystallizer;
- directing the filtrate or permeate stream to a sodium chloride crystallizer and crystallizing sodium chloride crystals;
- and
- separating the sodium chloride crystals.
11 more elements
A method for producing potassium sulfate from a wastewater stream containing sodium and sulfate, comprising:
- directing the wastewater stream to a membrane separation unit and producing a reject stream and a permeate stream;
- concentrating the reject stream to form a first brine solution or a slurry;
- directing the first brine solution or slurry to a glaserite reactor;
- mixing potassium liquor with the first brine solution or slurry in the glaserite reactor and producing glaserite crystals;
- separating the glaserite crystals and directing the glaserite crystals to a potassium sulfate reactor;
- mixing a potassium source with the glaserite crystals to form potassium sulfate crystals;
- separating the potassium sulfate crystals;
- wherein the potassium source mixed with the glaserite crystals in the potassium sulfate reactor forms the potassium liquor that is mixed with the first brine stream or slurry in the glaserite reactor;
- concentrating the permeate stream to form a second brine stream or a second slurry;
- directing the second brine stream or second slurry to a sodium chloride crystallizer and crystallizing sodium chloride crystals;
- and
- separating the sodium chloride crystals.
9 more elements
A method of producing potassium sulfate from a wastewater stream containing sodium and sulfate comprising:
- directing the wastewater stream to a membrane separation unit and producing a first reject stream and a first permeate stream;
- concentrating the first reject stream to form a first brine solution or a slurry;
- mixing the first brine solution or the slurry with a potassium liquor to form a mixture;
- crystallizing the mixture in a glaserite crystallizer and producing glaserite crystals;
- separating the glaserite crystals from the potassium liquor and directing the glaserite crystals to a potassium sulfate reactor;
- mixing a potassium source with the glaserite crystals to form potassium sulfate crystals;
- separating the potassium sulfate crystals;
- wherein the potassium source mixed with the glaserite crystals in the potassium sulfate reactor forms the potassium liquor that is mixed with the first brine stream or slurry in the glaserite crystallizer;
- directing the potassium liquor from the glaserite crystallizer to a nanofiltration unit and producing a second reject stream and a second permeate stream;
- recycling the second reject stream from the nanofiltration unit to the glaserite crystallizer;
- and
- directing the second permeate stream from the nanofiltration unit to a sodium chloride crystallizer and producing sodium chloride crystals.
9 more elements
A method of recovering potassium sulfate from wastewater produced in a coal-to-chemical or a coal-to-liquid process, the method comprising:
- converting coal-to-chemical or coal-to-liquid and in the course of converting coal-to-chemical or liquid producing the wastewater;
- concentrating the wastewater to form a brine that includes sodium and sulfate;
- directing the brine to a mirabilite crystallizer and forming mirabilite crystals and producing a mirabilite liquor;
- separating the mirabilite crystals from the mirabilite liquor;
- directing the mirabilite crystals to a glaserite reactor or glaserite crystallizer;
- mixing a potassium liquor with the mirabilite crystals;
- producing or forming glaserite crystals from the mirabilite crystals and the potassium liquor in a glaserite reactor or a glaserite crystallizer;
- separating the glaserite crystals from the potassium liquor;
- directing the glaserite crystals to a potassium sulfate reactor;
- mixing a potassium source with the glaserite crystals in the potassium sulfate reactor to form potassium sulfate crystals;
- separating the potassium sulfate crystals;
- and
- wherein the potassium source mixed with the glaserite crystals in the potassium sulfate reactor forms the potassium liquor that is mixed with the glaserite crystals in the glaserite reactor.
10 more elements
Dependencies are inferred from the claim text.