# US 8,771,380 B2 · Sodium chloride production process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,380 B2 - Document ID: US8771380B2 - Status: Granted - Kind: B2 - Application number: 13/055,185 - Filed: 2009-05-22 - Published: 2011-06-02 - Granted: 2014-07-08 - Earliest claimed: 2008-07-22 - Assignees: Akzo Nobel N.V. - Applicants: Hendrikus Wilhelmus Bakkenes; Johannes Albertus Maria Meijer; Allert Schokker - Inventors: Hendrikus Wilhelmus Bakkenes; Johannes Albertus Maria Meijer; Allert Schokker - Web page: https://patentgrep.com/patent/US8771380B2 ## CPC - C01D 3/06: Preparation by working up brines; seawater or spent lyes - C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20) ## Abstract The present invention pertains to a process for producing sodium chloride comprising the steps of (i) preparing a brine comprising at least 150 g/l of sodium chloride by dissolving a sodium chloride source in water, (ii) subjecting the resulting brine to a eutectic freeze crystallization step by indirect cooling of said brine, resulting in the formation of ice, sodium chloride dihydrate, and a mother liquor, (iii) separating the sodium chloride dihydrate formed in step (ii) from the ice and optionally mother liquor at the eutectic temperature, such that a sodium chloride dihydrate-rich stream is formed, and (iv) feeding said sodium chloride dihydrate-rich stream to a recrystallizer to form sodium chloride and a mother liquor. ## Claims ### Claim 1 A process for producing sodium chloride comprising the steps of (i) preparing a brine comprising at least 150 g/l of sodium chloride by dissolving a sodium chloride source in water, (ii) subjecting the resulting brine to a eutectic freeze crystallization step by indirect cooling of said brine, resulting in the formation of ice, sodium chloride dihydrate, and a mother liquor, (iii) separating the sodium chloride dihydrate formed in step (ii) from the ice at the eutectic temperature, such that a sodium chloride dihydrate-rich stream is formed, and (iv) feeding said sodium chloride dihydrate-rich stream to a recrystallizer to form sodium chloride and a mother liquor. ### Claim 2 (depends on 1) The process according to claim 1 wherein the brine prepared in step (i) has a NaCl concentration of at least 300 g/l. ### Claim 3 (depends on 1) The process according to claim 1 wherein mother liquor obtained in step (ii) and step (iv) is recycled to step (i). ### Claim 4 (depends on 1) The process according to claim 1 wherein step (ii) is carried out in a fluidized bed heat exchanger/crystallizer. ### Claim 5 (depends on 1) The process according to claim 1 wherein step (iii) takes place during the eutectic freeze crystallization step. ### Claim 6 (depends on 1) The process according to claim 1 wherein in step (iii) the ice, sodium dihydrate, and mother liquor are separated so that a dihydrate-rich stream and an ice-rich stream are formed. ### Claim 7 (depends on 6) The process according to claim 6 wherein the ice in the ice-rich stream is separated from the mother liquor, washed, melted, and at least in part used as wash liquid. ### Claim 8 (depends on 6) The process according to claim 6 wherein the ice in the ice-rich stream is not separated from the mother liquor but melted at sub-zero temperatures, and the cold generated is used to cool the brine prepared in step (i) and/or to condensate refrigerants to/at sub-zero temperatures. ### Claim 9 (depends on 1) The process according to claim 1 wherein brine prepared in step (i) is cooled to a temperature of between 0° C. and −15° C. and subsequently subjected to a separation step to remove any crystallized Glauber salt prior to step (ii). ### Claim 10 (depends on 1) The process according to claim 1 wherein the sodium chloride dihydrate formed in step (ii) is separated from the ice and mother liquor. ### Claim 11 (depends on 1) The process according to claim 1 wherein mother liquor obtained in step (ii) is recycled to step (i). ### Claim 12 (depends on 1) The process according to claim 1 wherein mother liquor obtained in step (iv) is recycled to step (i). ### Claim 13 (depends on 1) The process according to claim 1 wherein step (iii) takes place during and after the eutectic freeze crystallization step. ### Claim 14 (depends on 1) The process according to claim 1 wherein step (iii) takes place after the eutectic freeze crystallization step.