Table salts and the manufacturing methods and system

Patent metadata

Field	Value
Publication number	US-2020187536-A1
Application number	US-201816642377-A
Country	US
Kind code	A1
Filing date	Mar 19, 2018
Priority date	Aug 28, 2017
Publication date	Jun 18, 2020
Grant date	—

Abstract

The present invention provides table salts. The said table salts contains 50 to 600 mg/kg of strontium. The strontium-rich table salts provided by the present invention has significantly higher strontium content than traditional common table salts. As one of the essential trace elements, strontium plays an important role in human health. The said table salts provided by the present invention are rich in strontium, which can be assimilated by human body during taking the said table salts. Moreover, the strontium content in the table salts provided by the present invention ranges from 50 to 600 mg/kg, which enables human body to get enough strontium to meet human needs when taking normal amount of the said table salts daily.

First claim

1 . Table salts containing 50 to 600 mg/kg of strontium;

2 . The table salts according to claim 1 , wherein the said table salts further contains sodium chloride of ≥99.1 wt %, sulfate ion of ≤0.4 wt % and moisture of ≤0.3 wt %

3 . The table salts according to claim 1 , wherein the said strontium exists in one or more forms of strontium chloride, strontium sulfate or strontium carbonate.

4 . Methods for manufacturing the said table salts provided by claims 1 - 3 comprising the steps of:
a) Pretreatment of the raw brine to obtain pretreated brine;
b) Evaporation of the said pretreated brine obtained in step a) by a multi-effect evaporation process to obtain concentrated brine and gypsum mother liquor;
c) Post-treatment of the concentrated brine obtained in step b) by thickening and drying to obtain off-gas and the said table salts.

5 . The method according to claim 4 , wherein the raw brine is mining brine;

6 . The method according to claim 4 , wherein the mass ratio of sodium-to-strontium;

7 . The method according to claim 4 , wherein the said pretreatment in step a) is selected one or more combination of pH adjustment, electrodialysis, ion exchange, and membrane filtration treatments;
Preferably, the pH adjustment is performed by using one or more combinations of sodium carbonate, sodium bicarbonate, sodium hydroxide, calcium chloride, calcium sulfate, calcium carbonate and calcium oxide; Preferably, the pH of the pretreated brine is 7-11; Preferably, the electrodialysis treatment is bipolar membrane electrodialysis; Preferably, the membrane filtration treatment is nanofiltration; Optionally, the multi-effect evaporation in step b) is two to six-effect evaporation; Preferably, the multi-effect evaporation is performed by concurrent, countercurrent, cross-flow or combination thereof; Preferably, the concentrated brine is obtained from the pretreated brine in step b) by a countercurrent multi-effect evaporation; Preferably, the gypsum mother liquor is obtained from the pretreated brine in step b) by a concurrent multi-effect evaporation; Preferably, the temperature for multi-effect evaporation decreases at a temperature gradient of 10-30° C. from the first effect to the last effect: Preferably, the first effect evaporation is performed at a temperature of 120-180° C. and an absolute pressure of 0.2-10 MPa.

8 . The method according to claim 4 , wherein it further comprises the steps of:
d) centrifugal treatment of the said gypsum mother liquor obtained in step b) to obtain gypsum and supernatant; e) treatment of the said off-gas obtained in step c) by a dry de-dusting and further by a wet de-dusting with the said supernatant obtained in step d) or the condensed water obtained in the multi-effect evaporation process in step b) to obtain de-dusting brine; f) mixing and evaporate the said de-dusting brine obtained in step e) with the said pretreated brine obtained in step a) to obtain the said table salt; Optionally, step f) is performed when the concentration of salt in the de-dusting brine obtained in step e) reaches 150-300 g/L; Preferably, step b) further comprises the step of obtaining concentrated brine with different strontium contents from the evaporation chamber of different effects of the multi-effect evaporation system.

9 . A system for manufacturing the said table salt, wherein the said system comprises:
Pretreatment equipment that is used for pretreating the raw brine to obtain pretreated brine; Multi-effect evaporation equipment that is connected with the pretreatment equipment, and is used to obtain concentrated brine and gypsum mother liquor by multi-effect evaporation of the pretreated brine from pretreatment equipment. Thickening and drying equipment that is connected with the multi-effect evaporation equipment, and is used to thicken and dry the concentrated brine obtained from the multi-effect evaporation equipment to obtain the off-gas containing salt dust and the said table salts;

10 . The system for manufacturing the said table salts according to claim 9 , wherein the said system further comprises:
Gypsum treatment equipment that is connected with the multi-effect evaporation equipment, and is used to centrifuge the gypsum mother liquor obtained from the multi-effect evaporation equipment to obtain gypsum and supernatant; Dry de-dusting equipment that is connected with the thickening and drying equipment, and is used to remove the salt contained in off-gas obtained by the thickening and drying equipment; Wet de-dusting equipment that is connected with the said dry de-dusting equipment, the said gypsum treatment equipment and/or the said multi-effect evaporation equipment, and is used to further remove the residual salt contained in the treated off-gas from the said dry de-dusting equipment with the supernatant from the said gypsum treatment equipment or the condense water from the said multi-effect evaporation equipment; and Brine mixing equipment that is connected with wet de-dusting equipment, pretreatment equipment and multi-effect evaporation equipment, and is used to mix the de-dusting brine from the said wet de-dusting equipment with the pretreated brine from the pretreatment equipment and transfer the mixed brine back to the multi-effect evaporation equipment.

Assignees

• Univ Tsinghua
• Sichuan Zigong Chi Yu Salt Product Co Ltd

Inventors

• Zhao Xuebing
• Liu Dehua
• Dai Lingmei
• Zou Chenghua
• Yu Guilan

Classifications

• C01D3/06

  Preparation by working up brines; seawater or spent lyes · CPC title

• B01D1/26 Primary

  Multiple-effect evaporating · CPC title

• A23V2002/00

  Food compositions, function of food ingredients or processes for food or foodstuffs · CPC title

• C01D3/08

  Preparation by working up natural or industrial salt mixtures or siliceous minerals · CPC title

• A23L27/40 Primary

  Table salts; Dietetic salt substitutes · CPC title