JP2005343738A - Manufacturing process of marine salt and its apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process of a marine salt containing rich nutrients as they exist in seawater without heating and an apparatus which produces the marine salt inexpensively with a simple process. <P>SOLUTION: The manufacturing process of the marine salt comprises concentrating seawater by separating water by cooling and freezing, separating the precipitated salt to obtain the marine salt. The manufacturing apparatus of the marine salt is equipped with a seawater treatment tank in which seawater is cooled, a freezing means by which the seawater in the tank is frozen, a means of separation of the concentrated seawater by which frozen ice and the concentrated seawater are separated, a means of crystal separation for separating the salt crystal precipitated in the concentrated seawater and a means of drying by which the separated salt crystal is dried. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for producing sea salt containing seawater-rich nutrients as they are.

  With recent consumer health and nature orientations, there is an increasing demand for edible salt containing abundant natural minerals called bittern.

  In particular, seawater that is said to be deep seawater, which is said to be deeper than 200m, is excellent in eutrophication, low temperature, and cleanliness, and is used in various fields, and is also used for edible salt and is attracting attention. .

  Deep water is stable at low temperatures throughout the year compared to surface water, and is rich in minerals and trace elements that are considered essential for the growth of organisms as nutrients. Since there are few things, in recent years, it is utilized for various uses, such as a soft drink, a lotion, and a foodstuff.

  Therefore, natural salt produced from seawater containing abundant minerals has attracted attention.

  Most of the salts that have been commercially available in the past are boiled by heating the concentrated seawater, the water is evaporated, and crystals of the salt are precipitated. Therefore, a substantial amount of nutrients that should have been abundantly disappeared by heating, and in order to compensate for this, after separating the bittern component once, add the bittern component again to the crystallized salt and add minerals. The minute was adjusted and purified.

  Japanese Patent Application Laid-Open No. 10-150947 discloses a natural salt using deep ocean water as a raw material.

  This is a method of concentrating seawater taken from the deep sea 200m or more below sea level at room temperature without heating and crystallizing it without using thermal power to obtain natural salt, which is rich in natural minerals. Natural deep-sea salt can be obtained from deep water without loss of minerals by heating.

  By the way, bittern is produced by concentrating nutrient-rich seawater due to its high hygroscopicity, and salt with a high content of bittern is difficult to grind to reduce the grain size of the salt crystals, and it is also moistened. It will contain a lot.

  Because of this moist nature, salt particles are gathered together, and because the particles are large, the tongue feels bad, it is difficult to use only a small amount when cooking, and spots when sprinkled on ingredients It was avoided because of the poor usability.

  However, due to the diversity of tastes in recent years and the increase in nature and health consciousness, the value of natural salt itself has been reviewed, and we prefer natural salt that has a poor feeling of use, such as using different salt depending on the dish. The demand for natural salt has increased due to the fact that it has become easier to select and to collect new natural resources rich in nutrients such as deep ocean water.

  However, deep ocean water refers to seawater called deep sea deeper than the outer edge of the continental shelf. For example, at Muroto Cape, Kochi Prefecture, water is taken from about 2600 m offshore.

  In this way, the intake of deep ocean water requires enormous costs and complicated facilities depending on the plant installed on the sea surface.

  In addition, the method of extracting salt from seawater is also a method of removing salt from seawater (desalting) at the same time, and seawater desalination and salinity concentration are performed at the same time. Conventionally, the same method as salt production has been adopted.

  Therefore, Japanese Patent Application Laid-Open No. 08-318136 discloses seawater desalination and salt production.

This is the process of depositing and collecting salt from seawater by salt concentration, and separating salt from seawater that was previously discarded as unnecessary for salt production, and seawater with high salt concentration from seawater. In the process of the fresh water production process that produces fresh water, the concentrated salt water that was previously discarded as unnecessary for fresh water was combined with the plants that use each other process, and each was unnecessary. By using as a useful product, water production costs, salt production costs, and equipment costs can be reduced.
Japanese Patent Laid-Open No. 08-318136 Japanese Patent Laid-Open No. 10-150947

  However, the desalination and salt production method disclosed in Japanese Patent Application Laid-Open No. 08-318136 requires a primary concentration device such as an ion exchange membrane method concentration device and an electrodialysis membrane device. The cost of installing a plant for water production or salt production, such as dialysis membrane devices, is enormous, and it is actually difficult to simply combine the two plants to simplify the process. is there.

  In addition, since desalting with ion exchange membranes and electrodialysis membranes removes not only the salt content, but also abundant minerals contained in seawater at the same time, the salt produced and the fresh water produced It cannot be said that it can be produced so as to contain an appropriate amount of minerals in both.

  Furthermore, in an evaporator or a crystallizer in a secondary concentrator, heating for evaporation in the evaporator, or heat treatment in a crystallizer using a temperature difference crystallization method in which precipitation is caused by a temperature difference due to heating or cooling. A considerable amount of nutrients disappear.

  Moreover, although the natural salt in the said Unexamined-Japanese-Patent No. 10-150947 is produced by the method which does not heat-process, the salt concentration contained in seawater is said to be about 3.4%, The method of obtaining natural salt by crystallization at room temperature is not very realistic. In addition, this sun crystal is usually evaporated while ventilating in a greenhouse in order to prevent contamination of foreign matters such as dust, and the temperature in the greenhouse becomes 40 degrees or more, and partly due to evaporation. The disappearance of mineral components is inevitable.

  Therefore, the present invention has been made in view of the above problems, and its object is to reduce the cost of sea salt by a method and a simple process for producing sea salt that contains seawater-rich nutrients as they are without heat treatment. It is in providing the apparatus which can manufacture.

  The present invention can solve the above problems by the following means.

  The sea salt is obtained by cooling the seawater, separating water by freezing and concentrating the seawater, and separating the deposited salt to obtain sea salt.

  The seawater in the present invention includes deep seawater, and hereinafter the seawater includes deep seawater.

  In the present invention, when seawater is cooled and frozen to produce ice, it is gradually frozen from the fresh water portion of the seawater, and the desalination phenomenon in which most of the salinity contained in the seawater remains unfrozen. Utilizing this method, sea salt is obtained by a method of obtaining seawater having a high salinity concentration.

  Concentration of seawater is performed only by a cooling method, and no heat treatment is performed. Any method may be used for cooling the seawater as long as it can be cooled until the seawater freezes. A refrigerator using a water temperature control method or a method of circulating refrigerant piping in the seawater may be used.

  The concentrated seawater is further cooled to precipitate salt crystals. Even in the step of depositing salt crystals from the concentrated seawater, heat treatment is not performed, but only by cooling.

  Separation of the deposited salt is not limited as long as it can separate the precipitated salt from the concentrated seawater, and it is left in a draining wooden box that has been used in the salt-making process. Also good.

  Alternatively, it may be allowed to stand to precipitate the salt, and the precipitate may be separated only by the supernatant, separated by a centrifuge, or the like, or may be separated by filtration.

As described above, natural sea salt, which is a natural salt that does not undergo any chemical treatment, can be produced from concentrated seawater without damaging nutrients rich in seawater with low energy.

  A second aspect of the present invention is a method for producing sea salt, characterized in that seawater is rapidly cooled with a cryogenic refrigerant to freeze the seawater.

  As the cryogenic refrigerant, liquid helium or liquid nitrogen can be used. In addition, liquefied gas such as liquefied oxygen, liquefied argon, liquefied natural gas (LNG), and liquefied carbon dioxide gas may be used. Since liquid nitrogen is nonflammable and has a very low boiling point of −196 ° C., it has been conventionally used as a refrigerant.

  With this liquid nitrogen, seawater can be cooled to 0 ° C. or lower, concentrated to seawater with a high salt concentration, and further cooled to precipitate the salt.

  According to a third aspect of the present invention, there is provided a method for producing sea salt, characterized in that sea salt is obtained by filtering and separating salt crystals precipitated upon cooling.

  The salt precipitated by cooling the concentrated seawater is separated by filtration in order to remove it from the concentrated seawater.

  From the drain pipe etc. provided in the lower part of the seawater treatment tank, the deposited salt is drained together with the concentrated seawater, and the concentrated seawater that has been drained is filtered to take out only the salt crystals mixed in the concentrated seawater.

  Any filtration may be used as long as it is excellent in water permeability such as a filter or cloth and can take out salt crystals. Those having low temperature resistance are preferred.

  The seawater treatment tank for cooling the seawater, the cooling means for freezing the seawater in the tank, the concentrated seawater separating means for separating the frozen ice from the concentrated seawater, An apparatus for producing sea salt, comprising: a crystal separation means for separating the salt crystals precipitated in the seawater; and a drying means for drying the separated salt crystals.

  The seawater treatment tank is a tank for storing the taken-in seawater and cooling it. The taken-in seawater is stored in a seawater treatment tank after removing floating matters and dust such as dust in the seawater by filtration.

  A plurality of seawater treatment tanks may be connected to transfer the concentrated seawater, such as a primary seawater treatment tank and a secondary seawater treatment tank.

  Seawater stored in the seawater treatment tank is cooled by cooling means in the seawater treatment tank. Any cooling means may be used as long as it can freeze the seawater stored in the seawater treatment tank.

  By circulating liquid nitrogen as the cryogenic refrigerant, the seawater in the seawater treatment tank can be cooled and frozen.

  Liquid nitrogen may be circulated through a pipe provided in the seawater treatment tank, or liquid nitrogen may be circulated between an inner layer and an outer layer of a seawater treatment tank having a two-layer structure.

  The concentrated seawater separation means may be any means as long as it can separate the frozen ice in the seawater treatment tank from the unfrozen concentrated seawater, and can be drained by providing a concentrated seawater drain at the bottom of the seawater treatment tank. It may be something like this.

  The remaining ice may be discharged out of the tank by tilting the seawater treatment tank, or the tank is heated to melt the ice into water and drained from a drain outlet that drains only this water to the outside of the tank. You may make it do.

  The ice separated from the concentrated seawater by this concentrated seawater separation means is seawater in a desalted state suitable for drinking water and the like, so it may be used as it is, or the desalted seawater is further separated. Seawater with a lower salinity concentration may be produced by transferring it to the tank, storing it, thawing it again for desalting and refreezing it.

  When multiple seawater treatment tanks are connected and used, the ice in the secondary seawater treatment tank with a low cooling temperature is transferred to the primary seawater treatment tank with a high cooling temperature and recooled in the primary seawater treatment tank. Thus, a lower salinity concentration may be obtained.

  The crystal separation means is for separating salt crystals precipitated by cooling from concentrated seawater.

  From the drain pipe provided at the bottom of the seawater treatment tank, the precipitated salt is drained together with the concentrated seawater, and the concentrated seawater that has been drained is filtered, so that only the salt crystals mixed in the concentrated seawater are extracted. Alternatively, only the water of the concentrated seawater may be removed by a centrifugal separator or the like, and the deposited salt may be taken out.

  In addition, the concentrated seawater that has been drained is packed in a wooden box that has been conventionally used in the salt-making process and left for a long time to drain water, or the concentrated seawater is allowed to stand to precipitate the salt to obtain a supernatant liquid. It is also possible to use a method in which only the precipitate is separated.

  The drying means is for drying the salt separated from the concentrated seawater. The moisture of the salt is evaporated by natural drying, not by drying by heating.

  Water can be evaporated by filling the wooden box for draining and leaving it for several days, allowing the water to flow naturally and solidify in the wooden box, or the water can be evaporated by drying in the sun. .

  According to a fifth aspect of the present invention, there is provided a sea salt production apparatus, wherein the cooling means is a cooling means using a cooling pipe through which a cryogenic refrigerant installed in the seawater treatment tank is circulated.

  The cooling pipe is a pipe provided in the seawater treatment tank for circulating the refrigerant. As the refrigerant, liquid helium, liquid nitrogen, or the like, which is a cryogenic refrigerant, can be used. The cooling pipe is made of a high strength material such as a salt-resistant stainless steel pipe and is configured to have multiple stages in the seawater treatment tank.

  This multi-stage configuration is for increasing the cooling efficiency, and may be configured in any manner. For example, the multi-stage configuration may be provided in a zigzag manner in a seawater treatment tank or in a spiral shape.

  A sixth aspect of the present invention is a sea salt production apparatus, wherein the cooling means is provided with a stirring device for stirring the cooled seawater in the seawater treatment tank.

  This stirrer stirs in order to make the cooling state of the seawater in the seawater treatment tank uniform and quickly lower the temperature.

  Since the cooling pipe is fixed and installed in the seawater treatment tank, the cryogenic liquid nitrogen is circulated, so that it is frozen from the periphery of the cooling pipe.

  If it does so, a cooling state will not necessarily become uniform, and the seawater of a part far from a cooling pipe will not be cooled easily. Therefore, a stirring device is provided in the seawater treatment tank in order to make the cooling state uniform and promote cooling by the stirring means.

The stirring device may be configured to stir the seawater in the seawater treatment tank by rotating a stirring rod with a propeller-type stirring blade at the tip or at regular intervals, and the stirring blade is spiral. The stirring rod may be rotated. Alternatively, a magnetic stirring member may be placed in the tank and rotated by magnetic force from the outside of the tank.

  Claim 7 is a seawater treatment tank comprising a plurality of seawater treatment tanks provided with the cooling means, the temperature of which is set so that the cooling temperature decreases stepwise, and the seawater treatment tank having a lower temperature than the seawater treatment tank having a higher temperature. The sea salt production apparatus is characterized in that the concentrated seawater from which the frozen ice is separated is transported and concentrated in stages.

  The primary seawater treatment tank is set at a high cooling temperature, the secondary seawater treatment tank is set at a low cooling temperature, and the tertiary seawater treatment tank is set at a low cooling temperature. Each stage is changed and set in stages, and a plurality of seawater treatment tanks are connected in the order of the set temperature.

  The seawater is cooled in order from the seawater treatment tank with the highest cooling temperature setting, and the concentrated seawater is sequentially moved to the seawater treatment tanks with lower cooling temperatures, such as primary, secondary, and tertiary. It is transferred to.

  By gradually cooling the seawater step by step, highly concentrated concentrated seawater can be produced efficiently, and salts having different sodium chloride contents can be precipitated.

  Frozen ice is useful as a desalted seawater in various fields such as soft drinks, lotions and foods.

  Since salt production and useful raw water can be obtained at the same time, power costs, fresh water costs, and equipment costs can be significantly reduced. Moreover, the consumption of the operation energy of an installation can be reduced significantly.

  The cooling temperature of each seawater treatment tank is measured by a thermocouple or the like, and the temperature of each seawater treatment tank can be adjusted by controlling the flow rate of flowing liquid nitrogen through the cooling pipe.

  The present invention has the following effects.

  1) A method for producing sea salt that can produce natural sea salt, which is a natural salt that contains an excellent mineral balance, without any chemical treatment at low energy from seawater with excellent eutrophication. It is.

  2) It is a method for producing sea salt that can be rapidly cooled by a refrigerant regardless of electricity, thereby reducing operating costs and shortening salt production time.

  3) It is a method for producing a sea salt that can produce a natural salt rich in nutrients while minimizing the disappearance of minerals since the salt deposited from the concentrated seawater can be filtered out without any heat treatment.

  4) Due to the extremely simple structure, there is little cost burden such as equipment cost and operation cost, and it is economical, and through a process that does not perform heat treatment, it undergoes chemical treatment at low energy from seawater with excellent eutrophication. It is a sea salt production apparatus that can produce a natural sea salt that is a natural salt containing an excellent mineral balance as it is.

  5) A sea salt production apparatus capable of improving cooling efficiency and shortening cooling time by efficiently circulating a refrigerant for cooling seawater in a seawater treatment tank.

  6) A sea salt production apparatus that eliminates cooling spots in the seawater treatment tank, promotes cooling, and contributes to improving cooling efficiency and shortening cooling time.

  7) Efficiently obtain concentrated seawater with a high concentration rate and high salinity concentration by connecting multiple seawater treatment tanks whose temperatures are set to be gradually cooled and gradually cooling and concentrating the seawater. It is a sea salt production apparatus that can obtain salts having different sodium chloride contents.

  8) Using frozen ice, desalted ice or seawater with high utility value in various fields such as soft drinks, lotions, and foods can be obtained.

  Hereinafter, an embodiment of a sea salt production apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of a sea salt production apparatus according to the present invention.

  The sea salt production apparatus according to the present invention includes a seawater treatment tank 1, a crystal filter 2, and a crystal dryer 3.

  The seawater treatment tank 1 includes a refrigerant pipe 5 for cooling the seawater 4 in the tank 1, an ultra-low temperature liquefied gas container 6 for supplying liquid nitrogen to the refrigerant pipe 5, and for stirring the inside of the tank. The stirring device 7 is provided.

  The cooling pipe 5 is a liquid nitrogen gas supplied from the ultra-low temperature liquefied gas container 6 and is made of a stainless steel (SUS316) pipe, and is installed in the seawater treatment tank 1 in a spiral shape as shown in the figure.

  In addition, the cooling pipe 5 is preferably a multi-stage configuration in order to increase the cooling efficiency in the seawater treatment tank 1, but may be a zigzag pipe instead of a spiral shape.

  In the stirring device 7, a stirring rod having propeller-like stirring blades 8 attached at equal intervals from the tip of an iron rod is provided in the seawater treatment tank 1, and a drive motor 9 is installed outside the tank 1.

  The agitator 7 is for accelerating the cooling of the seawater in the seawater treatment tank 1 to make the cooling temperature uniform. Any shape and structure of the agitator may be used, and a propeller is attached to the inner wall of the seawater treatment tank 1. A shaped stirring blade may be provided, or the stored seawater may be stirred by the rotation of the seawater treatment tank itself. Further, a stirring element made of a magnetic material may be put into the tank, a magnetic coil may be provided outside the tank, and the stirring element may be rotated to stir seawater.

  The tank 1 includes a thermometer 10 by a thermocouple provided in the tank 1, liquid nitrogen thermometers 11 and 12 provided on the inlet and outlet sides of the pipe, and a liquid nitrogen gas flow meter 13 on the outlet side. The cooling temperature inside can be adjusted. Thereby, the cooling temperature in the seawater treatment tank can be kept constant.

  The liquid nitrogen sent from the ultra-low temperature liquefied gas container 6 flows in the cooling pipe 5 provided in the seawater treatment tank 1 to cool the seawater 4, thereby evaporating into nitrogen gas. It is discharged from the outlet pipe 14 to the atmosphere. Note that it may be reused without being released into the atmosphere.

  The frozen ice is discharged from the upper part of the tank by tilting the seawater treatment tank 1. Since this ice is seawater with excellent mineral balance in a desalted state suitable for drinking water, etc., it may be sent to another tank so that it can be used. In the case where it is configured, desalted seawater that is easier to use can be obtained by producing seawater with a lower salinity concentration by transferring it to another tank, storing it, and refreezing it.

  Moreover, although the seawater treatment tank in a present Example is only one tank, you may comprise it by connecting several seawater treatment tanks of two or more tanks.

  In the case of a two-tank configuration, the primary seawater treatment tank is set at a cooling temperature of −5 ° C., and the secondary seawater treatment tank is set at a cooling temperature of −20 ° C.

  Concentrated seawater cooled in the primary seawater treatment tank is transferred to the secondary seawater treatment tank through the connected pipes, and further cooled to be cooled to concentrated seawater with a higher salinity. A salt with a high sodium chloride content is deposited.

  Here, ice frozen in each seawater treatment tank may be thrown out of the tank, for example, by tilting the seawater treatment tank. For example, the ice in the secondary seawater treatment tank is transferred to the primary seawater treatment tank. Fresh ice with a lower salinity may be made by refreezing, etc., and used as drinking water with excellent mineral balance.

  The crystal filter 2 is configured to be connected to a drainage pipe 15 provided at the lower part of the seawater treatment tank 1. Concentrated seawater with a high salinity is drained from the drainage pipe 15 and filtered by the filter 16 in the crystal filter 2.

  The precipitated salt crystals 17 remain on the filter 16 and are separated from the concentrated seawater 18. The concentrated seawater 18 not containing the filtered salt crystals 17 is returned to the seawater treatment tank 1 and cooled again.

  The salt crystals 17 removed by filtration are dried by the crystal dryer 3. The crystal dryer 3 includes a wooden box-shaped container 19, and the filtered salt crystals 17 are spread in the container and dried.

  The salt crystals 17 filtered by the crystal filter 2 are in a state of containing a large amount of moisture, so they are left in the crystal dryer 3 for several days, drained and dried by natural drying.

  Next, an embodiment of a sea salt production method using the sea salt production apparatus of the present invention will be described with reference to FIG.

S-1) Seawater collection Seawater is collected from a clean sea and stored in a seawater treatment tank.

S-2) Supplying liquid nitrogen from the ultra-low temperature liquefied gas container to the cooling pipe installed to flow in the seawater-cooled seawater treatment tank, and using the cooling pipe installed to flow in the seawater treatment tank, Cool down.

S-3) Cooling temperature setting The cooling temperature of the seawater in the seawater treatment tank is measured, the flow rate of liquid nitrogen flowing through the cooling pipe is adjusted, and the seawater temperature is adjusted to -20 ° C.

S-4) In order to prevent only the periphery of the seawater agitation cooling pipe from being cooled, and to promote cooling in the seawater treatment tank, the agitator with a propeller-like agitating blade is rotated to agitate the seawater, Make the cooling uniform and cool quickly.

  When the seawater treatment tank is cooled by cooling means such as a large refrigeration system, it takes about 3 days to cool the seawater at about 20 ° C to 0 ° C. According to the method in which the seawater is stirred and cooled, it can be rapidly cooled from room temperature to 0 ° C. in about 2 to 3 hours.

S-5) Seawater frozen The water in the seawater begins to freeze gradually, first adheres to the cooling pipe, and ice with a lower specific gravity covers the upper part of the seawater treatment tank.

  This ice is discharged from the upper part of the seawater treatment tank as needed, and the same amount of seawater as it is discharged is injected, cooling is repeated, only the water is discharged as ice, and the salt concentration gradually increases. You may make it high.

S-6) When the concentration of the separated seawater separated seawater has been frozen and the amount of deposited salt has increased, the deposited salt is discharged together with the concentrated seawater to the crystal filter from the drain provided in the lower part of the seawater treatment tank.

S-7) The concentrated seawater separated and discharged from the precipitated salt is filtered by a filter in a crystal filter, and crystals of the precipitated salt are taken out.

  The concentrated seawater from which salt crystals have been removed by filtration is returned to the seawater treatment tank and cooled again.

S-8) Drying treatment The salt crystals taken out are transported to a crystal dryer and spread in a box-shaped container. The salt crystals spread out are allowed to stand for several days, so that moisture is removed and a lump of salt is produced.

S-9) Grinding treatment By crushing the lump of salt, natural cooled sea salt that has not undergone any heat treatment is completed.

  Since this sea salt contains a large amount of bittern components, it becomes a tactile sensation with large particles and moisture.

[Comparative example]
From the results of analysis of commercially available salt, sea salt by heat evaporation, and cooling sea salt according to the present invention by the Japan Food Analysis Center, the salt test method, a summary comparison is shown below. Shown in

Test salt NaOH Mg ion Sulfate ion

Commercial salt 93.79% 0.045% 0.31%
Evaporated sea salt 91.07% 0.23% 0.93%
Cooled sea salt of the present invention 26.67% 0.27% 22.67%

  As shown here, the cooling sea salt according to the present invention has a remarkably low ratio of sodium chloride (NaOH), and there are also a lot of Mg ions and a lot of sulfate ions.

  When salt is made by the method of evaporating water by heat treatment, a considerable amount of minerals disappears, and the seawater in the present invention is originally contained in seawater only by freezing the seawater and separating the water at all. It is possible to produce sea salt containing a large amount of minerals.

  The sea salt production method and apparatus of the present invention can also be applied to the production of desalted sea water. The method of removing salt from seawater is also a method of removing salt from seawater (desalting) at the same time, and since desalination of seawater and concentration of salt are performed simultaneously, production of desalted seawater has been Since the same method is used, desalted seawater can be produced.

  In addition, salt production and water production can be performed simultaneously, and useful raw material water can be obtained at the same time, so that power costs, water production costs, and facility costs can be significantly reduced.

It is a schematic block diagram which shows one Embodiment of the manufacturing apparatus of the sea salt by this invention. It is a flowchart which shows one Embodiment of the manufacturing method of the sea salt by this invention. It is a commercial salt analysis test report. This is a result of analysis test of sea salt by conventional heat evaporation. It is an analysis test result document of the cooling sea salt by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seawater treatment tank 2 Crystal filter 3 Crystal dryer 4 Seawater 5 Cooling piping 6 Ultra-low temperature liquefied gas container 7 Stirrer 8 Stirring blade 9 Drive motor 10, 11, 12 Thermometer 13 Flow meter 14 Outlet piping 15 Drainage piping 16 Filter 17 Crystal 18 Concentrated seawater 19 Wooden crate container

Claims (7)

A method for producing sea salt, comprising cooling seawater, separating water by freezing and concentrating seawater, and separating the deposited salt to obtain sea salt. The method for producing sea salt according to claim 1, wherein seawater is rapidly cooled with a cryogenic refrigerant to freeze the seawater. The method for producing sea salt according to claim 1 or 2, wherein sea salt is obtained by filtering and separating the salt crystals precipitated upon cooling. Seawater treatment tank for cooling seawater, cooling means for freezing seawater in the tank, concentrated seawater separating means for separating frozen ice and concentrated seawater, and precipitation in the concentrated seawater An apparatus for producing sea salt, comprising: a crystal separation means for separating the separated salt crystals; and a drying means for drying the separated salt crystals. The apparatus for producing sea salt according to claim 4, wherein the cooling means is a cooling means using a cooling pipe that circulates a cryogenic refrigerant installed in the seawater treatment tank. The sea salt production apparatus according to claim 4 or 5, wherein the cooling means is provided with a stirring device for stirring the cooling seawater in the seawater treatment tank. A plurality of seawater treatment tanks equipped with the above cooling means are connected, and the temperature is set so that the cooling temperature is lowered stepwise. The apparatus for producing sea salt according to any one of claims 4 to 6, wherein the concentrated seawater from which the separated ice has been separated is transferred and concentrated stepwise.