JP2016166106A - Salt production method, and salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing salt easily producible, high in quality and also satisfactory in taste.SOLUTION: Provided is a salt production method comprising: a residual liquid production step where saturated salt water concentrated with sea water is evaporated to produce a residual liquid concentrated with bittern, being the residual liquid exhausted in accordance with the production of salt; an addition step where the residual liquid is added to the saturated salt water; a crystallization step where the residual liquid and the saturated salt water are mixed and stirred to crystallize out the salt in the saturated salt water; and a filtration step where the crystallized-out salt is filtered with a filter so as to be recovered.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing salt, and more particularly, to a method for producing salt that can be easily produced and has high quality and good taste.

  In recent years, production methods for efficiently obtaining high-quality salt from seawater have been actively developed. For example, there is a method for producing sodium chloride for the purpose of reducing impurities of calcium and sulfate (see, for example, Patent Document 1).

  For example, in Patent Document 1, salt water (seawater) is evaporated in the sun to crystallize carbonate and gypsum to obtain concentrated salt water, (ii) adding alum to the concentrated salt water, and (iii) preliminary A step of purifying the salt water by allowing the suspended particles to settle under gravity in a crystallizer; and (iv) a step of supplying the purified salt water to the crystallizer and continuing to evaporate the sun to crystallize the salt. And (v) repeating steps (ii) to (iv) to deposit a salt layer on the crystallizer; and (vi) draining bittern from the crystallizer and then adding fresh salt water to the crystallizer. And a step of collecting the salt by supplying to a vessel.

  However, the conventional method for producing salt requires an additive such as alum, and the cost associated with the additive itself and the cost for removing the additive are added. There is also a risk of losing taste.

  Therefore, a method for producing high quality and good taste salt from seawater is expected by a simple method without using an extra additive, but no method for producing such salt is found at present. .

JP 2007-099605 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method for producing salt, which can be easily manufactured, has high quality and good taste.

  As a result of diligent research, the present inventor has found that the residual liquid discharged after the salt solution obtained by evaporating the saturated saline (commonly called “irrigation”), which is concentrated seawater, is obtained. When the concentration was higher than the concentration, it was found that by mixing this residual solution with the saturated saline solution, extremely good quality particulate salt can be obtained in a short time (rapidly) and at room temperature.

  That is, the salt production method disclosed in the present application is a residual liquid that is discharged as salt is produced by evaporating saturated saline concentrated in seawater, and produces a residual liquid with concentrated bittern. A residual liquid production process, an addition process of adding the residual liquid to the saturated saline, a crystallization process of mixing and stirring the residual liquid and the saturated saline to crystallize the salt in the saturated saline; And a filtration step of collecting the crystallized salt by filtration through a filter. Thus, the said residual liquid manufacturing process manufactures the said residual liquid concentrated rather than bittern, the said addition process adds the said residual liquid to the said saturated salt solution, and the said crystallization process is the said residual liquid. And the saturated saline are mixed and stirred, and the sodium chloride in the saturated saline is crystallized, and the filtration step collects the crystallized salt through a filter and collects it, which is more concentrated than the bittern. In addition, a simple method of adding the residual liquid to the saturated saline solution does not require an additive, so that a well-shaped salt solution can be obtained, and a high-quality salt solution can be easily produced.

  The salt production method disclosed in the present application is such that the residual liquid added in the addition step is 40 to 70% by volume of the mixed solution with the saturated saline as necessary. Thus, since the said residual liquid added at the said addition process is 40-70 volume% of the mixed solution with the said saturated salt solution, salt will be easily crystallized from the said residual solution and the said saturated saline solution. It becomes an optimal volume mixing ratio and can produce salt efficiently.

  In the salt production method disclosed in the present application, the residual liquid added in the addition step is set to a temperature higher than that of the saturated saline as necessary. Thus, since the residual liquid added in the addition step is at a higher temperature than the saturated saline, an optimal water temperature can be obtained by adding the relatively hot residual liquid to the saturated saline. With the change, a state in which the salt is easily manufactured is formed, and the salt can be manufactured efficiently.

  The salt production method disclosed in the present application is a recycling method that recirculates the discharged liquid discharged as the salt is collected in the filtration step to the residual liquid production step, and re-produces the residual liquid, if necessary. Including the step of adding the remanufactured residual liquid to the saturated saline solution. As described above, since the waste liquid discharged as the salt is recovered in the filtration step is refluxed to the residual liquid manufacturing step, and the recycling step for remanufacturing the residual liquid is included, the sodium chloride is recovered. The effluent is again used as a raw material for producing salt, so that effective use of resources and cost reduction of salt production can be realized.

  Further, the salt disclosed in the present application is obtained by evaporating a saturated saline solution obtained by concentrating seawater, and using a residual solution obtained by concentrating the bittern produced when the salt is produced as a coagulant for the saturated saline solution. It is obtained by doing. As described above, the salt disclosed in the present application is obtained by evaporating a saturated saline solution obtained by concentrating seawater, and using the residual solution obtained by concentrating the bittern produced when the salt is produced as a coagulant for the saturated saline solution. Since it is obtained by being used, it will be obtained by a simple method of adding the residual liquid concentrated over bittern to the saturated saline solution, and does not require an additive, and has a fine particle size. A good quality salt with

The flowchart of the salt manufacturing method which concerns on 1st Embodiment of this application is shown. The X-ray structural analysis result of the residual liquid (concentrated salt water) which concerns on 1st Embodiment of this application is shown. The flowchart of the salt manufacturing method which concerns on 2nd Embodiment of this application is shown. The flowchart shown with the kind of solution of the salt manufacturing method which concerns on 2nd Embodiment of this application is shown. The nucleation and growth photograph (a) of the sodium chloride crystal crystallized in Example 1 according to the present application, and the result (b) of the XRD diffraction pattern for the obtained salt are shown. The result (a) which analyzed the element component contained in the salt crystallized in Example 1 which concerns on this application (a), and the result (b) which analyzed the Mg component and S component which are contained in salt are shown. The result (a) of the electron micrograph of the salt crystallized in Example 1 according to the present application and the result (b) of analyzing the Mg component and the S component contained in the salt are shown. Relationship (a) between the crystallization weight of the salt crystallized in Example 2 according to the present application and the specific gravity of irrigation (d = 1.20-1.26), and the crystal of the salt crystallized in Example 3 according to the present application The relationship (b) of the analysis weight, the volume ratio of concentrated salt water, and the seawater specific gravity of a residual liquid is shown. Relationship (a) between the crystallization weight of the salt crystallized in Example 4 according to the present application and concentrated brine (d = 1.3-1.38), and irrigation of the salt crystallized in Example 5 according to the present application The result (b) which changed the liquid temperature of the liquid mixture of a salt water and concentrated salt water is shown.

(First embodiment)
A salt production method according to the first embodiment of the present application will be described with reference to the flowchart of FIG.

(Residual liquid production process)
First, a saturated solution that is discharged as salt is produced by evaporating a saturated saline solution obtained by concentrating seawater is produced (S1: Residual solution manufacturing step).

  The seawater used as the raw material is not particularly limited as long as it is general seawater. For example, a solution having a specific gravity d of 1.03 can be used. As the saturated saline solution obtained by concentrating the seawater, a solution having a specific gravity d larger than 1.03 and 1.22 or less (a solution called “irrigation” is also included as a target) is used.

  Further, the residual liquid (also referred to as “filtered salt water (chloride solution)” or “concentrated salt water”) discharged as the salt is produced by evaporating the saturated saline is the residual liquid in which bittern is concentrated. Therefore, the specific gravity of the general bittern has a specific gravity greater than 1.26. That is, the residual liquid has a specific gravity d larger than the bittern, for example, the specific gravity d = 1.26 to 1.38, and the specific gravity d = 1.32 from the viewpoint of more efficiently producing salt. More preferably, a solution of ˜1.38 is used. Each specific gravity described above is a dimensionless number that can be measured using a commercially available hydrometer (for example, standard hydrometer No. 4 (manufactured by ASONE Co., Ltd.)).

  As an example of preparing the residual liquid (concentrated salt water), the residual liquid (concentrated salt water) with seawater specific gravity d = 1.30 is used as the starting material, and the residual liquid (concentrated salt water) is prepared (seawater specific gravity d = 1.32 ~) FIG. 2 shows the result of analyzing the obtained solution with a horizontal X-ray structure analyzer (XRD7000, manufactured by Shimadzu Corporation).

  The remaining liquid is a solution containing Na, Cl, and Mg as main components. About this residual liquid, the residual liquid (seawater specific gravity d = 1.36) discharged | emitted after multistage (4th) crystallization is used for the energy dispersion type | mold fluorescence X-ray-analysis apparatus (Rayny EDX-800HS, Shimadzu Corporation make), The results of component analysis are shown below.

(Addition process)
Next, this residual liquid is added to the saturated saline solution (S2: addition step). From the viewpoint of obtaining salt more efficiently, the residual liquid is preferably 40 to 70% by volume of the mixed solution with the saturated saline. Moreover, it is preferable to make this residual liquid into temperature higher than the said saturated salt solution from a viewpoint of obtaining salt more efficiently.

(Crystallization process)
Next, the residual solution and the saturated saline are mixed and stirred to crystallize the salt in the saturated saline (S3: crystallization step). By this stirring, the residual liquid is dispersed in the saturated saline solution, whereby salt having a refined particle size can be easily obtained.

  For this stirring, a device that generates vibration by magnetic force, ultrasonic waves, or the like can be used. For example, a magnet stirrer, an ultrasonic vibrator, or the like can be used.

  Various conditions relating to this stirring are not particularly limited, but from the viewpoint of obtaining salt with a finer particle size, the stirring speed is preferably 5 to 300 revolutions per minute (rpm), and From the viewpoint of obtaining a salt having a fine particle diameter, it is more preferable that the speed is higher, that is, 100 to 300 revolutions / minute, and particularly preferably 250 to 300 revolutions / minute. The stirring time is preferably a relatively short stirring from the viewpoint of obtaining salt with a fine particle size, that is, preferably 1 to 60 seconds, for example, 30 seconds. .

(Filtering process)
Next, the crystallized salt is collected by filtration through a filter (S4: filtration step). Thus, according to this embodiment, fine salt can be obtained quickly and easily by room temperature crystallization using seawater as a raw material.

  The obtained salt has been confirmed to have a fine particle size (see Examples described later). This fine particle size salt has a feature that the bulk density is small (air is included and a soft and soft texture is obtained). The salt with a small bulk density obtained in this way will have its actual intake reduced due to the bulk of the salt, while maintaining the salty taste when eaten. An excellent salt reducing effect that the amount of salt intake can be suppressed can be achieved.

  Furthermore, the taste of the salt produced by this production method has been confirmed to be reduced in the magnesium sulfate component that causes a strong bitter taste and high in the magnesium chloride component, and has a sweet taste derived from the magnesium chloride component. It is done.

  Although the mechanism by which the method for producing salt according to the present application exhibits an excellent effect has not been elucidated in detail, the residual liquid concentrated to a higher specific gravity than the bittern is added to the saturated aqueous solution. As a result, chloride ions in the saturated aqueous solution temporarily become excessive, and from the ionization equilibrium of NaCl ⇔ Na + + Cl-, the action of maintaining the equilibrium state of hydrogen ions and chloride ions in the aqueous sodium chloride solution, It is presumed that a situation that promotes crystallization of sodium chloride has been brought about.

  That is, by adding another electrolyte (in this case, chloride ion) that generates ions (common ions) that are common to ions constituting the electrolyte to a saturated solution of sodium chloride, the solubility of the original electrolyte is reduced, It is inferred that the phenomenon of precipitation of sodium chloride occurs. Thereby, it is guessed that the salt with high crystallinity and quality is excellent as salt.

  As described above, since crystallization is possible at room temperature, nucleation and growth of sodium chloride crystals proceed rapidly by crystallization, and a temporal advantage is obtained that sodium chloride is generated in a short time.

(Second Embodiment)
A salt production method according to the second embodiment of the present application will be described with reference to the flowchart of FIG.

  As shown in the flowchart of FIG. 2, the second embodiment includes the residual liquid manufacturing process, the adding process, the crystallization process, and the filtering process, as in the first embodiment described above. Furthermore, the waste liquid discharged as the salt is recovered in the filtration step is recirculated to the residual liquid production step, and includes a recycling step for remanufacturing the residual liquid, and the addition step includes The remanufactured residual liquid is added to the saturated saline solution.

(Recycling process)
That is, as a subsequent step of the above-described filtration step (S4), the discharged liquid discharged as the salt is recovered in the above-described filtration step (S4) is refluxed to the residual liquid production step (S1), The remaining liquid is remanufactured (S5: recycling process). The residual liquid refluxed in the residual liquid production step (S1) is added to the saturated saline in the addition step (S2), and thereafter, as in the first embodiment, the crystallization step (S3). ) And the filtration step (S4).

  As described above, the method includes a recycling step in which the discharged liquid discharged as the salt is collected in the filtration step (S4) is returned to the residual liquid manufacturing step (S1) to remanufacture the residual liquid. Therefore, the effluent after recovering the salt is also reused as a raw material for manufacturing the salt again, so that effective use of resources and cost reduction of the salt manufacturing can be realized. A flowchart showing the types of solutions is shown in FIG. As shown in FIG. 4, it is preferable that the remaining liquid be returned to be collected and reused.

  In order to further clarify the features of the present invention, examples are shown below, but the present invention is not limited to these examples.

Example 1
Concentrated salt water 50 ml (seawater specific gravity d = 1.36) was added to 200 ml of the above irrigation water (seawater specific gravity d = 1.22), and stirred with a magnetic stirrer at 20 ° C. (stirring speed 200 rpm) to crystallize sodium chloride. A nucleation and growth photograph of the crystallized sodium chloride crystal is shown in FIG.

  FIG. 5B shows the result of the XRD diffraction pattern obtained by analyzing the obtained salt with a horizontal X-ray structure analyzer (XRD7000, manufactured by Shimadzu Corporation). Note that the data shown in the upper part of FIG. 5B is the result when evaporation crystallization is further performed after this crystallization (60 ° C., specific gravity d = 1.26). From this XRD diffraction pattern, it was confirmed that sodium chloride as a main component was produced.

  Moreover, about the obtained salt, the result of having analyzed the element component contained in salt with the energy dispersive X-ray fluorescence analyzer (Rayny EDX-800HS, Shimadzu Corporation Corp.) is shown in FIG. 6 (a). Further, the results of evaporation crystallization at 60 ° C. after crystallization are also shown. According to this analysis result, in the obtained salt, since the Mg component and the S component are present at almost the same ratio and at a high blending rate, the presence rate of magnesium sulfate that brings sweetness and umami is high, and the taste is excellent. It was confirmed that salt was obtained

  Furthermore, about the obtained salt, the result of having analyzed Mg component and S component contained in salt with an energy dispersive X-ray fluorescence analyzer (Rayny EDX-800HS, manufactured by Shimadzu Corporation) is shown in FIG. 6 (b). . As a comparative example, the salt obtained as sun salt by direct sunlight from irrigation is also shown. Further, the results of evaporation crystallization at 60 ° C. after crystallization are also shown. As shown in FIG. 6 (b), it was confirmed that the contents of the Mg component and the S component were significantly increased compared to the sun salt. It was confirmed that salt with a high abundance and excellent taste was obtained.

  About the obtained salt, the result of an electron micrograph is shown to Fig.7 (a). As a comparative example, FIG. 7B shows the result of an electron micrograph of sodium chloride obtained by simply subjecting the residual liquid to heat crystallization. From the results of FIG. 7, it was confirmed that the salt obtained in this example was a fine particle having a salt particle size of the order of 50 to 200 μm. Furthermore, compared with the salt of the comparative example, it was confirmed that the salt has a clearly arranged cubic shape.

(Example 2)
Using the same procedure as in Example 1, 200 ml of irrigation and 50 ml of concentrated brine (specific gravity d = 1.36) were used to produce salt, and the specific gravity of irrigation was changed in the range of d = 1.20 to 1.26. By doing so, the relationship between irrigation and crystallization weight was obtained. The obtained result is shown in FIG. From the obtained results, when the specific gravity d of irrigation is d = 1.2-1.26, a larger amount of crystallization is obtained, and in particular, the specific gravity d of irrigation is d = 1.22 to 1.25. In some cases, it was confirmed that a larger amount of crystallization was obtained.

(Example 3)
In the same procedure as in Example 1 above, salt was produced by changing the volume ratio (volume%) of concentrated brine in 250 ml of a mixed solution of irrigation and concentrated brine (specific gravity d = 1.36), and the volume ratio of concentrated brine The relationship between the weight of crystallization and the specific gravity of seawater in the residual liquid was obtained. The obtained result is shown in FIG. From the obtained results, it was confirmed that particularly a large amount of salt was crystallized when the residual liquid added in the adding step was 40 to 70% by volume of the mixed solution with the saturated saline. It was.

Example 4
In the same procedure as in Example 1, the volume ratio of concentrated brine to irrigation (specific gravity d = 1.22) was set to 20% by volume, and the specific gravity d of concentrated brine was varied in the range of d = 1.3 to 1.38. The sodium chloride was produced at 20 ° C., and the relationship between the specific gravity d of the concentrated brine and the salt crystallization weight was obtained. The obtained result is shown in FIG. From the obtained result, it was confirmed that more salt was crystallized in the specific gravity d of the concentrated salt water in the range of d = 1.34 to 1.38.

(Example 5)
In the same procedure as in Example 1, the volume ratio of the concentrated brine (specific gravity d = 1.36) to the irrigation (specific gravity d = 1.22) is 20% by volume, and the liquid temperature of the mixed solution of irrigation and concentrated brine is Salt was produced by varying the temperature, and the relationship between the temperature of the mixed solution of irrigation and concentrated brine and the weight of salt crystallization was obtained. The obtained result is shown in FIG. From the obtained results, it was confirmed that a large amount of salt was crystallized particularly when the concentrated brine (the residual solution) added in the addition step was at a higher temperature than irrigation (saturated saline). It was. It was also confirmed that the crystallization weight increased as the temperature of the mixed solution of irrigation and concentrated brine decreased.

Claims (5)

A residual liquid production step for producing a residual liquid that is discharged as the salt is produced by evaporating a saturated saline solution obtained by concentrating seawater;
An addition step of adding the residual liquid to the saturated saline solution;
The residual solution and the saturated saline are mixed and stirred, and a crystallization step of crystallizing salt in the saturated saline,
A filtration step of collecting the crystallized salt by filtration through a filter;
A method for producing salt, comprising: The salt production method according to claim 1,
The said residual liquid added at the said addition process is 40-70 volume% of the mixed solution with the said saturated salt solution, The salt manufacturing method characterized by the above-mentioned. In the salt manufacturing method according to claim 1 or 2,
The salt production method, wherein the residual liquid added in the addition step is set to a temperature higher than that of the saturated saline solution. In the salt manufacturing method in any one of Claims 1-3,
A recycling step of recirculating the effluent discharged as the salt is recovered in the filtration step to the residual liquid production step, and remanufacturing the residual liquid;
The said addition process adds the said remanufactured said residual liquid to the said saturated salt solution, The salt manufacturing method characterized by the above-mentioned. Salt obtained by evaporating a saturated saline solution obtained by concentrating seawater, and using a residual liquid obtained by concentrating the bittern produced when the salt is produced as a coagulant for the saturated salt solution.