JPH0259421A - Production of moistureproof salt - Google Patents

Abstract

PURPOSE:To suppress water absorption and to improve flowability by wet-adding a carbonate or hydrogencarbonate to a salt contg. a deliquescent component, e.g., MgCl2 or CaCl2 by a prescribed amt. basing on the amt. of the deliquescent component and by drying them. CONSTITUTION:A carbonate such as Na2CO3 or a hydrogencarbonate such as NaHCO3 is wet-added to a salt contg. 0.0001-0.01eg deliquescent component per 100g salt, e.g., MgCl2 or CaCl2 by an amt. satisfying 0.8-5.0 chemical equiv. ratio to the deliquescent component and they are mixed to obtain a mixture. This mixture is brought into a chemical reaction by drying at >=50 deg.C to form a nondeliquescent component and to produce a moistureproof salt contg. the nondeliquescent component.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a moisture-proof salt by wet addition of carbonate or hydrogen carbonate and drying.

[Conventional technology] Salt is widely used for food and industrial purposes.

However, magnesium chloride and calcium chloride contained in salt have the property of absorbing water when the relative humidity reaches 35% and 20%, respectively. Considering Japan's climate conditions, deliquescent components are in a state of absorbing water, and are the main cause of deterioration in the fluidity of salt containing them.

Therefore, research has been carried out to improve the hygroscopicity of such salts, and the following three methods have been put into practical use as methods for producing moisture-proofing salts.

■) Method of applying heat treatment 2) Method of coating crystals 3) Method of adding sodium carbonate or sodium bicarbonate in a dry method [Problem to be solved by the invention] However, method l) is known as baking salt. However, if the heat treatment temperature is limited to a range in which sodium chloride does not melt, it is difficult to convert the deliquescent component into a non-deliquescent component. The performance of method 2) is satisfactory because it completely covers the crystal surface, but when the salt prepared by this method is eaten, the taste and
In terms of texture, it has a very different texture compared to conventional table salt. In addition, in the dry method (addition of powder) of method 3), the additives hardly come into contact with the deliquescent components, so a considerable amount of the deliquescent components remained in the product, and both methods were unsatisfactory.

In view of these circumstances, it is an object of the present invention to provide a method for producing a moisture-proofing salt that eliminates the drawbacks of the conventional methods described above.

[Means for Solving the Problems] The present invention provides a salt containing a deliquescent component such as magnesium chloride or calcium chloride, and a carbonate or hydrogen carbonate, preferably sodium carbonate or sodium hydrogen carbonate, in an equivalent ratio of 0 per deliquescent component. .8 to 5.0 times preferably! ,0~3,0
The gist of this invention is a method for producing a moisture-proofing salt, which is characterized by double-humidity addition and humidification addition.

Generally, the salt contains a deliquescent component of 0.0001 to 0.01 eq/100 g salt. The method of the present invention can be applied to a buried metal containing the above-mentioned deliquescent component.

If the addition is carried out in a wet manner, the additive can be brought into full contact with the deliquescent components finely dispersed in the salt. In the wet addition of the present invention, the concentration of the carbonate or hydrogen carbonate aqueous solution to be added is not particularly limited, but in consideration of the energy cost in the subsequent drying step, a saturated aqueous solution or a slightly lower concentration is preferred. If the salt after this addition is dried at a temperature of 50°C or higher, preferably 70°C or higher, the additives (sodium carbonate, sodium hydrogen carbonate, etc.) and deliquescent components (magnesium chloride, calcium chloride, etc.) will cause a chemical reaction. Non-deliquescent components such as , magnesium carbonate, magnesium oxide, and calcium carbonate are produced. As long as the above-mentioned temperature conditions are satisfied, all drying methods such as a fluidized method, a mixed drying method, a batch method, and a continuous method can be used.

Magnesium carbonate, which is the main component of the product, is known as a fluidizing agent and can further improve the handling of common salt.

A fluidizing agent is a substance that adheres to salt crystals and physically improves fluidity by reducing the rejuvenating force between the crystals through actions such as removing charge.

Furthermore, the salt obtained by the method of the present invention can further enhance the effect of adding the fluidizing agent.

[Example] EXAMPLES The present invention will be explained in more detail by way of Examples below.

Example 1 The raw material salt shown in Table 1 below was mixed with sodium carbonate or sodium bicarbonate in an equivalent ratio of 1.2 times to the deliquescent component in a wet process (
(saturated aqueous solution) or dry, and dried under IHr at 100°C.

Table 2 Table 1 The salt treated as described above was left in an atmosphere with a humidity of 72±5% and a temperature of 25°C, and its water absorption rate was measured. The results are shown in Tables 2 and 3.

Table 3 The water absorption rates of the samples heat-treated at 400°C and 11 r were measured in the same manner as in Example 1 and compared. The results are shown in Table-5.

Table 4 Tables 2 and 3 show that wet addition of sodium carbonate and sodium hydrogen carbonate is superior.

Example 2 Sodium hydrogen carbonate was added to the raw material salt shown in Table 4 at an equivalent ratio of 2.0 to the deliquescent component in a humidified manner (saturated aqueous solution),
It was dried at 70° C. in 1 liter and added in Table 5 11.0 humidification method (saturated aqueous solution) and dried in IHr.

at 100℃ Table-6 It can be seen that the method of the present invention is superior to the heat treatment method.

Example 3 The equivalent ratio of sodium hydrogen carbonate to the deliquescent component of the raw material salt shown in Table 6 below was 0.4.0.5.0.6.0.8.
1.0.3.0.5.0.7.0.9.0, the salt treated as above was left in an atmosphere with a humidity of 72±5% and a temperature of 25°C, and its water absorption rate was determined. It was measured.

The results are shown in Table-7.

Table 7 Table 8 From Tables 7 and 8, it can be seen that wet addition within the range of 0.8 to 5.0 times is particularly effective.

Example 4 Sodium hydrogen carbonate was added to the salt shown in Table 9 below at an equivalent ratio of 3.0 to the deliquescent component in a humidified manner (saturated aqueous solution).
A fluidizing agent was added to the salt dried at 120° C. for 0.511r and the untreated salt, and the fluidity was compared.

0.3% by weight of magnesium carbonate or tribasic calcium phosphate was added as a fluidizing agent.

Table-9 6 salts with added fluidizing agent were added at a humidity of 72 ± 5% and a temperature of 25%.
Their fluidity was evaluated after being left in an atmosphere at ℃. Carr's comprehensive evaluation was used for fluidity evaluation. The results are shown in Table 10.

Table 10 It can be seen that the following can be done. Particularly for salts with a large amount of deliquescent components, it is highly effective to use the method of the present invention together with the addition of a fluidizing agent.

[Effects of the Invention] As is clear from the above explanation, the method of the present invention suppresses water absorption of salt by adding a small amount of carbonate or hydrogen carbonate in a wet manner, improves fluidity, and improves the effect of adding a superplasticizer. can be further increased.

Table-11 Patent applicant Shin Nippon Chemical Industry Co., Ltd. Agent Patent Attorney Hidetake Komatsu Agent Patent Attorney Hiroshi Asahi

Claims (1)

[Claims] Moisture-proofing property characterized by wet addition of carbonate or hydrogen carbonate at a chemical equivalent ratio of 0.8 to 5.0 times per deliquescent component to a salt containing a deliquescent component such as magnesium chloride or calcium chloride, and drying. Method of manufacturing salt.