KR101547350B1 - Eco-friendly solid deicer and manufacturing method thereof for ice melting unusing chloride compound - Google Patents

Abstract

  The present invention relates to a solid-state snow removing agent which is prepared by reacting a mixture of calcium hydroxide and magnesium hydroxide with acetic acid, adding potassium hydroxide, sodium hydroxide, and colloidal silica to the mixture, and then solidifying the mixture, Which is not corrosive to steel and exhibits a melting performance similar to that of calcium chloride, which is a conventional chloride remover, is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an eco-friendly solid deicing and freezing agent,

The present invention relates to a solid-state snow removing agent which is prepared by reacting a mixture of calcium hydroxide and magnesium hydroxide with acetic acid, adding potassium hydroxide, sodium hydroxide, and colloidal silica to the mixture, and then solidifying the mixture, The present invention relates to a high-performance eco-friendly solid-phase snow remover which exhibits a melting performance similar to that of calcium chloride which is a conventional chloride remover without corrosiveness to steel.

  If snow falls or freezing occurs in winter, it will cause traffic disturbance, which causes great inconvenience to road users and vehicles, and causes confusion and economic loss such as delay in logistics. Effective snow removal not only protects public safety but also prevents this economic loss. Every year, tens of millions of tons of salt or calcium chloride are used worldwide as snow removers. Salt is most commonly used because it is inexpensive and has excellent snow removal effect. Calcium chloride exothermic at low temperature and is very effective in snow removal but it is more expensive than salt because it is used.

  In Korea, calcium chloride, which has excellent snow removal effect, has been used the most. Until now, calcium chloride and sand have been mixed and sprayed according to snow depth. However, these methods of snow removal have a lot of manpower and cost for collecting sand in the spring, because sand, which acts as a sliding resistance between the pavement surface and automobile, melts snow or ice, In order to solve this problem, pre-wetted salt spreading snow removal method was adopted as a snow remover in which calcium chloride and salt were dissolved in water and was sprayed on the highway.

 The action of the snow remover includes an exothermic heat of dissolution that dissolves upon contact with water and causes an exothermic reaction. In this case, the icing action is immediate and corresponds to the hydrate absorbents such as calcium chloride. On the other hand, salt causes an endothermic reaction when dissolved in water and freezing point depression in the long term.

  However, the conventional calcium chloride spraying method has problems such as spending of huge repair expenses due to metal corrosion on concrete, steel structures and facilities such as automobiles, roads and bridges, pollution of soil and ecosystem such as soil and river pollution, And post-cleaning cost after spraying sand and other snow remnants, and traffic accidents and environmental and economic losses can not be estimated.

  Various non-saline-based snow removing agents have been developed to solve the above-mentioned problems of chloride-based snow removing agents. Representatively, urea, calcium magnesium acetate (CMA) is known. Korean Patent Registration No. 0588820 discloses a non-saline-based low-corrosive liquid snow remover composition comprising potassium acetate, disodium succinate, dipotassium succinate, ethylene glycol, ethanol, and PVC aqueous solution. However, ethanol, PVA, ethylene glycol And the like. Therefore, the burden on the environment is very large, and there is a problem in commercialization at a high price.

  Korean Patent Registration No. 0179334 discloses a method of producing acetic acid and sodium silicate by mixing acicular shell powder and / or dolomite powder in the preparation of non-salted snow-removing agent. However, this method has not been commercialized due to limitations of performance of snow removers and profitability due to complicated processes.

  U.S. Patent Nos. 4444672 and 5122350 disclose that calcium acetate and magnesium acetate are mixed at a ratio of 1 to 0.5, and that they are manufactured from dolomitic lime and quicklime, which exhibit far superior performance than when used alone and have a high magnesium content have. This has been successfully tested in the US and Canada, but mass production due to high production costs has not yet been achieved. In the present case, salt, calcium chloride and CMA, which are the existing snow removers, are mixed in a ratio of 8: 2 to 7: 3 .

  U.S. Patent No. 5,046,551 discloses a liquid composition for alkali metal acetic acid, formic acid, phosphoric acid, nitrate, which is low corrosive and environmentally friendly. However, even in this case, the price of raw material itself is high, so that it is limited to use for some special purposes.

  U.S. Patent No. 6821453 and Korean Patent No. 0636294 disclose compositions for alleviating the corrosiveness in chloride-based snow removers. The addition of additives to mitigate corrosion can slow down the extent of corrosion, but it is not the ultimate solution to corrosion problems and the environment.

Until now, the prior art related to environmentally friendly snow remover has not been able to complete a complete non-salted carvolume removing agent because it is non-toxic and has high biodegradability but does not have a large ice-making power and is mixed with sodium chloride or calcium chloride.

  Chlorine-based snow removers such as calcium chloride and salt are inexpensive and have excellent performance, but they are highly corrosive and cause damage to road structures and automobiles, and are a major cause of accelerating early deterioration of concrete. These salts are also causing many environmental pollution problems, such as damaging underwater ecosystems and plants around the roads.

  Corrosion after iron material surface removal by chlorine compounds such as salt or calcium chloride is removed by chlorine ion and iron oxide and hydrogen film formed by electrochemical effect, corrosion reaction continues on the surface of steel. If the steel is corroded, the concrete will be stressed and the structure will be damaged. Especially, the bridge is the most costly road structure and it is not easy to replace it. Since the problem is severe, it is urgent to use a snow removal agent which does not cause corrosion.

   For bridges, consideration should be given to the corrosion of the piers by the snow removers and the environmental impacts on the rivers. Phosphates commonly used as corrosion inhibitors in conjunction with chlorine compounding agents, nitrates and nitrogen-containing organic compounds known as non-corrosive snow removers, such as urea or carbamate snowmobiles, are fed to phytoplankton in the river, Resulting in a decrease in the amount of dissolved oxygen in the river. The biggest problem of snow removers currently in use or developed is corrosion, and in the case of snow removers, which are known to have less corrosive action, it is expensive and the efficiency of ice making is poor.

Recently, attention has been paid to calcium magnesium acetate (CMA) as an alternative remedial agent, which is most likely to be developed as a substitute for calcium chloride or salt. [Federal Highway Administration (FHWA), Process Development for Calcium Magnesium Acetate CMA), FHWA / RD-82/145 (1983)). CMA is non-toxic, biodegradable by carbon dioxide, and exothermic when dissolved in water, such as calcium chloride. CMA is obtained from dolomite lime and dolomite, which are rich in magnesium, and is used in the United States and Canada. However, the performance of CMA is significantly lower than that of chlorinated compound snowmobiles. Therefore, in the present invention, it is intended to provide an environmentally friendly snow remover manufacturing technology that does not corrode a steel material and has excellent snow-removing ability by overcoming technology.

The present invention solves the above problems by providing a method for producing a solid-phase snow remover which comprises reacting a mixture of calcium hydroxide and magnesium hydroxide with acetic acid, adding potassium hydroxide, sodium hydroxide, and colloidal silica to the mixture, and solidifying the mixture.

In addition, the melting ability of the snow removing agent prepared by the method provided in the present invention is evaluated, and the melting performance of calcium chloride and salt is also compared. The present invention solves the above problem by examining the corrosion resistance of the steel material to the snow remover and the chlorine compound snow remover manufactured by the technique provided by the present invention.

   Chlorine compound snow removers such as calcium chloride and sodium chloride, which are already used, remain on the road after spraying and easily corrode steel products such as automobiles and road facilities, deteriorate concrete and damage the bridges. In addition, the ecosystem around roads and bridges is adversely affected, thereby damaging plant and aquatic environments.

  CMA snowmobiling agent has been developed as an alternative snow remover that solves these problems. However, there is a problem that when compared with chlorine compound snowmobiling agent based on the same amount, the snow removal performance is only about 1/5.

However, the snow remover provided in the present invention is a high-efficiency eco-friendly snow remover that completely complements the disadvantages of existing snow removers because it has the property that the snow remover does not corrode the steel materials even though it is comparable to calcium chloride. The snow removing agent provided in the present invention has an effect of preventing economic loss due to damages to road facilities and automobiles by replacing existing snow removing agents and also has an effect of preventing environmental damages around the roads or bridges sprayed with snow removers There is an effect to prevent.

Fig. 1 shows the results of the evaluation of the melting ability of a solid snow remover prepared by reacting a mixture of calcium hydroxide and magnesium hydroxide with acetic acid, followed by addition of 0.3 part by weight of potassium hydroxide and 1.0 part by mole of colloidal silica, and (a) (b) is the result of an experiment at -12 ° C.
FIG. 2 is a photograph of a corrosion test of a steel material, which is comparatively evaluated with calcium chloride and sodium chloride as an evaluation of corrosiveness of a solid-phase snow removing agent.
Fig. 3 is a graph showing the corrosion rate calculated by the formula (1) for the corrosion test results of the respective snow removers.

  Hereinafter, the present invention will be described in detail.

According to the present invention, there is provided a method for producing a solid-phase snow remover comprising reacting a mixture of calcium hydroxide and magnesium hydroxide with acetic acid, adding potassium hydroxide, sodium hydroxide, and colloidal silica to the mixture, and then solidifying the mixture. The snow melting ability of snow remover was also evaluated and compared with the melting performance of calcium chloride and salt. The steel corrosion resistance of the snow removers and chlorine compound snow removers produced by the technique provided by the present invention was also investigated. The detailed configuration and operation of the present invention are presented through examples. The present invention is not limited by the examples.

[ Example  One]

  The reaction was carried out by adding 2.2 mol of acetic acid to the flask maintained at 25 ° C, stirring vigorously, and slowly pouring a sample mixed with calcium hydroxide and magnesium hydroxide. The reaction mixture was stirred for 3 hours, and then 0.2 to 0.8 mol of calcium hydroxide and 0.2 to 0.8 mol of magnesium hydroxide were mixed. At this time, the mixture of calcium hydroxide and magnesium hydroxide was such that the mixing amount of the two substances was 1.0 mol. That is, the mixed molar number of calcium hydroxide and magnesium hydroxide is 0.2 mol and 0.5 mol of magnesium hydroxide, 0.3 mol of calcium hydroxide and 0.7 mol of magnesium hydroxide, 0.5 mol of calcium hydroxide and 0.5 mol of magnesium hydroxide, 0.7 mol of calcium hydroxide and 0.3 mol of magnesium hydroxide, And 0.2 mol of magnesium hydroxide were mixed to prepare samples in which the molar ratios of calcium hydroxide and magnesium hydroxide were 2: 8, 3: 7, 5: 5, 7: 3, and 2: 8, respectively. After drying the mixture, the sample was placed in a drier maintained at 120 ° C and evaporated to dryness to obtain a powder sample.

1 mol% KOH solution or 1 mol% NaOH solution and colloidal silica (Ludox, 40%) were added and stirred, and the reaction was maintained for 3 hours. The amount of the potassium hydroxide solution or the sodium hydroxide solution was added to the reaction mother liquor in a molar ratio of potassium hydroxide to 0.3 to 1.0 based on 1 mole of potassium hydroxide and magnesium hydroxide. The colloidal silica was added for the purpose of improving the crystallization speed and improving the moldability, and colloidal silica was added so that the amount of silica was adjusted to 0.1 mole. The snow removers manufactured by this method were expressed as K (#) / CM (# 1, # 2) or Na (#) / CM (# 1, # 2). In parentheses, # indicates the number of moles of potassium hydroxide or sodium hydroxide added. # 1 and # 2 represent molar ratio ratios of calcium hydroxide and magnesium hydroxide, respectively. The dried powder samples were prepared from pellets having an average particle size of 2 mm using a pellet mill.

  The melting experiment is a method for comparing and investigating the ability to melt snow when spraying snow removers on the road. This method is described in the Handbook of Test Methods for Evaluating Chemical Deicers for Evaluating Chemical Deicers., SHRP H-205.1-2, Test Method for Ice Melting of Solid / Liquid Deicing Chemicals, Strategic Highway Research Program, National Research Council, Washington, DC 1992. According to this document, the test plate was made by using two Plexiglas of 28028010 mm in size, and one plate was punched with a hole having a diameter of 228.5 mm and then bonded to the other plate. 130 g of distilled water was frozen in a test dish, and 4.17 g of snowing agent sample was uniformly sprayed on an ice plate. The amount of ice melted at regular intervals was sucked by a syringe to measure the amount of accumulated ice.

  FIG. 1 shows the results of melting experiments at -5.degree. C. and -12.degree. C. for K / CM snow remover with addition of an enhancer. As the amount of potassium hydroxide added as an enhancer increased, the amount of ice was increased. When the addition amount of potassium hydroxide was 0.7 mol, the amount of melting ice reached nearly 90% of the calcium chloride. When the amount of potassium hydroxide added was 1.0 mol, the amount of calcium chloride was larger than that of calcium chloride. It was observed that the amount of ice continued to increase until 60 minutes, after which it was gradually frozen without re-icing. The increase in the amount of melting ice due to the addition of potassium hydroxide seems to result from the increase in the amount of ice melted by the addition of the effect of ice-melting due to the strong exothermic reaction of ice and potassium hydroxide. The higher the amount of potassium hydroxide added, the greater the amount of ice melted and the higher the exothermic reaction.

Table 1 summarizes the amount of melted ice measured at -5 ° C of the snow removers manufactured by varying the amount of KOH added to CM having different calcium and magnesium contents. K / CM (8: 2) or K / CM (2: 8) showed the largest amount of melting water when the amount of potassium hydroxide added was 1 mole, as in K / CM (5: 5)

Table 2 summarizes the ice amount measured at -5 ° C of the snow removers manufactured by varying the amount of sodium hydroxide added to the CM having different contents of calcium and magnesium. Overall, the amount of ice melt was slightly less than when the same amount of potassium hydroxide was added. The amount of melting of NA (1.0) / CM (5: 5) was also increased by the amount of melting of calcium chloride and the improvement of the cutting performance was improved. Melting amount was the largest when the addition amount of sodium hydroxide was 1 mole in both CM (8: 2) and CM (2: 8), as in CM (5: 5).

 The amount of melting ice at -5 ° C of the snow remover with addition of potassium hydroxide sample
KOH addition amount (mol)
Melting amount (mL / g)
60 min
120 min
CM (8: 2)
CM (5: 5)
CM (2: 8)
0.3
3.21
4.95
4.10
3.43
6.50
4.30
CM (8: 2)
CM (5: 5)
CM (2: 8)
0.5
4.20
6.30
4.75
5.33
8.30
6.53
CM (8: 2)
CM (5: 5)
CM (2: 8)
1.0
7.35
9.00
7.55
8.55
13.4
9.70

 The amount of snow melting at -5 ℃ of the snow remover with addition of sodium hydroxide Snow remover
NaOH addition amount (mol)
Melting amount (mL / g)
60 min
120 min
CM (8: 2)
CM (5: 5)
CM (2: 8)
0.3
3.16
4.53
4.05
3.41
6.30
4.25
CM (8: 2)
CM (5: 5)
CM (2: 8)
0.5
3.96
6.23
4.45
5.33
8.12
6.42
CM (8: 2)
CM (5: 5)
CM (2: 8)
1.0
6.98
8.67
7.23
8.32
12.7
9.21

[ Example  2]

The corrosion test of the conventional snow removing agent and the chlorine compound snow removing agent provided by the present invention was carried out. Corrosion resistance of steel by snow remediation was investigated for K (1.0) / CM (5: 5), Na (1.0) / CM (5: 5) and NaCl and CaCl ₂ as chlorine compound snow removers. Each of the snow removers was dissolved in distilled water and 200 mL of 3 wt% solution was prepared.

The steel specimens, each 8 cm in width, 1 cm in length, 0.05 cm in thickness, and 1.86 g in weight, were placed in a beaker with a beaker containing the snow remover solution and placed in a room kept at 25 ° C for corrosion of the specimen . The degree of corrosion was visually observed and photographs were taken and the weight change of steel specimens was measured at intervals of 24 hours. The corrosion rate is expressed by the weight increase rate ( F _w ) of the specimen due to corrosion, which is calculated from the initial weight ( W _i ) of the initial specimen and the final weight ( W _f ) of the specimen after 5 days.

(1)

(One)

  FIG. 2 shows photographs of the corrosion phenomenon of the solution of the solution in which each snow remover was dissolved. From one day, the solution of the calcium chloride snow remover dissolved in the steel and turned yellow. The solution in which the sodium chloride snow remover dissolved also showed yellowing by corrosion over time. On the other hand, the solution in which the K / CM and Na / CM snow remover dissolved remained clear as the first time, indicating that the corrosion of the steel did not occur.

Fig. 3 shows the steel corrosion test results for each snow remover by the steel corrosion rate calculated by equation (1). The corrosion rate of steel was the largest with calcium chloride. After 5 days, the corrosion rate of the iron specimen by the calcium chloride snow remover was 13.4%, which is nearly twice that of sodium chloride. Therefore, when calcium chloride or sodium chloride is used as a snow removing agent, corrosion of road structures, steel of bridges, and metal parts of automobiles is likely to cause damage. However, K / CM or Na / CM snow remover almost did not corrode iron specimens after 5 days. As a result, chlorine ions contained in the chlorine compound snow removing agent combine with iron ions to form iron chloride (FeCl ₂ ), or the chlorine component damages the surface film of the metal, thereby easily reacting with iron and oxygen to cause corrosion. The snow remediation agent proposed in the present invention is an acetate compound and does not cause corrosion because it has high biodegradability and does not contain a chlorine component and does not affect the metal surface.

none

Claims (3)

Adding a mixture of calcium hydroxide and magnesium hydroxide to acetic acid and stirring the mixture; Adding potassium hydroxide solution or sodium hydroxide solution and colloidal silica to the solution, and stirring the mixture; Drying the composition in a drier and pulverizing the composition; And a step of granulating the resulting powder using a pellet milling machine.
The method according to claim 1, wherein the mixed molar ratio of calcium hydroxide to magnesium hydroxide is in the range of 2: 8 to 8: 2 by weight of calcium hydroxide: magnesium hydroxide
The process for producing a non-saline solid snow remover as claimed in claim 1, wherein potassium hydroxide or sodium hydroxide is contained in a proportion of 0.3 to 1 mol based on 1 mol of a mixture of calcium hydroxide and magnesium hydroxide in the potassium hydroxide solution or the sodium hydroxide solution

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