JPS6155181A - Snow-melting and deciding agent - Google Patents

Abstract

PURPOSE:A snow-melting and deciding agent which has excellent effect and has almost no phytotoxicity, composed mainly of calcium chloride and magnesium sulfate, containing essentially no sodium chloride. CONSTITUTION:About 75-40wt% calcium chloride, about 25-60wt% magnesium sulfate and, if necessary, about 10wt% or less magnesium chloride, about 2wt% or less phosphate, and about 5wt% or less potassium chloride are mixed together to give a snow-melting and deciding agent.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention is applicable to frozen or snow-covered roads, roofs, roads,
The present invention relates to an anti-freezing agent and a snow-melting agent for effectively preventing or removing snow from accumulating on farmland, etc., and particularly to a snow-melting and anti-freezing agent that has great snow melting and anti-freezing effects and has almost no phytotoxicity to plants.

(Background of the Invention) Because Japan is located close to the east longitude of the Eurasian continent, its climate is characterized by a cold winter compared to regions located on the west side of the continent.

For this reason, roads often freeze during winter, causing not only traffic congestion but also serious traffic accidents. In addition, in the Yoshiki region and mountainous areas, a large amount of water vapor is emitted from the Sea of Japan heated by the Tsushima Warm Current, and this water vapor is cooled by the cold seasonal winds from the continent and turns into snow, resulting in a large amount of snow. Accumulated snow does not melt until late spring, making farming virtually impossible, as well as soaring prices due to traffic disruptions and traffic jams, and the huge expense of removing snow from roads and roofs. This causes great damage both physically and mentally, including the loss of human life due to traffic accidents, collapsed houses, and avalanches, which in turn impedes the economic development of these regions.

(Prior art and its disadvantages) As a countermeasure against snow accumulation and freezing, the most widely used method today is to spray crude calcium chloride produced as a by-product by the Solve-A method (ammonia soda method). Since crude calcium chloride contains at most over 70% calcium chloride, its antifreeze and snow melting effects are relatively low, and it is not effective unless it is frequently sprayed. Moreover, the large amount of 'iK' fabric causes phytotoxicity to plants and freshwater fish and shellfish. For this reason, in practice, calcium chloride is only sprayed on trunk roads, etc., but it still causes serious damage to trees in median strips and roadside strips. To alleviate this medicine man, early spring,
The only option is to actively flush the trees before they emerge from hibernation, but it is extremely difficult to flush the entire length of a long-distance road on a large scale due to the need for water and other reasons. As a result, road managers are forced to spend huge amounts of money every year to replace dead trees.

The drawbacks of known snow-melting agents have been outlined above, with a focus on phytotoxicity to plants, but known snow-melting agents also have the disadvantage of being susceptible to rust, which cannot be overlooked. Therefore, if a vehicle that has driven on a road surface where snow melting agent has been sprayed is not thoroughly washed with water afterwards, rust will form and the service life of the vehicle will be significantly reduced. This is also a cause of confusion for vehicle users in terms of time and cost.

(Problems to be Solved by the Invention) The present invention improves the composition of conventional calcium chloride-based snow melting agents (hereinafter referred to as "antifreezing agents" together), thereby achieving a greater antifreezing effect. In addition, the main purpose of the present invention is to provide a novel snow-melting agent that does not cause chemical damage to plants.An additional purpose of the present invention is to provide a novel snow-melting agent that does not easily cause rust on metals such as #, and is durable. The objective is to provide a snow melting agent which is excellent and, moreover, aids the growth of cultivated plants.

(Means for Solving Problems; Structure) The present inventor focused on the drawbacks of known calcium chloride-based snow melting agents, and as a result of intensive research into improving them, the inventor found that calcium chloride itself has almost no negative effects on plants. However, the conventional Solvay method calcium chloride is inevitably contaminated with salt, and this salt not only has harmful effects on plants, but also
It was confirmed that the positive heat of dissolution absorbed during melting had a detrimental effect on the overall calorific value. Therefore, magnesium chloride (approximately 36 kcal) has a heat of dissolution that is approximately twice as large as that of calcium chloride.
1 mol/800 mol H20] and magnesium chloride whose heat of solution is almost the same as that of calcium chloride (approximately 20 kca 11 mol/800 mol H20), we investigated the change in heat of dissolution when both components coexist with calcium chloride. As a result, the calorific value when the former calcium chloride and magnesium chloride coexist is vf. However, in the case of the latter compound of calcium chloride and magnesium sulfate, surprisingly, as shown in line B in the same figure,
Synergistic heat generation was observed only when the ratio of the two was within a certain range, and when the ratio was outside of this range, the amount of heat generated was rather reduced. And from this graph, it is clear that the composition consisting of calcium chloride and magnesium sulfate generates a synergistic heat of solution, and this synergistic effect is remarkable when the ratio of both is 75-40:25-60. It is observed that there is a peak at 70:30 and 50:50.

Therefore, the inventor of the present invention proceeded to investigate the effects of magnesium sulfate on plants, and found that it not only has a small effect, but also has the effect of promoting plant growth when used in an appropriate amount. In addition, Kisei Nagisa further investigated the effects of potassium chloride and phosphates in the coexistence with calcium chloride and magnesium Tilt acid, and found that the former had the same effect on promoting plant growth as magnesium Tilt acid. It has also been discovered that the latter has the effect of significantly inhibiting rusting caused by calcium chloride and potassium chloride.

Based on these findings, the present invention aims to utilize calcium chloride that does not substantially contain salt as a snow melting agent together with magnesium sulfate and, if necessary, magnesium chloride, soluble potassium salts and/or phosphates. This is related.

Below, the experimental results that formed the basis of this knowledge are shown in Tables 1 to 3. Note that "substantially no salt" mentioned above comes from impurities in the raw material limestone or marble. This means excluding unavoidable trace amounts of contaminated salt.

(Margin below) 24.5°C1 Sustained temperature 0.5°C), ■ Temperature difference between the temperature of the 20% aqueous solution 3 days after dissolution and the water left at room temperature.

Dilute it, add 4 so that the wood grain inside the pot is constant, ・j+
The calculated concentration of the most V sample added sow, (41 commercially available snow melting bound calcium (control), medium control (added only water).

(Margin below) (ri) Concentration in dry sample.

As shown in Table 1 and Figure 1, the pyrogenicity of the composition is substantially related to the ratio of calcium chloride to magnesium sulfate; It should be noted that the exotherm, which is essentially unaffected by the presence of secondary components such as potassium chloride, is not transient but persists over a long period of time (see Table 1).

Furthermore, according to Table 2, in the J8 cultivation test of Kaiware radish, conventional impure calcium chloride was clearly harmful to the growth of seedlings, but 1. It has been found that the compounds are harmless to plant larvae even at high cumulative concentrations, and in particular, compositions containing soluble potassium salts are effective in promoting plant growth. This is interpreted to be because the magnesium content in magnesium sulfate promotes the synthesis of chlorophyll, and the potassium content in the soluble potassium salt promotes root growth, but this result under high iM concentrations is , while it is a surprising fact,
This is a very significant fact in practice.

Furthermore, Table 3 shows that the presence of small amounts of phosphates, especially alkali metal salts of phosphoric acid, substantially suppresses the strong rust-forming power of calcium chloride, magnesium sulfate, and potassium chloride 4b=b. It is recognized that there are It is well known that phosphates are effective in preventing rust, but it is a fact that is difficult to explain that they exhibit a strong anti-rust effect at high salt concentrations such as in this experiment.

Calcium chloride, which contains virtually no salt, can be easily produced using limestone and hydrochloric acid, which are abundant throughout Japan, according to the chemical equation below.

CaC0+2HCl 1IICaC12” H2O+
GO2↑According to the above formula, calcium chloride should theoretically be obtained in the form of a hydrate salt, but in reality it is obtained in the form of a polyhydrate salt such as hexahydrate due to the large amount of water coexisting with hydrochloric acid. It can be obtained with Therefore, in order to use it in the present invention, it is necessary to heat and dehydrate it,
It is necessary to dehydrate preferably to an anhydrous salt, or at most to a dihydrate (the heat of dissolution of calcium chloride decreases as the water content increases, and hexahydrate salts endothermically when dissolved). During this reaction, small amounts of hydrochloric acid-soluble impurities in the limestone, such as iron, magnesium, and aluminum, are eluted in the form of chlorides, but the presence of these impurities does not pose a practical problem.

Magnesium sulfate, which is substantially free of salt, can be obtained in the laboratory by dissolving metallic magnesium in sulfuric acid, but industrially, natural Ebso-1, salt (MgS
It can be easily produced by red-hot dehydration of kieserite (MgSO4.In2O) obtained as a by-product of the rock salt industry. However, since kieserite itself generates considerable heat of dissolution, it can be used as it is in place of anhydrous salt. In addition, natural Kainai) (KCI・M, 30qP・3H20
) can be obtained in the form of a mixture with potassium chloride by heating and dehydrating, and this can also be advantageously used as a constituent of the composition of the present invention.

Calcium chloride (anhydrous salt), which is one of the main ingredients in the snow melting agent of the present invention, generates about 18 kcal of heat of dissolution when 1 mol of calcium chloride is dissolved in 800 mol of water, and its mixture with snow or ice produces Magnesium sulfate, which does not freeze up to -45°C and is another main component, has a slightly higher calorific value than the former (as mentioned above), and as mentioned above, has the effect of promoting plant growth. Therefore, in the present invention, calcium chloride and f! It is preferable to use magnesium acid as a major component, and to mix magnesium chloride, soluble potassium salt, and/or phosphates as minor components or auxiliary components. Incidentally, examples of phosphates include orthophosphates such as potassium phosphate, potassium hydrogen phosphate, sodium phosphate, and sodium hydrogen phosphate, as well as metaphosphoric acid, birophosphoric acid, trimetaphosphoric acid, and alkali metals attached to polyphosphorus. Examples of soluble potassium salts include, but are not limited to, potassium chloride-1, potassium sulfate, and potassium nitrate. The type is ¥11 and soluble potassium 11! It is also useful as a kind.

The blending ratio of each of the above components can vary widely depending on the purpose. Experimentally, magnesium sulfate may be present in much higher amounts than calcium chloride. However, if the amount of magnesium sulfate is too large, there is a risk of phytotoxicity to plants, the antifreeze effect is reduced, and rust prevention becomes difficult even with phosphates. Calcium chloride 75-40ffiffi% (
(same below) and magnesium sulfate at 25-60% (total lOO%), more preferably calcium chloride at 70-60%.
50% and magnesium sulfate 30-50% (total 100%
%), and it is appropriate to add magnesium chloride, soluble potassium salts, phosphorus Iv2 salts, etc. to this as necessary.

Magnesium chloride itself generates a large heat of dissolution and increases the calorific value of the entire composition, but its presence in large amounts may cause phytotoxicity to plants, so it is
It is preferable that it is added within a range of %.

Phosphates, especially alkali metal salts of phosphoric acid, have the effect of improving acidic soil through their buffering action, and at the same time work to weaken the soil acidification effect of the main ingredient, magnesium sulfate, so they are useful as snow melting agents for agricultural land. Purpose 1 is preferable as a component. In addition, phosphorus salts are useful components as road snow melting agent components because they suppress the rusting of vehicles due to their antirust action as described above. The appropriate amount of phosphates is preferably about 5% of the total composition for agricultural use, but since it may eutrophic the water quality, it is not sufficient for general use or road use to prevent rusting. The amount 1 should be kept small, for example below 2%.

Soluble potassium salts, such as potassium chloride.

Although it may be present in an amount of 10% or more in the total composition, since it absorbs heat when dissolved in water, its presence in large quantities deteriorates the original performance of the snow melting agent. Therefore, this component contains 5% of the total composition.
% or less.

Iron salts should be added in small amounts, no more than 1% of the total, unless the purpose is to supply iron to prevent yellowing disease, such as in old paddy fields with advanced reduction. is sufficient.

Copper sulfate, manganese chloride, copper sulfate, manganese chloride, and other trace elements necessary for plant growth, such as copper, manganese, zinc, and boron,
Small amounts of soluble forms such as zinc chloride, boric acid or borax may be added; however, these trace elements are universally present in normal soils in trace amounts required by plants. Therefore, the trace elements mentioned above do not necessarily have to be added in the form of water-soluble salts, but must be added in the form of cupric hydroxide or cupric hydroxide. Even those that are insoluble in water, such as dicopper, can be made solubilized by the presence of a chelator substance such as ethylenediaminetetraacetic acid or a complex salt-forming substance such as metaphosphate.

Examples of auxiliary components other than the above-mentioned components include nitrates, ammonium salts, ureides, and cyanamide.Specifically, examples include ammonium carbonate, ammonium sulfate, ammonium chloride, calcium cyanamide, and urea. I can give an example. Since these compounds exhibit a fertilizer effect as a nitrogen source for plants, they are useful as auxiliary components of snow-melting agents for agricultural land.

In addition to the above components, reactive components such as aluminum chloride, lime, and iron powder may also be added as desired.

These components are useful components as they react with oxygen or water and generate a large amount of heat of reaction, but they also react with water to generate hydrochloric acid like aluminum chloride, or leave a white residue like lime. Its disadvantage is that it creates things. However, the generation of hydrochloric acid due to aluminum chloride can be prevented by adding lime, and the formation of a residue (calcium hydroxide) due to lime can also be prevented.

Soluble potassium salts combine with large amounts of magnesium chloride to form the mineral carnalite. The roasted product is either a mixture of magnesium chloride and potassium chloride that contains a considerable amount of magnesia, or it is added to the composition if it is a small amount that does not form magnesia cement. Good too.

The composition according to the present invention may further contain inexpensive radiant heat absorbers such as coal shell powder, smoky charcoal powder, charcoal powder, various colorants or pigments, etc., if desired. Is the amount of colored granules to be sprayed determined by the sprayer? Typical examples of inorganic pigments are , yellow lead, zinc yellow, cadmium yellow, navels, 4, 7, ocher (more yellow), Bengara, lead red, cadmium red, vermilion (more red), Mars purple, Nuremberg purple, cobalt purple (more purple),
These include ultramarine, Berlin blue, Konoheld blue (hereinafter referred to as blue), chromium green, chromium oxide, cobalt green, and peacock powder (hereinafter referred to as "two green"). Also many iV4j! J.
Dyes, such as auramine, persian orange, niosin, rhodamine, methyl violet, malachite green, victoria blue, and other dye substances may also be used as water-soluble colorants or as insoluble colorants by lake formation. I can do it. In the present invention, these pigments or dyes can be freely selected depending on the purpose, but it is wise to avoid toxic heavy metals such as lead and cadmium and azo dyes from consideration of toxicity and carcinogenicity. .

The composition according to the present invention may be in crystalline or powdered form, but
In order to increase sustainability, it is preferably in granular form. Although granular compositions are somewhat inferior in immediate effect, they are long-lasting, so if sprayed before snowfall or freezing, they will prevent snowfall or freezing for a long period of time. In other words, when sprayed on a snowy or frozen surface, it melts and generates heat and sinks into the snow or water, but since the specific heat of snow and ice is small, the amount of heat is conserved and the snow or ice melting effect is sustained. play. The size of the granules is usually selected from the range of 1 to 81, but a mixture of various particle sizes with different average particle sizes is particularly suitable as a product that has both immediate and long-lasting effects. Become.

On the other hand, flake-like products with a thickness of about 0.5 to 2) are suitable for application to sloped surfaces such as roofs and slopes, and
It is much more durable than simple powder or crystal products.

A small amount of binder (paste agent) may be added to the above granular or flake composition as necessary. Preferred binders are inexpensive materials such as, for example, starch paste, soy whey or milk whey concentrate, sulfur, M6 valve waste, hydroxyethyl cellulose, methyl cellulose, blackstrap molasses or dextrin. The amount of water used to dissolve or disperse the sizing agent should be kept as small as possible to avoid hydrochlorination of the ingredients. In addition, when forming water-reactive components such as aluminum chloride or lime into granules or flakes, it is recommended to use a sizing agent soluble in organic solvents such as methyl cellulose with a degree of methoxylation of 38 to 43%. It is better to use this non-aqueous solvent.
It is also recommended for general granulation to avoid hydrochlorination.

Example Crude calcium chloride Ia made from marble scraps and hydrochloric acid
Add 300 g of magnesium sulfate, ≠150 g of potassium chloride, 15 g of sodium hydrogen phosphate, 20 g of magnesium chloride, 5 g of ferrous chloride, and Ig of malachite green lake to 1800 g, and thoroughly crush and mix using a dry air trommel of a small to medium size type. did.

The above mixed powder is placed in a small onion-shaped granule making machine, and a total of 200 ml of 5Z hydroxyethyl cellulose solution is gradually added dropwise while blowing dry hot air, and the powder is rotated and dried to obtain 1,000 ml of product in the form of one mouthful of granules. I got g.

Next, the 4-kongo granules obtained as above were made into 1 mm
and 5Illffl 6 sieves, (6)+
Approximately 985 g of a mixed T'f granular product having a vermilion layer diameter of m or more 5+nm was obtained. It is an excellent snow melting agent that has a calorific value, is easy to handle even as it is, and has both immediate and delayed effects and is non-toxic, but by further classifying it,
It can be made to have an appropriate particle size depending on the purpose.

Incidentally, although the above products are unsuitable for application to farmland or fields immediately before sowing, they have a remarkable growth-promoting effect on young seedlings once they have germinated, especially on the stems of seedlings. It is characterized by a marked increase in diameter. Therefore, as a snow melting agent for fields of wintering crops such as wheat, it has a remarkable effect as a fertilizer. Furthermore, when used as a road snow melting agent, it is an excellent long-lasting snow melting agent that does not cause any danger of killing planted trees or rusting vehicles.

Note) Analytical values of crude fAI calcium cation Anion Ca: 28.8% Cu: 53.6
%Na: 0.07% SO2: o, 01%
Mg: <0.01% Pb: <0.01% (Effect) As explained above, the present invention is in the public interest in that it can provide a snow melting agent that has great snow melting and antifreezing effects and is chemically harmless at a low cost. It has important significance.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the amount ratio of calcium chloride and magnesium chloride or magnesium sulfate and exothermic property. In the figure, line A represents the rising temperature of a mixture of calcium chloride and magnesium chloride, and line B represents the rising temperature of a mixture of calcium chloride and magnesium sulfate, when 1 g of each sample was added to 50 ml of water. Actual measurements (averaged twice) are shown. In addition, in the figure, line C indicates the calculated temperature increase of a four-component compound of calcium chloride and magnesium sulfate, when the actual calorific value of calcium chloride is Bn5. Ki, IF revision applicant Daikai Co., Ltd. September 27, 1982

Claims (6)

[Claims] (1) A snow melting and antifreezing agent characterized by containing calcium chloride and magnesium sulfate as main components and containing substantially no salt. (2) The weight ratio of calcium chloride and magnesium sulfate is
75-40: The snow melting and antifreezing agent according to claim 1, which has a ratio of 25 to 60. (3) Claim 1 containing magnesium chloride, phosphates and/or soluble potassium salts as auxiliary components
The snow melting and antifreezing agent according to item 1 or 2. (4) The snow melting and antifreezing agent according to any one of claims 1 to 3, wherein the agent is in the form of granules. (5) The snow melting and antifreezing agent according to claim 4, wherein the agent is a mixture of multiple types of granules having different average particle sizes. (6) The snow melting and antifreezing agent according to any one of claims 1 to 3, wherein the agent is in the form of flakes.