JPH044037A - Heating/cooling medium composition with suppressed combustion assisting property - Google Patents

Abstract

PURPOSE:To make storage and transportation of the composition easy by adding such a compd. that produces carbon dioxide, water or a surface coating material by thermal decomposition or chemical reaction so as to suppress the combustion assisting property of the base agent. CONSTITUTION:Alkali metal nitrate, alkali metal nitrite, etc., are used as a heating or cooling medium having high combustion assisting property for heat treatment of steel or nonferrous metal. To suppress the combustion assisting property of the base agent, an additive is added by 0.5-10wt.%. This additive is ammonium carbonate, ammonium hydrogencarbonate, etc., which produces carbon dioxide, water or a surface coating material by thermal decomposition or chemical reaction. By this method, the combustion assisting property can be suppressed with little or no influence on the physical properties of the main agent, and thereby, handling or storage of the heating or cooling medium is made easy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to heating in heat treatment of steel and non-ferrous metals,
The present invention relates to a composition that has suppressed combustion support and is less dangerous as a cooling medium and a reaction heat medium or heat exchanger in the chemical industry.

[Prior Art] In the field of heat treatment of steel and non-ferrous metals, quenching and tempering operations are carried out in the temperature range of 160 to 550°C by taking advantage of the physical property of high heat transfer ability in the molten salt state. or as a heating or cooling medium for organic synthesis chemical reactions in the temperature range of 200°C to 500°C in the chemical industry.
Single salts of alkali metal nitrates, alkali metal nitrites, or multi-component mixed preparations thereof have been widely used as bases as heat carriers and heat exchange agents for rubber vulcanization reactions.

However, from the viewpoint of chemical properties, these base materials significantly accelerate the combustion rate when they come into contact with or mix with various combustible materials. Because single salts or mixed salts act as agents, depending on their type and degree of mixing, it is necessary to suppress the combustibility of the base material and reduce the danger from the standpoint of safety during storage, transportation, etc. There is sex. However, since no effective countermeasures have been established in such cases, they may be subject to strict regulations that will be enforced from May 23, 1990 as Class 1 oxidizing solids based on the Fire Service Act.

[Problems to be Solved by the Invention] As mentioned above, alkali metal nitrates and alkali metal nitrites alone or in combination serve as strong oxidizing agents when mixed with various combustibles when combustibles burn. Because it acts as a combustion enhancer that significantly accelerates the combustion rate, special care and measures are required when handling such things as storage and transportation. It was necessary to establish measures to suppress its combustibility so that it could be stored and transported with the usual degree of care.

[Means for Solving the Problems 1] In order to improve the above-mentioned problems, the present invention improves the properties of the base to the extent that the essential physical properties of the base that are problematic in use are not affected at all or hardly. This problem was solved by incorporating an additive substance in the base material that suppresses combustion support.

[Function] In order to achieve the above object, the present invention uses additives that generate carbon dioxide gas, water, or surface-coating substances by thermal decomposition or chemical reaction, such as ammonium carbonate, ammonium hydrogen carbonate, alkanometal carbonate, carbonate. One or more of hydrogen alkali metal salts, alkali hydroxides, urea, ammonium dihydrogen phosphate, boric acid, etc., in a total of 0.
By containing 5 to 10% by weight in the above base,
When the base material comes into contact with a combustible material and burns, the cooling effect of the additive substance contained, the dilution effect, and the suffocation effect of the coating significantly reduce the effect of the base material as a combustion aid.

In addition, if the amount to be contained is 0.5% by weight or less, it may or may not be effective, and the reproducibility is insufficient.
If it exceeds % by weight, it may have an adverse effect on the physical properties of the base as a heating and cooling medium required for use.

[Example 1 Potassium nitrate 40% by weight, sodium nitrite 60% by weight
Using an oxidizing agent with the composition as a base, four types of preparations containing the additives shown in Table 1 were used as test substances, and the mixing ratio with combustibles was adjusted according to the provisions of the Fire Service Act, and a combustion test was conducted. I did it.

In addition, as comparative data for confirming the effects of the present invention, the above-mentioned base itself was prepared as a comparative example in which no additives shown in Table 1 were added to the base.

The test method is based on Law No. 5 promulgated on May 24, 1986.
No. 5, Article 1 of the Ministry of Home Affairs Ordinance No. 1 based on the [Act for Partial Amendment of the Fire Service Act] and the tests and properties of Class 1 hazardous materials stipulated in Appended Table 1, No. 2. can be,
The outline is as follows.

(1) The base and additive substances used were those that had passed through a mesh sieve with an opening of 1.18 m+n (the same was true for the comparative examples).

(2) The combustible material was Japanese cedar sapwood powder (referred to as wood flour), which was passed through a mesh sieve with an opening of 0.5 mm, and which did not pass through a 0.25 mrrl mesh sieve.

(3) The test article and the combustible material were mixed at a weight ratio of 11 and 41, and the total weight was 30 g.

(4) The mixture of (3) above has a height to bottom diameter ratio of 1.
It was made to have a conical shape of 175 mm and was deposited on an inorganic heat insulating board with a thickness of 10 mm or more.

(5) An ignition ring made of a 2 mm diameter nichrome wire that was in contact with the conical base of (4) above was energized and heated to about 1000°C to ignite it.

(6) The combustion time was defined as the time from when the entire circumference of the conical base was ignited until the flame was extinguished.

Remarks l) Regarding the combustion time for the two mixture ratios shown in (3) above, the shorter combustion time is defined as the combustion time of the test substance according to regulations.

2) The combustion time determined in this way was compared with the combustion time of a standard material specified in the Fire Service Act.

As a standard substance, reagent grade potassium bromate (mixing ratio was only 1:1) was used, which passed through a mesh sieve with a mesh opening of 0.31I1m but did not pass through a mesh sieve with a mesh opening of 0.15+++n.

The results of the above combustion test are shown in Table 2.

When the mixing ratio with wood flour is 1=1, the respective combustion times are 54.61.52.52 seconds, which are longer than the combustion time of the standard material, which is 43 seconds.

On the other hand, in the comparative example, when the mixing ratio with wood flour was 4:1, the combustion time was 35 seconds, which was shorter than the combustion time of the standard material, which was 43 seconds.

[Effect of the invention 1] The preparation according to the present invention has a significantly reduced action as a combustion aid compared to the base according to claim 1, so that
It is excluded from the strict regulations as a Class 1 oxidizing solid under the Fire Service Act, and is very advantageous in terms of safety when handling storage, transportation, etc.

Agent Patent Attorney Iso Fujimoto Agent: Patent Attorney Takeo Gofuji

Claims (1)

[Scope of Claims] 1. A base material as a heating or cooling medium with strong combustion support consisting of a single salt of an alkali metal nitrate and an alkali metal nitrite salt or a multi-component mixture thereof, and a thermal decomposition or chemical reaction. One or more additive substances that generate carbon dioxide gas, water, or surface-coating substances by a total of 0.5 to 10
% by weight of an additive, the heating/cooling medium composition having suppressed combustion auxiliary properties of the base. 2. The additive substance is selected from the group consisting of ammonium carbonate, ammonium hydrogen carbonate, alkali metal carbonate, alkali metal hydrogen carbonate, alkali hydroxide, urea, ammonium dihydrogen phosphate, and boric acid. A heating/cooling medium composition in which the combustibility of the base material is suppressed. 3. One or more of the above additive substances in a total of 1 to 5
3. The heating/cooling medium composition according to claim 1 or 2, wherein the base has a suppressed combustion auxiliary property.