JP5755537B2 - Non-dangerous nitrate production method - Google Patents

Description

  The present invention relates to a method for producing a non-hazardous nitrate.

  Since barium nitrate has the property of generating oxygen when heated, it is a granular material mainly used for manufacturing optical glass, fireworks, explosives and the like as an oxidizing agent. And because of its nature, the Fire Services Act (Act No. 186 of 1947), the Decree on the Regulation of Dangerous Goods (Act No. 306 of 1944) and the dangerous goods According to the dangerous goods judgment test specified in the ministerial ordinance on testing and properties (Ministry of Autonomous Ordinance No. 1 of February 17, 1989) There are significant legal restrictions on storage.

  However, when barium nitrate is reformed to a level that is not recognized as a dangerous goods class 1 by the dangerous goods judgment test, the barium nitrate after the modification is not subject to the above legal restrictions, Production and use efficiency of barium nitrate can be improved, transportation and management costs can be reduced.

  Here, barium nitrate is a powdered article (10% of which passes through the mesh sieve for 30 minutes when it is sieved by applying 160 vibrations per minute while rotating the mesh sieve having a mesh opening of 2 mm). As described above, a combustion test and a falling ball hitting sensitivity test are performed as the dangerous goods determination test. In the combustion test, the burning time when a mixture of the test article and wood powder is burned is measured, and this time is the burning time when the mixture of standard material (potassium perchlorate) and wood powder is burned. If it is equal to or shorter than (hereinafter referred to as the reference combustion time), it is judged to have the property specified by the Cabinet Order concerning the potential danger of oxidizing power. In the falling ball hitting sensitivity test, the steel ball was dropped into the mixture of the test article and red phosphorus from the height that exploded with a probability of 50% when the steel ball was dropped into the mixture of standard substance (potassium nitrate) and red phosphorus. In this case, the probability of the mixture exploding is obtained, and if the explosion probability is 50% or more, it is determined that the mixture has the property specified by the government ordinance relating to the sensitivity to impact.

  And, in the combustion test, if the combustion time of the barium nitrate after reforming is longer than the reference combustion time, and the explosion probability of the barium nitrate after reforming is less than 50% in the falling ball hitting sensitivity test, The reformed barium nitrate will be recognized as not a hazardous material first class (non-dangerous material). As a specific method for reforming barium nitrate to be recognized as a non-hazardous material by both of these tests, for example, addition of an inert inorganic substance to barium nitrate can be mentioned.

  However, in order to ensure that it is certified as a non-hazardous material, adding a large amount of an inorganic substance that is inert to barium nitrate and surrounding the barium nitrate with that substance is expected for barium nitrate. As a result, the function as an oxidant is hardly exhibited, and the commercial value is impaired. On the other hand, if the addition of an inorganic substance is suppressed to a small amount in order to maintain the commercial value, the contact area between barium nitrate and combustible material becomes large, and it is recognized as a dangerous material first class by the dangerous material judgment test.

  Such a problem may occur in the same manner for nitrates classified as the first class of dangerous goods other than barium nitrate.

The present invention has been made in consideration of the above-mentioned matters, and its purpose is to produce a non-hazardous nitrate which can be made non-hazardous while maintaining the commercial value of nitrate by an inexpensive and simple method. Is to provide.

  In order to achieve the above object, the non-hazardous nitrate production method according to the present invention deposits silica on the outside of the nitrate via a coating layer of an oxygen sealant formed on the surface of the nitrate (claim). Item 1).

  In the said method, it is preferable that the said coating layer is formed by adding the said oxygen sealing agent 0.01 mass% or more with respect to the said nitrate (Claim 2).

Moreover, in the said method, it is preferable that the said silica is 0.3 mass% or more added and made to adhere with respect to the said nitrate (Claim 3).
In the above method, the oxygen sealing agent may be a surfactant.

In the inventions according to claims 1 to 4 , a non-hazardous nitrate production method capable of achieving non-hazardous material while maintaining the commercial value of nitrate is obtained by an inexpensive and simple method.

  That is, in the method for producing a non-hazardous nitrate according to the claimed invention, the nitrate is modified so as to have a property that is recognized as a non-hazardous substance by a dangerous substance judgment test while ensuring a sufficient amount of nitrate. Without the need for expensive materials or extremely complex techniques.

  In addition, if the amount of the oxygen sealing agent added to the nitrate is less than 0.01% by mass, the entire nitrate is not coated and the surface is exposed, and may be determined as a dangerous substance in the dangerous substance determination test. However, in the non-hazardous nitrate production method according to the second aspect of the present invention, since the amount of the oxygen sealing agent added to the nitrate is 0.01% by mass or more, there is no such fear.

  If the amount of silica added to the nitrate is less than 0.3% by mass, most of the coating layer of the oxygen sealing agent is not covered with silica, and the coating layer is easily peeled off when impacted. In addition, when this coating layer is made of an organic substance, it can react with nitrate, so that it may be determined as a dangerous substance in the dangerous substance determination test. However, in the non-hazardous nitrate production method according to the third aspect of the present invention, since the amount of silica added to the nitrate is 0.3 mass% or more, there is no such fear.

  Embodiments of the present invention will be described below with reference to the drawings.

  The production method of non-hazardous nitrate according to the present embodiment includes white carbon (on the outside of a crystal of barium nitrate (an example of nitrate) via a coating layer of dodecylbenzenesulfonic acid (an example of an oxygen sealing agent). An example of silica is attached.

  First, the barium nitrate crystal is, for example, a crystal (purified product) obtained by crystallizing and dehydrating (solid-liquid separation) a barium nitrate solution (an example of a nitrate solution) by an appropriate means. In this example, a dodecylbenzenesulfonic acid coating layer is formed (surface coating) on the outside of the barium nitrate crystal by adding dodecylbenzenesulfonic acid during or after the dehydration. Thereafter, if necessary, the coated barium nitrate crystals are appropriately dried (with some moisture left), and then coated with barium nitrate and fine powdery white carbon in a predetermined ratio using, for example, a V-shaped mixer. And white carbon is adhered to the outside of the barium nitrate through the coating layer.

  Here, the addition amount of dodecylbenzenesulfonic acid (oxygen sealing agent) is preferably 0.01% by mass or more and 0.10% by mass or less with respect to barium nitrate (nitrate). If the amount added is less than 0.01% by mass, the entire crystal is not coated, the crystal plane of barium nitrate (nitrate) is exposed, and may be determined as a dangerous substance in the dangerous substance determination test. . On the other hand, if the amount added exceeds 0.10% by mass, the pure barium nitrate content is small and the commercial value may be impaired.

  On the other hand, the amount of white carbon (silica) added is preferably 0.3% by mass or more and 1.5% by mass or less with respect to barium nitrate. When the amount added is less than 0.3% by mass, most of the coating layer of dodecylbenzene sulfonic acid is not covered with white carbon, and the coating layer is easily peeled off when subjected to an impact. Since the layer is made of an organic substance and can react with barium nitrate, it may be determined as a dangerous substance in the dangerous substance determination test. On the other hand, if the amount added exceeds 0.10% by mass, the pure barium nitrate content is small and the commercial value may be impaired.

  In addition, the median diameter (D50) of the finely powdered white carbon (silica) is preferably 5 μm or less. When the thickness exceeds 5 μm, a large unevenness of adhesion of white carbon to the coating layer of dodecylbenzenesulfonic acid occurs, and a portion that is not covered with white carbon tends to be formed in the coating layer. Due to peeling, reactivity of dodecylbenzene sulfonic acid, and the like, there is a possibility that the dangerous substance determination test determines that it is a dangerous substance.

  When barium nitrate (composition) modified by the method of this embodiment is produced as described above, dodecylbenzenesulfonic acid contained in this barium nitrate can be removed by heating, and white carbon (silica). Is abundant in liquid crystal glass, and thus the obtained barium nitrate is particularly suitable for use in the production (additive) of liquid crystal glass.

  In order to confirm the effectiveness of the method of the present invention, samples of barium nitrate (No. 1 to No. 5) modified in accordance with the above-described embodiment were prepared, and the above dangerous substance determination test was performed on each sample. The results are shown in Table 1. No. 1-No. Sample No. 5 is obtained by varying the amount of dodecylbenzenesulfonic acid added, the median diameter of white carbon (silica), and the amount added within the specified range of the above embodiment.

  Here, in the combustion test, it is determined that the shorter the burning time, the stronger the oxidizing power, and the rank is determined by comparison with two kinds of standard substances (potassium perchlorate and potassium bromate). Specifically, if the combustion time is longer than the combustion time of potassium perchlorate, it is rank 3, if it is less than the combustion time of potassium bromate, it is rank 1, and if it is between, it is rank 2.

  Also, in the falling ball hitting sensitivity test, it is determined that the higher the explosion probability, the higher the sensitivity to impact, and the rank is determined by comparison with two kinds of standard substances (potassium chlorate and potassium nitrate). Specifically, if the explosion probability is lower than the explosion probability of potassium nitrate, it is rank 3, if the explosion probability is higher than the explosion probability of potassium chlorate, it is rank 1, and if it is between, it is rank 2.

  And it is recognized as a non-hazardous material (does not fall under the first category of dangerous goods) only when it is determined to be rank 3 in both the combustion test and the falling ball hitting sensitivity test. Certified.

  From Table 1, it can be understood that all the samples (No. 1 to No. 5) created in accordance with the above-described embodiment are recognized as non-dangerous goods. That is, the effectiveness of the method of the present invention is clear.

  In addition, this invention is not limited to said embodiment at all, Of course, it can change and implement variously in the range which does not deviate from the summary of this invention. For example, the following modifications can be given.

  In the above embodiment, an example has been shown in which barium nitrate is targeted as the nitrate, but other nitrates such as strontium nitrate, sodium nitrate, magnesium nitrate, and potassium nitrate may be targeted.

  The oxygen sealing agent only needs to have an oxygen sealing function and a silica adhesion function. In addition to dodecylbenzenesulfonic acid, for example, silane-based, titanate-based, aluminum-based, zircoaluminum-based, carboxylic acid-based, It is conceivable to use a coupling agent such as a phosphoric acid type or a surface treatment agent such as a fatty acid type, a fat type, a wax type, or a surfactant type as the oxygen sealing agent.

  In the above embodiment, white carbon (amorphous silica) is used as the silica, but either regular silica (crystalline α quartz) or amorphous silica (amorphous silicon dioxide) may be used.

  In the above embodiment, the V-shaped mixer is used for mixing the coated nitrate (barium nitrate) and silica (white carbon). A machine may be used.

Needless to say, the above modifications may be combined as appropriate.

Claims (2)

A non-hazardous nitrate production method in which silica having a median diameter (D ₅₀ ) of 5 μm or less is attached to the outside of a nitrate through an oxygen sealing agent coating layer formed on the surface of the nitrate ,
The coating layer is formed by adding 0.01 mass% or more of the oxygen sealing agent to the nitrate,
The method for producing a non-hazardous nitrate, wherein the silica is added by 0.3% by mass or more based on the nitrate. The non-hazardous nitrate production method according to claim 1 , wherein the oxygen sealing agent is a surfactant.