JPH0775662B2 - Diamond synthesis method by underwater explosion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for explosive synthesis of diamond.

(Prior art and its problems) In the conventional method for synthesizing diamond by utilizing the explosion of explosives, (1) graphite or a mixture of this and cooling additive is collided with an object accelerated by the explosion to form graphite into diamond. A method of converting, (2) a method of accelerating graphite with an explosive explosive and colliding with a water surface, etc. to recover diamond from water, etc. Etc.

Among these methods, the method (1) has a method in which an object accelerated by an explosive is collided with a container containing raw materials, and then the container is picked up in the air or in water to recover the diamond from the container. The equipment required for accelerating is only one operation which is destroyed by one explosion acceleration, and the container containing the diamond raw material cannot be used again due to this collision treatment. Also, the amount of explosive used is several ten times that of graphite, which is the raw material for diamond. Therefore, synthesizing diamond by this method has the disadvantage of being labor intensive and costly due to the large amount of manufacturing materials and explosives. The method (2) also requires a great deal of labor for producing the accelerator and also destroys it only once, so that it also has a drawback that it requires a great deal of cost.

The method of (3) does not have such a device that can be operated only once, but instead uses an explosive container, in which a mixture of explosive and graphite is detonated and adhered to the inner wall of the explosive container. Since this is a method of collecting the product and refining it to obtain diamond, the explosion container needs to be closed at the time of the explosion, and needs to be openable / closable for taking out the reaction product. Then, it is necessary to have a strength that can endure the explosion, and it is necessary to replace the air in the container with an inert gas or reduce the pressure so that the reaction products do not burn during the explosion. As described above, since it is necessary to open and close the explosive container and perform other operations for each explosive treatment, this method also requires a great deal of labor in the same manner as the above-mentioned method.

(Problems of the invention) The present invention solves the above-mentioned problems found in the prior art, and it is possible to easily repeat a desired number of explosions any number of times,
Moreover, it is an object of the present invention to provide an explosive synthesis method of diamond in which reaction products can be easily recovered, and thereby to reduce the labor required for diamond synthesis.

(Means for Solving the Problems) The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, the present invention, after repeatedly exploding a molded product of a raw material mixture consisting of explosive and graphite and having a density of 1.4 g / cm ³ or more in water in a water tank a plurality of times, recovers diamond formed in the water in the water tank. The present invention provides a diamond synthesizing method characterized by the above.

In the present invention, the depth of water that explodes a mixture of explosive and graphite, etc. must be at a water depth such that the diamond of the reaction product of interest does not scatter out of the tank, which is the amount of explosive used and the size of the tank. However, it is preferable that the water depth is 50 cm or more. This explosion process produces diamond in water. Since the density of diamond is much higher than that of water, it easily precipitates on the bottom of the aquarium. Therefore, it is possible to easily collect the precipitate by a method of removing the supernatant liquid or a method of exposing the bottom of the water tank after performing the explosion treatment a desired number of times.

Alternatively, a method may be adopted in which a tube having both ends open or one end open is suspended in a water tank so that a raw material mixture consisting of explosive and graphite exists in water, and the raw material mixture consisting of explosive and graphite is exploded in the tube. In this method, the explosion noise can be reduced, and the reaction products are mainly deposited on the bottom of the water tank outside the pipe by performing a desired number of explosions. Therefore, the reaction product can be easily recovered by the above method. Also, when it is desired to collect the generated reaction product in a pipe, a pipe with one end sealed, that is, a sealed pipe with one end open, is hung in a water tank so that its major axis is almost horizontal and exploded in the pipe. And then lift it from the water tank with the opening facing up. After standing, the precipitate is collected.

The reaction product thus obtained is first dissolved and removed of metals with nitric acid as in the case of a normal diamond synthesis method, then treated with a mixed solution of chloric acid and nitric acid until the graphite is exhausted, and finally, By treating with a mixed solution of hydrofluoric acid and nitric acid, highly pure diamond can be obtained.

The raw material mixture consisting of explosive and graphite used in the present invention may be the same as that used in the above-mentioned conventional method (3). In the present invention, the raw material mixture consisting of explosive and graphite is advantageously used as a molded product. In this case, the density of the molded product is preferably as high as possible, and normally, it is advantageous to perform pressure molding so that the density is 1.4 g / cm ³ or more. The shape is not particularly limited, but it is usually used as a columnar molded body. In addition, it is preferable to use paraffin or the like as a molding aid for this molded product.

In the present invention, the explosion of the raw material mixture consisting of explosive and graffite is carried out in water in the water tank. In this case, the size and strength of the water tank are designed so as not to be destroyed by the explosion. Further, the shape of the bottom of the water tank is preferably an inverted conical shape so that the reaction products can easily settle and can be easily collected to the outside.

(Examples) The present invention will be described in more detail based on the following examples.

Example 1 10 g of a mixture of 80% explosive (hexogen), 14.2% graphite, and 5.8% paraffin was compression molded into a column having a diameter of 2 cm. The density of this molding is 1.47 g / cc. Hexogen 1.5g and No. 6 voltage detonator were attached to this, diameter 1.5m, height
An explosion was made at a water depth of 1 m in an aquarium tank with a 2 m bottom. This explosion process was repeated 10 times. The total amount of the explosive-treated molded product is 100 g. Since the desired reaction product had a high density and easily precipitated on the conical bottom of the water tank, it was collected by a suction pump. Then, the reaction product was treated with nitric acid, then with a mixture of chloric acid and nitric acid, then with a mixture of hydrofluoric acid and nitric acid, washed with water and dried, as in the case of ordinary diamond synthesis. The obtained powder was scanned by an X-ray diffraction method (Cu Kα ray, tube voltage 30 kV, tube current 15 mA), and the diffraction line peak showed a single phase of diamond. The yield of diamond was 11.5% of the graphite used.

As described above, according to the present invention, it was found that the diamond can be easily synthesized without the labor of opening and closing the explosion container and collecting the reaction product for each explosion treatment unlike the conventional diamond synthesis method.

Example 2 85% hexogen, 10% graphite, 5% paraffin
10 g of the mixture was molded into a column having a diameter of 2 cm. The density of the molded product is 1.65 g / cc. Hexogen 1.5g and No. 6 electric detonator were attached to this, and it was set inside a cylinder with an inner diameter of 27cm, a length of 150cm, and a wall thickness of 1cm with one end open. At this time, a wire-like member was used to fix and support the molded product so that the molded product was located at approximately the central position in the lengthwise direction of the cylinder and at approximately the central position within the cylinder. Then, the cylinder was hung at a depth of 1 m so that the cylinder was horizontal, and the molded product was exploded by energizing it as in Example 1. And after pulling out from the water with the opening of the cylinder facing upwards, letting it stand and separating the precipitate,
Treated with nitric acid as in Example 1, then treated with a mixture of chloric acid and nitric acid, then treated with hydrofluoric acid and nitric acid, and dried. The resulting powder was X as described in Example 1.
Line diffraction showed that this was a single phase of diamond. The yield of diamond was 13.5% of the graphite used.

Also in the case of the first embodiment, the explosion sound and the like are extremely weak as compared with the time of the explosion in the atmosphere, but the method of the second embodiment, that is, the above-mentioned cylindrical method becomes even weaker. This is probably because most of the explosion energy is converted into the kinetic energy of a cylinder suspended in water.

Further, the explosive molded product having the above-mentioned composition was repeatedly exploded in this cylindrical system, and the product precipitated on the outside of the cylinder, that is, on the bottom of the water tank was recovered as in Example 1. As a result, it was found that, unlike the conventional diamond synthesizing method, it is not necessary to open and close the explosion container, and the reaction product can be easily recovered, so that the labor can be remarkably saved as in Example 1.

(Effects of the Invention) As described above, the method of the present invention does not have a single-time destruction device unlike the conventional flying object collision-type diamond synthesizing method. The explosion container is opened and closed for each explosion process,
In addition, there is no step that requires a great deal of labor to recover the reaction product in each case. That is, the container and the like used in the present invention can be repeatedly used, and the desired reaction product can be collected once or continuously. That is, the method of the present invention is very labor-saving, which allows diamonds to be obtained easily and easily.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuaki Iida 1-1, Higashi Tsukuba City, Ibaraki Industrial Technology Institute, Institute of Chemical Technology (72) Inventor Katsumi Tanaka 1-1, East Tsukuba City, Ibaraki Institute of Industrial Technology In-house (72) Inventor Ichizo Tada, 1-1, Higashi, Tsukuba-shi, Ibaraki Industrial Technology Institute, Institute for Chemical Research

Claims (3)

[Claims] 1. A diamond produced in water in a water tank is recovered after repeatedly exploding a molded product of a raw material mixture consisting of explosive and graphite and having a density of 1.4 g / cm ³ or more in the water in the water tank. A diamond synthesizing method characterized by: 2. The method of synthesizing diamond according to claim 1, wherein the explosive treatment is carried out in a state where the molded product of the raw material mixture is fixedly supported at a proper position in water in an inverted conical water tank. 3. An explosive treatment in which a molded product of the raw material mixture is fixedly supported at an appropriate position in a pipe body having one end or both ends opened, and the pipe body having the molded product fixedly supported is left standing in water in a water tank. The method for synthesizing diamond according to claim 1, wherein