JPS6087855A - Ruthenium tetroxide collecting agent - Google Patents

Abstract

PURPOSE:To collect easily and efficiently ruthenium tetroxide at ordinary temps. by using rubber. CONSTITUTION:The product of natural rubber, chloroprene rubber, silicone rubber, etc. is cut into particles of 1-2mm.<3> which are packed into a collecting tube. Ruthenuium tetroxide is collected by passing a substance contg. the ruthenium tetroxide through the collecting tube.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a collection agent that rapidly reacts with volatile ruthenium tetroxide to collect it and prevents ruthenium tetroxide from flowing out from handling equipment or facilities. It is something.

Compounds of ruthenium, a white metal, have extremely unique properties, and many industrial applications are being actively developed to take advantage of these properties.

One of its unique properties is that although ruthenium tetroxide is a heavy metal oxide, it has a low boiling point, evaporates even at room temperature, and is known to be toxic to the human body. Since the low boiling point of ruthenium tetroxide is significantly different from that of many other metals, it is frequently used in industrial and analytical chemistry to separate it from other metals. In addition, ruthenium tetroxide is formed from many ruthenium compounds by various oxidizing agents, or even in the absence of oxidizing agents when heated in the air, making it an extremely common ruthenium compound.

Nuclear fission of uranium and other materials still produces large amounts of radioactive ruthenium, but some of this has a fairly long half-life and emits gamma rays and strong beta rays. As mentioned above, the chemical properties of ruthenium are both unique and complex.
This is the biggest obstacle when reprocessing nuclear fuel and processing and disposing of radioactive waste. If radioactive ruthenium were accidentally released from these facilities, it is known to be dangerous and contaminate the environment and the human body.

Among these, radioactive ruthenium tetroxide is generated at each stage because nuclear fuel reprocessing is usually carried out as a nitric acid solution, and high temperatures are often used to treat and dispose of waste, and if it leaks, it will cause a light nuisance. It is said to be especially dangerous because it can cause contamination of the human body, and requires sufficient protection.

In the past, it has been known that these countermeasures have not been sufficient, resulting in radioactive contamination of facilities and laboratories, as well as accidents involving humans due to contamination.

In the present invention, although ruthenium tetroxide is a metal oxide, it is easily dissolved in water and organic solvents such as carbon tetrachloride, and has strong covalent bonding properties, so its ionic bonding properties are small and its covalent bonding properties are superior. It was discovered that it reacts well with rubber and quickly and completely fixes it as a non-volatile compound, and based on this discovery, it was found to be useful as a rubber scavenger.

It is already known that ruthenium tetroxide reacts with rubber to deposit a black substance, and it has been reported that it can be used to examine the microstructure of rubber using optical and electron microscopy. In this case, only a portion of the ruthenium tetroxide present in the air is used by reacting with it over time, and there is much interest in what happens to most of the ruthenium tetroxide. Therefore, this is different from the content of the present invention.

As a method for industrially collecting the volatilized radioactive ruthenium tetroxide, the vapor is passed through a refractory brick containing iron oxide heated to about 600°C to collect R,u04 −+ RuO
2↓”-〇2↑ reaction is performed and collected. It is said that the reaction temperature can be lowered by using silica gel containing iron oxide or other silica gel as a scavenger.

In any case, these collection methods require heating the collection agent to a certain temperature range, which not only causes a loss of heat, but also requires a large-scale device, making it difficult to use for small-scale devices or experimental equipment. is difficult to use.

The present invention improves these points and uses rubber or its composition, which is a readily available product, to easily and completely collect ruthenium tetroxide at room temperature. Since the reaction is carried out at room temperature, the present invention can be similarly used for collecting and removing ruthenium tetroxide in an aqueous solution.

Note that since all rubbers are solid, they are easy to handle.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A natural rubber product was cut into small pieces to produce 1-2-sized particles, and one end was filled with a fine-mesh breathable wire mesh, etc., with an inner diameter of 811111.
Fill the rubber tube of No. 1 to a height of 200111N and use it as a collection tube.

Ruthenium compounds are difficult to standardize, and there is no good analytical method for those fixed in collection agents, so we conducted experiments using radioactive ruthenium (Ruthenium-103), and its gamma rays Quantitated.

The experimental equipment consists of an air filtration device followed by a glass reaction vessel, in which an oxidizing agent is used to generate ruthenium tetroxide. The reaction vessel can be heated to a constant temperature using a water bath. Next, place the collection tube, connect the second collection device to the rear of the collection tube,
The rear part of the second collection device is connected to a third collection pipe, and the rear part thereof is connected to a device for sucking air at a constant speed.

A common glass joint is used for each connector up to the third collection tube, and the connections are airtight.

In the experiment, first a certain amount of radioactive ruthenium dissolved in dilute hydrochloric acid is placed in a reaction vessel, and an oxidizing agent and dilute sulfuric acid are added to generate radioactive ruthenium tetroxide. At the same time, the rear suction device is operated to send the generated ruthenium tetroxide together with air to the collection tube, where the radioactive ruthenium is collected by reaction.

After a certain period of time, the collection tube is removed and cut into several predetermined lengths, the cut ends are sealed with adhesive, etc., and used as samples for radioactivity measurement. This measurement sample is placed at a certain distance above a germanium semiconductor detector with lithium diffused in it, surrounded by lead bricks, and the radioactivity is measured using a pulse height analyzer. In this case, the radioactivity value of ruthenium-103, that is, the amount of collected ruthenium can be determined from the magnitude of the 497 keV energy peak obtained in a fixed measurement time.

Figure 1 shows this measurement result by extrapolating this measurement result to the point where the length of the collection tube is 0ctn.
As a side note, it is standardized and graphed. 4゜It is known that in such a reaction trapping device, if the temperature of the device is constant, the trapping efficiency is determined by the speed of the air passing through it. In this experiment, when the air velocity was 50 cc/min (curve 1) and when it was 100 cc/min (curve 2), the latter collection curve was much lower! They come to bed, but they are all 2-3c.
More than 99% in the rn layer, 99.9 in the 10c1n layer
This shows that more than 99% of ruthenium is collected. In addition, almost no ruthenium radioactivity was detected from the second and third collection devices.

When natural rubber is used as a collecting agent in this way, ruthenium tetroxide can be efficiently collected at room temperature. The same amount of ruthenium-103 was used, the air flow rate was 50 CC/min, and the other conditions were as in Example 1.
The experiment was conducted under the same conditions. A good collection curve between the 11th curves 1 and 2 was obtained from the radioactivity measurements.

Example 3 A silicone rubber product was cut into pieces and an experiment was conducted under the same conditions as in Example 2. From the measured radioactivity of the collection agent, 1 in Figure 1.
A good collection curve was obtained, which was almost the same as the curve of .

Example 4 2) Cut the IJ/levtadiene rubber product into pieces, Example 2
The experiment was conducted under the same conditions. From the measured values of the radioactivity of the scavenger, a good scavenging curve between curves 1 and 2 in FIG. 1 was obtained.

Example 5 Small volume boiling point measuring device (written by Seitabe Yamaguchi, Pharmaceutical Magazine No. 434,
When the boiling point of ruthenium tetroxide (non-radioactive) was measured using ruthenium tetroxide (p. 252, 1918), as the heating progressed, the ozone odor characteristic of ruthenium tetroxide was present.
If a longer period of time passes, the objects near you will begin to turn black.

In order to improve this unpleasant and unsanitary situation, we conducted an experiment by connecting a piece of natural rubber (commonly known as Ame-rubber) made of natural rubber with an inner diameter of 5 mm and a length of 300 mm to the opening of the device. Only the inside of the centimeter turned black; there was no ozone odor outside, and the instruments near the centimeter did not darken.

[Brief explanation of drawings]

Figure 1 shows the collection curve of radioactive ruthenium tetroxide using natural rubber particles, and the vertical axis is 10
The count value of radioactivity for 0 seconds is expressed on a logarithmic scale, and the horizontal axis is the distance from the leading end of the collecting agent expressed in m on a diagonal scale. Curve 1 (black circle) in the figure indicates the air flow rate of 5
Curve 2 (white circle) is the same (100 CC/min).
This is the result when it is set as cc/min. Fifth Leap

Claims (1)

[Claims] (1) Rubber as a scavenger for ruthenium tetroxide and its composition. 2. Rubbers and compositions made of natural rubber. 3. Rubber and composition made of chloroprene rubber. 4. Rubber and composition made of silicone rubber. 5. Comb and composition made of nitrile butadiene rubber.