JPS5883259A - Measuring method for cyanogen concentration - Google Patents

Abstract

PURPOSE:To analyze continuously concn. of a cyanogen compd. in a short time, by separating and extracting gaseous hydrogen cyanide in a sample through a gas permeation tube, and allowing an aq. soln. of sodium hydroxide in said tube to absorb it. CONSTITUTION:A sample is introduced into a device through a sample introduction tube 6 with a pump P1, simultaneously acid and a complexing agent are introduced through their introduction tube 7 with a pump P2 as analytical reagents, resulting in acidifying the sample and converting free cyanide and a part of complex cyanogen of the total cyanogen of the sample into hydrogen cyanide. In this state, the complex cyanogen is almost perfectly converted into HCN when the sample enters a UV irradiation tube 9. The sample enters a gas permeation tube 10 consisting of porous plastic tubes made of ''Teflon '' or silicon rubber or the like transmitting a gas but not water, where HCN is absorbed into an aq. soln. of sodium hydroxide in the inside through the walls of the tubes to give cyanogen ion. The ions are sent to an ion electrode 11 with a pump P3 to produce potential in accordance with cyanogen ion concn, permitting the concn. to be determined by measuring the potential with a voltmeter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring cyanide concentration, and provides a method for measuring the concentration of cyanide in a sample continuously and in a short time.

Conventionally, as shown in Figure 1, in this type of product, a certain amount of sample 3 is adjusted to acidity and then placed in a gas cleaning bottle 2, and the air from which carbon dioxide has been removed is vented through the air inlet 1 and distilled out. Hydrogen cyanide gas was collected in a gas washing bottle 4 with a filter plate containing a sodium hydroxide solution 6. However, in the conventional method described above, it takes a long time (about 1 hour) to distill off the hydrogen cyanide in the sample.
and sample processing cannot be performed continuously.
It has drawbacks such as difficulty in applying it to automatic measuring devices that perform continuous measurements.

The present invention eliminates these conventional drawbacks,
An embodiment of the present invention will be described below with reference to the drawings. Figure 2 is a block diagram of the cyan measuring device. In Figure 1, 6 is the sample introduction lower, acid and complexing agent inlet;
8 is a sodium hydroxide solution inlet, 9 is a Shiba external beam irradiation tube,
10 is a gas permeation tube, 11 is an ion electrode, 12 is a sample drain, 13 is a sodium hydroxide drain, Pl, P2.
P3 are sample, acid + silvering agent, and sodium hydroxide injection pump, respectively. FIG. 3 is a configuration diagram of the gas permeation tube 10. In FIG. 3, 14 is a sample inlet provided in the gas permeation tube case 15, 16 is a sample drain provided in the gas permeation tube case 15, and 17 is 18 is a sodium hydroxide drain; 19 is a gas permeation tube made of a porous plastic tube such as Teflon or silicone rubber; Connected to sodium drain 18.

Next, the operation based on this configuration will be described.

A sample is introduced into the apparatus through the sample inlet 6 by the pump P1. At the same time, an acid and a complexing agent are introduced as analysis reagents from the acid and complexing agent introduction lower part by pump P2, and are injected into the reagent, making the sample acidic. part becomes hydrogen cyanide. When the sample enters the Shiba external ray irradiation tube 9 in this state, the complex cyanide in the sample becomes almost completely hydrogen cyanide, and enters the gas permeation tube 1o through the sample inlet 14. Complexing agents are used to stabilize decomposed hydrogen cyanide. Gas permeation tube 1
o has the structure shown in FIG. 3, and a sample containing hydrogen cyanide is placed in the gas permeation tube case 15. A gas permeable tube 19 made of a porous plastic tube such as Teflon or silicone rubber that allows gas to pass through but not water is attached to the center of the gas permeable case 16. Inside this gas permeable tube 19, 0.1 to 0.6 mol/
1 sodium hydroxide solution is flowing, and the hydrogen cyanide contained in the sample flowing outside the gas permeation tube 19 passes through the gas permeation tube 19 and is absorbed into the IJium solution and becomes cyanide. It becomes an ion. When the sodium hydroxide solution containing cyanide ions is sent to the ion electrode 11 by the pump P3, a potential corresponding to the cyanide ion concentration is generated, so the cyanide ion concentration can be determined by measuring this potential with a voltmeter. .

With this configuration, the cyan concentration of the sample can be continuously measured. In addition, gas permeable tube 1
In step 9, it is not necessary to absorb 100% of the hydrogen cyanide in the sample; it is sufficient to keep the flow rate of the sample and the sodium hydroxide solution constant, and calibrate with the standard solution to create a calibration curve. Therefore, the measurement time can be shortened compared to conventional aeration methods. That is, according to the present invention, what conventionally took one hour can be shortened to five minutes. Note that there is also an example of the configuration of the gas permeation tube shown in FIG. 4. This configuration integrates the Shiba external ray irradiation tube and the gas permeation tube, and in addition to the above-mentioned effects, a complexing agent is not required. Fourth
In the figures, the same parts as in the previous embodiment are given the same numbers. 20 is a Shiba external beam irradiation tube, and 21 is an O-ring.

The present invention has the above configuration, and has the advantage that the concentration of cyanide in a sample can be analyzed continuously and in a short time.

[Brief explanation of the drawing]

Fig. 1 is a front view of a part of a conventional cyan concentration measuring device, Fig. 2 is a block diagram of a measuring device implementing a cyan concentration measuring method according to an embodiment of the present invention, and Fig. 3 is a gas permeation of the same device. FIG. 4 is a cross-sectional view of a gas permeable tube according to another embodiment of the present invention. 6... Sample inlet, 7... Acid, complexing agent inlet, 8... Sodium hydroxide solution inlet,
9...Shiba external beam irradiation tube, 1o...Gas permeation tube, 11...Ion electrode, 12...
Sample drain, 13... Sodium hydroxide drain, 14... Sample inlet, 16...
Gas permeation tube case, 16...Sample drain, 1
7... Sodium hydroxide inlet, 18...
...Sodium hydroxide drain, 19...Gas permeation tube, 2o...Shiba external radiation tube, 21.
...0 ring. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure (g)

Claims (1)

[Claims] A sample is poured outside a gas permeable tube made of a porous plastic tube, and an aqueous IJ solution is poured into the inside of the gas permeable tube, and hydrogen cyanide gas in the sample is separated by the gas permeable tube. ,
A method for measuring cyanide concentration, which comprises extracting and absorbing cyanide into an aqueous sodium hydroxide solution in the gas permeable tube, and measuring the concentration of cyanide ions in the aqueous sodium hydroxide solution.