JPS5837244B2 - Method for producing chlorine dioxide - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for producing chlorine dioxide.

Chlorine dioxide is widely used for bleaching pulp and fibers, decolorizing fats, removing phenol from industrial waste, denitrifying salt, and for the same purposes; as a raw material for the production of chlorite, etc. There is.

Chlorine dioxide is produced industrially by refluxing a tetraacid solution of chlorate to generate arsenic acid, and is used in the form of an aqueous solution or a gas depending on the application.

The generation of chlorine dioxide can be caused by using, for example, sodium chlorate or calcium chlorate as a chlorate, hydrochloric acid, sodium chloride, or diacid as a reducing agent, and hydrochloric acid or sulfuric acid as an acid. Each is performed according to the following formula.

2N a C 10 + 4HC l →2C 102
+C I 2 + 2Na C 13 +2H20 (1)
2NaC 10 +2Na. C I +2H2 804
-+2C 1023 +C I 2-1-2Na2SO4-+-2H20
(2) C a (C
103) 2 4HC l→2c 102 +C I
2 +C aCl 2+2H20
(3:12NaCIO3+SO2+H
2SO4→2ClO++2NaHS04
<4) In the chlorine dioxide generation reaction,
Side reactions that may or may not produce chlorine dioxide occur in the main reaction ponds as shown in equations (1) to (4) above.

For example, when the above-mentioned chlorate, reducing agent, and acid are used, the side reactions}1 are each represented by the following formula.

Na C I O3+ 6HC I→3 C l 2
+Na Cl + 3H2 0 (5>NaC10
+5NaCl+3H2So4-)3Cl23 +3Na2SO4+3H20 (6
)Ca(CIO3)2+12HC1-+6Cl2+Ca
Cl26H20
(7) 2NaCIO3+5SO2+4H20-+cl2
+Na2SO4+4H2S04
(8) The above-mentioned main anti-wide P-pack 11 running to the opposite liver differs depending on the firing method and operating conditions.

The generated diacid [arsenic] is diluted with a diluting medium to prevent explosion, or it is absorbed into an aqueous medium and used as an aqueous solution for the above-mentioned applications.

When arsenic diacid is used as a raw material for producing chlorite, usually the by-product chlorine in the arsenic diacid generated gas is separated and removed and used as high-purity chlorine dioxide gas.

In general, the generation efficiency of chlorine dioxide increases as the concentration ratio of chlorate and reducing agent increases, and the rate of generation of arsenic chloride dioxide depends on the respective degrees of chlorate, reducing agent, and acid. It is known.

If the concentration of chlorate, reducing agent, and/or acid changes during chlorine dioxide generation, not only will the chlorine dioxide generation efficiency decrease and the generation rate change, but the chlorine dioxide concentration in the gas phase will also fluctuate. may cause a chlorine dioxide explosion.

For this purpose, in the past, chlorine dioxide, chlorine dioxide, and chlorine in the gas phase of the reaction system and chlorine were fractionated and quantified in the liquid phase, and each component in the liquid phase was manually analyzed. The media feed rate was adjusted manually.

Therefore, in the conventional method, not only does it take a lot of manpower and time to separate and quantify the amount and adjust the amount of supply, but it is also difficult to generate chlorine dioxide gas at a constant concentration because the amount of supply cannot be adjusted accurately. there were.

In addition, in the conventional method, in order to avoid the risk of explosion due to fluctuations in the chlorine dioxide concentration in the gas phase, it was necessary to keep the set value of the chlorine dioxide concentration lower than necessary, but this required excessive equipment. However, it is economically disadvantageous.

In addition, in the conventional method, the chlorine dioxide concentration in the generated gas fluctuates greatly, especially when the operation is performed in batch mode or during unsteady conditions such as when starting or stopping continuous operation, so the chlorine dioxide is absorbed. The concentration of chlorine dioxide in the aqueous solution thus obtained also fluctuates, which sometimes causes problems such as not being able to obtain chlorine dioxide water with a desired concentration.

Therefore, it is possible to automate the chlorine dioxide production process, stably generate chlorine dioxide at the highest possible concentration, keep the concentration of chlorine dioxide water constant at the desired value, and easily switch to a predetermined concentration as necessary. There has been a strong need for a method for producing chlorine dioxide.

The present inventors automated the chlorine dioxide manufacturing process to efficiently and safely generate high-concentration chlorine dioxide at a constant concentration.
As a result of extensive research aimed at providing a method for producing chlorine dioxide that efficiently absorbs the chlorine dioxide into an aqueous solvent, we have developed a chlorine dioxide analyzer and flow rate that automatically separates and quantifies chlorine dioxide or chlorine dioxide and chlorine. By interlocking the control valve and/or metering pump, chlorate, which is the raw material for generating chlorine dioxide, a reducing agent, an acid, a chlorine dioxide diluting medium, an aqueous solvent that absorbs chlorine dioxide, and the aqueous solvent releases S chlorine dioxide. for air one or two
The present inventors have found that the above objects can be achieved by automatically adjusting the supply amounts of at least one supply amount, and have completed the automated production method of chlorine dioxide of the present invention for the first time.

The chlorine dioxide analyzer used in the present invention automatically separates and quantifies chlorine dioxide in the gas phase and/or liquid phase, preferably chlorine dioxide and chlorine, using an optical method, an electrochemical method, or a gas chromatography method. For example, Cigar Da/Fox (S
IGGER-DIOX Japanese Patent Application No. 1977
3-tsu 75956 (see Japanese Patent Application Laid-Open No. 55-4502), 5
3 1 3 (1 0 3 6 (Japanese Unexamined Patent Publication No. 55-5
No. 8458) and No. 53-134.487 (see Japanese Patent Publication No. 55-62356)) can be used.

Figure 1 shows an example of the configuration of a chlorine dioxide analyzer that applies gas chromatography.

When the sample is in a gaseous state, 15 and 16 are closed and the sample gas is guided to the gas sampler 2 through the flow path switching valve 1, and the flow path switching valve 1 is operated to intermittently supply a fixed amount of the sample gas. The analog signal from the detector of the gas chromatograph 3 is amplified by the variable gain amplifier 4, and the analog signal of the gas chromatograph 3 is amplified by the variable gain amplifier 4.
The signal is converted into a digital signal by a D converter 5 and inputted to an electronic computer 6 to calculate the respective concentrations of chlorine dioxide or chlorine dioxide and chlorine.

When the sample is liquid, valves 15 and 16 are closed and the sample liquid is introduced into the gas-liquid equilibrium cell 7 equipped with a temperature sensor 8;
1 to 14 are closed, valves 15 and 16 are opened, air is blown into the gas-liquid equilibrium cell 7 from the air pump 9, and the gas phase is transferred to the flow path switching valve 1.
After circulating the gas through the gas sampler 2 to bring the gas and liquid into an equilibrium state (after 3 to 5 minutes), the flow path switching valve 1 is activated to introduce a certain amount of sample gas into the gas chromatograph 3, and the following steps are performed. Analyze the concentrations of dissolved salt dioxide or chlorine dioxide and chlorine in the same way as for gas samples.

However, the temperature of the sample liquid is detected by the temperature detector 8, and the temperature of the sample liquid is detected by the amplifier 1.
The analyzed value is amplified by 0 and input to the electronic computer 6 via the A/D converter 5 to perform temperature correction on the analysis value.

All of the above-mentioned valves are operated by commands from the electronic computer 6.

In the chlorine dioxide analyzer shown in FIG. 1, a colorimeter or the like may be used instead of the gas chromatograph 3.

Although this chlorine dioxide analyzer can achieve the above-mentioned purpose of the present invention even if the object to be analyzed is only chlorine dioxide, it is better to use a chlorine dioxide analyzer that can analyze the respective concentrations of chlorine dioxide and chlorine than the above-mentioned types 1 to 4. This is preferable because the ratio of the main reactions such as , and the side reactions of formulas 5 to 8 occurring can be calculated, and the amount of generated sac material to be supplied can be more accurately adjusted.

The chlorine dioxide analyzer is coupled via an interface and a transmitter to a flow control valve and/or metering pump for the supply of generated raw material, aqueous solvent and/or air for chlorine dioxide dispersion.

The chlorine dioxide analyzer analyzes the concentration of chlorine dioxide and chlorine in the generated gas and sends an analog or digital signal to the interface, which also receives the signal from the generated gas flow rate word 1 and analyzes the concentration of chlorine dioxide and chlorine in the generated gas. Each flow rate of chlorine is calculated and compared with each predetermined flow rate value, and the calculated results are transmitted through a transmitter to an air signal or an electric signal to operate the flow rate control valve and/or the metering pump to calculate the amount of generated raw material. The feed rates of one or more of a certain chlorate, a reducing agent, an acid, and a chlorine dioxide diluent are automatically adjusted to efficiently and safely generate a high concentration of chlorine dioxide at a constant concentration.

Furthermore, the interface calculates the flow rate of chlorine dioxide originating from the generated gas, compares it with a predetermined flow rate value, and transmits the calculated result to an aqueous solvent flow rate control valve or metering pump via an air signal or electric signal via a transmitter. The system automatically adjusts the amount of aqueous solvent supplied to efficiently produce chlorine dioxide water at a predetermined concentration.

In addition, a part of the chlorine dioxide water is introduced into the chlorine dioxide analyzer to analyze the concentration of chlorine dioxide in the chlorine dioxide water, and the interface compares the concentration with a predetermined concentration value using a flow control valve or a metering pump for the aqueous solvent. The chlorine dioxide water can also be adjusted to a predetermined concentration by automatically adjusting the supply amount of the aqueous solvent.

When removing the by-product chlorine in the generated gas to produce high-purity chlorine dioxide gas, the generated gas is absorbed into an aqueous solvent in which chlorine has low solubility, and then air is introduced to produce high-purity chlorine dioxide gas. A portion of the emitted gas is guided to the chlorine dioxide analyzer to analyze the respective concentrations of chlorine dioxide or chlorine dioxide and chlorine, and the interface compares the concentrations with predetermined concentration values of the aqueous solvent and/or The air flow control valve is operated to automatically adjust the supply amount of the aqueous solvent and/or the air to efficiently and stably produce high-purity chlorine dioxide gas at a constant concentration.

Any flow control valve, such as a pneumatic type or an electronic type, can be used as the flow control valve to be linked with the chlorine dioxide analyzer.

As the metering pump, a remotely operated one can be used.

Examples of chlorates used in the present invention include chlorates of alkali metals such as sodium and potassium; chlorates of supra-alkali metals such as magnesium and calcium; examples of reducing agents include hydrochloric acid; Chlorides of alkali metals such as helium and potassium and alkaline metals such as magnesium and calcium; sulfur dioxide; methanol, etc.; sulfuric acid, hydrochloric acid, etc. can be used as the acid, and air is used as the chlorine dioxide dilution medium. or steam can be used.

In addition, as the aqueous solvent, water or a dilute aqueous solution of an acid is used, and as the acid, mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid are preferable, and when producing high-purity chlorine dioxide gas, dilute hydrochloric acid with low chlorine solubility is used. is preferred.

Furthermore, the present invention can be applied to either continuous or batch production methods.

According to the present invention, chlorine dioxide can be generated at a desired concentration and at a constant concentration, so even if the chlorine dioxide concentration is set to about 15 volumes (compared to the conventional method), only 10
(The capacity could only be around φ) and can be operated safely.

Therefore, compared to the conventional method, the production capacity per unit volume of the generating tank can be increased, and when the operation is performed in batches, the operation time per batch can be shortened.

Furthermore, even during unsteady operation, such as when starting or stopping operation, chlorine dioxide water with a desired constant concentration can always be produced.

Furthermore, automation of the manufacturing process saves labor and reduces labor costs.The present invention will now be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 High purity chlorine dioxide gas was produced in a batch manner using the production process shown in FIG.

A sodium chlorate aqueous solution (Na.CI03
320g/A, NaC18 0&/A! ) 3.
4 @' was charged with the liquid supply pump 43, heated to 40°C, and then pumped with 35φ hydrochloric acid (7 to 8 l/min) by the pump 42 and air (2.5 to 3.5 NmA) through the flow rate control valve 41.
j-) to generate 15 volumes of chlorine dioxide gas (2.5 to 3.5 ml), and the generated gas is passed through the flowmeter 33.
It is led to the refining tower 23 through.

The purification tower 23 is connected to an absorption tower 22 and a radiation tower 24 as shown in FIG. The chlorine dioxide is absorbed by the diluted hydrochloric acid, led to the stripping tower 24, and diffused by air (5 to 7 Nml) introduced through the flow rate control valve 45, resulting in a chlorine dioxide concentration of 7.5% by volume and purity (97%).
) is produced and sent to the sodium chlorite production process.

On the other hand, chlorine and a small amount of chlorine dioxide not absorbed in the purification tower 23 are removed by air (0.5
~0.7Nml) is sent to the absorption tower 22, where the chlorine dioxide is absorbed into the diluted hydrochloric acid, and then sent to the purification tower 23 again.
On the other hand, chlorine and a very small amount of chlorine dioxide that were not absorbed in the absorption tower 22 are sent to the absorption tower 26 and circulated through the circulation pump 62.
Sodium hydroxide is circulated by l-. It is absorbed into an IJium aqueous solution (240 g/l) and returned to the electrolytic process to be reused as sodium chlorate.

A part of the inlet gas of the purification tower 23 and a part of the outlet gas of the stripping tower 24 are introduced into a cigar gas analyzer (the above-mentioned chlorine dioxide analyzer) 31 to automatically separate and quantify the concentrations of chlorine dioxide and chlorine.

The cigar gas gas 31 is configured as shown in FIG. 1, and automatically adjusts the two types of sample gases to 0.0 and 0.000, alternately at 3-minute intervals, according to instructions from the electronic computer 6. 5 rul sampling and gas chromatograph 3 (column inner diameter 3
Stainless steel column with a length of 3m, the packing material is diatomaceous earth supporting 10φ of polychlorinated biphenyl, the column temperature is 408C1, the carrier gas is helium 60m
The electric signal is amplified by a variable gain amplifier 4, converted into a digital signal by an A/D converter 5, and then sent to an electronic computer 6. to calculate the respective concentrations of chlorine dioxide and chlorine.

Cigar gas 31 is connected via an interface 32 and a transmitter 34 to a flow control valve 41 for air diluted with chlorine dioxide, a metering pump 42 for supplying 35% hydrochloric acid, a flow control valve 44 for air for dispersing chlorine gas, and a flow control valve 44 for high-purity chlorine dioxide gas. They are respectively interlocked with the flow rate control valve 45 for the dispersion air.

The interface also receives signals from the generated gas flowmeter, calculates the flow rate of chlorine dioxide and chlorine in the generated gas, and calculates the set value (CIO2 15 capacity 1 1 0 kg./h).
), the transmitter 34 converts the result into an electrical signal and operates the flow control valve 41 and/or metering pump 42 to automatically control the amount of air for diluting generated chlorine dioxide and the amount of hydrochloric acid (35) supplied. Adjust.

For example, if the concentration of chlorine dioxide in the generated gas is the set value (15
If the amount of chlorine dioxide generated is higher than the set value (110 kg
/h), reduce the supply amount of 35% hydrochloric acid and automatically adjust to the respective set values.

Furthermore, the interface 32 compares the concentrations of chlorine dioxide and chlorine in the outlet gas of the stripping tower 24 with set values (7.5 and 0.2 volume ff, respectively) and sends the results to the transmitter 3.
4, the signal is converted into an electric signal and the flow rate control valves 44 and 45 are operated to automatically adjust the supply amount of the dissipation air.

For example, if the chlorine dioxide concentration is lower than the set value (J,
The amount of air supplied to the stripping tower 24 is reduced, and if the chlorine concentration is higher than the set value, the amount of air supplied to the purification tower 23 is increased, and each is automatically adjusted to the set value.

The results of producing high-purity chlorine dioxide gas using the above production process are shown in Table 1 and Figure 2.

Comparative Example 1 The concentrations of chlorine dioxide and chlorine in the inlet gas of the purification tower 23 and the outlet gas of the stripping tower 24 were manually analyzed every 3 hours, and the concentrations of the generated gas absorption air, 35 polyhydrochloric acid, the purification tower 23 and the stripping tower were analyzed by hand. High purity chlorine dioxide gas was produced in the same manner as described above, except that the supply amount of the diffusion air supplied to No. 24 was manually adjusted.

However, in order to avoid the danger of explosion, the concentrations of the generated gases were set to 28.0 volumes of CIO and 20.2 volumes of Cl.

The results are shown in Table 1 and Figure 2.

Figure 2 shows the relationship between the chlorine dioxide concentration in the generated gas and the reaction time.As is clear from this figure and Table 1, the method of the present invention is much more effective than the conventional method. The reaction time required to generate a given amount of chlorine dioxide is greatly reduced, reducing the cycle time of manufacturing equipment and increasing productivity. will improve.

Further, the concentration of the chlorine dioxide gas diffused from the stripping tower 24 can be set to a much higher concentration than in the conventional method, and the concentration and purity can be substantially constant.

Furthermore, since the manufacturing process is automated, labor is saved and labor costs are reduced.

(1) Values excluding the values immediately after the start of the reaction and immediately before the end of the reaction.

Chlorine dioxide concentration (volume %), concentration (capacity ratio)? CI] is Chlorine Example 2 Figure 4 shows the process of reducing sodium chlorate with sodium chloride to generate chlorine dioxide and absorbing it into water to produce chlorine dioxide water.

98 polysulfuric acid was introduced into the generation tank 21 containing about two-thirds of water using the metering pump 46, and an aqueous solution of about 10N sulfuric acid was prepared, which was indirectly heated with steam and maintained at 40°C.

Then metering pumps 46-4 whose strokes are automatically adjusted.
8 and flow rate control valve 49, 98% sulfuric acid 1.6~
2. ol. /min, 700g/l sodium chlorate aqueous solution 164~1.817min, 300g/l sodium chloride aqueous solution 1.7~2.3Vmin, and air 1000~
It is continuously supplied to the generation tank 21 at a rate of 1500 l/min.

Chlorine dioxide, a mixed gas of chlorine and air generated in the generation tank 21 is sent to the absorption tower 28 through the flow meter 33, where the chlorine dioxide is absorbed by water supplied through the flow rate control valve 50 and becomes chlorine dioxide water. It is stored in a storage tank 29.

At the same time as each raw material is supplied, a part of the mixed gas at the outlet of the generation tank 21 is introduced into the Cigar Diox chlorine oxide analyzer 31 of Example 1, and the concentrations of chlorine dioxide and chlorine are automatically separated and quantified by the method described above. , the output proportional to each concentration and the output of the flowmeter 33 were led to the interface 32.

The interface 32 receives the output from the chlorine dioxide analyzer 31 and the flowmeter 33 and performs the following operation.

The generated amount of chlorine dioxide and chlorine is calculated and compared with a predetermined value (chlorine dioxide 0.7 kg/min). If the value is negative, a signal is sent via the transmitter 34 to reduce the discharge amount. If the value is the same, the signal to increase the discharge amount is sent to metering pump 4.
6, and the amount of 98% sulfuric acid supplied was automatically adjusted.

In addition, the chlorine dioxide concentration in the mixed gas at the outlet of the generation tank is compared with a predetermined value (1.4%), and based on the result, a signal is sent to the flow control valve 49 in the same manner to automatically adjust the air supply amount. did.

Further, the ratio between the chlorine dioxide concentration and the chlorine concentration in the mixed gas at the outlet of the generation tank is set to a predetermined value ((CIO,]/(Cl 2
) - 1.87) Based on the results, a signal was sent to metering pumps 47 and 48 in a similar manner to automatically adjust the ratio of the supply amounts of sodium chlorate and sodium chloride.

In addition, a part of the chlorine dioxide water at the outlet of the absorption tower 28 is led to a Cigar Diox chlorine dioxide analyzer, the chlorine dioxide concentration is separately quantified, and a signal is sent to the flow rate control valve 50 in the same manner to prevent the water from flowing into the absorption tower. The supply amount was automatically adjusted.

Table 2 shows the results of continuous operation for 100 hours in the above manufacturing process.

Comparative Example 2 Chlorine dioxide gas was analyzed every 8 hours, and 98φ sulfuric acid, 7
0 0 &/l sodium chlorate l-IJium aqueous solution, 3
Example 1 was carried out in the same manner as in Example 2, except that the feed rates of 0 0 g/l sodium chloride, air and water were manually adjusted.
The results of continuous operation for 00 hours are shown in Table 2.

As is clear from Table 2, the method of the present invention was able to efficiently and safely generate high-concentration chlorine dioxide at a constant concentration.

In addition, the concentration of chlorine dioxide in the product chlorine dioxide water could be kept constant.

Example 3 FIG. 5 shows the process of reducing sodium chlorate with sulfur dioxide gas to generate chlorine dioxide and absorbing it into water to produce chlorine dioxide.

98 polysulfuric acid was introduced into the generation tank 21 containing about two-thirds of water using the pump 51 to prepare a sulfuric acid aqueous solution of about 1'O normality, which was indirectly heated with steam and maintained at 35°C.

Next, pump 51, pump 52, flow rate control valve 53, and flow rate control valve 54 are operated, and 98% sulfuric acid is applied at 0.4 to 0.6V.
min, 6009/l sodium chlorate 1.6-2.
The gas was continuously supplied to the generating tank 21 at a rate of 2 l/min, sulfur dioxide gas at a rate of 120 to 180 l/min, and air at a rate of 1,300 to 1,600 l/min.

The pumps 51, 52,
The flow control valves 53, 54 and 55 were adjusted to produce chlorine dioxide water.

Table 3 shows the results of 100 hours of continuous operation in the above manufacturing process.

Comparative Example 3 Chlorine dioxide gas was manually analyzed every 8 hours, and 98φ sulfuric acid,
Table 3 shows the results of continuous operation for 100 hours in the same manner as in Example 3, except that the supply amounts of the 600 g/l sodium chlorate aqueous solution, sulfur dioxide gas, air, and water were manually adjusted.

Example 4 In the manufacturing process shown in FIG. 6, calcium hydroxide was reduced with hydrochloric acid to continuously generate chlorine dioxide gas.

The generation tanks 211 to 214 consist of four tanks, which are connected in series in a cascade manner as shown in FIG.
Hold at 0'0 and 60'C respectively.

Calcium chlorate solution (Ca(CIO3)
)2500 g/l, CaCl2300 gA:15
~20 l/min) and 35% hydrochloric acid (45 to 717%) are continuously supplied by adjusting their respective flow rates using metering pumps 56 and 57 whose strokes are automatically adjusted.

On the other hand, air (2 to 4 Nrl/'
A-) is continuously supplied by adjusting the flow rate with the flow rate control valve 5B to bubble and dilute the chlorine dioxide in the reaction solution, and generate chlorine dioxide gas (set concentration CIO2) from the generation tank 211 of the uppermost tank.
15 volume) is drained.

A part of the exhaust gas was introduced into the cigar diox used in Example 1, and the supply amounts of the calcium chlorate aqueous solution, hydrochloric acid, and air were adjusted to the set concentration and flow rate (11 sk6/h) in the same manner as in Example 1. ) is automatically adjusted to obtain chlorine dioxide gas.

Table 4 shows the results when the above manufacturing process was continuously operated for 100 hours.

Comparative Example 4 Chlorine dioxide in the outlet gas of the generation tank 211 was manually analyzed.
Continuous operation was carried out for 100 hours in the same manner as in Example 4, except that the feed rate of the generated raw material was adjusted manually.

However, in order to avoid the risk of explosion, the concentration of the outlet gas was set to be well above the capacity of CIO210.

The results are shown in Table 4.

[Brief explanation of the drawing]

Figure 1 shows the configuration of the chlorine dioxide analyzer, Figure 2 shows the batch manufacturing process according to the present invention, Figure 3 shows the relationship between chlorine dioxide concentration and reaction time, and Figures 4 to 6 show the method according to the present invention. This is a continuous manufacturing process diagram. 1 is a gas flow path switching valve, 2 is a gas sampler, 3 is a gas chromatograph, 4 is a variable gain amplifier, 5 is an A/D converter, 6 is an electronic computer, 7 is a gas-liquid equilibrium cell, 8 is a temperature detector, 9 is an air pump, 10 is an amplifier, 11 to 16 are valves,
21 and 211-214 are generation tanks; 22. 26 and 28 are absorption towers, 23 is a purification tower, 24 is a stripping tower, 25 and 27 are receiving tanks, 31 is a Shikani-Giotsu nitride chlorine oxide analyzer, 3
2 is an interface, 33 is a flowmeter, 34 is a transmitter,
41, 44, 45, 49, 50, 53, 54, 55 and 5
8 is a flow control valve, 42, 46, 47, 48, 51, 5
2, 56 and 57 are metering pumps whose strokes can be automatically adjusted, 43, 61 and 62 are pumps, and 29 is a storage tank.

Claims (1)

[Claims] 1. A method for producing diacid f arsenic which comprises reducing an acidic solution of chlorate to generate diacid [arsenic],
A chlorine dioxide analyzer that automatically separates and quantifies the concentration of chlorine dioxide is linked with a flow rate control valve and/or a constant discharge pump to collect chlorate, which is the raw material for generating chlorine dioxide, acid, reducing agent, and chlorine dioxide diluent medium. A method for producing chlorine dioxide with little concentration fluctuation, characterized by automatically adjusting the supply amount of one or more of an aqueous solvent for absorbing chlorine dioxide and air for dissipating chlorine dioxide from the aqueous solvent. 2. The method for producing chlorine dioxide according to claim 1, wherein the chlorine dioxide analyzer is a chlorine dioxide analyzer that automatically separates and sets the concentrations of diacid [arsenic and chlorine]. 3. The method for producing chlorine dioxide according to claim 1 or 2, wherein the aqueous solvent is dilute hydrochloric acid. ? The method for producing arsenic acid diacid according to claim 1 or 2, wherein the aqueous solvent is water.