WO2017033825A1

WO2017033825A1 - Water treatment agent composition for cyanogen-containing waste water

Info

Publication number: WO2017033825A1
Application number: PCT/JP2016/074086
Authority: WO
Inventors: 平嶋英則
Original assignee: 株式会社片山化学工業研究所
Priority date: 2015-08-21
Filing date: 2016-08-18
Publication date: 2017-03-02

Abstract

Provided is a water treatment agent composition for cyanogen-containing waste water, the water treatment agent composition having improved stability and containing a monovalent copper salt in one or a plurality of embodiments. The present invention relates to a water treatment agent composition for cyanogen-containing waste water, the water treatment agent composition containing: (A) cuprous chloride; (B) at least one selected from the group consisting of an alkali metal chloride, an alkali metal bromide, an alkaline earth metal chloride, and an alkaline earth metal bromide; and (C) inorganic acids and/or organic acids. The content of the (C) inorganic acids and/or organic acids in the water treatment agent composition is 10 weight% or less, and the pH of the water treatment agent composition is 2 or less.

Description

Water treatment composition for cyanide-containing wastewater

The present disclosure relates to a water treatment composition for cyanide-containing wastewater and a method for treating cyanide-containing wastewater.

Since cyan has a strong adverse effect on the ecosystem, cyanate-containing wastewater cannot be released into nature as it is. For cyanide, drainage standards are established based on the Water Pollution Control Law, and cyan removal processing is performed to satisfy this standard (1 mg / L or less), and wastewater cannot be discharged unless it is detoxified wastewater. ing. In addition, there are many areas that have established additional drainage standards that are even lower than the above-mentioned drainage standards due to regulations.

As a method for removing cyan in waste water containing cyanide, Patent Document 1 discloses a reaction equivalent with cyanide in waste water without substantially adding zinc and ozone treatment to waste water containing free cyanide and cyanate complex salt. Disclosed is a treatment method characterized by adding the above divalent copper salt and a reducing agent to form a hardly soluble precipitate and separating it.

Patent Document 2 discloses that after adding a ferric salt and a cuprous salt in an amount capable of removing cyan contained in cyanine-containing wastewater in a weight ratio of 16: 1 to 1: 1, Disclosed is a method for treating cyanide-containing wastewater, characterized in that the pH of the wastewater is adjusted to 6 to 8, the generated water-insoluble salt is removed from the wastewater, and cyan in the wastewater is removed.

JP-A-2-48315 Japanese Patent No. 4639309

It is a monovalent copper salt that forms a hardly soluble precipitate with cyanide in a waste liquid containing free cyanide and cyanate complex salt (hereinafter referred to as “cyan-containing waste liquid”). Therefore, when a water treatment agent composition containing a monovalent copper salt was prepared in order to easily treat wastewater containing cyanide, precipitation, dust, or both occurred, and stability improvement was necessary as a formulation. The problem of being was found.

The present disclosure provides a water treatment agent composition for cyanide-containing wastewater containing a monovalent copper salt with improved stability in one or more embodiments.

The present disclosure, in one aspect, is a water treatment composition for cyanide-containing wastewater,
(A) cuprous chloride,
(B) at least one selected from the group consisting of alkali metal chlorides, alkali metal bromides, alkaline earth metal chlorides, and alkaline earth metal bromides, and
(C) contains an inorganic acid and / or an organic acid,
The water treatment agent composition wherein the content of the (C) inorganic acid and / or organic acid in the water treatment agent composition is 10% by weight or less, and the pH of the water treatment agent composition is 2 or less. (Hereinafter also referred to as “water treatment agent composition according to the present disclosure”).

In another aspect of the present disclosure, the water treatment agent composition according to the present disclosure is added to cyanide-containing wastewater so as to have cuprous chloride having a reaction equivalent to or higher than cyanide in the wastewater. The present invention relates to a method for treating cyanogen-containing wastewater, which comprises producing a soluble substance and separating the hardly soluble substance.

In one or a plurality of embodiments, the water treatment agent composition for cyanide-containing wastewater of the present disclosure can exhibit an effect that precipitation and turbidity are suppressed and stability as a preparation is improved. In one or a plurality of embodiments, the water treatment agent composition for cyanide-containing wastewater of the present disclosure can further exhibit an effect that handling properties are improved.

FIG. 1 is a schematic diagram showing an example of a cyan-containing wastewater treatment apparatus used in a method for treating cyan-containing wastewater.

In the present disclosure, the problem that turbidity and precipitation occur when a preparation containing cuprous salt is prepared to treat cyanide-containing wastewater is solved by adding a predetermined amount of alkali metal chloride and acid. Based on the knowledge that it can.

[Cyanide wastewater]
Examples of the cyanate-containing wastewater to be treated in the present disclosure include wastewater discharged from an iron factory, a chemical factory, a plating factory, a coke manufacturing factory, a metal surface treatment factory, and the like. Cyan-containing wastewater containing a cyanide compound, cyanide, cyanide complex salt, cyano complex ion and the like can be mentioned. In one or a plurality of embodiments, the water treatment agent composition according to the present disclosure can suitably perform treatment of cyanide-containing wastewater having a strong buffering action such as coke oven wastewater.

[Component A: Cuprous chloride]
Component A in the water treatment agent composition according to the present disclosure is cuprous chloride. Monovalent copper ions come into contact with free cyanide, cyanide complex salts, and the like in wastewater to form hardly soluble substances. The poorly soluble material is a precipitate in one or more embodiments. By removing the hardly soluble substance, cyan can be removed from the wastewater.

In one or more embodiments, the content of component A in the water treatment agent composition according to the present disclosure is preferably 1.5% by weight or more, more preferably 5% by weight, from the viewpoint of improving the stability of the composition. % To 15% by weight.

[Component B: Alkali metal chloride, etc.]
Component B in the water treatment agent composition according to the present disclosure is at least one selected from the group consisting of alkali metal chlorides, alkali metal bromides, alkaline earth metal chlorides, and alkaline earth metal bromides. Examples include sodium chloride, calcium chloride, magnesium chloride, sodium bromide, and magnesium bromide. Component B may be one type or two or more types. In one or a plurality of embodiments, Component B in the water treatment agent composition according to the present disclosure is selected from the group consisting of alkali metal chlorides and alkaline earth metal chlorides from the viewpoint of improving the stability of the composition. At least one is preferred. Alkali metal chlorides and alkaline earth metal chlorides include sodium chloride, calcium chloride, and magnesium chloride in one or more embodiments.

In one or more embodiments, the content of Component B in the water treatment agent composition according to the present disclosure is preferably 1% by weight or more and 45% by weight or less, more preferably, from the viewpoint of improving the stability of the composition. 1% by weight or more and 35% by weight or less.

[Component C: Acid]
Component C in the water treatment agent composition according to the present disclosure is an inorganic acid, an organic acid, or a combination of an inorganic acid and an organic acid. Component C may be one type or two or more types. Examples of the inorganic acid include hydrochloric acid, nitric acid, and sulfuric acid in one or a plurality of embodiments. Examples of the organic acid include, in one or a plurality of embodiments, an oxycarboxylic acid, a polyvalent carboxylic acid, an aminopolycarboxylic acid, And amino acids.

In one or more embodiments, the content of Component C in the water treatment agent composition according to the present disclosure is preferably such that the pH of the water treatment agent composition is 2 or less from the viewpoint of improving the stability of the composition. Is the amount. In one or a plurality of embodiments, the content of component C in the water treatment agent composition according to the present disclosure is preferably a concentration that is not designated as a deleterious substance, more preferably from the viewpoint of improving the handleability of the composition. It is 10 wt% or less, more preferably 5 wt% or less, and even more preferably 1 wt% or less.

[Component D: Sodium sulfite]
In one or a plurality of embodiments, the water treatment agent composition according to the present disclosure is a compound that forms sodium sulfite as a component D or sodium sulfite in an aqueous solution (such as sodium bisulfite) from the viewpoint of improving the stability of the composition. ) May be contained.

In one or more embodiments, the content of component D in the water treatment agent composition according to the present disclosure is preferably 1% by weight or less, more preferably 0.1% by weight, from the viewpoint of improving the stability of the composition. % Or less, more preferably 0.01% by weight or less, and still more preferably 0.005% by weight or less.

[Component E: Water]
The water treatment composition according to the present disclosure may be water (component E) other than the components A to C or A to D described above. As the water, industrial water, tap water, distilled water, ion-exchanged water, ultrapure water, or the like can be used. Alternatively, the water treatment agent composition according to the present disclosure may include the following other components in addition to the components A to E within a range not impairing the stability of the composition.

[Other ingredients]
The water treatment agent composition according to the present disclosure may be used in combination with known agents such as a rust inhibitor, a corrosion inhibitor, a scale dispersant, and a slime control agent as long as the effects of the present invention are not impaired.

[PH]
The water treatment agent composition according to the present disclosure has a pH of 2 or less, preferably 1.7 or less, from the viewpoint of improving the stability of the composition.

The water treatment composition according to the present disclosure may be distributed as a concentrate in one or a plurality of embodiments. In one or a plurality of embodiments, the concentrate of the water treatment composition according to the present disclosure can be used by diluting the components A to D so as to have the above-described content at the time of use.

[Preparation of water treatment composition]
The water treatment composition according to the present disclosure can be prepared by mixing the above components A to E. In one or more embodiments of the preparation of the water treatment agent composition according to the present disclosure, a bubbling treatment with nitrogen gas may be performed in order to obtain a more stable water treatment agent composition.

In one or a plurality of embodiments, the water treatment agent composition according to the present disclosure may be stored in a container such as a polytank, or may be used in a state stored in a storage tank or container. .
In one or a plurality of embodiments, after introducing the water treatment agent composition according to the present disclosure into a container such as a polytank from the viewpoint of being able to be stored in a state where stability is maintained for a longer period in a container such as a polytank, The space in the container may be purged (replaced) with an inert gas such as nitrogen or argon. Therefore, the form arrange | positioned in the container purged with the inert gas as one or some embodiment of the water treatment agent composition which concerns on this indication is mentioned.
In one or a plurality of embodiments, the water treatment agent composition according to the present disclosure is introduced into a storage tank, a container, or the like from the viewpoint of being usable in a state where the stability is maintained for a longer period of time by putting it in a storage tank, a container, etc. After that, the space in the storage tank or container may be brought into a slightly pressurized state (1 to 5 kPa) from the atmospheric pressure with an inert gas such as nitrogen or argon. In one or a plurality of embodiments, the slightly pressurized state can be maintained by attaching a regulator (precision pressure regulator) and a flow meter with a needle valve to an inert gas cylinder arranged in a storage tank or a container. Therefore, the form arrange | positioned in the container maintained in the slightly pressurized state as one or some embodiment of the water treatment agent composition which concerns on this indication is mentioned.

The present disclosure relates, in one aspect, to a method for preparing a water treatment agent composition for cyanide-containing wastewater, which comprises mixing the above components A to C and optionally component D and / or component E. In one or a plurality of embodiments, a method for preparing a water treatment agent composition according to the present disclosure includes arranging a mixed composition in a container such as a polytank, and purging the container in which the composition is arranged with an inert gas. May include. In addition, in one or a plurality of embodiments, the method for preparing a water treatment agent composition according to the present disclosure is a composition obtained by mixing the above components A to C and, if necessary, the component D and / or the component E. The inside of a space such as a storage tank or a container in which is placed may be made to be slightly pressurized from the atmospheric pressure by an inert gas. Examples of the slightly pressurized state include, in one or a plurality of embodiments, a state in which 1 to 5 kPa or 2 to 5 kPa is pressurized from atmospheric pressure.

[Treatment method of wastewater containing cyanide]
The water treatment agent composition according to the present disclosure can be used for cyan removal treatment of cyanide-containing wastewater. Accordingly, in one aspect, the present disclosure is a method for treating cyan-containing wastewater, and the water treatment according to the present disclosure is such that the cyan-containing wastewater has cuprous chloride having a reaction equivalent to or higher than cyan in the wastewater. Adding an agent composition to form a hardly soluble substance of cyanide and separating the hardly soluble substance.

The content of cyan in the cyan-containing wastewater to be treated in the treatment method according to the present disclosure is not particularly limited, but wastewater having a total cyan concentration of 2 to 100 mg / L can be suitably treated. In the case of treating such cyanide-containing wastewater, in one or a plurality of embodiments, the water treatment agent composition according to the present disclosure is converted to cyanide-containing wastewater so as to be cuprous chloride having a reaction equivalent to or higher than cyanide. Alternatively, the water treatment agent composition according to the present disclosure may be added to the cyanide-containing waste water so that cuprous chloride is 4 to 1000 mg / L, preferably 10 to 100 mg / L. Can be mentioned.

In one or a plurality of embodiments, the water treatment method according to the present disclosure is configured such that a storage tank or a container into which the water treatment agent composition according to the present disclosure has been introduced is brought into a slightly pressurized state from an atmospheric pressure by an inert gas. In this state, the water treatment agent composition according to the present disclosure may be added to the cyanide-containing wastewater.

The cyan-containing wastewater treatment method according to the present disclosure will be specifically described with reference to a schematic diagram (FIG. 1) illustrating an example of a cyan wastewater treatment apparatus, but this aspect does not limit the present invention.
Cyanide wastewater to be treated (indicated by solid arrows in the figure) is measured for cyan concentration at point A, sent to the reaction treatment tank 1, and based on the measured values such as cyan concentration, the treating agent composition tank From 2 the water treatment agent composition according to the present disclosure is added. After the cyan-containing wastewater is stirred for a predetermined time while stirring in the reaction treatment tank 1, the cyan-containing wastewater containing the generated poorly water-soluble salt is sent to the thickener 3 from below the reaction treatment tank 1. In the thickener 3, the solid content is recovered from below the thickener 3 by being precipitated by a formation reaction of a poorly water-soluble salt. On the other hand, the supernatant is discharged from above the thickener 3, the cyan concentration of the supernatant is measured at point B, and it is confirmed that the measured value is the drainage standard value or the added drainage standard value or less. Drain the water. In addition, there is no problem in reusing the treated waste water.

That is, the cyanide-containing wastewater treatment apparatus that can be used in the method for treating cyanide-containing wastewater according to the present disclosure basically includes an additive tank for adding the water treatment agent composition according to the present disclosure, a poorly water-soluble salt. It consists of a reaction tank for generating, a precipitation tank for recovering the poorly water-soluble salt, piping connecting them, stirring means, a pump, and the like. The reaction tank and the precipitation tank can also be used together. In such a case, an apparatus such as a thickener can be used.

The present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[Preparation of water treatment agent composition and appearance evaluation confirmation test]
Add water to a 200 milliliter beaker and add an aqueous solution by adding a predetermined amount in the order of chlorides or bromides of alkali (earth) metal, acid, and sodium sulfite or potassium iodide as required. And stirring with a stirrer for 10 minutes while carrying out nitrogen bubbling. Then, the thing which added cuprous chloride and stirred for 30 minutes was made into the water treating agent composition. After the obtained water treatment composition was transferred to a glass bottle, the appearance after storage for 1 hour was observed. The evaluation of appearance was based on the criteria shown in Table 1 below. The numbers for each component in Table 2 are all by weight and the balance is water.

From the results in Table 2, the water treatment agent compositions of Examples (Examples 1 to 14) were colored but transparent without precipitation or turbidity. In contrast, in the water treatment agent compositions of the comparative water treatment agent compositions (Comparative Examples 1 to 11), although the concentration of cuprous chloride was 2% by weight or less, the clogging of the pump Turbidity and precipitation, which are feared to be insufficient in concentration, occurred, and some cuprous chlorides were hardly dissolved. Thus, the composition was practically unusable.

[Stabilization confirmation test of water treatment agent composition in container]
100 ml each of the water treating agent composition of Example 9 was added to a sealed plastic bottle having a capacity of 200 ml, and the one purged with nitrogen gas in the space of the container was allowed to stand at the temperature shown in Table 3 for 50 days. After 50 days, it was transferred to a glass bottle and the appearance of the water treatment agent composition was observed. The results are shown in Table 3.

From the results in Table 3, it can be confirmed that the water treatment composition after storage for 50 days maintained the same appearance as before storage at any storage temperature and maintained a stable state as a preparation for a long time. It was.
Moreover, storage and appearance observation were performed in the same manner as described above except that nitrogen purging was not performed. As a result, it was confirmed that by storing the container after purging with nitrogen, it was possible to store the container in a stable state for a longer period of time than when storing without performing the nitrogen purge.
Furthermore, when the same confirmation test was performed with the water treatment agent composition not containing Na ₂ SO ₃ (component D), the same result was obtained in the water treatment agent composition not containing Na ₂ SO ₃ .

[Stabilization confirmation test of water treatment agent composition in storage tank]
After adding 750 L of the water treatment agent composition of Example 9 to a 1000 L storage tank and purging the space of the storage tank with nitrogen gas, the water treatment agent was further maintained while maintaining a slightly pressurized state (3 kPa) with nitrogen. The composition was withdrawn and used at a flow rate of 100 L / day (7 days).

As a result, it was able to be pulled out from the tank and used in good condition for 7 days. Moreover, when the external appearance of the water treatment agent composition in a storage tank was confirmed after completion | finish of extraction use (seven days after the start of extraction use), it was the same brown transparent liquid as before use start.
Moreover, it was used in the same manner as described above, except that a (air) hole was made in the storage tank so as not to be in a slightly pressurized state. As a result, it was confirmed that the water treatment agent composition was excellent in stability and can be used satisfactorily when used in a slightly pressurized state as compared with the case where the slightly pressurized state was not used.
Moreover, when the same test was performed with the water treatment agent composition not containing Na ₂ SO ₃ (component D), the same result was obtained in the water treatment agent composition not containing Na ₂ SO ₃ .

[Confirmation of cyan removal effect]
For the water treatment agent compositions of Examples 2 and 9, a cyan removal experiment was conducted under the following conditions.

(Conditions for cyan removal experiment)
Cyan-containing waste liquid A (free cyan; 1.6 mg / L) and cyan-containing waste liquid B (free cyan; 1.3 mg / L) collected from two coke oven waste water lines at Sakai Steel Works were used. Into a 1000 mL beaker, 1000 mL each of the cyan-containing waste liquid was dispensed, and the water treatment agent compositions of Example 2 and Example 9 were added so as to have a predetermined chemical concentration (Cu ⁺ concentration), and 30 rpm at 130 rpm. Stir with a stirrer for minutes. Thereafter, the mixture was allowed to stand for 1 hour, and the total cyan density of the supernatant was measured according to JIS K0102. Table 4 shows the measurement results.

As shown in Table 4, by treating the cyanide wastewater of the steelworks with the water treatment composition of Example 2 and Example 9, the total cyanide concentration is 1 mg / L or less based on the drainage standard based on the Water Pollution Control Law. I was able to.

1 Reaction Treatment Tank 2 Treatment Agent Composition Tank 3 Thickener

Claims

A water treatment composition for cyanide-containing wastewater,
(A) cuprous chloride,
(B) at least one selected from the group consisting of alkali metal chlorides, alkali metal bromides, alkaline earth metal chlorides, and alkaline earth metal bromides, and
(C) contains an inorganic acid and / or an organic acid,
The water treatment agent composition in which the content of the (C) inorganic acid and / or organic acid in the water treatment agent composition is 10% by weight or less, and the pH of the water treatment agent composition is 2 or less. object.
The water treatment agent composition according to claim 1, wherein the content of the (A) cuprous chloride in the water treatment agent composition is 1.5% by weight or more.
The content in at least one water treatment agent composition selected from the group consisting of (B) alkali metal chloride, alkali metal bromide, alkaline earth metal chloride, and alkaline earth metal bromide is 1% by weight or more. The water treatment agent composition of Claim 1 or 2 which is 45 weight% or less.
The water treatment agent composition according to any one of claims 1 to 3, wherein the water treatment agent composition further comprises (D) sodium sulfite.
The water treatment agent composition according to claim 4, wherein a content of the (D) sodium sulfite in the water treatment agent composition is less than 0.05% by weight.
The water-treating agent composition according to any one of claims 1 to 5 is added to cyanide-containing wastewater so as to have cuprous chloride having a reaction equivalent to or higher than that of cyanide in the wastewater. A method for treating cyanide-containing treated wastewater, comprising producing and separating the hardly soluble substance.