JP2579773B2 - Purification method of alkaline solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for purifying an alkaline solution. More specifically, the present invention relates to a method for adsorbing and removing heavy metal ions in an alkaline solution using a special chelating agent.

<Conventional technology> Heavy metals such as iron, nickel, and chromium are eluted from raw materials or materials of equipment or containers during the manufacturing process or storage of these alkaline solutions for strong alkalis such as caustic soda and caustic potash. Most of the eluted heavy metal precipitates as a metal hydroxide that is hardly soluble in water, and thus can be relatively easily removed to some extent by filtration or the like.

For this reason, heavy metal ions in an alkaline solution have not been regarded as a problem so far.

However, in recent years, product diversification and high quality have progressed,
High-purity products have been desired mainly for electronic materials.

As a method for separating and purifying heavy metal ions in these alkaline solutions for which high purity is desired, caustic soda whose alkaline solution components cannot be separated and purified by operations such as distillation is produced by adding MgO or Mg (OH) _2. Adsorbed on the precipitate that forms and removed by filtration (Japanese patent:
No. 71492) and a method of depositing a heavy metal on a cathode by electrolytic treatment (Japanese Patent Publication No. 52-44879).

<Problems to be Solved by the Invention> However, the conventional methods are not always satisfactory, such as the degree of separation and purification being inadequate, or the need for complicated equipment or complicated processing. In many cases, measures are taken to minimize elution contamination from product tank materials. Therefore, there is a disadvantage that the alkaline solution once eluted and contaminated cannot be used for high-purity products. If the alkaline solution contaminated with metal can be purified by a simple method, the alkaline solution discharged as a by-product in the manufacturing process and the discharged alkaline solution can be used for extremely limited applications such as neutralization disposal or raw materials for neutralization. What was passively used can be turned around and can be actively used for high-purity use or as a raw material for production.

In view of such circumstances, the present inventors have conducted intensive studies in order to find a method for efficiently and easily removing heavy metal ions dissolved in an alkaline solution.As a result, a chelating agent having a specific functional group was combined with an alkaline solution. The inventors have found that heavy metal ions can be easily adsorbed and removed by contact, and have completed the present invention.

<Means for solving the problems> That is, the present invention is selected from the group consisting of oxine groups, polyaminocarboxylic acid groups, aminophenoxy groups, aminonaphthoxy groups, hydroxyimino groups, hydroxyamino groups, and aminoalkylenephosphonic acid groups. A method for purifying an alkali solution, comprising: bringing a chelating agent having at least one chelating functional group into contact with an alkali solution containing heavy metal ions to adsorb and remove heavy metal ions in the alkali solution. .

The chelating agent used in the present invention is at least one selected from the group consisting of an oxine group, a polyaminocarboxylic acid group, an aminophenoxy group, an aminonaphthoxy group, a hydroxyimino group, a hydroxyamino group, and an aminoalkylenephosphonic acid group. Any shape may be used as long as it has a chelating functional group, and its shape and production method are not particularly limited.
For example, a chelating resin or a liquid chelating agent having any of the functional groups described above can be employed, and there is no particular limitation on the resin substrate when the chelating resin is used, and any of them can be manufactured by a known method. . Specific examples of such chelating agents include the following.

(1) As a chelating agent having an oxine group,
7- (5,5,7,7-tetramethyl-1-octene-3-i
Ru) -8-hydroxyquinoline [Mesa's Ashland
・ Made by Chemical Company: Kelex 100], 7- (1,4,4,5-
Tetramethylhexyl) -8-hydroxyquinoline, 7
-Undecyl-8-hydroxyquinoline, 7-dodecy
Ruphenyl-8-hydroxyquinoline, 7-phenylide
Decyl-8-hydroxyquinoline, 7-octylbenzy
A liquid chelating agent such as ru-8-hydroxyquinoline,
Copolymer with vinyl oxine polymer or vinyl oxine
Styrene, divinylbenzene, acrylic acid
Ter, acrylonitrile, vinyl acetate, ethylene glyco
Copolymer with chlorodimethacrylate, chloromethyl
Group, sulfonyl chloride group, carbonyl chloride group,
Amines such as socyanate group, epoxy group and aldehyde group
Styrene-divinylbenzene copolymer having reactive group
Body, phenolic resin, polyethylene, polypropylene,
Polymers such as polyvinyl chloride (hereinafter, amine-reactive groups
Is referred to as a resin. )) To 5-amino-8-hydroxy
Norin, 5-ethylenediamino-8-hydroxyquinol
, 5-diethylenetriamino-8-hydroxyquinol
, 5-triethylenetetraamino-8-hydroxy
Norin, 5-tetraethylenepentaamino-8-hydro
Xyquinoline, 5,7-diamino-8-hydroxyquinol
, 5-diethylenetriamino-7-ethylenediamino
-8-hydroxyquinoline, 5,7-bis (ethylenedia
Mino) -8-hydroxyquinoline, 5,7-bis (diethyl
Lentriamino) -8-hydroxyquinoline, 5,7-bi
(Triethylenetetraamino) -8-hydroxyquino
Phosphorus, 5,7-bis (tetraethylenepentaamino) -8
-Reacting an aminated oxine such as hydroxyquinoline
, Oxine or oxine derivative obtained by
Polymerization of aldehydes with aldehydes such as formaldehyde
Body, or phenol, resorcin, urea, thiourea,
Condensation polymerization of melamine, guanidine, aniline, etc.
Condensed polymer with a compound, a tree having the amino-reactive group
Ammonia, ethylenediamine, diethylenetria in fat
Min, Triethylenetetramine, Tetraethylenepenta
Min, pentaethylenehexamine, hexamethylenedia
Trees obtained by reacting amino compounds such as min and guanidine
Aminated trees having primary or secondary amino groups in fat
Chloromethyl, sulfonyl chloride, carbonyl
Luchloride group, isocyanate group, epoxy group, aldehyde
Oxin derivatives having amine-reactive groups such as hydr groups
(2) a chelating agent having a polyaminocarboxylic acid group
Are nitrile, chloromethyl, sulfonyl
Chloride group, carbonyl chloride group, isocyanate
Group, epoxy group, aldehyde group, chlorine, bromine, iodine, etc.
Polymers with amine-reactive groups such as halogen atoms
Tylenediamine, trimethylenediamine, tetramethyle
Diamine, pentamethylenediamine, hexamethylene
Diamine, octamethylenediamine, nonamethylenedia
Min, diethylene triamine, triethylene tetrami
, Tetraethylenepentamine, hydrozine, guanidinium
In the molecule obtained by reacting polyamines such as
For polyamino resin having primary or secondary amino group
Monochloroacetic acid, monobromoacetic acid, monochloropropion
Acid, monobromopropionic acid or their alkali
Al halides such as salts of metals or alkaline earth metals
Resin obtained by reacting a carboxylic acid compound,
Acrylic acid, methacrylic acid, acetyl
Dicarboxylic acids, maleic acids, alkalis of these acids
Metal or alkaline earth metal salts, or methyl, ethyl
Ester (hereinafter referred to as acrylic acid compound)
And, in the case of an ester, hydrolysis
(3) aminophenoxy group or aminonaphthoxy
Examples of the chelating agent having a group include a nitrile group and chloro.
Methyl group, sulfonyl chloride group, carbonyl chloride
Group, isocyanate group, epoxy group, aldehyde group, salt
Amine-reactive groups such as halogen atoms such as iodine, bromine and iodine
2,4-diaminophenol, 2-a
Mino-4-diethylenetriaminophenol, 2-amino
No-4-ethylenediaminophenol, 2,4-bis (d
(Tylenediamino) phenol, 2-amino-4-ethylene
Diaminobenzyl alcohol, 1,4-diamino-2-
Naphthol, 1,5-diamino-2-naphthol, 1-A
Such as mino-4-diethylenetriamino-2-naphthol
2-aminophenol and amino-2-naphthol derivatives
(4) a hydroxyimino group or a hydroxyamino group
As a chelating agent having the formula, tri-n-butyl-
Acetohydroxamic acid, 5,8-diethyl-7-hydroxy
-5-iminooxy-dodecane, hydroxyimino group
Or a commercially available LI containing a compound having a hydroxyamino group
X 65, LIX 64N, LIX 70, LIX 71 (or more, general
Mills), acrylonitrile, α-chloroacryl
Ronitrile, vinylidene cyanide, methacrylonitrile
Polymers of vinyl cyanide monomers such as
Other ethylenically unsaturated monomers that can be copolymerized with
Copolymer with a polymer or a polymer having an amino group
In the molecule obtained by reacting vinyl cyanide monomer
Hydroxylamine and
Or by reacting a derivative of hydroxylamine
A hydroxyimino group and an amino group, a so-called amidoxime group
Resin having the hydroxyimino group and the amino group
Deammonia decomposition by heat-treating the resin
Dehydroxyamine decomposition, hydrolysis, etc.
Midomonooxime, imidodioxime, imidinemonoio
(5) a chelate having an aminoalkylenephosphonic acid group
Has a primary or secondary amino group as a toning agent
Chloromethylphosphonic acid,
Alkyl phosphorylating agents such as
With alkylating agents such as mualdehyde and trioxymethylene
Phosphorus trichloride, phosphorous acid, hypophosphorous acid, methyl phosphite or phosphorous acid
Phosphorylating agents such as ethyl acid are reacted under acidic catalysts such as hydrochloric acid and sulfuric acid.
Chelating agents, and the like.

In particular, a chelating agent having an oxine group or a chelating resin in which a chelating functional group such as a polyaminocarboxylic acid group is bonded to a polymer main chain via a polyaminoalkylene group is a heavy metal ion in a highly concentrated alkali solution. Is preferably used because it can be removed to a low concentration.

The alkaline solution to be purified according to the present invention is a heavy metal containing quinoline group, polyaminocarboxylic acid group, aminophenoxy group, aminonaphthoxy group, hydroxyimino group, hydroxyamino group, aminoalkylene phosphonic acid group from the group consisting of Any material capable of chelating with a chelating agent having at least one selected chelating functional group may be used. Alkali solution components include caustic soda,
Alkali metal hydroxides such as caustic potash, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, octylamine, dioctylamine, trioctyl Ammonia or alkylamines such as amines,
Ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyalkylenepolyamine such as hexamethylenediamine, p-aminophenol, aniline,
Examples thereof include amines of cyclic compounds such as aminoanthraquinone and cyclohexylamine.

The present invention has a remarkable effect on a highly concentrated aqueous solution containing about 10% by weight or more of an alkali solution component, particularly an alkali metal hydroxide. Examples thereof include an aqueous sodium aluminate solution having a sodium hydroxide concentration of 150 to 250 g / in a Bayer method alumina production process and an aqueous sodium hydroxide solution of a salt electrolysis process having a sodium hydroxide concentration of 150 to 500 g /.

Typically, it is advantageously applied to alkaline solutions having an alkali metal hydroxide concentration of 10 to 50 weight percent.

It has never been proposed that the chelating agent of the present invention has a remarkable effect on the removal and purification of heavy metals in a high-concentration alkaline solution, and the chelating agent of the present invention is useful for the purification of a strongly basic alkaline solution. It was quite unexpected to be very effective.

Heavy metals in the alkaline solution include iron, nickel, cobalt, chromium and the like.

In the contact treatment of the alkali solution and the chelating agent of the present invention, the contact treatment can be usually performed with the alkali solution as it is. However, when the colloidal metal compound is suspended, the contact treatment with the chelating agent is simply performed. Since it cannot be completely removed only by the treatment, the colloidal material is removed in advance by filtration or the like, and then the contact treatment is performed.

In addition, the chelate forming ability of a metal ion with respect to a chelating agent generally has a higher chelate binding force in a higher ionic state, and therefore has a lower ionic state than an ionic number that a dissolved metal in an alkaline solution can take. In this case, if necessary, a known oxidation treatment with hydrogen peroxide, ozone, electrolysis or the like is performed in advance, and then a contact treatment with a chelating agent is performed.

The method of contact between the alkali solution and the chelating agent is not particularly limited. For example, when the chelating agent is a solid, a method of passing the alkali solution into a column filled with the chelating agent or chelating into the alkali solution The method of immersing the agent and then separating it by filtration is as such, when the chelating agent is a liquid, or as necessary, dissolving the chelating agent and mixing and contacting with the alkali solution in a solvent insoluble in the alkali solution. A method of treating and then separating and separating is adopted.

The contact temperature between the alkali solution and the chelating agent is not particularly limited, and is usually carried out at 0 to 100 ° C.

 Also, the contact time is not particularly limited.

The amount of chelating agent used relative to the amount of alkali solution,
The contact temperature, the contact time and the like can be set by conducting preliminary experiments as appropriate.

Heavy metal ions, which are impurities adsorbed by the chelating agent of the present invention, can be eluted and recovered using a suitable eluent. As an eluent, an acidic aqueous solution such as hydrochloric acid, nitric acid, phosphoric acid, and sulfuric acid is used.

The chelating agent after desorbing the heavy metal ions adsorbed in this manner may be used as it is or as necessary with water and / or a base such as sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, ammonia or the like. After treatment with a neutral aqueous solution or an aqueous solution of a mineral acid such as nitric acid, hydrochloric acid, or sulfuric acid, it can be repeatedly used for the adsorption of heavy metal ions as impurities in the alkaline solution.

<Effects of the Invention> The present invention has a large adsorption capacity for a heavy metal ion in an alkaline solution of a chelating agent used in the present invention, and can significantly lower the adsorption equilibrium temperature of a heavy metal ion, and the treatment operation is easy. Therefore, its industrial value is extremely large.

<Examples> Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

Example 1 Commercially available liquid chelating agent Kelek having an oxine group
S 100 (Mesa's Ashland Chemical Co .;
Below, it is referred to as chelating agent A. 1) 1 part by weight and aliphatic calcium
Versatic, a borate compound Acid (Shell Chemica)
0.25 parts by weight and n-dotesyl alcohol 1.25 parts by weight
Of kerosene and 10.25 parts by weight of kerosene at 6 mg / concentration
200 g of caustic soda aqueous solution of 200 g / concentration containing ions
After the contact treatment with 1 part by volume, the chelating agent and caustic
Separation and separation of soda solution, iron ion in caustic soda solution
Analysis of the concentration was 0.1 mg / or less.

Examples 2 to 17, Comparative Examples 1 and 2 (Chelating agent B) having aminomethylene phosphonic acid group
Commercially available resin [Duolite ES-467 (Diamond
・ Shamrock Co.)] (Chelating agent C) 600 parts by weight of polyacrylonitrile
5150 parts by weight of diethylenetriamine and 1290 parts by weight of water are mixed with 120
After conducting the reaction at 4 ° C for 4 hours, the mixture was filtered and washed with water, 2420 parts by weight.
(Undried) aminated resin and then aminated
2,400 parts by weight of a 25% by weight aqueous solution of formalin in 2420 parts by weight of resin
Parts, 1640 parts by weight of phosphorous acid and 2000 parts by weight of 36% by weight hydrochloric acid.
After reacting at 90-100 ° C for 4 hours, filter and wash
[3230 parts by weight (undried)] diethylene tri
A chelating agent having an aminomethylene phosphonic acid group.

(Chelating agent D) 940 parts by weight of phenol and resorcinol 1
After pre-polymerizing 10 wt% and 25 wt% formalin at 1200C for 4 hours at 80 ° C, 1440 wt% of triethylenetetramine, 1000 wt% of 36 wt% hydrochloric acid and 2400 wt% of 25 wt% formalin are added. The reaction is further carried out at 80 ° C. for 2 hours, and then 1000 parts by weight of 36% by weight hydrochloric acid and 820 parts by weight of phosphorous acid are added, and the reaction is carried out at 90 to 100 ° C. for 6 hours, followed by filtration and washing with water. [4100 parts by weight (undried)] A chelating agent having a triethylenetetraminomethylenephosphonic acid group.

(Chelating agent E) 206 parts by weight of diethylenetriamine and 36 parts by weight of water were added to 64 parts by weight of an acrylonitrile-divinylbenzene copolymer having a degree of crosslinking of 6 mol%, and the mixture was reacted at 120 to 125 ° C. for 6 hours. Thus, an aminated resin [230 parts by weight (undried)] was obtained. Then, 14.4 parts by weight of acrylic acid and 50 parts by weight of water were added to 23 parts by weight of the aminated resin, reacted at 40 ° C. for 8 hours, and filtered and washed with water. And the obtained resin
A chelating agent having a polyaminocarboxylic acid group [34 parts by weight (undried)] obtained by immersing in 50 parts by weight of a 10% by weight aqueous solution of caustic soda at room temperature for 30 minutes, followed by filtration and washing with water.

(Chelating agent F, G, H, I) The chelating agent E was used except that the amino compounds shown in Table 1 were used in place of diethylenetriamine, which is the amino compound used in the production of the chelating agent E. After the amination reaction is carried out in the same manner as in the production of the chelating agent E, the reaction is carried out with 1/10 of the obtained aminated resin and acrylic acid in the same manner as in the production of the chelating agent E. Agent.

(Chelating agent J) 35 parts by weight of 5-bromo-8-hydroxyquinoline hydrobromide and 18 parts by weight of pyridine as chelating agents in 24 parts by weight of the same aminated resin used in the production of chelating agent E And 392 parts by weight of toluene
A chelating agent having an 8-hydroxyquinoline group obtained by reacting at 0 to 90 ° C. for 4 hours, and then washing the resin by filtration with water and then with ethanol [32 parts by weight (undried)].

(Chelating agent K, L, M, N, O) 24 parts by weight of the same aminated resin used in the production of chelating agent E and the chelating agent shown in Table 2 were used in respective amounts. A chelating agent obtained by performing a reaction in the same manner as in the production of the chelating agent J, except for the above.

(Chelating agent P) 60 parts by weight of acrylonitrile resin and 50
132 parts by weight of an aqueous hydroxylamine solution were reacted at 80 ° C. for 6 hours, filtered, washed with water and dried [87 parts by weight]. A chelate having a hydroxyimino group and an amino group, a so-called amidoxime group, in the molecule. Agent.

(Chelating agent Q) Water is added to 8.7 parts by weight of the chelating agent P.
A chelating agent having a carboxylic acid group, a hydroxyamino group, and a hydroxyimino group in a molecule obtained by adding 6 parts by weight and performing hydrothermal treatment at 95-100 ° C. for 6 hours [7.4 parts by weight].

 Chelating agents B to Q and commercially available styrene divinylben
DU, which is an iminodiacetic acid type chelate resin
Olite ES-466 (Diamond Shamrock)
The same amino acids as used in the preparation of chelating agent C
1 part by weight of resin (dry product), 6mg / concentration of iron ion
Containing, 200 g / concentration of caustic soda aqueous solution 200 parts by weight
After the contact treatment for 1 hour, the chelating agent and the alkali
The solution was separated by filtration and the iron in the alkaline solution was analyzed.
In addition, the results were obtained as shown in Table 3.

Examples 18 to 23, Comparative Example 3 Fe ion 3 mg / Cr ion 2 mg / Ni ion 2 m
g / concentration, 50 g / 150 g / concentration potassium hydroxide solution
In parts, chelating agents E, F, G, J, K, L and commercially available styrene-divinyl
Nylbenzene copolymer substrate with iminodiacetic acid type chelate resin
A deeolite Add 1 part by weight of ES-466, 15:00
After the shaking treatment, the chelating agent and potassium hydroxide aqueous solution
Of Fe, Cr and Ni in caustic potassium solution
When the concentration was analyzed, the results shown in Table 4 were obtained.

Example 24 1000 parts by volume of an aqueous sodium aluminate solution in a Bayer method alumina production process containing Fe ions at a concentration of 2 mg / concentration was flowed from the top of a column filled with 10 parts by volume of a chelating agent E at a rate of SV10 hr ^-1 to give a column. When the Fe concentration in the outlet effluent was analyzed, it was less than 0.1 mg /.

Comparative Example 4 Commercially available styrene divinyl vinyl was used instead of chelating agent E
Iminodiacetate-type chelate resin deo on benzene copolymer base
Light Except for using ES-466, exactly the same as Example 24
When the test was performed by the method described in
The concentration was 1.3 mg /.

Claims (6)

(57) [Claims] 1. An alkali solution having an alkali metal hydroxide concentration of 10% by weight or more and containing a heavy metal ion, comprising: an oxine group, a polyaminocarboxylic acid group, an aminophenoxy group, an aminonaphthoxy group, a hydroxyimino group,
An alkali which is brought into contact with a chelating agent having at least one chelating functional group selected from the group consisting of a hydroxyamino group and an aminoalkylenephosphonic acid group to adsorb and remove heavy metal ions in the alkali solution; How to purify the solution. 2. The method for purifying an alkaline solution according to claim 1, wherein the chelating agent is a chelating resin, and the chelating functional group is bonded to the polymer main chain via a polyaminoalkylene group. 3. The method for purifying an alkaline solution according to claim 1, wherein the chelating functional group is an oxine group. 4. The method according to claim 1, wherein the alkali metal hydroxide is caustic soda or caustic potash. 5. The method according to claim 1, wherein the heavy metal ions are selected from iron ions, nickel ions, cobalt ions and chromium ions. 6. The method for purifying an alkaline solution according to claim 1, wherein the alkaline solution has an alkali metal hydroxide concentration of 10 to 50% by weight.