JPH11116938A - Metal collector composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metal collector compsn. excellent in metal-collecting capacity by compounding a metal collector having a dithiocarbamic-acid-type functional group with a potassium sulfide compd. and/or an ammonium sulfide compd. SOLUTION: This compsn. contains a metal collector having a dithiocarbamic- acid-type functional group and a potassium sulfide compd. and/or an ammonium sulfide compd. in a wt. ratio of metal collector to sulfide compd. of (99.9/0.1)-(5.0/95.0). In the case of waste water treatment, the compsn. is added in an amt. of 0.6-1.5 mol per mol of metals in the waste water, pref. at a pH of waste water of 3-12. In the case of waste gas treatment, the amt. of the compsn. added is pref. 0.5-2.5 mol per mol of metals in the waste gas. When a solid waste is treated, the compsn. pref. in an amt. of 0.05-0 wt.% (based on metals in the waste) is mixed and kneaded with the waste. A metal collector of a dithiocarbamic acid type is obtd. by reacting a monoamine or polyamine with carbon disulfide in the presence of an alkali.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a metal scavenger composition.

[0002]

2. Description of the Related Art Wastewater such as industrial wastewater, slag discharged from a mine, contaminated soil, sludge after wastewater treatment, solid waste such as incineration ash from a garbage incineration plant, and discharged from a garbage incineration plant. Various metals are contained in waste gas such as flue gas. Strict regulations are set in particular for metals such as mercury, cadmium, zinc, lead, copper, and chromium, which are harmful to the human body.They remove metals from wastewater and waste gas and remove metals from solid waste. It is an important issue in treating wastes to immobilize and treat the metals so that they do not elute. For this reason, various methods have been studied for treating wastewater and waste gas by removing metal contained in wastewater and waste gas, and for treating solid waste by fixing metal in solid waste. .

[0003] As a method for removing metals contained in wastewater or waste gas, or for fixing metals in solid wastes, the method has excellent metal removal efficiency and metal fixing efficiency, as well as operability and running. In recent years, processing methods using a metal collecting agent have been widely used because of their excellent cost and the like.

[0004] As the above-mentioned metal collecting agent, a metal collecting agent having a dithiocarbamic acid type functional group which exhibits excellent adsorption power to mercury, lead and the like (this type of metal collecting agent is hereinafter referred to as dithiocarbamine Is widely used, and the applicant of the present invention reacts polyalkylene polyamines such as ethylenediamine and triethylenetetramine or polyethyleneimine with carbon disulfide to form polyamines. A metal scavenger with a structure in which a dithioic acid group or a salt of a dithioic acid group is bonded to the nitrogen atom of the compound (that is, a dithiocarbamic acid-type functional group), and a method of treating wastewater using the metal scavenger. (Japanese Patent Publication No. 5-7079, Japanese Patent Publication No. 5-7080, etc.). In addition, the applicant of the present invention disclosed dithiocarbamic acid-type metal collectors with sodium monosulfide, sodium polysulfide such as sodium disulfide, sodium trisulfide, sodium tetrasulfide, and sodium pentasulfide, and sodium sulfides such as sodium hydrogen sulfide. By using together,
It has been found that wastewater treatment and solid waste treatment can be performed more effectively than when only a dithiocarbamic acid-type metal collector is used.
No. 4-3549, No. 5-7078, No. 5-7
No. 079, Japanese Patent Publication No. 5-7080, Japanese Patent Laid-Open No. 5-5005
No. 5, JP-A-9-108683 and the like).

[0005]

The metal-collecting agent composition comprising the dithiocarbamic acid-type metal collecting agent and sodium sulfide is more effective than the metal-collecting agent composition using only the dithiocarbamic acid-type metal collecting agent. The sedimentation speed of the floc generated by the reaction between the agent composition and the metal in the wastewater is high, so that efficient wastewater treatment can be performed.The moisture content in the generated floc can be reduced, and the floc can be transferred. When used for the treatment of solid waste, which can reduce the cost and treatment cost, no metal is eluted from the solid waste even if the treated solid waste is exposed to acid rain etc. Can firmly immobilize the metal in solid waste,
It has various advantages such as being excellent in metal collecting ability and metal fixing ability.

[0006] The metal collector composition is preferably a high-concentration aqueous solution from the viewpoint of ease of handling and transfer cost, and from the viewpoint of facilitating the processing operation by reducing the amount added during the processing. . However, the conventional metal-collecting agent composition comprising a dithiocarbamic acid-type metal-collecting agent and sodium sulfide has a problem that, when used as a high-concentration aqueous solution, the viscosity increases and it becomes difficult to use. In addition, because the permeability to solid waste is low, it is necessary to use an unnecessarily large amount of the metal collecting agent composition, or it takes a long time until the metal in the solid waste is fixed. And so on.

The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, potassium sulfides and ammonium sulfides were used in combination with dithiocarbamic acid type metal-collecting agents instead of sodium sulfides to obtain dithiocarbamic acid type The present inventors have found that the above-mentioned problems of the conventional metal collecting agent composition can be solved without impairing the advantages of the conventional metal collecting agent composition comprising a metal collecting agent and sodium sulfide, and the present invention. Was completed.

[0008]

That is, the metal collecting composition of the present invention comprises a metal collecting agent having a dithiocarbamic acid type functional group and potassium sulfides and / or ammonium sulfides. And In the present invention, the dithiocarbamic acid type functional group in the metal collecting agent is preferably a potassium salt type and / or an ammonium salt type.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The dithiocarbamic acid-type metal collecting agent which is one of the constituents of the metal collecting agent composition of the present invention is a compound obtained by reacting monoamines or polyamines with carbon disulfide. Is mentioned. Examples of the monoamines include monomethylamine, dimethylamine, monoethylamine, diethylamine, monopropylamine, dipropylamine, monobutylamine, dibutylamine,
Isopropylamine, diisopropylamine, piperidine, piperazine, morpholine, methylphenylamine,
Ethylphenylamine and the like. Examples of the polyamines include, for example, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenediamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tributylenetetramine, tetraethylenepentamine, and tetrapropylenepentamine. Aliphatic polyamines such as tetrabutylenepentamine, pentaethylenehexamine, iminobispropylamine, monomethylaminopropylamine and methyliminobispropylamine; cycloalkane-based polyamines such as 1,3-bis (aminomethyl) cyclohexane; Piperazines such as aminoethylpiperazine and piperazine; polyethyleneimine, polypropyleneimine, poly-3-methylpropylimine, Polymers of cyclic imines such as 2-ethyl-propyl imine, polyvinyl amine, polymers of unsaturated amines of the polyallylamine and the like. In addition, unsaturated amines such as vinylamine and allylamine, and unsaturated amines that can be copolymerized with unsaturated amines such as dimethylacrylamide, styrene, methyl acrylate, methyl methacrylate, acrylic acid, methacrylic acid, styrene sulfonic acid, and salts thereof. Copolymers with other monomers having a saturated bond are also included. In the case of a cyclic imine polymer, an unsaturated amine polymer and a copolymer thereof, those having an average molecular weight of 300 to 2,000,000 are preferred, and those having an average molecular weight of 1,000 to 500,000 are more preferred.

The above polyamines may have a hydroxyalkyl group, an acyl group, an alkyl group or the like as an N-substituent. N-hydroxyalkyl substituents can be introduced by reacting the polyamines with epoxyalkanes, N-acyl substituents can be introduced by reacting the polyamines with fatty acids, and N- Alkyl substituents are introduced by reacting the polyamines with alkyl halides. N
The -hydroxyalkyl substituent preferably has 2 to 28 carbon atoms in the alkyl group, and the N-acyl substituent preferably has 2 to 26 carbon atoms. The N-alkyl substituent preferably has 2 to 22 carbon atoms.

Further, polycondensed polyamines obtained by polycondensation of the above polyamines and epihalohydrin can also be used. Epihalohydrin includes epichlorohydrin, epibromohydrin, epiiodohydrin and the like. In the present invention, as the polyamines, those having an active hydrogen atom bonded to a nitrogen atom and capable of forming a dithiocarbamic acid group by reacting carbon disulfide are used. Is also good.

A reaction for introducing an N-substituent such as a hydroxyalkyl group, an acyl group or an alkyl group into the above polyamines;
The polycondensation reaction between the polyamines and the epihalohydrin may be performed before or after the reaction between the polyamines and the carbon disulfide, but when the polycondensation reaction is performed before the reaction with the carbon disulfide, the polyamines may be used. After introducing an N-substituent into the polyamine or performing polycondensation of the polyamine and epihalohydrin, the polyamine has as many active hydrogen atoms as can react with carbon disulfide to form a dithiocarbamic acid group. There is a need.

The reaction between polyamines and carbon disulfide can be carried out, for example, by dissolving the above-mentioned polyamines in a solvent such as water or alcohol, and adding carbon disulfide to the resulting mixture to cause a reaction. The dithiocarbamic acid type functional group may be an acid type or a salt type, and after completion of the reaction, a hydroxide or carbonate of an alkali metal (eg, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc.) ) Or hydroxides or carbonates of alkaline earth metals (for example, calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, etc.), or alkalis such as ammonia, or polyamines and carbon disulfide. By performing the reaction in the presence of these alkalis,
A metal collector having a salt type dithiocarbamic acid type functional group can be obtained. From the viewpoint of sufficiently achieving the intended purpose of the present invention, the dithiocarbamic acid-type functional group of the metal collector is particularly preferably a potassium salt type and / or an ammonium salt type.

The dithiocarbamic acid-type metal scavenger used in the present invention is not limited to the above as long as it is a metal scavenger having a dithiocarbamic acid group or a salt thereof as a functional group. A metal collecting agent having a functional group of

The metal scavenger composition of the present invention comprises one or more of the above-mentioned dithiocarbamic acid type metal scavengers and potassium sulfides and / or ammonium sulfides. Examples of the potassium sulfide include potassium monosulfide, potassium disulfide, potassium trisulfide, potassium tetrasulfide, potassium pentasulfide, and potassium hydrogen sulfide. Among them, potassium monosulfide and potassium hydrogen sulfide are preferable. As ammonium sulfides, ammonium monosulfide, ammonium disulfide, ammonium trisulfide, ammonium tetrasulfide,
Examples thereof include ammonium pentasulfide, ammonium nonsulfide, and ammonium hydrogen sulfide. Among them, ammonium monosulfide and ammonium hydrogen sulfide are preferable. Potassium sulfides and ammonium sulfides can be used as a mixture of two or more.

The mixing ratio of the dithiocarbamic acid type metal trapping agent and potassium sulfides and / or ammonium sulfides (these are collectively referred to as sulfides) is by weight ratio, and the dithiocarbamic acid type metal trapping agent: sulfide Object = 99.9-5.
0: 95.0 to 0.1 is preferred.

The metal scavenger composition of the present invention removes metals contained in wastewater discharged from factories and the like and waste gas discharged from garbage incineration plants and the like, and removes slag, soil, sludge and incinerated ash. It can be used to immobilize metals contained in solid wastes such as (EP ash, cyclone ash, Bak filter ash, etc.) so as to prevent the metals from being eluted from the solid wastes.

When treating wastewater with the metal-collecting agent composition of the present invention, a method of adding the metal-collecting agent composition of the present invention to wastewater, separating and removing generated flocs, and then discharging the wastewater is used. Adopted. The addition amount of the composition of the present invention is preferably 0.6 to 1.5 moles in total of the dithiocarbamic acid type metal collector and sulfide per mole of metal in the wastewater. Further, the pH of the wastewater is preferably from 3 to 12, and when the pH is too high or too low, it is preferable to add an acid or an alkali to the wastewater and adjust the pH of the wastewater to the above range in advance. . Examples of the acid used for adjusting the pH of the wastewater include mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid and acetic acid. Examples of the alkali include alkali metals such as potassium hydroxide, sodium hydroxide, calcium hydroxide and magnesium hydroxide, hydroxides of alkaline earth metals, and carbonates of alkali metals and alkaline earth metals.

When the waste gas is treated with the metal scavenger composition of the present invention, an aqueous solution of the present composition is sprayed on a flue through which the waste gas passes, and the metal is collected by the present composition. After separating and removing the waste gas from the waste gas, a method of discharging the waste gas is employed. The amount of the composition of the present invention to be added at the time of waste gas treatment is 0.5 to 2.0 in total of the dithiocarbamic acid-type metal collector and the sulfide per mole of metal in the waste gas.
5 moles are preferred.

In the case of treating solid waste such as slag, soil, sludge, incineration ash, etc., a method is employed in which the composition of the present invention and, if necessary, water are added to the solid waste and kneaded.
The amount of the metal-collecting agent composition of the present invention when treating solid waste is based on the amount of metal contained in the solid waste.
Usually, the total amount of the dithiocarbamic acid-type metal collector and the sulfide is about 0.05 to 0% by weight, and the kneading time after the addition of the metal collector composition is usually about 10 to 30 minutes. However, compared to the case of using a metal collecting agent composition comprising a dithiocarbamic acid type metal collecting agent and sodium sulfide,
It is possible to reduce the amount of the metal-collecting agent composition and to effectively fix the metal even by short-time kneading.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. The dithiocarbamic acid type metal scavengers used in Examples and Comparative Examples are as follows.

Metal Scavenger A A compound having two dithiocarbamic acid-type functional groups (sodium salt) per molecule obtained by reacting 2 moles of carbon disulfide per mole of diethylenetriamine. Metal scavenger B A compound having one dithiocarbamic acid-type functional group (potassium salt) per molecule obtained by reacting one mole of carbon disulfide with one mole of diethylamine. Metal Scavenger C Ratio of 0.8 dithiocarbamic acid type functional groups (potassium salt) per monomer of polyethyleneimine obtained by reacting 0.8 mol of carbon disulfide with respect to polyethyleneimine monomer units A compound having the formula:

Examples 1 to 3 and Comparative Examples 1 to 3 A metal collecting composition comprising a metal collecting agent and a sulfide shown in Table 1 was prepared by adding copper (Cu) 6 mg / l, cadmium (Cd) 1
mg / l, lead (Pb) 5 mg / l, nickel (Ni)
To 1 liter of wastewater containing 1.2 mg / l, the amount of the metal-collecting agent composition was added so as to be 3 mg / l, and the mixture was stirred for 10 minutes. , Filtered off. Table 2 shows the results of measurement of the floc sedimentation time, the floc generation amount, and the residual metal concentration in the wastewater after the floc filtration. Table 1 also shows the results of a liquid feeding test of a 50% by weight aqueous solution of each metal collecting agent composition with a diaphragm pump.

[0024]

[Table 1]

* The results of the liquid sending test in Table 1 were evaluated as an index of the viscosity of a 50% aqueous solution of the metal-collecting agent composition.

[0026]

[Table 2]

Examples 4 to 6 and Comparative Examples 4 to 6 A metal collecting agent composition comprising a dithiocarbamic acid type metal collecting agent and a sulfide shown in Table 3 was prepared by using cadmium (Cd) 60
3 mg / l, lead (Pb) 3250 mg / l, nickel (Ni) 3350 mg / l, zinc (Zn) 540 mg / l
The metal scavenger composition was added in an amount of 0.5 g per 100 g of slag containing l, and kneaded for 5 minutes. Metal dissolution test from slag after treatment
The test was performed based on the No. 3 test method. Table 4 shows the results of measuring the metal elution amount from the slag.

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

As described above, the metal collecting composition of the present invention comprises a dithiocarbamic acid type metal collecting agent and potassium sulfides and / or ammonium sulfides to form a highly concentrated aqueous solution. However, unlike a conventional metal-collecting agent composition comprising a dithiocarbamic acid-type metal-collecting agent and sodium sulfide, the viscosity does not increase and the metal collecting agent becomes unusable. Further, the metal-collecting agent composition of the present invention has excellent permeability to solid waste, and as a result, the amount of addition to solid waste is reduced as compared with the conventional case, and the treatment time is shortened and efficient and reliable. This has the effect that the metal can be fixed to the metal.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C02F 1/62 C02F 1/62 CB Z 11/00 C 11/00 B01D 53/34 136Z (72) Inventor Masafumi Moriya Tokyo 4-66-1, Horikiri, Katsushika-ku Miyoshi Oil & Fat Co., Ltd.

Claims (2)

[Claims] 1. A metal collector composition comprising a metal collector having a dithiocarbamic acid-type functional group and potassium sulfides and / or ammonium sulfides. 2. The metal scavenger composition according to claim 1, wherein the dithiocarbamic acid type functional group of the metal scavenger is a potassium salt type and / or an ammonium salt type.