JPH0790403A - Method for capturing valuable metals in plating solution - Google Patents

Abstract

(57) [Summary] [Purpose] A valuable metal of a plating solution containing a valuable metal ion and a complexing agent or a chelating agent is captured in a precipitate at a high concentration. [Structure] High-temperature and high-pressure treatment is performed in the presence of a metal scavenger composed of a sulfide under the conditions of at least 130 ° C and at least 2.7 x 10 5 Pa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of capturing valuable metals by treating valuable metal ion-containing liquid such as plating waste liquid in the presence of sulfide at high temperature and high pressure. Hereinafter, the plating waste liquid mainly containing cyan will be described.
The present invention is similarly applied to a plating waste liquid containing no cyanide.

[0002]

2. Description of the Related Art Cyan decomposition is performed as a wastewater treatment of a plating waste liquid. In the most general alkali chlorine method as a cyan decomposition method, cyan is decomposed by a reaction formula such as Cl2 + NaCN = CNCl + NaCl (1) CNCL + 2 NaOH = NaCNO + NaCl + H2 O (2) 3Cl2 + 2NaCNO + 6 NaOH = 2 NaHCO3 + N2 +6 NaCl + 2 H2 O (3). In order to precipitate and remove heavy metals from the treatment liquid after decomposition, lime or the like is added to precipitate hydroxides such as Cu, Ni and Zn.

FIG. 2 shows a flow sheet of the "boil-down high temperature combustion method". In this method, the plating waste liquid is concentrated and dried,
Perform a process to dry the product. This dried solid is sent to a metal smelting factory of a metal mine and put in a high temperature furnace together with the metal ore to be burned to detoxify cyan and collect and reuse valuable metals such as gold and silver in the dried solid.

Japanese Patent Publication No. Sho 63- "entitled" Method for Decomposing Cyanide Compound in Liquid Containing Gold Cyanide Compound and Separation of Gold and Method for Decomposing Cyanide Compound in Liquid Containing Gold Cyanide Compound and Silver Cyanide Compound and Separation of Gold and Silver " According to No. 26184, a liquid containing a gold cyanide compound is treated with LiOH, KOH, NaOH, B
A method has been proposed in which gold and silver are recovered and cyan is decomposed by heat treatment in the presence of a water-soluble metal hydroxide such as a (OH) 2, Ca (OH) 2, Sr (OH) 2. There is. The present invention is based on the finding that these water-soluble metal hydroxides are effective in decomposing cyanide compounds and precipitating gold and silver as simple substances.

Further, Japanese Patent Laid-Open No. 1-194997 proposes thermal hydrolysis (primary treatment) + microorganism treatment method (secondary treatment) for treatment of cyanide-containing plating waste fluid, soft nitriding waste fluid and the like. The primary treatment of this method is (1) capable of decomposing the hardly-decomposable iron cyanide complex; (2) capable of treating a high concentration of cyan wastewater; (3) cyanide reacts with water at a high temperature to produce cyanide In principle, no chemicals other than sulfuric acid for neutralization are required because they can be decomposed, and the running cost is low; (4) Sludge generation is extremely small because almost no chemicals are used; (6) Equipment is simple It is automated and has features not found in the above-mentioned alkali chlorine method and boiling high temperature combustion method.

[0006]

[Problems to be Solved by the Invention] In the alkaline chlorine method,
After the decomposition of cyanide, alkali such as lime is added to remove the metals, and the metal hydroxide is precipitated to treat the metals, but the sludge generated at that time has a high water content, so the scouring efficiency is high. When the metal is recovered by the smelting method, it is difficult to separate the water content, and the sludge volume is large, which increases the transportation cost. In addition, sludge contains calcium salts in addition to metal hydroxides, which complicates metal recovery.

Next, the high-temperature packed combustion method requires heating energy equal to or higher than the latent heat of vaporization, resulting in high energy cost. Furthermore, since dried solids of cyan are concentrated together with valuable metals, it is necessary to perform detoxification of cyan and to perform high temperature combustion at a metal refining factory after high temperature combustion. However, in recent years, as the metal smelting factory of a metal mine has been abolished, it has been obliged to outsource the high temperature combustion treatment to the dry solid matter generated by the high temperature combustion method. Since these industrial waste disposal companies only detoxify cyan without recovering and reusing gold, silver, etc., the processing cost inevitably rises.

Next, in the method for recovering gold and silver in Japanese Examined Patent Publication No. 63-26184, treatment of a liquid containing various metal ions other than gold and silver is not considered.

Further, although cyan can be almost completely decomposed by the thermal hydrolysis method, valuable metals cannot be recovered as they are because the metal ions are dissolved in the treatment liquid after thermal hydrolysis. Also, simple pH control is not suitable for precipitation of valuable metals due to the features of the chemical reaction of the thermal hydrolysis method described below.

Cyan wastewater undergoes a hydrolysis reaction at 130 to 150 ° C. or higher as shown in the formula (1). CN- + 2H2O = NH3 + HCOO- (4) The reaction equations for the tufftride wastewater are considered to be (5) and (6). NaCN + H2 O = NH3 + HCOONa (5) NaFe (CN) 6 + 2NaOH + 11H2 O + 1 / 6O2 = 6NH3 + 6HCOONa + 1 / 3Fe3 O4 (6)

The thermal hydrolysis reaction equations of the cyan complexes of various metals contained in the plating waste liquid are considered to be (7) to (15).

Na2Ni (CN) 4 + 2NaOH + 8H2O = 4NH3 + Ni (OH) 2 + 4HCOONa (7) Na2Zn (CN) 4 + 2NaOH + 8H2O = 4NH3 + Zn (OH) 2 + 4HCONa (8) 2Na3Cu (CN + 17 + 2 + 4HCOONa4) 2O2 = 8NH3 + 2Cu (OH) 2 + 8HCOONa (9) Na2Cd (CN) 4 + 2NaOH + 8H2O = 4NH3 + Cd (OH) 2 + 4HCOONa (10) NaAg (CN) 2 + NaOH + 3H2O = 2NH3 + 11HCO2O2 + HCOONa (9) ) 2 + NaOH + 3H2 O = 2NH3 + Au + + OH- + 2HCOONa (12) NaCr (CN) 6 + 3NaOH + 12H2 O = 6NH3 + Cr (OH) 3 + 6HCOONa (13) Na2 Mn (CN) 4 + 2NaOH + 8H2O = 4NH3 + Mn (OH) 2 + 4HCOONa (14) Pb (CN) 2 + 2NaOH + 4H2O = 2NH3 + Pb (OH) 2 + 2HCOONa (15) (7), the metal hydroxide of the formula (8) is It is also possible to react with the formulas (16) and (17) by a hydrothermal reaction. NaNi (CN) 4 + 2NaOH + 7H2O = 4NH3 + NiO + 4HCOOH (16) Na2Zn (CN) 4 + 2NaOH + 7H2O = 4NH3 + ZnO + 4HCOONa (17) Also, metal cyanides other than Ni and Zn, such as Mn and Cu, are (16) and (17). It is considered that the reaction as shown in the formula becomes a metal oxide.

When the treated water is filtered after the thermal hydrolysis reaction, a large amount of Cu, Ni, Zn, etc. remains in the filtrate except iron. This is because the above reaction completely occurs in the iron cyano complex but not in the cyan complex such as Cu, Ni, Zn, etc. The reason is that a large amount of ammonia generated as a reaction product and the following formula This is because a reaction to form an ammonia complex occurs in the solution, so that part of the solution is dissolved and a precipitate is not completely formed.

Cu + 4NH3 = [Cu (NH3) 4] 2+ (18) Zn + 4NH3 = [Zn (NH3) 4] 2+ (19) Ni + 6NH3 = 6NH3 = [Ni (NH3)] 2+ (20) Ag + NH3 = [ Ag (NH3)] 2+ (21) Further, in the case of the plating waste liquid, since a chelating agent such as EDTA is contained from the beginning, it is considered that a chelate with Cu, Zn or the like is formed and dissolved. Note that noble metals such as Au and Ag do not completely form precipitates like Cu.

Although the cyan-containing plating solution has been described above, various metals also form a complex in the electroless plating solution, and therefore these metals cannot be precipitated by pH control.

In view of the above points, the present invention provides a method capable of obtaining a precipitate in which valuable metal is concentrated to a high concentration without the need for a cyanide detoxification treatment in a metal refining plant for a cyanide-containing plating waste liquid. The purpose is to

[0017]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies and experiments for the purpose of removing valuable metal ions, particularly precipitating metal ions such as gold, silver, copper and nickel.
As a method for treating waste liquids containing valuable metal ions and complexing agents or chelating agents, such as electrolytic plating waste liquid and electroless plating waste liquid, a method of performing sulfide precipitation under high temperature and high pressure was found.

The treatment method is a plating containing valuable metal ions, in which a sulfide is added to a waste liquid containing valuable metal ions and the sulfide is kept at a high temperature of at least 130 ° C. and a high pressure of at least 2.7 × 10 5 Pa for a required time. This is a method for capturing valuable metals in waste liquid.

Further, this treatment method is a method in which a cyan-containing waste liquid is subjected to a thermal hydrolysis treatment for cyan decomposition and at the same time a sulfide is added, and a method in which a cyanide-containing waste liquid is subjected to a thermal hydrolysis treatment and then sulfurized into the treatment waste liquid. A method of adding a substance and maintaining it at high temperature and high pressure for a required time is included.

In each of the above processing methods, the high temperature condition is 1.
30 to 250 ° C, high pressure condition is 2.7 x 10 5 to 40 x 1
It is preferably set to 05 Pa. As the sulfide, it is preferable to use an alkali metal sulfide such as sodium sulfide or potassium sulfide, an ammonium sulfide, a hydrogen sulfide such as sodium hydrogen sulfide, or hydrogen sulfide.

The added amount of sulfide (as S--) is an equivalent ratio (S / Me) to the metal (Me) in the plating waste liquid of 0.
In the case of 6, the metal precipitation effect is considerably good, and 1.0 to
Very good results are obtained with 1.3. Since the residual sulfide increases as the added amount of sulfide increases, the added amount (S--) is preferably in the range of 2.0 or less in terms of metal equivalent ratio (S / Me).

When sulfide is added after decomposition of cyan, the amount of sulfide added is the equivalent ratio (S / Me) of sulfur ion to the amount of metal ion (Me) in the cyan-containing waste liquid before thermal hydrolysis. , 0.6 to 2.0 is preferable.

Ni 1500 ppm, Cu 3900 pp
m, Zn 1600ppm, Au 4.8ppm, Ag25
Metal equivalent ratio (S / M to cyan waste liquid containing 0 ppm)
Table 1 shows the metal ion concentrations in the waste liquid after the addition of 1.1 (as S--) in e) and treatment under high temperature and high pressure treatment conditions.

[0024]

[Table 1] Temperature (° C) Pressure (Pa) Metal ion concentration (ppm) Ni Au Ag 100 1.0 × 10 5 133.5 4.8 250 130 130 × 10 5 4.0 0.4 1.8 210 210 19 × 10 5 0.5 0.2 0.4

In general, it is difficult to raise the temperature of the reaction vessel to 250 ° C. or higher due to legal regulations regarding pressure resistant vessels, and the temperature at which the effect of removing Ni, Au, and Ag in Table 1 is remarkable is 1.
Considering that the temperature is 30 ° C. or higher, the temperature of the sulfide addition treatment is preferably 130 ° C. to 250 ° C. Therefore, the pressure is 2.7 × 10 5 Pa to 19 × 10 5 Pa.
Is preferred. The high temperature / high pressure reaction carried out in the presence of sulfide is preferably carried out at the above temperature and pressure range for at least 5 minutes, and the residual metal ions tend to increase at lower temperatures.

Further, the pH condition of the metal ion-containing waste liquid treated by the method of the present invention is preferably pH 7 or higher, more preferably pH 9 or higher. P
If it is less than H7, the metal ion removal efficiency decreases.

A preferred embodiment for industrially carrying out the above method will be described with reference to the flow sheet shown in FIG.

In FIG. 1, "cyan concentrated waste liquid" is a mixture of electrolytic or electroless plating waste liquid or the like, which is the object of the present invention, or a single liquid of each. The soft nitriding waste liquid contains iron as a metal ion and does not contain a noble metal such as gold or silver, but this waste liquid can also be treated by mixing with the above liquid.

This mixture is subjected to settling treatment in a settling tank, solid-liquid separation is carried out by a filter, and further left in a supernatant storage tank, and then solid-liquid separation is carried out by a microfiltration machine. In this two-stage solid-liquid separation, foreign substances that interfere with the subsequent treatment are removed from the treatment liquid.

That is, the liquid obtained by the above solid-liquid separation is a stock solution which undergoes cyan decomposition and valuable metal precipitation treatment. Sodium hydroxide is added to this stock solution to adjust the pH to a value suitable for the precipitation of valuable metals, and steam is added to preheat. Subsequently, the treatment of the present invention is performed in the autoclave. For valuable metal precipitation, sulfide is added as a metal scavenger into the autoclave.

After the high temperature and high pressure treatment for a required time, the precipitate is collected as a slurry in a relay tank, and after adding a coagulant, it is separated into a cake and a filtrate by a centrifugal dehydrator. The filtrate is sent to the ammonia stripping tank described later.

On the other hand, high temperature in the autoclave for a certain time
After the high-pressure treatment, the treatment liquid is temporarily transferred from the autoclave to a cushion tank, cooled to about 100 ° C. with hot water, and then gradually introduced into an ammonia stripping tank for aeration. Most of NH3 can be removed by this ammonia stripping treatment.
NH3 removed by ammonia stripping is NH3 generated from autoclave and cushion tank
It is sent together with the scrubber for processing.

Next, ferrous sulfate and a flocculant are added in order to remove the sulfide remaining in the treatment liquid. The amount of ferrous sulfate added is a Fe ion equivalent ratio (Fe / S) to the amount of sulfide ions (S ~ ~), and is preferably 1.0 to 1.1. It is also possible to return the treatment liquid containing the remaining sulfide to the autoclave.

The precipitate is treated with a centrifugal dehydrator, the treated liquid is neutralized with sulfuric acid, sodium hydroxide, etc. in a neutralization tank, and further microfiltered with a vacuum filter, and if necessary, secondary treatment (microorganism treatment) is performed. , Adjust the pH and discharge.

The treatment method of the present invention can be directly applied to a plating waste liquid, but can also be applied to a cleaning liquid obtained by cleaning a product to be plated. 3 to 7 for a method of combining the "semi-closed system for cleaning plating solution" and the "valuable metal capturing method" which is a preferred embodiment in the latter case.
Will be described with reference to.

FIG. 3 shows a plated layer 10 (active ingredient concentration 10
0g / L) plating solution together with the product to be plated is 2L / h
One-step cleaning method (n = 1) in which the liquid is transferred to the cleaning tank 20 at a ratio of r
Is illustrated. In this case, in order to adjust the concentration of the plating effective component in the cleaning tank 20 to 0.01 g / L, 20000 L
/ Hr of water must be supplied and drained.

When the product to be plated treated in the same plating bath 10 is washed in two stages (n = 2), the concentration of the active ingredient of plating is similarly 0.0 in the final (second) washing bath 20b.
The washing method with 1 g / L is shown in FIG. When the component concentrations of the first washing tank 20a and the second washing tank 20b are kept constant, the mass balance of the active ingredient in each washing tank per unit time is expressed as follows (the left side is the amount , The amount on the right side is). First water washing tank c0 θ + c2 W = c1 θ + C1 W (22) First water washing tank c1 θ = c2 θ + c2 W (23) where c0 is the component concentration of the plating tank 10, and c1 and c2 are the first and second plating tanks, respectively. , W is the amount of supplied water (waste water), and θ is the pumping speed. From these equations, c
1 = 0.01; c2 = 0.99. As mentioned above,
By using the two-step cleaning, the amount of cleaning water supplied can be 1/100 of that of the first-step cleaning. Further, the concentration of the plating effective component in the first cleaning tank can be increased 99 times.

Further, FIGS. 5 and 6 illustrate the three-step cleaning method and the four-step cleaning method. As is apparent from FIGS. 3 to 6, by increasing the number of washing steps, it is possible to reduce the amount of water supplied and to increase the concentration of the plating active ingredient in the first washing tank. Further, in FIG. 6, the liquid in the first cleaning tank is subjected to the autoclave treatment of the present invention. That is, it is preferable to reduce the amount of washing water by performing multi-step washing of four or more steps, and at the same time, increase the concentration of the plating component in the solution used for the decomposition of cyanide and the capture of valuable metals to improve the efficiency of this treatment. Can be increased. In addition, the liquid flow in the plating factory can be semi-closed.

When only the plating cleaning liquid is treated as a waste liquid, the number of times of multi-stage cleaning is such that the concentration in the first cleaning tank is 1/10 or more (see FIG. 6) of the concentration of the active ingredient in the plating liquid. Preferably. Particularly, the metal ion concentration is preferably several 1000 ppm or more. Needless to say, the concentration of the former is not particularly limited when treating a mixed solution of a plating cleaning solution and a waste solution from the plating tank as a waste solution.

Further, as shown in FIG. 7, the final cleaning tank 20
The amount of washing water can be further reduced by circulating the liquid of d through the ion exchange resin 30 to perform the purification treatment.

[0041]

It is considered that the ammonia complex is formed after the thermal hydrolysis reaction in the cyanide-containing waste liquid containing various metal ions such as iron, copper, zinc, nickel and silver.

When a sulfide such as sodium sulfide is added to such waste liquid under high temperature and high pressure conditions, [Cu (NH3) 4] 2 ++ S2- = CuS ↓ + 4NH3 (23) [Zn (NH3) 4] 2 ++ S2- = ZnS ↓ + 4NH3 (24) [Ni (NH3) 6] 2 ++ S2- = NiS ↓ + 6NH3 (25) [Ag (NH3) 6] 2 ++ S2- = AgS ↓ + 6NH3 (26), and the metal ions are sulfided. Make a sediment of things.

The plating waste liquid contains a chelating agent (complexing agent) such as gluconate, Rochelle salt, EDTA, and NTA, and these ions with copper, zinc, nickel, etc. form stable chelate compounds. ing. Therefore, at room temperature, it is difficult to remove metal ions from the plating waste liquid even if sulfide is added. However, when the sulfide is added under high temperature and high pressure conditions, the efficiency of removing valuable metals is significantly improved as shown in Table 3. As described above, the present invention is most preferably applied to the case where valuable metal ions form an ammonia complex, but the method of the present invention is applied to other compound forms because the precipitation of metal sulfide is possible. it can.

[0044]

EXAMPLES The results of treating the plating waste liquid (cyan concentrated waste liquid) shown in Table 2 will be described below.

[0045]

TABLE 2 Ingredient average value pH 13.18 gravity 1.10 moisture content 88.07 T-CN 19200 Au 4.15 Ag 166.5 Cu 6330 Zn 2610 Cd 126.3 Ni 1170 Fe 325 Pb 12.3 Cr 17.9 F-CN 13200 Unit: ppm except pH and specific gravity

In addition to these, there are organic contaminants such as sodium gluconate, Rochelle salt, EDTA, NTA, and metanitrobenzene sulfonic acid. Also, since a large amount of sodium hydroxide and sodium carbonate are present, the concentration of the plating active ingredient is 12%. near.

The cyan concentrated waste liquid was treated by the process shown in the flow sheet of FIG. The processing conditions were as follows. Preheating temperature: 80 ° C .; Autoclave treatment: Boiled steam was blown from the boiler to raise the temperature to 185 ° C. (internal pressure was about 11 kg / cm 2 as a gauge pressure). When thermal hydrolysis starts, the partial pressure of ammonia in the autoclave rises, so degassing operation is performed several times. The metal scavenger is based on the concentration of Au, Ag, Cu, Zn, Ni etc.
The amount was 1.3 times the required amount. As the addition method, a method of adding at the beginning, a method of adding before and after the thermal hydrolysis reaction, or a method of adding at the end of the reaction were performed at any time. After reaching 185 ° C., it was left for 6 hours for autoclave treatment. The thermal hydrolysis reaction reduced the cyan concentration to 1.0 ppm or less, producing ammonia and formate. The metals also precipitated.

At the end of the reaction, the liquid in the autoclave was sampled from a small heat exchanger for sampling and analyzed for cyan to confirm whether or not the reaction was completed, and then flushed from the upper part of the autoclave to a cushion tank.

Table 3 shows the processing results from the first batch to the twelfth batch.

[0050]

[Table 3]

Cyan has an average initial density of 16750 ppm.
From 0.26 ppm. Not only cyan, but also high-concentration Cu and Zn ions are treated to a very low concentration in the autoclave.

Table 4 shows the analysis results of sludge obtained by centrifugally dehydrating the treated water after the 20th to 23rd batches after thermal hydrolysis. The water content is 20% or less on average, which is extremely low. It is collected compactly in a dry state and contains a large amount of valuable metals such as Au, Ag, Cu and Ni so that it can be sold as a non-ferrous metal refining raw material.

[0053]

[Table 4]

[0054]

Since the present invention is constructed as described above, it is extremely useful in the plating industry in which the recycling of metals is sought after. That is, it is possible to reuse precious metals such as gold and silver as well as precious metals such as copper and nickel to be recovered. According to the ammonia stripping treatment method of claim 2, ammonia can be easily expelled from the treatment liquid.

According to the third aspect, most of the ammonia can be removed from the treatment liquid by subjecting the filtrate from which the valuable metal precipitate has been separated to the ammonia stripping treatment. .

According to the fourth aspect, the residual metal scavenger is removed from the treatment liquid by a simple method, whereby the concentration of the effective plating component in the treatment liquid can be reduced to a very low level.

According to the method of claim 6 in which the first-stage cleaning liquid of the multi-stage cleaning liquid for the product to be plated is treated, the valuable metal concentration in the treatment liquid can be increased and the treatment efficiency can be increased.

In the method of claim 7, wherein the final stage cleaning liquid in the multi-stage cleaning is subjected to a purification treatment with an ion exchange resin, the amount of cleaning water used can be reduced.

[Brief description of drawings]

FIG. 1 is a flow chart showing steps according to the method of the present invention.

FIG. 2 is a flow chart showing steps of a boiling high temperature combustion method.

FIG. 3 is a diagram illustrating a one-step cleaning method of a plating solution.

FIG. 4 is a diagram illustrating a two-step cleaning method of a plating solution.

FIG. 5 is a diagram illustrating a three-step cleaning method of a plating solution.

FIG. 6 is a diagram illustrating a method of performing four-step cleaning of a plating solution and subjecting the first-step cleaning solution to treatment by an autoclave.

FIG. 7 is a diagram illustrating a method in which a plating solution is subjected to four-step cleaning, the first-step cleaning solution is subjected to an autoclave treatment, and the cleaning solution is subjected to a cleaning treatment with an ion exchange resin.

[Explanation of symbols]

 10 Plating tank 20 Cleaning tank 30 Ion exchange resin tower

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[Procedure amendment]

[Submission date] December 12, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Cyan decomposition is performed as a wastewater treatment of a plating waste liquid. In the most general alkali chlorine method as a cyan decomposition method, cyan is decomposed by a reaction formula such as Cl2 + NaCN = CNCl + NaCl (1) CNCL + 2 NaOH = NaCNO + NaCl + H2 O (2) 3Cl2 + 2NaCNO + 6 NaOH = 2 NaHCO3 + N2 +6 NaCl + 2 H2 O (3). To precipitate and remove heavy metals from the process liquid after the decomposition by the addition of such lime Cu, Ni, thereby hydroxides precipitated gluteal such as Zn.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

Further , the applicant of the present invention has proposed a method of thermal hydrolysis (primary treatment) + microorganism treatment (secondary treatment) for treating waste liquid such as cyanide-containing plating waste liquid and soft nitriding treatment.
Proposed in No. 4997. The primary process of this method is
(1) Can decompose hardly-decomposable iron cyanide complex; (2) Can treat highly concentrated cyanogen wastewater; (3) Neutralize because cyanide can be decomposed by hydrolysis reaction in which cyanide reacts with water at high temperature In principle, no chemicals other than sulfuric acid are required, and the running cost is low; (4) Sludge generation is extremely small because almost no chemicals are used; (6) Equipment is simple and automated, etc. It has features not found in the above-mentioned alkali chlorine method and boiling high temperature combustion method.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

[Problems to be Solved by the Invention] In the alkaline chlorine method,
After the decomposition of cyanide, alkali such as lime is added to remove the metals, and the metal hydroxide is precipitated to treat the metals, but the sludge generated at that time has a high water content, so the scouring efficiency is high. If you try to recover the metal in the smelting process, smelting
The water separation required previously is awkward and the large sludge volume adds to the cost of transportation. In addition, sludge contains calcium salts in addition to metal hydroxides, which complicates metal recovery.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007] Then, the boiled filling hot combustion method requires heating energy than the evaporation latent heat, the energy cost is high. Furthermore, since the cyan is concentrated dry solid with valuable metals, it is necessary to perform a high temperature treatment with a metal scouring plant after boiling justified hot combustion process detoxification of cyanide. However, in recent years, due to the metal mine metal refining plant will be abolished, dryness things that occur in boiled justified high temperature combustion method was no longer forced to outsource high-temperature combustion process in industrial waste treatment company. Since these industrial waste disposal companies only detoxify cyan without recovering and reusing gold, silver, etc., the processing cost inevitably rises.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

Cyan wastewater undergoes a hydrolysis reaction at 130 to 150 ° C. or higher as shown in the formula (1). CN- + 2H2O = NH3 + HCOO- (4) The reaction equations for the tufftride wastewater are considered to be (5) and (6). NaCN + 2 H2 O = NH3 + HCOONa (5) Na4 Fe (CN) 6 + 2NaOH + 11H2 O + 1 / 6O2 = 6NH3 + 6HCOONa + 1 / 3Fe3 O4 (6)

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Na2Ni (CN) 4 + 2NaOH + 8H2O = 4NH3 + Ni (OH) 2 + 4HCOONa (7) Na2Zn (CN) 4 + 2NaOH + 8H2O = 4NH3 + Zn (OH) 2 + 4HCOONa (8) 2Na3Cu2CN + 2 + 15H2O2 + 1 / 2O2 = 8NH3 + 2Cu (OH) 2 + 8HCOONa (9) Na2 Cd (CN) 4 + 2NaOH + 8H2 O = 4NH3 + Cd (OH) 2 + 4HCOONa (10) 2NaAg (CN) 2 + 2NaOH + 7H2 O = 4NH3 + 2Ag2 O + 4HCOONa (11) NaAu (CN) 2 + NaOH + 4H2 O = 2NH3 + Au + + OH- + 2HCOONa (12) Na3 Cr (CN) 6 + 3NaOH + 12H2 O = 6NH3 + Cr (OH) 3 + 6HCOONa (13) Na2 M (CN) 4 + 2NaOH + 8H2O = 4NH3 + Mn (OH) 2 + 4HCOONa (14) Pb (CN) 2 + 2NaOH + 4H2O = 2NH3 + Pb (OH) 2 + 2HCOONa (15) (7), The metal hydroxide of the formula (8) has a high temperature. It is also conceivable that the reaction with the formulas (16) and (17) is performed by a hydrothermal reaction below. Na2Ni (CN) 4 + 2NaOH + 7H2O = 4NH3 + NiO + 4HCOONa (16) Na2Zn (CN) 4 + 2NaOH + 7H2O = 4NH3 + ZnO + 4HCOONa (17) Further, metal cyanides other than Ni and Zn, such as Mn and Cu, are also (16), (16), It is considered that a metal oxide is formed by the reaction represented by the formula (17).

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Cu + 4NH3 = [Cu (NH3) 4] 2+ (18) Zn + 4NH3 = [Zn (NH3) 4] 2+ (19) Ni + 6NH3 = [Ni (NH3) 6] 2+ (20) Ag + NH3 = [Ag (NH3)] 2+ (21) Further, in the case of the plating waste liquid, since a chelating agent such as EDTA is contained from the beginning, it is considered that a chelate with Cu, Zn or the like is formed and dissolved. It should be noted that noble metals such as Au and Ag do not completely form precipitates like Cu.

Claims (7)

[Claims] 1. A plating solution containing a valuable metal ion and a complexing agent or a chelating agent in the presence of a metal scavenger composed of sulfide at least 130 ° C. and at least 2.7 × 10 7.
A method for trapping a valuable metal in a plating solution, which comprises precipitating the valuable metal by high-temperature and high-pressure treatment under a condition of 5 Pa. 2. The method for capturing valuable metals in a plating solution according to claim 1, wherein the processing solution obtained by separating the precipitate generated by the high temperature / high pressure processing is subjected to an ammonia stripping process. 3. The slurry separated from the autoclave used for the high temperature / high pressure treatment is dehydrated to separate a precipitate and a filtrate, and the filtrate is subjected to an ammonia stripping treatment. A method for capturing a valuable metal in the plating solution described. 4. The method for capturing valuable metals in a plating solution according to claim 1, wherein ferrous sulfate is added to the processing solution from which the precipitate produced by the high-temperature and high-pressure treatment is separated. 5. The plating according to claim 1, wherein at least a part of a plating solution containing the valuable metal and a complexing agent or a chelating agent is a cleaning solution after cleaning a product to be plated. Method for capturing valuable metals in liquid. 6. The method for capturing valuable metals in a plating solution according to claim 5, wherein the solution for cleaning the product to be plated is a first-stage cleaning solution for multi-step cleaning. 7. The method for capturing valuable metals in a plating solution according to claim 6, wherein the final stage cleaning solution in the multi-stage cleaning is subjected to a purification treatment with an ion exchange resin.