JP2001048537A - Gold compound solution and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gold compound solution improved in long-term storage stability and applicable to all of the industrial fields including technical fields such as gold catalyst support and gold plating, and to provide a method for producing such a gold compound solution. SOLUTION: This gold compound solution is obtained using chloroauric acid HauCl4 as starting material, through neutralization step using an alkali hydroxide solution, washing step, and dissolving step using an alkali hydroxide; wherein the following practices are done: (1) a hypochlorous acid compound is added, (2) a washing operation using an alkali hydroxide solution is conducted, and (3) an acidic solution is added to a gold compound solution to form gold hydroxide Au(OH)3, which, in turn, is dissolved with an alkali hydroxide solution again, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gold compound having improved long-term storage stability and a method for producing the same. This theory of producing a gold compound can be widely applied in technical fields such as gold catalyst loading and gold plating.

[0002]

2. Description of the Related Art Hitherto, gold compounds have been widely used in various fields such as plating and colloids for supporting a catalyst. These gold compounds generally lack long-term stability, and are likely to cause a phenomenon in which gold precipitates when stored for a long time (generally referred to as “gold precipitation”, and thus referred to below). It is. That is, the decomposition rate is high, and it is difficult to maintain stable quality as a compound, and as a result, it is not suitable for commercial transactions.

Accordingly, many of the gold compounds referred to in this specification have been produced at the laboratory level in many cases, but it cannot be said that they are actually at a level at which business can be performed with complete quality assurance. Things.

[0004] The fact supporting this is remarkably found in gold compound solutions such as plating and catalyst colloids. It is said that the lifetime of the gold plating solution is about 2 to 10 hours.
In addition, the gold plating solution naturally precipitates in a heated state, and if the used gold plating solution is used again, the properties of the solution are remarkably changed, and the gold plating solution often becomes unusable. Was done.

[0005] From these facts, even if a gold plating solution used in any field is used, it is necessary to establish a bath every time immediately before performing a plating treatment or carrying a catalyst and to efficiently and intensively treat the solution in a short time. We have tried to solve it.

[0006]

However, since gold is a very expensive metal by nature, it is necessary to use the gold compound solution efficiently and to maximize the use of gold contained in the plating solution, catalyst colloid and the like. desired. For example, for those skilled in the art of plating, catalysts, and the like for small-lot production of other products, a long-term storage stability for use at a suitable timing when desired, and a gold compound solution that can be used repeatedly by processing a small number of products and re-use. desirable.

[0007] Further, for those who intend to manufacture and supply the gold compound solution according to the present invention, if at least long-term storage stability can be ensured, it is possible to secure the inventory of the gold compound solution as a product, which will greatly increase the transportation time. Problems such as deterioration in quality due to temperature change and occurrence of gold deposition can be eliminated, and the product quality can be greatly improved, and product transactions can be activated.

[0008] From the above, a gold compound solution has been required to have further long-term storage stability and characteristics that can be used for a long time. Japanese Patent Application Laid-Open No. 2-93091 aims at stabilizing the gold plating solution by adding hydrogen peroxide solution or sodium nitrate as an oxidizing agent to the electroless gold plating solution for the same purpose. Quality improvement is desired.

[0009]

The inventors of the present invention have conducted intensive studies and as a result of studying the gold compound solution or the method for producing the gold compound solution as described below, it has been found that the gold compound solution can be stored in a very stable and long-term manner. It has been concluded that it is possible to impart properties of stability and long-term use. Hereinafter, the present invention will be described.

According to the first aspect of the present invention, the first gold compound is obtained by using HAuCl ₄ chloroaurate as a starting material, through a neutralization step with an alkali hydroxide, a washing step, and a dissolution step with an alkali hydroxide. By adding a compound containing hypochlorous acid to the gold compound solution, a gold compound solution in which reductive precipitation of gold is suppressed is obtained. This means that a gold compound containing a compound containing hypochlorous acid as an oxidizing agent in the gold compound solution was used to suppress the reductive precipitation of gold.

The hypochlorous acid in the gold compound solution exists in the form of hypochlorite ion (ClO ⁻ ). This hypochlorous acid itself is known as a strong oxidizing agent that exhibits a bleaching action. Therefore, by allowing a compound containing hypochlorous acid to coexist in the gold compound solution, it is possible to effectively suppress the occurrence of gold precipitation, and to secure long-term storage stability exceeding one month on average, It enables long-term stable use.

According to a second aspect of the present invention, the gold hypochlorite-containing compound is potassium hypochlorite KClO, and the gold compound solution is used, and potassium hypochlorite is used. Clarifies what is desirable. In addition, it is also possible to use hydrogen peroxide, chlorine gas, permanganic acid, dichromic acid, etc. according to the purpose of use, but considering that it can be applied in all fields, including catalyst support, A gold compound solution using potassium hypochlorite exhibits long-term storage stability of one to two months without deterioration in quality, and is most excellent in quality stability.

Further, claim 5 describes a method for producing a gold compound solution according to claims 1 and 2. In this production method, chloroauric acid HAuCl ₄ is neutralized with an alkali hydroxide to form gold hydroxide Au (OH) ₃ , the gold hydroxide Au (OH) ₃ is washed with water, and the gold hydroxide Au washed with water is washed.
(OH) ₃ is dissolved in an alkali hydroxide solution, and a solution containing hypochlorous acid as an oxidizing agent is added to the obtained gold compound solution.

The alkali hydroxide solution used for neutralizing chloroauric acid HAuCl ₄ includes potassium hydroxide KOH, calcium hydroxide Ca (OH) ₂ , sodium hydroxide NaOH
And so on. The amount of alkali hydroxide to be used is 100 to 140 g in the case of potassium hydroxide KOH and 65 to 95 g in the case of calcium hydroxide Ca (OH) ₂ per 100 g as the amount of gold of chloroauric acid HAuCl _4. And 70 to 100 in the case of sodium hydroxide NaOH.
Use g as a guide. In the following, potassium hydroxide KO
A description will be given of a manufacturing method using H as an example.

As a result of this neutralization, gold hydroxide Au (OH) ₃
Is obtained. In this state, gold hydroxide Au (OH) ₃ containing residual chlorine is obtained. Therefore, for the purpose of removing residual chlorine and other impurities, water washing was performed to obtain pure gold hydroxide Au (OH) ₃ .

Next, this clean gold hydroxide Au (OH) ₃
Is dissolved in an alkali hydroxide solution. The alkali hydroxide solution used at this stage has a concentration of 21.30 to
23.50 g / l potassium hydroxide KOH solution.
By this reaction, the desired gold compound solution (KAu (O
H) ₄ ) is produced.

Then, the gold compound solution (KAu (O
H) ₄ ), 6.5 to 19.5 ml of potassium hypochlorite KClO is added to the final product. The method for producing a gold compound solution according to claim 1 and claim 2 is also described as claim 8,
It is considered that it is better to perform the description later, and will be described later.

The second gold compound according to claim 3,
The third gold compound according to claim 4 and a method for producing the same will be described. Conditions for using an alkali hydroxide and the like used in the production method are the same as those described above unless otherwise specified.

According to a third aspect of the present invention, as the second gold compound, starting from HAuCl ₄ chloroaurate, a neutralizing step with an alkali hydroxide, a washing step, and a dissolving step with an alkali hydroxide solution are performed. A gold compound solution obtained, wherein gold hydroxide Au (OH) obtained through a neutralization step
₃ is a gold compound solution in which reduction precipitation of gold is suppressed by washing with an alkali hydroxide solution and washing with water in a washing step.

Here, instead of using a compound containing hypochlorous acid as the gold compound described in claim 1, gold hydroxide A obtained by a neutralization step with an alkali hydroxide is used.
In the washing step, u (OH) ₃ is not simply washed with water,
It is characterized in that it is a gold compound obtained by washing with an alkali hydroxide solution before washing with water.

In the manufacturing step, by performing a method such as washing with an alkali hydroxide solution as described above in the washing step, it is possible to ensure long-term storage performance equivalent to that of the gold compound described in claim 1, and It can be used for a long time.

According to a sixth aspect of the present invention, there is provided a method for producing a gold compound according to the third aspect, wherein chloroauric acid HAuCl ₄ is neutralized with an alkali hydroxide to produce gold hydroxide Au (OH) _3.
The gold hydroxide Au (OH) ₃ is washed with an alkali hydroxide solution, then washed with water, and washed with water to obtain gold hydroxide Au (O).
And a method for producing a gold compound according to claim 3 H) ₃ is obtained by dissolving the alkali hydroxide solution.

An alkali hydroxide used for neutralizing chloroauric acid,
The production flow except for the addition of the alkali hydroxide solution for dissolving the gold hydroxide Au (OH) ₃ after water washing and the potassium hypochlorite KClO is no different from that described in the production method of claim 5. , Duplicate descriptions are omitted.

Therefore, in the production method according to the present invention, the chloroauric acid HAuCl ₄ is neutralized with alkali hydroxide to form gold hydroxide Au (OH) _3, and the gold hydroxide Au (O) ₃
H) It can be said that the method is characterized in that ₃ is washed with an alkali hydroxide solution.

The alkaline hydroxide solution used for this washing includes potassium hydroxide KOH, sodium hydroxide NaOH
And the like, and the solution concentration is 1.0 to 2.0 g / l for potassium hydroxide KOH and 0.7 to 1.5 g / l for sodium hydroxide NaOH. By washing with this alkali hydroxide solution, gold hydroxide Au after neutralization
Chlorine remaining in (OH) ₃ can be removed to an extremely low level. Thereafter, further washing with water makes it possible to obtain even more pure gold hydroxide Au (OH) ₃ .

The clean gold hydroxide Au (OH) ₃ is dissolved in an alkali hydroxide solution and reacted to obtain a gold compound solution (KAu (O)
H) ₄ ) is produced.

According to a fourth aspect of the present invention, as the third gold compound, HAuCl ₄ chloroaurate is used as a starting material, which is obtained through a neutralization step with an alkali hydroxide, a washing step, and a step of dissolving the alkali hydroxide. A gold compound solution, which is obtained by washing gold hydroxide Au (OH) ₃ obtained through a neutralization step with water in a washing step, and then dissolving the gold hydroxide Au (OH) ₃ after washing with water in an alkali hydroxide solution. A gold compound solution was added, an acidic solution was added to the gold compound solution, and gold hydroxide Au (OH) was again added.
_{3, which} is a gold compound solution obtained by dissolving the gold hydroxide Au (OH) ₃ with an alkali hydroxide solution to suppress reductive precipitation of gold.

This gold compound solution is prepared by preparing an intended gold compound solution, further purifying gold hydroxide Au (OH) ₃ from the gold compound solution by using an acidic solution, and preparing the gold hydroxide Au (OH). ₃ ) is obtained by redissolving ₃ with an alkali hydroxide solution. Hereafter,
This is referred to as "redissolution method".

The gold compound solution produced by this re-dissolving method is
Since the purity is improved, it exhibits very excellent long-term storage stability and long-term use stability, which are equivalent to the gold compound according to the first aspect.

According to a fourth aspect of the present invention, there is provided a method for producing a gold compound according to the seventh aspect, wherein chloroauric acid HAuCl ₄ is neutralized with an alkali hydroxide to form gold hydroxide Au (OH) _3. gold Au (OH) ₃ was washed with water, the gold hydroxide Au (OH) ₃ after washing with water and then gold compound solution dissolved in alkali hydroxide solution, again gold hydroxide by adding an acidic solution to the gold compound solution Au (OH) ₃ and this gold hydroxide A
This is a method for producing a gold compound solution in which u (OH) ₃ is dissolved in an alkali hydroxide solution.

In this production method, chloroauric acid HAuC
l ₄ is neutralized by an alkali hydroxide metal Au
_{(OH) 3} and then, washed with water the gold hydroxide Au _{(OH) 3,} is a gold hydroxide Au _{(OH) 3} after washing with water until the then gold compound solution dissolved in alkali hydroxide solution, according to claim 5 There is no difference in the manufacturing method from that described above. Therefore, redundant description on this point will be omitted.

Therefore, the gold compound solution (KAu (OH)
₄ ) Add an acidic solution to the solution and add gold hydroxide Au (OH) again.
₃ and the process up to the final product will be described. The acidic solution used here is sulfuric acid, phosphoric acid, nitric acid or the like. Among them,
It is preferable to use about 5 to 15% sulfuric acid. This is because it has the least effect on product quality.

Here, a gold compound solution (KAu (O
By adding an acidic solution to H) ₄ ), gold hydroxide Au (OH) ₃ is generated again from the gold compound solution.
The gold hydroxide Au (OH) ₃ was dissolved again with an alkali hydroxide solution, and a gold compound solution (KAu (O
H) ₄ ) is obtained. The alkali hydroxide solution used here is the same potassium hydroxide KOH solution as described above. Therefore, detailed description is omitted.

The features of the manufacturing method according to claim 5, claim 6, and claim 7 can be used arbitrarily in combination. However, as a manufacturing method having all the features, claim 8 Is obtained by neutralizing chloroauric acid HAuCl ₄ with alkali hydroxide to obtain gold hydroxide Au (OH) ₃ ,
The gold hydroxide Au (OH) ₃ is washed with an alkali hydroxide solution, then with water, and the washed gold hydroxide Au (OH) _{3 is} washed.
Is dissolved in an alkali hydroxide solution to obtain a gold compound solution, an acidic solution is added to the gold compound solution, and gold hydroxide Au is again formed.
(OH) ₃ , wherein the gold hydroxide Au (OH) ₃ is dissolved in an alkali hydroxide solution, and a solution containing hypochlorous acid as an oxidizing agent is added thereto. 2. The method for producing a gold compound solution according to item 2.

The production method shown here shows the production method of the gold compound solution according to the first or second aspect as a result. However, since it has all the features of the above production method, it is very Thus, a gold compound solution having stable performance can be obtained.

The production conditions and chemicals used are not different from those described above, and will not be described because they are duplicated. Hereinafter, in the embodiment,
This will be described in more detail.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a gold compound solution according to the present invention which are considered to be optimal will be described.

First Embodiment Here, a gold compound solution containing hypochlorous acid as an oxidizing agent is manufactured according to the flow shown in FIG. HAuCl chloroauric acid
The solution of No. ₄ was prepared by adding water to 150 g of chloroauric acid solution as gold to make a solution of 500 ml.

There, 180 g of potassium hydroxide KOH
, A neutralization reaction is performed, and gold hydroxide Au (OH)₃To
Precipitated and separated. And residual chlorine and other
Rinse with distilled water for the purpose of removing pure substances,
Pure gold hydroxide Au (OH) ₃And

Next, using 2 liters of a potassium hydroxide solution having a concentration of 22.6 g / l, this clean gold hydroxide Au was used.
(OH) ₃ is dissolved, and the desired gold compound solution (KA
u (OH) ₄ ).

Then, the gold compound solution (KAu (O
H) ₄ ), 20 ml of potassium hypochlorite KClO was added, and a gold compound solution (KAu (O
H) ₄ ) was obtained.

This gold compound solution was put into a bottle made of light-shielded polyethylene, allowed to stand at room temperature, and the amount of gold precipitation was examined as appropriate. In this measurement method, a gold compound solution after a predetermined time has elapsed is filtered, the amount of generated gold precipitation is examined, and converted as a ratio to the total amount of gold originally contained in the solution. As a result, the gold compound solution according to this embodiment was 0.001% or less after one month, and 0.005% after two months.

Second Embodiment Here, a target gold compound solution (KAu (Ou)
H) ₄ ). HAuC chloroauric acid
solution of l _4, the water was added to chloroauric acid solution 150g as gold was formed with a solution of 500 ml.

There, 180 g of potassium hydroxide KOH
Was added to carry out a neutralization reaction to precipitate gold hydroxide Au (OH) ₃ and fractionated. Then, for the purpose of removing residual chlorine and other impurities, first, washing is performed using a potassium hydroxide solution having a concentration of 1.5 g / l, followed by washing with distilled water to obtain clean gold hydroxide. Au (OH) ₃ was used.

Next, using 2 liters of a potassium hydroxide solution having a concentration of 22.6 g / l, this clean gold hydroxide Au was used.
(OH) ₃ was dissolved to produce a gold compound solution (KAu (OH) ₄ ) as a final product.

The gold compound solution was placed in a light-shielding polyethylene bottle, allowed to stand at room temperature, and the amount of gold precipitation was examined as appropriate. In this measurement method, a gold compound solution after a predetermined time has elapsed is filtered, the amount of generated gold precipitation is examined, and converted as a ratio to the total amount of gold originally contained in the solution. As a result, the gold compound solution according to this embodiment was 0.005% after one month, and 0.01% after two months.

Third Embodiment Here, a gold compound solution is manufactured according to the flow shown in FIG. A solution of chloroauric acid HAuCl ₄ is 200
Water was added to g of the chloroauric acid solution to make a 670 ml solution.

Then, 240 g of potassium hydroxide KOH
, A neutralization reaction is performed, and gold hydroxide Au (OH)₃To
Precipitated and separated. And residual chlorine and other
Rinse with distilled water for the purpose of removing pure substances,
Pure gold hydroxide Au (OH) ₃And

Next, 2.6 l of a potassium hydroxide solution having a concentration of 23.0 g / l was used to prepare this clean gold hydroxide A.
u (OH) ₃ is dissolved and the desired gold compound solution (K
Au (OH) ₄ ) was produced.

By adding 500 ml of a 5% sulfuric acid solution to the gold compound solution, gold hydroxide was formed again, and the gold hydroxide Au (OH) ₃ was fractionated.

Using 2.7 liters of a potassium hydroxide solution having a concentration of 22.6 g / l, the separated gold hydroxide Au was used.
(OH) ₃ was dissolved to produce a gold compound solution (KAu (OH) ₄ ) as a final product.

This gold compound solution was placed in a light-shielding polyethylene bottle, allowed to stand at room temperature, and the amount of gold precipitation was examined as appropriate. In this measurement method, a gold compound solution after a predetermined time has elapsed is filtered, the amount of generated gold precipitation is examined, and converted as a ratio to the total amount of gold originally contained in the solution. As a result, the gold compound solution according to this embodiment was 0.005% after one month, and 0.01% after two months.

Fourth Embodiment: Here, a gold compound solution is manufactured according to the flow shown in FIG. A solution of chloroauric acid HAuCl ₄ is 200
Water was added to g of the chloroauric acid solution to make a 670 ml solution.

Thereto, 240 g of potassium hydroxide was added to carry out a neutralization reaction, and gold hydroxide Au (OH) ₃ was precipitated and separated. Then, for the purpose of removing residual chlorine and other impurities, first, washing is performed using a potassium hydroxide solution having a concentration of 1.5 g / l, followed by washing with distilled water to obtain clean gold hydroxide. Au (OH) ₃ was used.

Next, 2.6 l of a potassium hydroxide solution having a concentration of 23.0 g / l was used to prepare this clean gold hydroxide A.
u (OH) ₃ is dissolved and the desired gold compound solution (K
Au (OH) ₄ ) was produced.

By adding 500 ml of a 5% sulfuric acid solution to this gold compound solution, gold hydroxide Au (OH) ₃
Was generated, and the gold hydroxide Au (OH) ₃ was separated.

Using 2.7 liters of a potassium hydroxide solution having a concentration of 22.6 g / l, the separated gold hydroxide Au was used.
(OH) ₃ is dissolved and a gold compound solution (KAu (OH)
₄ ) was generated.

Then, this gold compound solution (KAu (O
H) ₄ ), add 20 ml of potassium hypochlorite,
A gold compound solution (KAu (OH) ₄ ) was obtained as a final product.

This gold compound solution was put in a bottle made of light-shielding polyethylene, allowed to stand at room temperature, and the amount of gold precipitation was examined as appropriate. In this measurement method, a gold compound solution after a predetermined time has elapsed is filtered, the amount of generated gold precipitation is examined, and converted as a ratio to the total amount of gold originally contained in the solution. As a result, the gold compound solution according to the present embodiment was 0.001% or less after one month, and 0.002% or less after two months.

Further, in order to compare the long-term storage stability of the gold compound solution described in each of the above-described embodiments with that of the conventional gold compound solution, the present inventors show the conventional gold compound solution below. Manufactured by the method.

A conventional gold compound solution was manufactured according to the flow shown in FIG. The solution of chloroauric acid HAuCl ₄ is prepared by adding water to 150 g of chloroauric acid solution as gold,
The solution was made up to 00 ml.

There, 180 g of potassium hydroxide KOH
, A neutralization reaction is performed, and gold hydroxide Au (OH)₃To
Precipitated and separated. And residual chlorine and other
Rinse with distilled water for the purpose of removing pure substances,
Pure gold hydroxide Au (OH) ₃And

Next, using 2 liters of a potassium hydroxide solution having a concentration of 22.6 g / l, this clean gold hydroxide Au was used.
(OH) ₃ was dissolved to produce a desired conventional gold compound solution (KAu (OH) ₄ ).

This gold compound solution was placed in a light-shielding polyethylene bottle, allowed to stand at room temperature, and the amount of gold precipitation was examined as appropriate. This measuring method is the same method as described in the above embodiment. As a result, the conventional gold compound solution was 0.04% or less after one month, and 0.06% after two months. When this value is compared with the value described in each of the above-described embodiments, it can be seen that the long-term storage stability of the gold compound solution described in the embodiment is very excellent.

[0065]

The gold compound solution according to the present invention is in an extremely stable state and has excellent chemical stability as compared with the conventional gold compound solution due to the characteristics of the production method. Therefore, using the gold compound solution according to the present invention,
It is easy to maintain stable quality as a compound, and it is suitable for commercial transactions. Further, the production theory of a gold compound solution described in the present specification has a possibility that it can be applied not only to a catalyst colloid and a plating solution but also to an extremely wide field.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a production flow of a gold compound solution.

FIG. 2 is a schematic diagram of a production flow of a gold compound solution.

FIG. 3 is a schematic diagram of a production flow of a gold compound solution.

FIG. 4 is a schematic diagram of a production flow of a gold compound solution.

FIG. 5 is a schematic diagram of a production flow of a gold compound solution.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G069 AA08 AA20 BA42A BA42C BA50 BB05A BB05B BB05C CA08 FC02 FC03 4K023 AA25 BA08 BA22 CA09

Claims (8)

[Claims] 1. A compound containing hypochlorous acid in a gold compound solution obtained through a neutralization step with an alkali hydroxide solution, a washing step, and a step of dissolving an alkali hydroxide using HAuCl ₄ chloroaurate as a starting material. A gold compound solution that suppresses the reductive precipitation of gold by adding a compound. 2. The gold compound solution according to claim 1, wherein the compound containing hypochlorous acid is potassium hypochlorite KClO. 3. A gold compound solution obtained from a neutralization step with an alkali hydroxide solution, a washing step, and a step of dissolving alkali hydroxide using HAuCl ₄ chloroaurate as a starting material, wherein the gold compound solution is obtained through a neutralization step. Gold hydroxide Au (OH)
₃ is a gold compound solution in which reduction precipitation of gold is suppressed by washing with an alkali hydroxide solution and washing with water in a washing step. 4. A gold compound solution obtained from a neutralization step with an alkali hydroxide solution, a washing step, and a step of dissolving alkali hydroxide using HAuCl ₄ chloroaurate as a starting material, wherein the gold compound solution is obtained through a neutralization step. Gold hydroxide Au (OH)
₃ in the washing step, and then washed with gold hydroxide Au (O
The H) ₃ and dissolved gold compound solution in alkali hydroxide solution, the gold hydroxide Au (OH) ₃ again by adding an acidic solution to the gold compound solution, the gold hydroxide Au (OH) ₃ Water A gold compound solution in which reductive precipitation of gold obtained by dissolving with an alkali oxide solution is suppressed. 5. Chloroauric acid HAuCl ₄ is neutralized with alkali hydroxide to obtain gold hydroxide Au (OH) _3, and the gold hydroxide Au (OH) ₃ is washed with water, and the gold hydroxide Au (OH) after water washing is obtained. _{3. The} method for producing a gold compound solution according to claim 1, wherein OH) ₃ is dissolved in an alkali hydroxide solution, and a solution containing hypochlorous acid as an oxidizing agent is added thereto. 6. A chloroauric acid HAuCl ₄ is neutralized with an alkali hydroxide to obtain a gold hydroxide Au (OH) _3, and the gold hydroxide Au (OH) ₃ is washed with an alkali hydroxide solution and subsequently washed with water. The method for producing a gold compound according to claim 3, wherein gold hydroxide Au (OH) ₃ after water washing is dissolved in an alkali hydroxide solution. 7. The chloroauric acid HAuCl ₄ is neutralized with an alkali hydroxide to form gold hydroxide Au (OH) _3, and the gold hydroxide Au (OH) ₃ is washed with water, and the gold hydroxide Au (OH) after water washing is obtained. OH) ₃ is dissolved in an alkali hydroxide solution to form a gold compound solution. An acidic solution is added to the gold compound solution, and gold hydroxide Au is again added.
The method for producing a gold compound solution according to claim 4, wherein (OH) ₃ is used, and the gold hydroxide Au (OH) ₃ is dissolved in an alkali hydroxide solution. 8. HAuCl ₄ chloroaurate is neutralized with alkali hydroxide to form gold hydroxide Au (OH) _3, and the gold hydroxide Au (OH) ₃ is washed with an alkali hydroxide solution and subsequently washed with water. Then, the gold hydroxide Au (OH) ₃ after the washing is dissolved in an alkali hydroxide solution to form a gold compound solution. An acidic solution is added to the gold compound solution, and the gold hydroxide Au is again added.
(OH) ₃ , wherein the gold hydroxide Au (OH) ₃ is dissolved in an alkali hydroxide solution, and a solution containing hypochlorous acid as an oxidizing agent is added thereto. 3. The method for producing a gold compound solution according to item 2.