KR100893627B1 - Method for smelting pgc - Google Patents

Abstract

The present invention relates to a method for refining potassium gold cyanide, which is prepared from a low-purity waste metal scrap having a gold content of 60% or less through a simple process, and the potassium gold cyanide is reacted by reaction of the gold and cyanide. The purpose of the present invention is to purify the metal, and completely dissolve the gold-containing waste metal scrap in aqua regia solution (Aqua Regia, HCl: HNO ₃ = 3: 1), and then cool and adjust pH to remove impurities present in the aqua regia solution. The primary impurity to be removed is removed, and the gold-dissolved aqua regia solution is reacted with a solvent extractant to extract gold ions in the aqua regia solution, and the gold is extracted to react with hydrochloric acid to remove impurities, and gold Reacting the extracted solvent with a back extracting agent to recover a plethora precipitate; Reacting the plethora precipitate with an aqueous potassium cyanide solution to purify the liquid potassium gold cyanide (PGC); Purifying the potassium gold cyanide into a powder.

Now, Scrap Metal Scrap, Thunderbolt, Potassium Gold Cyanide, Manufacturing

Description

Refining method of potassium gold cyanide {METHOD FOR SMELTING PGC}

1 is a process chart for explaining the refining method of potassium gold cyanide according to the present invention.

The present invention relates to a method for refining potassium gold cyanide, and more particularly, to shorten the reaction time and to newly develop a process for producing a plenum, which is an intermediate of explosive potassium gold cyanide, to generate a plenum in an effective and stable manner. The present invention relates to a method for refining potassium gold cyanide, which enables the use of a plethora after a blood vessel.

In general, the chemical formula of potassium gold cyanide (PGC) used for gold plating is KAu (CN) ₂ (also called potassium cyanide potassium). As a refining method, gold (Au) is potassium cyanide (KCN). ) and there is a generation method of intermediate made after the medium is water dissolved direct reaction method, an aqueous solution of gold on Wang (王水) noegeum (main component Au ₂ O ₃ · 3NH ₃₎ potassium cyanide and reaction material known to react directly.

The method for preparing potassium gold cyanide by the direct reaction method as the former of the refining method is as follows. Dissolving gold directly in an aqueous potassium cyanide solution while applying heat in a waterbath state, and directly dissolving the gold; After filtering, the filtered crystals were dried to prepare potassium gold cyanide, and the product was packaged in about 100 grams. In the case of the reaction in which gold is dissolved in an aqueous potassium cyanide solution by the direct reaction method, heat must be applied, and the reaction formula is as follows.

Scheme 1

2Au + 4KCN + 1 / 2O ₂ + 2H ₂ O + HEAT → 2KAu (CN) ₂ + 2KOH + H ₂ ↑ (H ₂ O)

When potassium gold cyanide is manufactured by a direct reaction method in which gold is directly reacted with potassium cyanide, as shown in Scheme 1, only three kinds of chemicals are required, but the reaction time is very long, about 12 hours, resulting in decreased productivity. There is a problem.

On the other hand, the latter intermediate production method of the conventional refining method that was performed to shorten the reaction and production time during the production of potassium gold cyanide is as follows. Gold dissolving step in which gold is dissolved in aqua regia solution (hydrochloric acid: nitric acid mixed at about 3: 1) in a water bath, and excess ammonia (NH ₃ ) is added to the resulting gold tetrachloride solution to add gold (Au ₂ O ₃ · 3NH ₃ ) to prepare a cerebrospinae, and re-dissolve the precipitated cerebrum in potassium cyanide (KCN) aqueous solution to obtain a gold gold cyanide (KAu (CN) ₂ ) re-dissolution step, The resulting solution is evaporated in a water bath and left to form crystals, the precipitated crystals are filtered, and the filtered crystals are dried to obtain a potassium gold cyanide product, which is then packaged in about 100 grams. .

Reaction of the process of dissolving the gold (Au) in aqua regia solution is shown in the following scheme 2.

Scheme 2

2Au + 2HNO ₃ + 6HCl → 2AuCl ₃ + 2NO ↑ + 4H ₂ O
AuCl ₃ + HCl → HAuCl ₄

The reaction of precipitating the cerebral gold by adding ammonia to the gold tetrachloride solution produced by dissolving the gold in aqua regia solution is shown in Scheme 3 below.

Scheme 3

^{_{2HAuCl 4 - + 11NH 4 OH -}} > Au 2 O 3 · 3NH 3 ↓ + 8NH 4 + Cl - + 8H 2 O

The reaction in which the precipitated cephalus is redissolved in an aqueous solution of potassium cyanide (KCl) is shown in Scheme 4 below.

Scheme 4

_{Au 2 O 3 · 3NH 3 +} 6KCN + 5H 2 O
^{_{→ 2KAu (CN) 2 - +}} 3NH 4 + OH - + 2KCNO - + 2KOH + H 2 O

As described above, according to the intermediate production method of dissolving gold in aqua regia solution to make an intermediate thrombus, and then reacting with potassium cyanide, the reaction time is shortened to about 6 hours, but the safety of work is impaired due to the explosiveness of the intermediate thrombus. do. In addition, the number of chemicals required for this method is increased to six types, and the manufacturing cost is also increased. The reaction process of Reaction Equation 2, Reaction Equation 3, and Reaction Equation 4 above is required. There is a problem in that the manufacturing process is complicated because the process of washing the effusion is required before making it.

In other words, using a conventional refining method of potassium gold cyanide, if gold is directly reacted with potassium cyanide or gold is dissolved in aqua regia solution to make an intermediate blood briquette and then reacted with potassium cyanide again, There has always been a problem of productivity deterioration due to a long time, complexity of the process by the addition of the process and the washing process of the effusion, and the deterioration of the safety of the work due to the explosiveness of the effusion.

The present invention is to solve the above problems, shorten the reaction time and newly developed the process of producing a plenum, the intermediate of explosive potassium gold cyanide to produce a plenum in an effective and stable way to use the plenum The purpose is to provide a method for refining potassium gold cyanide.

A feature of the present invention for achieving the above object is that the gold-containing waste metal scrap is completely dissolved in aqua regia solution (Aqua Regia, HCl: HNO ₃ = 3: 1) and then present in the aqua regia solution through cooling and pH adjustment. Primary impurities are removed to remove impurities, and the gold-dissolved aqua regia solution is reacted with a solvent extractant to extract gold ions in the aqua regia solution, and the gold is extracted to react with hydrochloric acid to remove impurities. Removing and reacting the gold-extracted solvent with the back extractant to recover the plethora deposits; Reacting the plethora precipitate with an aqueous potassium cyanide solution to purify the liquid potassium gold cyanide (PGC); Characterized in that the step of purifying the potassium gold cyanide into a powder.

Hereinafter, a method of refining potassium gold cyanide according to the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

1 is a process chart for explaining the refining method of potassium gold cyanide according to the present invention.

Referring to Figure 1, the method for refining potassium gold cyanide according to the present invention, a solid waste containing a small amount of impurities and a small amount (less than 60% by weight based on 100% by weight) of various components of aqua regia solution (Aqua Regia, HCl: HNO ₃ = 3: 1) and reacting to dissolve step (S10); Performing silver chloride in the dissolved aqua regia solution (S20); A primary impurity removal step (S30) for removing impurities present in the aqua regia solution; Solvent extraction of gold ions in the aqua regia solution by reacting the aqua regia solution in which the impurities are removed and gold is dissolved through the primary impurity removal step with a solvent extractant (S40); Removing (second washing) secondary impurities using hydrochloric acid (S50); Injecting ammonia into the extracted solvent to prepare a brain gold (S60); Reacting the plethora with an aqueous potassium cyanide solution to generate potassium gold cyanide (PGC) (S70); It comprises a step (S80) of transforming the liquid potassium gold cyanide into a powder, which will be described in detail below.

(S10) Dissolve waste metal scrap.

When the waste metal scrap is added to the aqua regia solution and heated and dissolved at a temperature of 90 to 110 ° C., preferably at 100 ° C. for 25 to 35 minutes, the entire amount of the scrap metal scrap is dissolved in the aqua regia solution. After all of the gold-containing waste is dissolved in the aqua regia solution, the aqua regia solution is cooled to room temperature (25 ° C) with cooling water to precipitate silver chloride in the form of AgCl.

(S20) Remove silver chloride.

When the aqueous solution of aqua regia precipitated with silver chloride passes through the filter paper, the liquid aqua regia solution passes through the filter paper and silver chloride, which is an impurity, remains on the filter paper to separate the silver chloride.

(S30) removal of primary impurities.

To remove the impurities (Fe, Cu, etc.) by adding sodium hydroxide (NaOH) to the aqueous solution of silver chloride is removed to adjust the pH of the aqueous solution to 3.5. Specifically, the aqua regia solution in which the first gold-containing waste is dissolved is in a strong acid state, and a small amount of sodium hydroxide is produced therein and a small amount (not specifically limited because the amount is added to the pH) is added to pH up to 3.5. The amount of sodium hydroxide added to the increase is determined by continuously measuring the pH using a pH meter. When the pH rises above 2, impurities are precipitated in the form of Goethite (FeO (OH), etc.) and the precipitated impurities are removed by solid-liquid separation using filter paper.

(S40) Gold ion solvent extraction.

After the solid-liquid separation, the pH is adjusted to 3.5, which is the initial state, in order to apply the liquid whose pH is adjusted to 3.5 in the solvent extraction process. The pH is adjusted by adding an amount of HCl equivalent to NaOH added to the aqueous solution to adjust the pH to the optimum condition for the solvent extraction reaction.

After the impurities are removed, the solution is reacted with diethylene glycol Di-n-butyl ether (hereinafter referred to as cabitol), which is used as a solvent extractant, in an aqueous solution of which pH is initialized. That is, gold ions are extracted by reacting the gold ions in the aqua regia solution with cavitol which is an organic phase. At this time, the reaction amount of the aqua regia solution and the cavitol is reacted in a ratio of aqua regia solution: cavitol = 1.5 ~ 2: 1 in volume ratio.

Generally, about 70 g of gold reacts with 1 L of cavitol and is extracted. Therefore, the gold dissolved in the aqua regia solution is analyzed by Atomic Absorption Spectrophotometer (AAS) and then reacted by adding a cavitol corresponding to the gold content. When the aqua regia solution and the cavitol are put in a container and stirred, the gold ions dissolved in the aqua regia solution are transferred to the cavitol and the solvent is extracted. Solvent extraction reaction is completed within 30 minutes.

(S50) Remove Second Impurity (Washing Process)

The aqueous solution and the solvent form a layer of the aqueous phase (aqua solution) and the organic phase (cavitol) due to the difference in specific gravity, which are separated through a solvent extraction reactor, and the separated cavitol is dissolved using 2 M hydrochloric acid (HCl). To remove impurities such as copper and iron contained in the cavitol. Gold in the cavitol is not eluted by hydrochloric acid, while copper, iron, and the like extracted in small amounts as impurities in the cavitol are extracted by hydrochloric acid to remove impurities. The hydrochloric acid used in the reaction is reacted with hydrochloric acid at a concentration of 2 to 3M in the solvent extractor for 30 minutes using the same amount (volume ratio) as the cavitol, and the solvent extractor automatically separates the cavitol and hydrochloric acid solution.

(S60) Recovery of the plethora.

The separated gold-containing organic phase is reacted with ammonia water (NH ₄ OH) to recover the gold contained in the cavitol in the form of pulminating gold. Ammonia water is used to remove NH3 groups attached to gold present in the state of plethora in addition to hydrazine, and commercial commercial ammonia water (28%, 8M) and cavitol in a volume ratio of 1: 1 are 25 to 35 minutes at room temperature, preferably 30 When the reaction is stirred while stirring at a speed of 90 to 110 rpm, preferably 100 rpm for a minute, thrombus is formed as a precipitate in the form of a yellow powder.

^{_{2AuCl 4 - + 9NH 4 OH +}} 2NH 4 + -> Au 2 O 3 · 3NH 3 ↓ + 6H 2 O + 8NH 4 + Cl -

Through the (S10) ~ (S60) process to produce a plenum, which is a step of high purity gold.

(S70) Formation of liquid potassium gold cyanide.

When the recovered cephalus is reacted with potassium cyanide (20 g of KCN per 1 liter of distilled water) solution at a temperature of 90 to 110 rpm, preferably 100 rpm for about 25 to 35 minutes, preferably for 30 minutes, the powder of the cerebrum is powdered with potassium cyanide. The reaction results in a liquid potassium gold cyanide.

_{Au 2 O 3 · 3NH 3 +} 6KCN + 5H 2 O
^{_{→ 2KAu (CN) 2 - +}} 3NH 4 + OH - + 2KCNO - + 2K + OH - + H 2 0

(S80) Formation of powdered potassium gold cyanide.

The resulting liquid potassium gold cyanide is evaporated at 80 to 100 ° C. to precipitate the powdered potassium gold cyanide. At this time, the heating temperature should be slowly heated to about 5 ℃ per minute and when the evaporation is about 70%, all the potassium gold cyanide of the powder precipitates.

Therefore, according to the present invention, using a low-purity waste alloy waste having a gold content of 60% or less and high-purity gold, a gold cyanide is produced by producing a effusion, which is an intermediate of potassium gold cyanide, in a safe manner. KCN) can be reacted with an aqueous solution to finally prepare potassium gold cyanide having a purity of 99.9% or more.

In addition, according to the conventional method of generating a plethora, the generation time of the plethora is long, and there is an inherent risk of explosiveness in the production process. Have In order to compensate for these disadvantages, the present invention extracts gold with high purity using a solvent extraction method, and uses a extracted gold to generate a progenitor in a safe manner, and uses high-purity potassium gold cyanide. Can be prepared.

Hereinafter, the present invention will be described in detail through specific examples.

Example 1

After dissolving about 100 g of haeju in 2L of aqua regia solution, the result of quantitative analysis using AAS (Atomic Absorption Spectrophotometer) is shown in the table below.

Au Ag Pt Pd Cu Fe Zn PPM 95331.5 41.94 69.1 844.05 3323.91 31.26 156.86 (g / L) 95.332 0.042 0.069 0.844 3.324 0.031 0.157

The scrap metal scrap having such a composition is made into fine particles, which are easily reacted by using the Automizer method, and then dissolved in an aqua regia solution heated to the boiling point for 1 hour. After the reaction, the aqua regia solution is cooled to room temperature (25 ° C.) and silver dissolved in the aqua regia solution precipitates with AgCl. The precipitated silver chloride is isolated by filtration.

In order to remove impurities through pH adjustment of aqua regia solution, 2.7 L of NaOH (2M) was added to adjust the pH to 3.5 to remove impurities precipitated in the form of Geothite (FeO (OH)). After filtration, 550 ml of the same amount of HCl (10M) was added to the filtrate to adjust the solvent extraction reaction to reset the pH of the aqua regia solution.

The pH-adjusted aqua solution is mixed with 2L of cavitol and stirred for 30 minutes to extract gold from the cavitol. After separating the aqua regia solution and the organic phase by phase separation, the result of analyzing the aqua regia solution from which gold was removed using AAS is shown in the table below.

 Aqua regia after carbitol reaction Au Ag Pt Pd Cu Fe Zn PPM 6.12 37.5 98.8 909.72 3346.2 19.68 145.8 (g / L) 0.00612 0.0375 0.0988 0.90972 3.3462 0.01968 0.1458

By comparing the analysis results of the aqua regia solution before and after the gold is extracted into the cavitol, the primary recovery rate and purity of the gold can be measured.

As can be seen from the table, more than 99% of gold was recovered in the organic solvent, but a small amount of silver, Fe and Cu were extracted together.

The gold-containing cavitol was mixed with 2M HCl 2L and stirred for 30 minutes to remove impurities contained in the cavitol.

After separating the cavitol and hydrochloric acid (HCl), the organic phase and the aqueous ammonia (NH ₄ OH) 2L is mixed again and stirred for 30 minutes, the gold contained in the cavitol is recovered as pulminating gold (Fulminating Gold).

The collected cephalum and potassium cyanide (20g KCN per 1 liter of distilled water) were added to the stirrer and reacted for 30 minutes at a speed of 100rpm. do.

Put the liquid potassium gold cyanide into the container and slowly heated while raising the temperature by about 5 ° C. per minute to precipitate the powder of potassium gold cyanide.

As described above, according to the method for refining potassium gold cyanide of the present invention, impurities such as iron, copper, and zinc through selective separation, solvent extraction, and removal process of gold through solvent extraction using low purity now Can be effectively removed, and can be produced immediately without a separate process in the solvent extraction process can produce a high quality encephallium with less impurities than conventional methods, and finally using potassium fluoride is generated using In manufacturing, it is more effective in terms of cost and working time than the existing methods through the improvement of the working speed and the simplification of the purification process.

As those skilled in the art would realize, the described embodiments may be modified in various ways, all without departing from the spirit or scope of the present invention. It is to be understood, however, that the present invention is not limited to the specific forms referred to in the description, but rather includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. Should be.

Claims (3)

delete delete Gold-containing waste metal scrap was added to an aqua regia solution (Aqua Regia, HCl: HNO ₃ = 3: 1) and dissolved by heating for 30 minutes at 90 to 110 ° C. for 30 minutes to 35 ° C. Remove impurities present in the primary, react the aqua regia solution in which the gold is dissolved with a solvent extractant to extract the gold ions in the aqua regia solution, and remove the impurities by reacting the gold extracted solvent with hydrochloric acid. Recovering the plethora precipitate by reacting the solvent from which the gold is extracted with the back extract; Reacting the plethora precipitate with an aqueous potassium cyanide solution to purify the liquid potassium gold cyanide (PGC); Purifying the potassium gold cyanide into a powder, In the liquid potassium gold cyanide purification step, The recovered cephalum is reacted with potassium cyanide (20 g KCN per 1 liter of distilled water) at a rate of 90 to 110 rpm at room temperature for 25 to 35 minutes to react the powdered plenum with potassium cyanide to produce liquid potassium gold cyanide. , In the potassium gold cyanide generation step of the powder, potassium gold cyanide refining method characterized in that the potassium gold cyanide of the powder is precipitated by heating by increasing the liquid gold gold cyanide by 5 ℃ per minute.

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