KR102021524B1 - Method for recycling of waste nitric acid containing copper - Google Patents

Abstract

According to a desired embodiment of the present invention, provided are: a recycling method of copper-containing waste nitric acid which is able to recover copper carbonate from copper-containing waste nitric acid at high recovery efficiency and low cost; and a recycling method of copper-containing waste nitric acid capable of recovering copper of high purity by using copper carbonate. According to a desired embodiment of the present invention, the recycling method of copper-containing waste nitric acid comprises: a step of preparing copper-containing waste nitric acid; a step of preparing liquid type mixed alkali neutralizer including 5-15 wt% of sodium carbonate (Na_2CO_3), 5 to 35 wt% of one or two kinds of sodium hydroxide and calcium hydroxide, and water; a neutralization step of adding the liquid type mixed alkali neutralizer to the copper-containing waste nitric acid at a weight ratio of 0.6 to 1.5:1, and neutralizing the copper-containing waste nitric acid by controlling pH into 6.0 to 8.5; a filtration step of filtering the neutralized copper-containing waste nitric acid and obtaining a copper carbonate (CuCO_3) precipitate and a filtrate. The recycling method of copper-containing waste nitric acid is able to recover copper of high purity by using the copper carbonate (CuCO_3) precipitate.

Description

Recycling method of waste nitrogen containing copper {METHOD FOR RECYCLING OF WASTE NITRIC ACID CONTAINING COPPER}

The present invention relates to a method for recycling copper-containing waste nitric acid for recovering copper carbonate and copper from copper-containing waste nitric acid, and more particularly, to a method for recycling copper-containing waste nitric acid for recovering copper carbonate from copper-containing waste nitric acid. It relates to a recycling method of copper-containing waste nitric acid for recovering copper by using copper carbonate recovered from the containing waste nitric acid.

Waste nitric acid is generated in copper plating and manufacturing equipment washing processes.

For example, when manufacturing printed circuit board (PCB), which is a core material of the electronics industry, a large amount of waste acid containing copper is generated, and in the form of waste copper chloride, waste copper sulfate, and waste copper nitrate.

Waste copper chloride and waste copper sulfate are made of iron or aluminum in the waste acid to concentrate and recover copper by substitution reaction, so it is easy to recycle, and many recycling technologies have been developed and commercialized.

On the other hand, nitric acid, unlike hydrochloric acid and sulfuric acid, generates a large amount of nitrogen oxide (NOx) fumes, and it is difficult to recover copper through a substitution reaction using iron or aluminum. Therefore, it is known that copper-containing waste nitric acid is the only method of neutralizing nitric acid, which is a strong inorganic acid, to precipitate and recover copper in hydroxide form. In addition, there are no cases of commercialization due to excessive chemical costs such as sodium hydroxide, calcium hydroxide, potassium hydroxide and the like used as a neutralizing agent.

In addition, after the neutralization, the generated waste liquor is enormously expensive in wastewater treatment due to the very high nitrogen concentration (T-N, total nitrogen) due to nitric acid.

Pickling using nitric acid is used to remove copper film generated in PCB manufacturing equipment and copper target manufacturing equipment. At this time, the generated copper nitrate contains 3 to 8% by weight of copper, and the residual free acid concentration is about 5 to 10% by weight.

However, when recovering copper through copper extraction processes such as organic solvent extraction, metal hydroxide precipitation, and electrolytic extraction, 3 to 8% by weight copper-containing nitric acid has a high process operation cost and a large amount of waste liquid. There is a problem that the economic value of the wastewater treatment costs by the amount generated is significantly reduced.

Therefore, 3-8 wt% of copper-containing waste nitric acid is buried after dilution, neutralization, or the like without a copper extraction step.

Republic of Korea Patent Publication No. 2008-00730038

 A preferred embodiment of the present invention is to provide a method for recycling copper-containing waste nitric acid which can recover copper carbonate from copper-containing waste nitric acid at high recovery rate and low cost.

Another preferred embodiment of the present invention is to provide a method for recycling copper-containing waste nitric acid which can recover high purity copper from copper-containing waste nitric acid at high recovery rate and low cost.

Another preferred embodiment of the present invention is a copper-containing waste can be recovered from the copper-containing waste nitric acid with high recovery rate and low cost, as well as the addition of nitrogen to the waste liquid from which copper carbonate is recovered to prepare a nitrogen fertilizer raw material It is to provide a method for recycling waste nitric acid.

Preferred embodiments of the invention

Preparing copper-containing waste nitric acid;

Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; One or two of sodium hydroxide and calcium hydroxide: 5 to 35% by weight; And preparing a liquid mixed alkaline neutralizer including the remaining water;

Neutralization step of neutralizing the copper-containing waste nitric acid by adding the liquid mixed alkaline neutralizing agent in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 ~ 1.5 in a weight ratio to the copper-containing waste nitric acid by adjusting the pH to 6.0 ~ 8.5. ; And

It provides a method for recycling copper-containing waste nitric acid comprising the; filtration step of filtering the neutralized copper-containing waste nitric acid to obtain a copper carbonate (CuCO ₃ ) precipitate and filtrate.

Another preferred embodiment of the present invention

Preparing copper-containing waste nitric acid;

Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; One or two of sodium hydroxide and calcium hydroxide: 5 to 35% by weight; And preparing a liquid mixed alkaline neutralizer including the remaining water;

Neutralization to neutralize the copper-containing waste nitric acid by adding the liquid mixed alkaline neutralizing agent to the copper-containing waste nitric acid in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 ~ 1.5 and adjusting the pH to 6.0 ~ 8.5. step;

A filtration step of filtering the neutralized copper-containing waste nitric acid as described above to obtain a copper carbonate (CuCO ₃ ) precipitate and a filtrate;

A leaching step of leaching copper by adding a hydrochloric acid-containing leaching agent to the copper carbonate (CuCO ₃ ) precipitate obtained in the filtration step;

Substituting the iron-containing substituent in the leaching solution obtained in the leaching step to substitute copper with iron to obtain a copper substitution step; And

It provides a method for recycling copper-containing waste nitric acid, comprising; a recovery step of filtering and washing the copper obtained by the substitution reaction with iron in the substitution step to high purity copper, recovering the filtrate with ferrous chloride.

Another preferred embodiment of the present invention provides a method for recycling copper-containing waste nitric acid further comprising the step of obtaining a liquid fertilizer raw material by adding one or two of calcium nitrate and sodium nitrate to the filtrate obtained in the filtration step. do.

According to a preferred embodiment of the present invention, not only copper carbonate can be recovered from copper-containing waste nitric acid at high recovery rate and low cost, but copper carbonate can be recovered using the copper carbonate thus recovered.

1 is a process chart showing an example of a method for recycling copper-containing waste nitric acid according to a preferred embodiment of the present invention.
2 is a process chart showing an example of a method for recycling copper-containing waste nitric acid according to another preferred embodiment of the present invention.

 Copper-containing waste nitric acid is generated in many copper product manufacturing processes.

It is known that copper-containing waste nitric acid is the only method of neutralizing nitric acid, a strong inorganic acid, to precipitate copper and recover it in hydroxide form. In addition, there are no cases of commercialization due to excessive chemical costs such as sodium hydroxide, calcium hydroxide, potassium hydroxide and the like used as a neutralizing agent.

In addition, after the neutralization, the generated waste liquor is enormously expensive in wastewater treatment due to the very high nitrogen concentration (T-N, total nitrogen) due to nitric acid.

Recycling copper when recovering copper from copper-containing waste nitric acid, in particular, copper-containing waste nitric acid containing 3 to 8% by weight of copper through a copper extraction process such as organic solvent extraction, metal hydroxide precipitation, and electrolytic extraction Compared to the economic benefits due to the high process operation costs and waste water treatment costs due to the large amount of waste liquid generated, there is a problem that the economic value is significantly reduced.

That is, when recovering copper from copper-containing waste nitric acid containing 3 to 8% by weight of copper, the acidity in copper-containing waste nitric acid is very high, and the amount of neutralizing agent used is enormous. Since it contains a high concentration of nitrogen, there is a problem that takes a huge cost when wastewater treatment.

Therefore, 3-8 wt% of copper-containing waste nitric acid is buried after dilution, neutralization, or the like without a copper extraction step.

Accordingly, the present inventors have conducted research on recycling of copper-containing waste nitric acid, and have completed the present invention based on the results.

The present invention is a method for recycling copper-containing waste nitric acid which recovers copper of high purity using copper carbonate recovered from copper-containing waste nitric acid, or recovering copper carbonate from copper-containing waste nitric acid. It is about.

The present invention can be more effectively applied to recycling of copper-containing waste nitric acid, particularly, copper-containing waste nitric acid containing 3 to 8% by weight of copper.

One of the main concepts of the present invention is to sufficiently precipitate the copper carbonate in the low pH range by optimizing the components and the range of components of the neutralizer added to the copper-containing waste nitric acid.

Another one of the main concepts of the present invention is to recover the copper of high purity by specifying the optimum leaching conditions and substitution conditions for the copper carbonate precipitate using the copper carbonate precipitate precipitated as described above.

Hereinafter, a method for recycling copper-containing waste nitric acid according to a preferred embodiment of the present invention will be described.

1 shows an example of a process diagram of a method for recycling copper-containing waste nitric acid according to a preferred embodiment of the present invention.

A method for recycling copper-containing waste nitric acid according to a preferred embodiment of the present invention

Preparing copper-containing waste nitric acid;

Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; One or two of sodium hydroxide and calcium hydroxide: 5 to 35% by weight; And preparing a liquid mixed alkaline neutralizer including the remaining water;

Neutralization step of neutralizing the copper-containing waste nitric acid by adding the liquid mixed alkaline neutralizing agent in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 ~ 1.5 in a weight ratio to the copper-containing waste nitric acid by adjusting the pH to 6.0 ~ 8.5. ; And

And a filtration step of filtering the neutralized copper-containing waste nitric acid as described above to obtain a copper carbonate (CuCO ₃ ) precipitate and a filtrate.

Preparing copper-containing waste nitric acid ;

Prepare copper-containing waste nitric acid.

The said copper containing waste nitric acid (waste copper nitrate) can be any waste waste acid containing copper.

Copper-containing waste nitric acid that can be more effectively applied to the present invention is copper-containing waste nitric acid containing 3 to 8% by weight of copper. The copper content may be 4 to 6% by weight.

The copper-containing waste nitric acid may contain, as impurities, one or two or more selected from Fe, Mo, Pb, and Cr, each of which is 100 mg / kg or less.

For example, the copper-containing waste nitric acid (waste copper nitrate) is generated in the process of pickling the manufacturing equipment using nitric acid to remove copper tin film in the equipment generated during the use of advanced electronic manufacturing equipment such as PCB and OLED. Can be.

Preparing a liquid mixed alkaline neutralizer ;

Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; One or two of sodium hydroxide and calcium hydroxide: 5 to 35% by weight; And a liquid mixed alkaline neutralizer including the remaining water.

The sodium carbonate is a component added to adjust the precipitation pH range of copper so that copper precipitates in the form of copper carbonate, not copper hydroxide, and when the amount is small, carbonate ions are insufficient to lower the precipitation pH range of copper. Will precipitate in hydroxide form. When the addition amount of the sodium carbonate is less than the copper precipitation pH range of pH 8.6 to 10, copper precipitates in the form of hydroxide, thus, copper carbonate cannot be sufficiently recovered, and the pH of the waste liquid may be out of the target range. .

Therefore, the addition amount of the sodium carbonate is preferably set to 5 to 15% by weight. The addition amount of more preferable sodium carbonate is 5-10 weight%, and the addition amount of still more preferable sodium carbonate is 7-10 weight%.

The sodium carbonate may be added in excess of 15% by weight. For example, up to 20% by weight can be added. In view of cost, the upper limit of the amount of sodium carbonate added is preferably limited to 15% by weight.

The sodium hydroxide is a component added to increase the pH by using a hydroxyl group, and when the amount is too small, a sufficient increase in pH may not be obtained, and the amount of sodium carbonate may increase.

Sodium carbonate has a form of HCO ₃ ^- ions in the CO ₃ ^2- ion above pH 4, the pH rises because of the combined H. Therefore, it is difficult to neutralize the sodium carbonate, the lung acid strong acid to be used only, OH ^-, it is important to raise the pH from the neutralization reaction of the> H ₂ ^{O-H +} + OH added to the - When OH ^- it is that sodium hydroxide is used as the source (NaOH).

When the amount of the sodium hydroxide is added, the cost increases, and the higher the concentration of NaOH, the higher the viscosity of the mixed alkali solution (neutralizing agent), which is difficult to handle.

The calcium hydroxide is a component that is added to increase the pH by using a hydroxyl group, if the addition amount is too small can not bring sufficient pH increase, too much can lead to an excessive increase in pH, lowering the fluidity of the neutralizer tube When moving the mixed alkali neutralizer in the liquid state may cause problems such as clogging the inside of the tube, and generates a lot of precipitate, the copper content (based on the dry weight) of the precipitate may be lowered. In addition, in the subsequent step of leaching the copper precipitate and recovering it through a substitution reaction, when leaching the precipitate having a low copper content and a large amount of calcium hydroxide, there may be a problem that the amount of hydrochloric acid in the leaching solution should be large.

The content of one or two of the sodium hydroxide and calcium hydroxide is preferably set to 5 to 35% by weight, more preferably 5 to 20% by weight.

When the sodium hydroxide and calcium hydroxide are included together, the content is

 Sodium hydroxide: 3-15% by weight and calcium hydroxide: 10-30% by weight.

At this time, the addition amount of more preferable sodium hydroxide is 5-15 weight%.

 The addition amount of more preferable calcium hydroxide is 10-20 weight%, and the addition amount of still more preferable calcium hydroxide is 10-15 weight%.

The amount of water added may be determined in consideration of the management, storage and movement of the mixed alkali neutralizing agent in the liquid phase, the facility for adding the mixed alkaline neutralizing agent to the waste-containing nitric acid containing copper, the charging process, the charging conditions, and the like.

Neutralization stage

The mixed alkali neutralizing agent in the liquid phase is added to the copper-containing waste nitric acid in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 to 1.5, and the pH is adjusted to 6.0 to 8.5 to neutralize the copper-containing waste nitric acid.

When the amount of the mixed alkali neutralizing agent solution is too small, sufficient neutralization may not be achieved, and thus the copper carbonate may not be sufficiently recovered because the pH of the final solution is low.

When the amount of the mixed alkali neutralizing agent in the liquid phase is too high, copper may be precipitated in the form of copper hydroxide instead of copper carbonate.

Therefore, the input amount of the mixed alkaline neutralizing agent in the liquid phase preferably satisfies the conditions of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 to 1.5, more preferably copper-containing waste nitric acid: neutralizing agent = 1: 0.6 to 1.3, Even more preferred is copper-containing waste nitric acid: neutralizing agent = 1: 0.6 to 1.0.

When the pH is less than 6.0, the copper carbonate is not sufficiently formed, so that the copper in the leaching solution is self-sustaining, it is difficult to recover sufficient copper, and when the pH exceeds 8.5, the copper may be recovered in the form of copper hydroxide together with the copper carbonate form.

Therefore, the pH is preferably set to 6.0 ~ 8.5. More preferable pH is 6.5-7.5.

Filtration stage

The copper-containing waste nitric acid neutralized as above is filtered to obtain a copper carbonate (CuCO ₃ ) precipitate and a filtrate.

The filtration step is not particularly limited as long as it can obtain a copper precipitate and a filtrate. For example, it can be filtered using a filter press, and the filter press filter paper may be one having a thickness of 1 to 1.5 mm made of PP (polypropylene) and having a ventilation degree of 4.5 to 30 m ³ / m ² / sec. In another example, after filtering with a qualitative filter of 3 ~ 5 ㎛, It can be filtered with a glass fiber filter paper (GF / C) of 0.5 ~ 3 ㎛.

The copper carbonate (CuCO ₃ ) precipitate may contain 30 to 40% by weight of copper on a dry weight basis.

The filtrate may contain up to 150 mg / kg of copper, preferably up to 80 mg / kg of copper, and even more preferably up to 30 mg / kg of copper.

The filtrate may contain 5 to 8% by weight of nitrogen. If necessary, one or two of calcium nitrate and sodium nitrate may be added to the filtrate in order to secure a nitrogen content of 9% by weight or more.

In this case, the content of the calcium nitrate may be 10 to 20% by weight based on the waste solution, the content of the sodium nitrate may be 10 to 30% by weight based on the waste solution.

 As described above, the filtrate having a nitrogen content of 9% by weight or more may be used as a liquid fertilizer.

According to a method for recycling copper-containing waste nitric acid according to another preferred embodiment of the present invention, a copper carbonate (CuCO ₃ ) precipitate can be obtained, and a liquid fertilizer raw material can be obtained together with a copper carbonate (CuCO ₃ ) precipitate if necessary. have.

Hereinafter, a method for recycling copper-containing waste nitric acid according to another preferred embodiment of the present invention will be described.

Figure 2 shows an example of a process diagram of a method for recycling copper-containing waste nitric acid according to another preferred embodiment of the present invention.

According to another preferred embodiment of the present invention, the method for recycling copper-containing waste nitric acid

A leaching step of leaching copper by adding a hydrochloric acid-containing leaching agent to the copper carbonate (CuCO ₃ ) precipitate obtained in the filtration step;

Substituting the iron-containing substituent in the leaching solution obtained in the leaching step to substitute copper with iron to obtain a copper substitution step; And

And a recovery step in which the copper obtained by the substitution reaction with iron in the substitution step is filtered and washed with high purity copper and the filtrate is recovered with ferrous chloride.

Leaching stage

Hydrochloric acid-containing leaching agent is added to the copper carbonate (CuCO ₃ ) precipitate obtained in the filtration step to leach copper.

The hydrochloric acid-containing leaching agent may be, for example, one or two of hydrochloric acid and spent hydrochloric acid.

The waste hydrochloric acid may include 5 to 9% by weight of Fe (iron) and 3 to 10% by weight of hydrochloric acid.

The spent hydrochloric acid may include about 100 to 1,000 mg / kg of heavy metals such as Zn, Pb, Cu, Cr, and Cd.

The waste hydrochloric acid may be generated in a pickling process using hydrochloric acid to remove an oxide film on the iron surface in a steel pickling process.

In the case of leaching general copper oxide sludge or copper hydroxide sludge using only hydrochloric acid as the hydrochloric acid-containing leaching agent, the amount of hydrochloric acid is small so that all copper is not leached out of the sludge, and the rate of substitution reaction in the substitution step after the leaching step is also reduced. Since it is very slow, in general, a certain amount of hydrochloric acid is added to increase the leaching effect and reactivity of the substitution reaction.

As a result of the researches of the present inventors, even if the copper carbonate precipitate recovered according to the present invention is leached using only hydrochloric acid without adding hydrochloric acid, copper combined with carbonic acid is easily dissociated and completely dissolved, using only waste hydrochloric acid. Leaching is also very easy, and during the substitution reaction, it was confirmed that the reaction is very active even without the addition of hydrochloric acid. In the substitution reaction, since the reaction is very active even without adding hydrochloric acid, it is possible to reduce the additional iron consumption to match the iron concentration in the final substitution solution.

As described above, one of the characteristics of the present invention is that leaching of the copper carbonate precipitate recovered according to the present invention without adding hydrochloric acid and using only hydrochloric acid is made very easy, and during the substitution reaction, hydrochloric acid is not added. It is possible to reduce the amount of additional iron used to adjust the iron concentration in the final replacement solution as well as very active substitution reaction.

The present inventors confirmed that when only hydrochloric acid is used as the hydrochloric acid-containing leaching agent, the leaching effect is very good, but when leaching using a small amount of hydrochloric acid, the amount of leaching liquid in the substitution reaction is insufficient, so that the substitution reaction is not performed smoothly.

That is, the present inventors confirmed that in order to leach more efficiently, it is necessary to control the input amount of the leach agent together with the hydrochloric acid concentration of the leachate containing hydrochloric acid.

In view of the foregoing, even when only hydrochloric acid is used as the hydrochloric acid-containing leachant, the amount of copper carbonate (CuCO ₃ ) precipitate: hydrochloric acid-containing leachant is preferably set to 1: 1.5 to 4.5.

On the other hand, when only hydrochloric acid is used as the hydrochloric acid-containing leaching agent, the iron content in the substitution filtrate (ferrous chloride) is very low after the substitution reaction of the leachate, and the iron reaction amount in the substitution reaction is excessively increased, thereby increasing the cost burden. Can be.

When a mixture of hydrochloric acid and waste hydrochloric acid is used as the hydrochloric acid-containing leaching agent, leaching is easy and substitution reaction is also easy. The lower the amount of hydrochloric acid, the slower the reaction, but the less iron is required for the reaction.

When using a mixture of hydrochloric acid and waste hydrochloric acid as the hydrochloric acid-containing leaching agent, the mixing ratio of hydrochloric acid and waste hydrochloric acid may be 1: 1 to 1: 4 in the hydrochloric acid: waste hydrochloric acid = weight ratio.

The amount of the hydrochloric acid-containing leaching agent may be a copper carbonate (CuCO ₃ ) precipitate: hydrochloric acid-containing leaching agent in a weight ratio of 1: 1.5 to 4.5.

When the amount of the hydrochloric acid-containing leaching agent is too high, the substitution reactivity is lowered in the substitution step, and the amount of metal required for substitution may increase, and when too small, the leaching reaction is not sufficiently performed, and the substitution reaction is well performed in the substitution step. Without recovery, copper recovery can also be reduced.

In the present invention, since copper is recovered using the copper carbonate precipitate, it is not necessary to remove the leach residue after leaching. In the conventional copper recovery method using copper sludge, a large amount of leaching residues may occur, and in order to recover high purity copper, it is necessary to remove the leaching residues. In the case of recovering copper using the recovered copper carbonate precipitate according to the present invention, the copper combined with the carbonic acid ion is easily dissociated and completely dissolved, so that leaching residue does not occur separately.

Substitution step

An iron-containing substituent is added to the leaching solution obtained in the leaching step, and copper is substituted with iron to obtain copper.

At this time, the substitution reaction is made as in the following [Formula 1] to [Formula 3].

[Formula 1]

_{^{Fe Metal + 2HCl → Fe 2 +}} + 2Cl - + H 2 gas

[Formula 2]

Fe _Metal + Cu ^{2 +} → Fe ^{2 +} + Cu _Metal

[Formula 3]

+ 2HCl → Cu ^{2 +} _Metal Cu + 2Cl ^- + H ₂ gas

Formula (1) is a reaction in which iron reacts with hydrochloric acid to dissolve without iron and copper substitution reaction, Formula (2) is a substitution reaction in which iron is ionized and copper is reduced, and Formula (3) is reduced copper over time This is a redissolved reaction that ionizes again.

The iron-containing substituent may be used as long as it contains iron, and may be, for example, scrap iron in terms of economy.

If the amount of the iron-containing substituent is too small, copper may remain and copper may not be sufficiently recovered. If too much, the substitution reaction time may be too long, re-elution of metallic copper may occur, and the amount of copper recovered may be small. There is concern about quality. Therefore, the amount of the iron-containing substituent is preferably specified to 1 to 15% by weight based on the weight of the leachate.

At this time, during the substitution reaction, initially, the leachate may be heated to a temperature range of 60 ~ 80 ℃.

 In other words, during the substitution reaction, heating to promote the reaction is initially required, but when a sufficient amount of iron-containing substituent is added to the reaction tank and the reaction is started, the reaction temperature can be maintained without the additional energy input.

Recovery Step

The copper obtained by the substitution reaction with iron in the substitution step is filtered and washed to recover high purity copper, and the filtrate is recovered with ferrous chloride.

The purity of the high purity copper recovered as described above may be, for example, 99.9% or more.

The filtrate may be a high quality ferrous chloride containing 12% by weight or more of iron (Fe).

According to a recycling method of copper-containing waste nitric acid according to another preferred embodiment of the present invention, for example, high purity copper of 99.9% or more can be recovered, and copper recovery of 99.88% or more can also be achieved.

If necessary, liquid fertilizer can be obtained with high purity copper.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example 1)

Copper containing waste nitric acid containing 5% by weight of copper was neutralized with a neutralizing agent having the composition of Table 1 below.

At this time, the input amount of the neutralizing agent and the pH after the neutralization treatment are shown in Table 1 below.

The neutralized copper containing waste nitric acid was filtered to obtain a copper precipitate and a filtrate.

At this time, the filtration was carried out by filtration with a qualitative filter paper of 3 ~ 5 ㎛, and then filtered with a glass fiber filter paper (GF / C) of 1 ㎛.

The type of the copper precipitate, the copper concentration in the filtrate, and the nitrogen concentration in the filtrate were measured, and the results are shown in Table 1 below.

Test Example No.
Neutralizer composition (% by weight) Neutralization amount (wt%) PH after neutralization Type of copper precipitate Copper concentration in the filtrate
(mg / kg)
(Means unrecovered copper) Nitrogen concentration in the filtrate
(weight%) Sodium carbonate Sodium hydroxide Calcium hydroxide water One 10 10 15 Remainder 70 7.1 Copper carbonate 12 8.2 2 120 9.1 Copper hydroxide 156 7.5 3 5 10 15 Remainder 70 7.0 Copper Carbonate 11 8.1 4 120 8.9 Copper hydroxide 177 7.7 5 5 15 10 Remainder 65 7.3 Copper Carbonate 16 8.4 6 115 9.3 Copper hydroxide 183 7.7 7 0 10 15 Remainder 75 7.2 Copper hydroxide 569 8.1 8 130 9.3 Copper hydroxide 166 7.1 9 10 0 15 Remainder 120 5.6 Copper Carbonate 154 5.5 10 150 6.8 Copper Carbonate 23 3.4 11 10 10 0 Remainder 110 6.2 Copper carbonate 110 4.8 12 150 8.1 Copper carbonate 98 4.2 13 20 10 15 Remainder 60 8.5 Copper carbonate 33 7.9 14 100 9.8 Copper hydroxide 143 7.5 15 10 20 15 Remainder 40 7.2 Copper carbonate 48 7.1 16 80 11.5 Copper hydroxide 211 6.8

As shown in Table 1, it can be seen that a high purity copper carbonate can be obtained when the neutralizing agent and the neutralizing agent having a composition corresponding to the present invention is added to the copper-containing waste nitric acid and neutralized.

(Example 2)

After leaching the leaching agent under the conditions of Table 2 to the copper precipitate (copper carbonate precipitate) prepared according to Experimental Example 1 of Example 1 and the copper precipitate (copper hydroxide precipitate) prepared according to Experimental Example 2, Substituted under the conditions shown in Table 2, filtered and washed to recover copper and ferrous chloride.

In Table 2, waste hydrochloric acid was used comprising 9 wt% Fe (iron) and 5 wt% hydrochloric acid.

At this time, the heating temperature of the initial leachate was 80 ℃, filtration was performed using a filter press, filter press filter paper polypropylene A material of 1 to 1.5 mm thick and 4.5 to 30 m ³ / m ² / sec air permeability was used.

The purity of the recovered copper, the iron content of the ferrous chloride and the recovery rate were investigated, and the results are shown in Table 2 below.

Test Example No. Leaching condition Substitution condition Copper purity (%) Iron content of ferrous chloride (% by weight) Recovery
(%) Leaching agent Input amount (% by weight) Substituent
(weight%) Input amount (% by weight, leachate) One Waste hydrochloric acid 300 Fe 5 99 13 99 Waste hydrochloric acid + hydrochloric acid (1: 1 weight) 300 Fe 7 99 8 96 Hydrochloric acid 300 Fe 10 99 5 98 2 Waste hydrochloric acid 300 Fe 7 98 11 50 (leakage failure) Waste hydrochloric acid + hydrochloric acid (1: 1 weight) 300 Fe 11 99 6 71 (Replacement defective) Hydrochloric acid 300 Fe 15 99 6 98

As shown in Table 2, when recovering copper and ferrous chloride through the leaching, substitution, filtration and washing process according to the present invention using a copper precipitate prepared according to the method according to the present invention with high recovery rate It can be seen that ferric chloride with high purity copper and iron content can be recovered.

(Example 3)

Leaching the leaching agent in the copper precipitate (copper carbonate precipitate) prepared according to Test Example 1 of Example 1 under the conditions of Table 3, and then substituted by the conditions of the following Table 3, filtered and washed to copper And ferrous chloride were recovered.

In Table 3 below, waste hydrochloric acid containing 9 wt% Fe (iron) and 5 wt% hydrochloric acid was used.

At this time, the heating temperature of the initial leachate was 80 ℃, filtration was performed using a filter press, filter press filter paper polypropylene A material of 1 to 1.5 mm thick and 4.5 to 30 m ³ / m ² / sec air permeability was used.

The purity of the recovered copper, the iron content of the ferrous chloride and the recovery rate were investigated, and the results are shown in Table 3 below.

Test Example No. Leaching condition Substitution condition Copper purity (%) Iron content of ferrous chloride
(weight%) Recovery
(%) Leaching agent Input amount (% by weight) Substituent Input amount (% by weight, leachate) 1-1 Waste hydrochloric acid 300 Fe 5 99 13 99 1-2 Waste hydrochloric acid 100 Fe 5 97 14 93 1-3 Waste hydrochloric acid 500 Fe 8 99 11 98 1-4 Waste hydrochloric acid + hydrochloric acid (1: 1 weight) 100 Fe 7 98 9 88 1-5 Waste hydrochloric acid + hydrochloric acid (1: 1 weight) 300 Fe 7 99 8 96 1-6 Waste hydrochloric acid + hydrochloric acid (1: 1 weight) 500 Fe 10 98 5 97 1-7 Hydrochloric acid 100 Fe 10 99 6 97 1-8 Hydrochloric acid 300 Fe 10 99 5 98 1-9 Hydrochloric acid 500 Fe 14 99 3 98

As shown in Table 3, when recovering copper and ferrous chloride through the leaching, substitution, filtration and washing process according to the present invention using a copper precipitate prepared according to the method according to the present invention with high recovery rate It can be seen that ferric chloride with high purity copper and iron content can be recovered. In particular, in the case of using waste hydrochloric acid as a leaching agent (Test Examples 1-1, 1-2, 1-3), not only the purity of copper recovered is high but also the iron content in ferrous chloride is high and the recovery rate is high. .

Claims (16)

Preparing copper-containing waste nitric acid;
Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; Sodium hydroxide: 3-15% by weight; Calcium hydroxide: 10-30% by weight; And preparing a liquid mixed alkaline neutralizer including the remaining water;
Neutralization step of neutralizing the copper-containing waste nitric acid by adding the liquid mixed alkali neutralizing agent in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 ~ 1.0 to the copper-containing waste nitric acid by adjusting the pH to 6.0 ~ 8.5. ; And
Filtering the neutralized copper-containing waste nitric acid as described above to obtain a copper carbonate (CuCO ₃ ) precipitate and a filtrate; recycling method of waste copper-containing waste nitric acid comprising a.
The method for recycling copper-containing waste nitric acid according to claim 1, wherein the copper-containing waste nitric acid contains 3 to 8% by weight of copper.
delete delete The copper carbonate (CuCO ₃ ) precipitate contains 30 to 40% by weight of copper on a dry weight basis, and the filtrate contains 150 mg / kg or less of copper. A method for recycling copper-containing waste nitric acid, characterized by the above-mentioned.
The method for recycling copper-containing waste nitric acid according to claim 1, further comprising the step of adding one or two of calcium nitrate and sodium nitrate to the filtrate obtained in the filtration step to obtain a liquid fertilizer.
7. The method for recycling copper-containing waste nitric acid according to claim 6, wherein the filtrate contains 5 to 8% by weight of nitrogen.
The method of recycling copper-containing waste nitric acid according to claim 6, wherein the addition amount of calcium nitrate is 10 to 20% by weight based on the filtrate, and the addition amount of sodium nitrate is 10 to 30% by weight based on the filtrate.
7. The method for recycling copper-containing waste nitric acid according to claim 6, wherein the nitrogen content in the liquid fertilizer raw material is 9% by weight or more.
Preparing copper-containing waste nitric acid;
Sodium carbonate (Na ₂ CO ₃ ): 5-15% by weight; Sodium hydroxide: 3-15% by weight; Calcium hydroxide: 10-30% by weight; And preparing a liquid mixed alkaline neutralizer including the remaining water;
Neutralization to neutralize the copper-containing waste nitric acid by adding the liquid mixed alkali neutralizing agent to the copper-containing waste nitric acid in a weight ratio of copper-containing waste nitric acid: neutralizing agent = 1: 0.6 ~ 1.0 and adjusting the pH to 6.0 ~ 8.5. step;
A filtration step of filtering the neutralized copper-containing waste nitric acid as described above to obtain a copper carbonate (CuCO ₃ ) precipitate and a filtrate;
A leaching step of leaching copper by adding a hydrochloric acid-containing leaching agent to the copper carbonate (CuCO ₃ ) precipitate obtained in the filtration step;
Substituting the iron-containing substituent in the leaching solution obtained in the leaching step to substitute copper with iron to obtain a copper substitution step; And
And a recovery step in which the copper obtained by the substitution reaction with iron in the substitution step is filtered and washed with high purity copper and the filtrate is recovered with ferrous chloride.
The method for recycling copper-containing waste nitric acid according to claim 10, wherein the copper-containing waste nitric acid contains 3 to 8% by weight of copper.
The method for recycling copper-containing waste nitric acid according to claim 10, wherein the hydrochloric acid-containing leaching agent is one or two of hydrochloric acid and waste hydrochloric acid.
The method according to claim 12, wherein the spent hydrochloric acid is 5 to 9% by weight of Fe (iron) and 3 to 10% by weight of A method for recycling copper-containing waste nitric acid, comprising hydrochloric acid.
The method for recycling copper-containing waste nitric acid according to claim 12, wherein the amount of the hydrochloric acid-containing leaching agent satisfies the conditions of copper carbonate (CuCO ₃ ) precipitate: hydrochloric acid-containing leaching agent = 1: 1.5 to 4.5. .
The method for recycling copper-containing waste nitric acid according to claim 10, wherein the amount of the iron-containing substituent is 1 to 15% by weight based on the weight of the leachate.
The method for recycling copper-containing waste nitric acid according to claim 10, wherein the ferrous chloride contains 12 wt% or more of iron (Fe).

Images