KR100351942B1 - Process for simultaneously preparing cupric sulfate and calcium chloride from cupric chloride waste - Google Patents

Abstract

The present invention neutralizes the copper chloride or copper chloride waste solution with calcium carbonate or calcined to obtain calcium chloride and copper hydroxide or copper carbonate, and then filtered to obtain calcium chloride from the filtrate, and the separated copper hydroxide or copper carbonate with sulfuric acid to obtain copper sulfate, This is washed with an alcohol such as methanol to disclose a process for producing copper sulfate of high purity.

Description

Method for Simultaneous Production of Copper Sulfate and Calcium Chloride from Waste Copper Chloride {PROCESS FOR SIMULTANEOUSLY PREPARING CUPRIC SULFATE AND CALCIUM CHLORIDE FROM CUPRIC CHLORIDE WASTE}

The present invention relates to a method of simultaneously producing copper sulfate and calcium chloride from copper chloride waste liquid. More specifically, the copper chloride or copper chloride waste solution is neutralized with calcium carbonate or calcined to obtain calcium chloride and copper hydroxide or copper carbonate, and then filtered to obtain calcium chloride from the filtrate, and the treated copper hydroxide or copper carbonate with sulfuric acid to obtain copper sulfate. The present invention relates to a method for producing high purity copper sulfate by washing with alcohol such as methanol.

In recent years, due to the development of the electronic industry, a large amount of copper chloride liquid, which is a waste liquid for electronic circuit board corrosion, is generated.

These copper chloride liquids contain about 15 to 20% of copper chloride and about 10 to 12% of hydrochloric acid and other impurities. Until now, this waste liquid can be recycled into products such as copper cyanide (CuCN) and copper powder. This has been taken. However, the production of copper cyanide by the conventional method is rapidly increasing due to the rapid increase in the amount of waste liquid for substrate corrosion, and the industrial waste is insufficient to treat the waste liquid. We are troubled with disposal of waste liquid.

Conventionally, in order to solve the above situation, the copper chloride waste liquid was heated and concentrated while adding and stirring sulfuric acid in an equivalent ratio, to remove hydrochloric acid, and copper sulfate was recovered and recrystallized several times to prepare copper sulfate pentahydrate. However, in such a method, the reactor is expensive to manufacture by adding sulfuric acid and concentrated, and the durability of the reactor becomes weak, and when a crack occurs in the reactor, problems related to the reactor such as the reactor itself explode are always present. In addition, since the equipment for recovering the generated hydrochloric acid is corroded, it is necessary to use expensive equipment to prevent this, and also high purity hydrochloric acid cannot be obtained, and the sale of the recovered low-purity hydrochloric acid is a problem. This has brought great difficulties in the manufacture of copper sulfate. Furthermore, since the residual chlorine standard of the manufactured copper sulfate is required to be 30 ppm or less, repetition of recrystallization or the like in order to meet such a standard increases the manufacturing cost and weakens the product competitiveness. Therefore, the above method is regarded as a method which is hardly used at present.

In order to solve the above problems, the present inventors neutralize by adding a zinc material to a copper chloride waste solution containing hydrochloric acid, and adding zinc sulfate to react with copper chloride to obtain zinc chloride and copper sulfate, which is treated with alcohol to zinc chloride and copper sulfate. Patent application method of separation (Patent Application 2000-11877). However, since this method does not generate hydrochloric acid as compared with the prior art, the recovery apparatus is inexpensive and safe, but there is a problem that the production cost is high due to the recent increase in the price of zinc materials.

Therefore, the present inventors have diligently studied to improve the above method, and after neutralizing the copper chloride waste solution containing hydrochloric acid using inexpensive calcium carbonate or slaked lime, the reaction product calcium chloride and copper carbonate or copper hydroxide were filtered. Calcium chloride was obtained from and separated into a precipitate of copper carbonate or copper hydroxide, which was then washed with alcohol to obtain high purity copper sulfate, thereby completing the present invention.

As described above, the waste liquid for corrosion of an electronic circuit board is a strongly acidic liquid containing about 15 to 20% of copper chloride and about 10 to 12% of hydrochloric acid.

When this copper chloride waste solution is put into a reactor with a stirrer and neutralized by adding calcium carbonate or slaked lime while stirring, hydrochloric acid in the waste liquid reacts with calcium carbonate or slaked lime to form calcium chloride and simultaneously produce copper carbonate or copper hydroxide. In doing so, the reaction solution is neutralized. At this time, the reaction is preferably carried out at 70 ~ 95 ℃.

The reaction is represented by the following formula.

(CuCl ₂ + HCl) + CaCO ₃ → CaCl ₂ + CuCO ₃ ↓ or

(CuCl ₂ + HCl) + Ca (OH) ₂ → CaCl ₂ + Cu (OH) ₂ ↓

(In the formula, the coefficients are not adjusted)

Compound that is actually generated due to the reaction carried out in an aqueous solution of yeomhwadong and calcium carbonate in the above reaction is the addition CuCO ₃ CuCO ₃ · Cu (OH) ₂ complex of theoretically may exist. However, most of the compounds actually produced are copper carbonate, and even if copper hydroxide is contained therein, it is not necessary to confirm the presence or absence of copper hydroxide because it reacts with sulfuric acid to form copper sulfate in the next reaction.

Among the reaction products obtained above, calcium chloride is easily dissolved in water, but copper carbonate and copper hydroxide are insoluble in water. Therefore, after adding a little more water and stirring, all of the calcium chloride is dissolved in water, and copper carbonate or copper hydroxide precipitates, so that it is inclined or separated by filtration.

When the calcium chloride obtained here is heated to evaporate water, it is recovered as a solid. The filtered precipitate, copper carbonate or copper hydroxide, is washed again with water, dried and reacted with sulfuric acid in an equivalence ratio. Is generated. Carbon dioxide is all removed in the gas phase and only copper sulfate is obtained. Such copper sulfate is present as pentahydrate, if not dried in a drying oven, and is dissolved at 14.3 mg / 100 ml in water at 0 ° C.

Chlorine remains in the copper sulfate thus obtained, and in order to remove it, when the recovered copper sulfate is put into methanol and stirred, all of the remaining chlorine is dissolved in methanol, but copper sulfate is hardly dissolved. That is, the solubility of copper sulfate in methanol is 1.8 g / 100 g at 18 ° C., so that it can be almost ignored. On the other hand, copper sulfate treated with methanol is almost pure, and the remaining chlorine is about 15 ppm, but in order to further remove the chlorine content, the copper sulfate having high purity of about 10 ppm or less can be obtained.

As the alcohol used here, methanol is preferable, and the alcohol preferably has a water content of 75% or more. Treatment with 75% or less methanol causes copper sulfate to migrate to water, resulting in poor recovery of copper sulfate and poor chlorine removal in copper sulfate.

In addition, the treated methanol can be reused by treatment such as distillation.

Hereinafter, an Example is given and this invention is demonstrated further more concretely. However, these examples do not limit the scope of the present invention.

Example 1

1 liter of copper chloride waste liquid containing 12% hydrochloric acid and 20% copper chloride was placed in a reactor, and while stirring, 317 g of calcium carbonate was added and heated and stirred at 85 to 90 ° C for 40 minutes. The product was cooled to room temperature and then filtered to separate 184 g of precipitate and filtrate. The precipitate was again washed twice with a small amount of water, and then the washing solution and the filtrate were combined. The combined filtrates were evaporated to yield 463 g of calcium chloride.

On the other hand, while slowly adding about 146g of sulfuric acid to the precipitate obtained above to confirm the acidity of the reaction to complete the reaction. The obtained copper sulfate was put into 500 cc of 75% or more of methanol, stirred, and filtered. This was dried to obtain 370 g of copper sulfate. As a result of analyzing the obtained copper sulfate, the residual amount of chlorine was 15 ppm.

Example 2

The copper sulfate obtained in Example 1 was analyzed as it is without washing with methanol, and as a result, chlorine component was present at about 1000 ppm.

Example 3

1 liter of copper chloride waste liquid containing 12% hydrochloric acid and 20% copper chloride was placed in a reactor, and while stirring, 245 g of calcined lime [Ca (OH) ₂ ] powder was added thereto, and the mixture was heated and stirred at 85 ° C. for 50 minutes. The product was cooled to room temperature and then filtered to separate 145 g of precipitate and filtrate. The precipitate was again washed twice with a small amount of water, and then the washing solution and the filtrate were combined. The combined filtrates were evaporated to yield 463 g of calcium chloride.

On the other hand, while slowly adding about 145g of sulfuric acid to the precipitate obtained above to confirm the acidity of the reaction to complete the reaction. The obtained copper sulfate was washed twice with 350 cc of 75% or more of methanol, and then dried to obtain 370 g of copper sulfate. As a result of analyzing the obtained copper sulfate, the amount of chlorine remaining was 10 ppm.

As described above, according to the present invention, the PCB substrate corrosion waste liquid containing copper chloride and hydrochloric acid is neutralized with calcium carbonate or calcined to obtain calcium chloride and copper hydroxide or copper carbonate, and then filtered to obtain calcium chloride from the filtrate, and separated copper hydroxide. Alternatively, copper carbonate may be reacted with sulfuric acid to obtain copper sulfate, which may be washed with an alcohol such as methanol to recover high purity copper sulfate. Thus obtained calcium chloride and copper sulfate can be obtained simultaneously with high purity and economically advantageous. By treating the copper chloride waste liquid containing hydrochloric acid, which has been difficult to solve by the method of the present invention, expensive copper sulfate and calcium chloride can be safely and economically obtained.

Claims (2)

In the method for producing calcium chloride and copper sulfate from the waste liquid for corrosion of an electronic circuit board containing hydrochloric acid and copper chloride, Neutralize the hydrochloric acid contained in the substrate copper waste solution with calcium carbonate or hydrated to obtain calcium chloride and copper carbonate or copper hydroxide, separate it, react with copper carbonate or copper hydroxide with sulfuric acid to obtain copper sulfate, and then convert copper sulfate to 75% or more of methanol. A process for the simultaneous production of high purity copper sulfate having a calcium chloride and residual chlorine content of 30 ppm or less, characterized in that the treatment. delete