Method for preparing cupric carbonate from printed circuit board alkaline etching waste liquid

Abstract

The invention belongs to the technical field of industrial waste liquid regeneration recycling and chemical material manufacturing, and provides a method for preparing cupric carbonate from printed circuit board alkaline etching waste liquid, which comprises the following steps: step 1, mixing the printed circuit board alkaline etching waste liquid with alkali, heating and stirring for reaction, suction filtration and washing until filtrate is neutral, and taking out a filter cake; step 2, adding the filter cake into a hydrochloric acid solution, uniformly stirring, filtering, and taking out filtrate; and 3, mixing the filtrate with an ammonium bicarbonate solution, adjusting the pH value, carrying out a stirring reaction at 55-60 DEG C, standing for 1-2 h, carrying out suction filtration, washing for 2-3 times, and drying in an oven at 100-105 DEG C until the weight is constant, thereby obtaining the copper carbonate. According to the method for preparing the cupric carbonate from the printed circuit board alkaline etching waste liquid, the recovery rate of copper is high, the prepared cupric carbonate is high in quality, the technological process is simple, operation is convenient, the number of devices is small, and industrial production is easy to achieve.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste liquid recycling and chemical material manufacturing technology, specifically relating to a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards. Background Technology

[0002] Printed circuit boards (PCBs) are fundamental components of electronic products, often referred to as the "mother of electronic products." With the rapid development of the electronics industry, the global PCB manufacturing industry has also grown rapidly, with demand increasing daily.

[0003] Among the many processes in PCB manufacturing, copper etching is one of the most important. This process mainly involves using an etching solution to remove the unwanted copper foil from the copper-clad laminate, leaving the necessary copper foil to form the desired circuit pattern. Currently, the etching solutions used for copper etching are mainly divided into alkaline etching solutions and acidic etching solutions. Among them, alkaline etching solutions are widely used in PCB production due to their advantages such as fast etching rate, low lateral etching, strong copper dissolving ability, easy control of etching rate, convenient maintenance, and low cost. However, the waste liquid after etching with alkaline copper ammonia etching solution contains a large amount of copper ions. When the copper ion concentration in the etching solution reaches a certain level, it is discharged as waste liquid. Direct discharge of this waste liquid not only causes serious environmental pollution but also wastes valuable resources. Copper-containing waste liquid has a high pollution index but is also a valuable composite resource with great potential for resource recovery and recycling. Therefore, extensive research on the recycling and utilization of waste etching solutions is crucial for ensuring the sustainable use of resources needed for human production and life and promoting sustainable development.

[0004] Currently, the main methods for treating alkaline copper-containing etching wastewater include chemical precipitation, liquid membrane separation, electrolysis, and solvent extraction. Chemical precipitation is simple, has a large processing capacity, and can quickly and effectively remove copper from alkaline etching wastewater. Liquid membrane separation has simple equipment, a large contact area, and low energy consumption, but measures for liquid membrane swelling and demulsification are not ideal. Electrolysis has a wide processing range and large processing capacity, but it is costly, and the electrolysis process can easily generate other metals, reducing the purity of the copper. Solvent extraction is effective, and the extractant can be recycled, but the extractant is expensive, back-extraction requires sulfuric acid, the process is long, and copper recovery is incomplete.

[0005] Therefore, developing a new process for producing copper carbonate from alkaline copper-containing etching waste liquid from PCBs is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards. Using alkaline etching waste liquid of alkaline printed circuit boards as raw material, copper carbonate is prepared. This method can not only eliminate the pollution of copper-containing waste liquid to the environment, but also protect the environment. It has high economic and social benefits and has certain application and promotion value.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards includes the following steps:

[0009] Step 1: Mix the alkaline etching waste liquid of printed circuit boards with alkali, heat and stir to react, filter, wash until the filtrate is neutral, and take out the filter cake.

[0010] Step 2: Add the filter cake to the hydrochloric acid solution, stir until uniform, filter, and remove the filtrate;

[0011] Step 3: Mix the filtrate with ammonium bicarbonate solution, adjust the pH, stir the reaction at 55-60℃, let stand for 1-2 hours, filter, wash 2-3 times, and dry in an oven at 100-105℃ to constant weight to obtain copper carbonate.

[0012] In some possible implementations, the composition of the alkaline etching waste liquid for printed circuit boards in step 1 is: copper content of 115-120 g / L.

[0013] In some possible implementations, the ratio of alkaline etching waste liquid to alkali in step 1 is 100 mL: 18-20 g. Too little alkali will easily lead to incomplete reaction, resulting in low copper recovery; too much alkali may produce other reactions, thus inhibiting the reaction and also reducing the copper recovery rate.

[0014] In some possible implementations, the alkali mentioned in step 1 is either sodium hydroxide or potassium hydroxide.

[0015] In some possible implementations, the temperature is raised to 80-90°C in step 1.

[0016] In some possible implementations, the concentration of the hydrochloric acid solution in step 2 is 0.5 mol / L.

[0017] In some possible implementations, the ratio of filter cake to hydrochloric acid solution in step 2 is 4-6 g: 12-15 mL.

[0018] In some possible implementations, step 3 involves adjusting the pH to 7.0-7.5. pH has a significant impact on the recovery rate of copper ions in the waste liquid. If the pH is too low, there will be more residual copper ions, resulting in incomplete precipitation and a lower copper recovery rate. If the pH is too high, some of the precipitate will dissolve, further reducing the copper recovery rate.

[0019] In some possible implementations, the concentration of the ammonium bicarbonate solution in step 3 is 0.5 mol / L.

[0020] In some possible implementations, the volume ratio of filtrate to ammonium bicarbonate solution in step 3 is 4-5:10.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards. The specific process includes: firstly, adding alkali to the alkaline etching waste liquid of printed circuit boards, which generates copper hydroxide, which then decomposes into copper oxide under heating conditions. This copper oxide then reacts with hydrochloric acid to generate copper salt, and finally, the copper carbonate is mixed with ammonium bicarbonate solution to generate copper carbonate. The process method provided in this invention achieves a high copper recovery rate, exceeding 98.5%; moreover, the prepared copper carbonate is of high quality, meeting market requirements.

[0023] The present invention provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards. In this process, a strong alkali (sodium hydroxide, potassium hydroxide) is used to neutralize the acidic substances in the waste liquid, rapidly adjusting the pH value of the waste liquid to a neutral or alkaline range. This effectively reduces the corrosiveness of the etching waste liquid and creates conditions for subsequent treatment or discharge. Furthermore, under alkaline conditions, heavy metal ions such as copper and iron in the waste liquid react with hydroxide ions (OH-). - The reaction produces insoluble hydroxide precipitates (such as Cu(OH)2 and Fe(OH)3). These precipitates can be further separated through processes such as precipitation and filtration, significantly reducing the concentration of heavy metal ions in the waste liquid and meeting emission standards or resource recovery requirements.

[0024] This invention provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, which realizes the effective recycling of copper resources in PCB etching waste liquid, thereby effectively reducing resource waste and environmental pollution, and has the characteristics of being green and environmentally friendly.

[0025] The present invention provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards. The process is simple, easy to operate, requires less equipment, and is easy to realize industrial production. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The alkaline etching waste liquid used in this invention is alkaline etching waste liquid of printed circuit boards collected by a hazardous waste comprehensive utilization company in Anhui Province. The composition of the alkaline etching waste liquid is as follows:

[0028] Element Cu(g / L) Cl(g / L) Fe(g / L) As (g / L) pH alkaline etching waste liquid 116.3 157 2.1 16.3 10.1

[0029] Example 1

[0030] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0031] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0032] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0033] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0034] Example 2

[0035] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0036] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 20g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0037] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0038] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0039] Example 3

[0040] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0041] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 90℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0042] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0043] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0044] Example 4

[0045] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0046] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0047] Step 2: Add 6g of filter cake to 15mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0048] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0049] Example 5

[0050] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0051] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0052] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0053] Step 3: Mix 5 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0054] Example 6

[0055] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0056] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0057] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0058] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 60 °C, let stand for 2 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0059] Example 7

[0060] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0061] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0062] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0063] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash 3 times with deionized water, and dry in an oven at 105 °C to constant weight to obtain copper carbonate.

[0064] Example 8

[0065] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0066] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0067] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0068] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.4, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0069] Example 9

[0070] This embodiment provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0071] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 19g of sodium hydroxide, heat to 85℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0072] Step 2: Add 5.5g of filter cake to 14mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0073] Step 3: Mix 4.8 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.5, stir the reaction at 58 °C, let stand for 2 h, filter, wash 3 times with deionized water, and dry in an oven at 102 °C to constant weight to obtain copper carbonate.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0076] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 16g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0077] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0078] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0079] Comparative Example 2

[0080] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0081] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 70℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0082] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0083] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0084] Comparative Example 3

[0085] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0086] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0087] Step 2: Add 3g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0088] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0089] Comparative Example 4

[0090] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0091] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0092] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0093] Step 3: Mix 3 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0094] Comparative Example 5

[0095] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0096] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0097] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0098] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 6.5, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0099] Comparative Example 6

[0100] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0101] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0102] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0103] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 6.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0104] Comparative Example 7

[0105] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0106] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 18g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0107] Step 2: Add 4g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0108] Step 3: Mix 4 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 45 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0109] Comparative Example 8

[0110] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0111] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 16g of sodium hydroxide, heat to 80℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0112] Step 2: Add 3.5g of filter cake to 12mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0113] Step 3: Mix 3 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0114] Comparative Example 9

[0115] This comparative example provides a method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, including the following steps:

[0116] Step 1: Mix 100mL of alkaline etching waste liquid from printed circuit boards with 17g of sodium hydroxide, heat to 75℃ and stir to react, filter, wash with deionized water until the filtrate is neutral, and take out the filter cake.

[0117] Step 2: Add 4g of filter cake to 11mL of hydrochloric acid solution (concentration of 0.5mol / L), stir until uniform, filter, and take out the filtrate;

[0118] Step 3: Mix 6 mL of filtrate with 10 mL of ammonium bicarbonate solution (concentration of 0.5 mol / L), adjust the pH to 7.0, stir the reaction at 55 °C, let stand for 1 h, filter, wash twice with deionized water, and dry in an oven at 100 °C to constant weight to obtain copper carbonate.

[0119] Performance tests were conducted on Examples 1-9 and Comparative Examples 1-9 to determine the copper recovery rate in the waste liquid and the purity of the prepared copper carbonate. The test results are shown in Table 1.

[0120] Table 1

[0121] project Copper recovery rate (%) Purity (%) of copper carbonate Example 1 98.8 99.3 Example 2 98.7 99.4 Example 3 99.0 99.1 Example 4 99.1 99.2 Example 5 98.9 99.5 Example 6 98.6 99.5 Example 7 98.9 99.3 Example 8 99.0 99.3 Example 9 98.8 99.1 Comparative Example 1 95.4 97.1 Comparative Example 2 95.5 96.8 Comparative Example 3 96.1 96.7 Comparative Example 4 95.8 96.5 Comparative Example 5 96.5 97.2 Comparative Example 6 95.4 97.1 Comparative Example 7 95.8 97.3 Comparative Example 8 95.3 97.1 Comparative Example 9 94.6 95.5

[0122] As shown in Table 1, compared to the methods for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards provided in Comparative Examples 1-9, the methods for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards provided in Examples 1-9 exhibit superior copper recovery rate and product copper carbonate purity. This demonstrates that in the method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, the amount of waste liquid and other reagents, temperature, and pH value all affect the copper recovery rate and copper carbonate purity during the preparation process. Therefore, the method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards provided in this invention exhibits a high copper recovery rate, exceeding 98.5%; furthermore, the prepared copper carbonate is of high quality, with a purity exceeding 99.0%, meeting market requirements.

[0123] In summary, the method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards provided in this invention has a simple process flow, is easy to operate, requires fewer equipment, and is easy to implement for industrial production. Furthermore, the simple process flow, easy operation, and fewer equipment requirements make it easy to implement for industrial production.

[0124] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards, characterized in that, Includes the following steps: Step 1: Mix the alkaline etching waste liquid of printed circuit boards with alkali, heat and stir to react, filter, wash until the filtrate is neutral, and take out the filter cake. Step 2: Add the filter cake to the hydrochloric acid solution, stir until uniform, filter, and remove the filtrate; Step 3: Mix the filtrate with ammonium bicarbonate solution, adjust the pH, stir the reaction at 55-60℃, let stand for 1-2 hours, filter, wash 2-3 times, and dry in an oven at 100-105℃ to constant weight to obtain copper carbonate.

2. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, The composition of the alkaline etching waste liquid for printed circuit boards in step 1 is: copper content of 115-120 g / L.

3. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 1, the ratio of alkaline etching waste liquid to alkali used in the printed circuit board process is 100mL: 18-20g.

4. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, The alkali mentioned in step 1 is either sodium hydroxide or potassium hydroxide.

5. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 1, the temperature is raised to 80-90℃.

6. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 2, the concentration of the hydrochloric acid solution is 0.5 mol / L.

7. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 2, the ratio of filter cake to hydrochloric acid solution is 4-6g: 12-15mL.

8. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 3, adjust the pH to 7.0-7.

5.

9. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 3, the concentration of the ammonium bicarbonate solution is 0.5 mol / L.

10. The method for preparing copper carbonate from alkaline etching waste liquid of printed circuit boards according to claim 1, characterized in that, In step 3, the volume ratio of filtrate to ammonium bicarbonate solution is 4-5:10.