A method for extracting copper hydroxide from copper-containing etching waste liquid

Abstract

The application discloses a treatment method of extracting copper hydroxide from copper-containing etching waste liquid, and belongs to the technical field of waste liquid recovery treatment, and comprises the following steps: step one, heating the acid etching waste liquid to boiling through oil bath, stirring and adding sodium hydroxide solution to adjust pH, cooling, adding alkyl diazoacetate, ultrasonic dispersion, centrifugal filtration, washing with water and ethanol respectively, vacuum drying to constant weight, and obtaining pretreated powder; step two, stirring and adding sodium hydroxide solution to the pretreated powder to adjust pH, cooling, adding alkyl diazoacetate, ultrasonic dispersion, centrifugal filtration, washing with water and ethanol respectively, vacuum drying to constant weight, and obtaining copper hydroxide. The product obtained in steps one and two does not present mud shape by adding alkyl diazoacetate to the reaction system, so that the product is easy to wash, only a small amount of water and ethanol are needed for washing, and the washing liquid can be further recycled.

Description

Technical Field

[0001] This invention belongs to the field of waste liquid recycling and treatment technology, specifically relating to a method for extracting copper hydroxide from copper-containing etching waste liquid. Background Technology

[0002] Etching solution is a raw material used for copperplate engraving, a liquid that carves by eroding the material. In modern industrial development, the electronics industry is moving towards very large-scale integrated circuits. Printed circuit boards (PCBs), as components, are used in all electronic devices to mount integrated circuits and other components and provide interconnections between them. Etching is an essential step in PCB manufacturing. The production process generates a large amount of etching wastewater with high copper content, 60% of which is acidic, mainly composed of HCl and CuCl2. Direct discharge without treatment not only causes serious environmental pollution but also results in a huge waste of resources. Summary of the Invention

[0003] The purpose of this invention is to provide a method for extracting copper hydroxide from copper-containing etching waste liquid, in order to solve the following technical problem: Direct discharge of acidic etching waste liquid without treatment not only causes serious environmental pollution, but also results in a huge waste of resources.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0006] Step 1: Heat the acidic etching waste liquid containing HCl and CuCl2 to boiling in an oil bath, stir and add sodium hydroxide solution to adjust the pH to 5-8, cool to -9 to -5℃, add alkyl diazonium acetate, ultrasonically disperse for 10-30 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80-90℃ to constant weight to obtain pretreated powder; During the process of adding sodium hydroxide solution to the acidic etching waste liquid containing HCl and CuCl2, basic copper chloride (CuCl2·3Cu(OH)2) is first formed in the pH range of 5-8;

[0007] Step 2: Add sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5-13. Cool to -9 to -5℃, add alkyl diazoacetate, sonicate for 10-30 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80-90℃ to constant weight to obtain copper hydroxide; at pH=13, react with Cl in CuCl2·3Cu(OH)2. - Combined Cu 2+The product is completely converted into copper hydroxide, resulting in a product containing only copper hydroxide as a single component, at which point the product purity reaches over 99.9%.

[0008] As a further aspect of the present invention, Cu in the acidic etching waste liquid 2+ The concentration of the substance is 100-140 g / L, and the concentration of HCl is 3.7-6.0 mol / L.

[0009] As a further aspect of the present invention, the concentration of the sodium hydroxide solution in steps one and two is 1-10 mol / L.

[0010] As a further aspect of the present invention, the alkyl diazoacetate mentioned in steps one and two is any one of octyl diazoacetate, dodecyl diazoacetate, tetradecyl diazoacetate, and octadecyl diazoacetate.

[0011] As a further aspect of the present invention, the volume ratio of alkyl diazoacetate to sodium hydroxide solution in steps one and two is 75-460:1000.

[0012] The beneficial effects of this invention are:

[0013] This invention introduces alkyl diazonium acetate into the reaction system of acidic etching waste liquid and sodium hydroxide solution in step one and pretreatment powder and sodium hydroxide solution in step two. After ultrasonic dispersion, the alkyl diazonium acetate forms a polymer-encapsulated composite morphology on the surface of basic copper chloride / copper hydroxide particles, which imparts hydrophobicity to the basic copper chloride / copper hydroxide particles. When basic copper chloride particles or copper hydroxide particles approach each other, the presence of the long-chain polymer alkyl diazonium acetate prevents the particles from getting too close, weakening van der Waals forces and thus preventing the particles from agglomerating to form a mud-like colloid.

[0014] Compared to existing technologies where acidic etching waste liquid reacts with sodium hydroxide solution and is centrifuged and filtered to obtain a colloid, which is enriched with heavy metals such as arsenic and other impurities and appears muddy, making washing difficult and requiring a large amount of washing water, the product obtained by this invention is easy to wash and only requires a small amount of water and ethanol to wash alkyl diazonate and other impurities. The washing liquid after water washing can be further recycled for heavy metal recovery, and the washing liquid after ethanol washing can be evaporated, crystallized, and filtered to obtain alkyl diazonate, which can be added back to the system for continued use. This invention achieves full utilization of acidic copper-containing etching waste liquid and also prevents environmental pollution. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1

[0017] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0018] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the active ingredient was 100 g / L, the concentration of HCl was 3.7 mol / L, and a 1 mol / L sodium hydroxide solution was added with stirring to adjust the pH to 5. The mixture was cooled to -9°C, and octyl diazonate was added. The volume ratio of octyl diazonate to sodium hydroxide solution was 75:1000. The mixture was ultrasonically dispersed for 10 min, centrifuged and filtered, washed three times with water and ethanol respectively, and vacuum dried at 80°C to constant weight to obtain the pretreated powder.

[0019] Step 2: Add 1 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Cool to -9°C, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 75:1000. Disperse by sonication for 10 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0020] Example 2

[0021] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0022] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the active ingredient was 140 g / L, the concentration of HCl was 6.0 mol / L, and a 10 mol / L sodium hydroxide solution was added with stirring to adjust the pH to 8. The mixture was cooled to -5°C, and octyl diazonate was added. The volume ratio of octyl diazonate to sodium hydroxide solution was 460:1000. The mixture was ultrasonically dispersed for 30 min, centrifuged and filtered, washed three times with water and ethanol respectively, and dried under vacuum at 90°C to constant weight to obtain the pretreated powder.

[0023] Step 2: Add 10 mol / L sodium hydroxide solution to the pretreated powder and adjust the pH to 13.0. Cool to -5℃, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 460:1000. Disperse by sonication for 30 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 90℃ to constant weight to obtain copper hydroxide.

[0024] Example 3

[0025] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0026] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the HCl was 120 g / L, the concentration of the sodium hydroxide solution was 5 mol / L, and the pH was adjusted to 5 by stirring and adding a 5 mol / L sodium hydroxide solution. The mixture was cooled to -9°C, and octyl diazonate was added. The volume ratio of octyl diazonate to sodium hydroxide solution was 200:1000. The mixture was ultrasonically dispersed for 20 min, centrifuged and filtered, washed three times with water and ethanol respectively, and vacuum dried at 80°C to constant weight to obtain the pretreated powder.

[0027] Step 2: Add 5 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Cool to -9°C, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 200:1000. Disperse by sonication for 20 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0028] Example 4

[0029] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0030] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the HCl was 130 g / L, the concentration of the HCl was 4 mol / L, and the pH was adjusted to 8 by adding a 6 mol / L sodium hydroxide solution while stirring. The mixture was cooled to -5℃, and octyl diazonate was added. The volume ratio of octyl diazonate to sodium hydroxide solution was 300:1000. The mixture was ultrasonically dispersed for 20 min, centrifuged and filtered, washed three times with water and ethanol respectively, and vacuum dried at 80℃ to constant weight to obtain the pretreated powder.

[0031] Step 2: Add 6 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Cool to -95°C, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 300:1000. Disperse by sonication for 20 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0032] Comparative Example 1

[0033] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0034] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the HCl was 100 g / L and the concentration of the sodium hydroxide solution was 3.7 mol / L. The pH was adjusted to 5 by stirring and adding a 1 mol / L sodium hydroxide solution. The mixture was centrifuged and filtered, washed with water until no chloride ions were found, and dried under vacuum at 80°C to constant weight to obtain the pretreated powder.

[0035] Step 2: Add 1 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Cool to -9°C, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 75:1000. Disperse by sonication for 10 min, centrifuge and filter, wash three times with water and ethanol respectively, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0036] Compared with Example 1, this comparative example did not include the addition of octyl diazonate in step one.

[0037] Comparative Example 2

[0038] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0039] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the active ingredient was 100 g / L, the concentration of HCl was 3.7 mol / L, and a 1 mol / L sodium hydroxide solution was added with stirring to adjust the pH to 5. The mixture was cooled to -9°C, and octyl diazonate was added. The volume ratio of octyl diazonate to sodium hydroxide solution was 75:1000. The mixture was ultrasonically dispersed for 10 min, centrifuged and filtered, washed three times with water and ethanol respectively, and vacuum dried at 80°C to constant weight to obtain the pretreated powder.

[0040] Step 2: Add 1 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Centrifuge and filter, wash with water until no chloride ions are present, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0041] Compared with Example 1, this comparative example did not include the addition of octyl diazonate in step two.

[0042] Comparative Example 3

[0043] A method for extracting copper hydroxide from copper-containing etching waste liquid includes the following steps:

[0044] Step 1: Heat 100mL of acidic etching waste solution containing HCl and CuCl2 to boiling in an oil bath. The Cu in the acidic etching waste solution... 2+ The concentration of the HCl was 100 g / L and the concentration of the sodium hydroxide solution was 3.7 mol / L. The pH was adjusted to 5 by stirring and adding a 1 mol / L sodium hydroxide solution. The mixture was centrifuged and filtered, washed with water until no chloride ions were found, and dried under vacuum at 80°C to constant weight to obtain the pretreated powder.

[0045] Step 2: Add 1 mol / L sodium hydroxide solution to the pretreated powder and stir to adjust the pH to 12.5. Cool to -9°C, add octyl diazonate, with a volume ratio of octyl diazonate to sodium hydroxide solution of 75:1000. Disperse ultrasonically for 10 min, centrifuge and filter, wash with water until no chloride ions are present, and vacuum dry at 80°C to constant weight to obtain copper hydroxide.

[0046] Compared with Example 1, this comparative example did not include the addition of octyl diazonate in steps one and two.

[0047] Performance tests were conducted on Examples 1-4 and Comparative Examples 1-3:

[0048] (1) Purity test of copper hydroxide in the product: Referring to GB / T 21696-2008, the method for determining the content of basic copper chloride was used, and the purity of copper hydroxide in the product was calculated according to the following formula:

[0049] The purity of copper hydroxide (%) = (c × V × 0.1068) / m × 100%;

[0050] The copper recovery rate in copper-containing etching waste liquid is calculated using the following formula:

[0051] Copper recovery rate in copper-containing etching waste liquid / % = (c × V × 0.06355) / M × 100%;

[0052] In the formula: c is the concentration of sodium thiosulfate standard titration solution (mol / L), V is the volume of sodium sulfate standard solution consumed during titration (mL), m is the mass of the copper hydroxide product to be tested (g), and M is the theoretical mass of copper in the copper-containing etching waste liquid (g) (calculated by the concentration of the copper-containing etching waste liquid × volume).

[0053] (2) Statistics on the total amount of washing water / water and ethanol used in steps one and two of each example or comparative example: The total amount of washing water and ethanol used in steps one and two is counted / mL and recorded.

[0054] The test results are shown in Table 1:

[0055] Table 1

[0056]

[0057] As can be seen from Table 1, the copper hydroxide prepared in Examples 1-4 has higher purity than that prepared in Comparative Examples 1-3. Furthermore, the copper hydroxide extraction method for copper-containing etching waste liquid in Examples 1-4 has a higher copper recovery rate in the copper etching waste liquid than the copper hydroxide extraction method for copper-containing etching waste liquid in Comparative Examples 1-3, and the recovery rate is stable at over 99.9%. The amount of washing water used is also less.

[0058] 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.

[0059] 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 treatment method for extracting copper hydroxide from a copper-containing etching waste liquid, characterized by, It comprises the following steps: Step one, heating the acid etching waste liquid to boiling in oil bath, stirring to add sodium hydroxide solution to adjust pH to 5-8, cooling to -9--5℃, adding alkyl diazoacetate, ultrasonic dispersion for 10-30min, centrifugal filtration, washing with water and ethanol for three times respectively, vacuum drying at 80-90℃ to constant weight to obtain pretreated powder; Step two, stirring to add sodium hydroxide solution to the pretreated powder to adjust pH to 12.5-13, cooling to -9--5℃, adding alkyl diazoacetate, ultrasonic dispersion for 10-30min, centrifugal filtration, washing with water and ethanol for three times respectively, vacuum drying at 80-90℃ to constant weight to obtain copper hydroxide; The alkyl diazoacetate is any one of octyl diazoacetate, dodecyl diazoacetate, tetradecyl diazoacetate and octadecyl diazoacetate.

2. The method according to claim 1, wherein the copper-containing etching waste liquid is an etching waste liquid containing copper ions and sulfuric acid ions. Cu in the acidic etching waste liquid 2+ The concentration of the substance is 100-140 g / L, and the concentration of HCl is 3.7-6.0 mol / L.

3. The method according to claim 1, wherein the copper-containing etching waste liquid is an etching waste liquid containing copper ions and sulfuric acid ions. The concentration of the sodium hydroxide solution in step one and step two is 1-10mol / L.

4. The method according to claim 1, wherein the method is characterized by, The volume ratio of the alkyl diazoacetate to the sodium hydroxide solution in step one and step two is 75-460:1000.

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