Membrane concentration method for dilute solution of copper chloride

Abstract

The invention discloses a membrane concentration method for a dilute copper chloride solution, which comprises the following steps: selecting proper nanofiltration membranes and reverse osmosis membranes, reasonably matching and designing the number and position of the nanofiltration membranes and the reverse osmosis membranes, and then carrying out membrane concentration on the pretreated dilute copper chloride solution for multiple times. The copper chloride can be efficiently intercepted under relatively low membrane pressure, so that copper ions in a dilute solution of the copper chloride can directly enter an electrolytic deposition system to recover cathode copper after being increased from 0.5-3g / L to 20g / L or above, and the problems that the copper chloride is difficult to intercept by a nanofiltration membrane and the copper chloride interception pressure of a reverse osmosis membrane is high are solved; the problem of copper loss in cleaning water after acid etching is solved, and the purposes of protecting the environment, reducing cost and improving efficiency are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of etching waste liquid treatment and metal recovery, in particular to a copper chloride dilute solution membrane concentration method. Background Art

[0002] At present, the acid etching process is mainly used to prepare circuit boards (PCBs). Gu Mingshi et al. recorded in the Journal of Environmental Engineering, March 2018, Volume 8, Issue 2, "Research on the Current Situation and Management Countermeasures of the Disposal and Utilization of Copper-Containing Etching Waste Liquid in Jiangsu Province", that in 2016, PCB companies in Jiangsu Province alone produced 520,000 tons of PCB copper-containing etching waste liquid. After acid etching, the circuit boards need to be cleaned. The amount of water required for cleaning is about 150 times the amount of etching waste liquid. The main component of these cleaning waters is dilute copper chloride solution, containing 0.5-2g / L of copper and low acidity.

[0003] At present, the treatment method for these cleaning waters is mainly to adjust the pH with composite alkali after being discharged to the comprehensive sewage treatment station, then add sodium sulfide to remove copper, and then enter the biochemical treatment system to further remove organic pollutants, etc., and discharge after meeting the standards. However, this treatment method has many problems such as large sludge production, low copper content in sludge (1-4%), high treatment cost, low sludge value (10-20% of copper price), large wastewater discharge, etc. Some people have also tried to use membrane concentration method to increase the copper ion concentration, but due to the strong penetration of copper ions in copper chloride dilute solution, the nanofiltration membrane has almost zero interception ability for copper chloride, while the reverse osmosis membrane can intercept copper chloride, but the membrane pressure is very high. For example, the copper ion concentration can be concentrated from 0.5-2g / L to 20g / L through the reverse osmosis membrane, and the reverse osmosis membrane pressure must reach more than 8Mpa. Ordinary reverse osmosis membranes cannot withstand such high pressures. Therefore, how to develop a membrane concentration process with low membrane pressure and high copper chloride interception efficiency is of great significance for protecting the environment and reducing costs and increasing efficiency. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a copper chloride dilute solution membrane concentration method, comprising:

[0005] Pretreatment of copper chloride dilute solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected in the transfer tank, filtered and impurities are removed, and the washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated copper chloride dilute solution. The pretreated copper chloride dilute solution has an oxidation-reduction potential of 350-450mv and a total organic carbon of less than 50ppm;

[0006] First membrane concentration: the pretreated copper chloride dilute solution is concentrated through a primary membrane to obtain a primary concentrate and primary produced water, the primary membrane includes two nanofiltration membranes and one reverse osmosis membrane, both of which are arranged in the first membrane tube;

[0007] Second membrane concentration: the primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water, the secondary membrane includes two reverse osmosis membranes and one nanofiltration membrane, both of which are arranged in the second membrane tube;

[0008] The third membrane concentration: the primary produced water is concentrated through the tertiary membrane to obtain the tertiary concentrated liquid and the tertiary produced water. The tertiary membrane includes a three-core reverse osmosis membrane, and the three-core reverse osmosis membranes are all arranged in the third membrane tube.

[0009] Preferably, the first membrane tube, the second membrane tube and the third membrane tube are all three-core membrane tubes, and the diameter of the three-core membrane tube is 8 inches.

[0010] Preferably, in the first membrane concentration process, the copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent water, is 2 to 8 g / L.

[0011] Preferably, during the first membrane concentration process, the copper ion concentration in the primary concentrate, i.e., the copper ion concentration in the secondary inlet water, is 6-12 g / L, and the copper ion concentration in the primary produced water, i.e., the copper ion concentration in the tertiary inlet water, is 0.5-3 g / L.

[0012] Preferably, during the first membrane concentration process, the flow rate ratio of the primary concentrate to the primary produced water is 1:2 to 1:3, and the membrane pressure is 1.5 to 3 MPa.

[0013] Preferably, during the second membrane concentration process, the copper ion concentration in the secondary concentrate is 20-25 g / L, the copper ion concentration in the secondary produced water is 1-6 g / L, the flow rate ratio of the secondary concentrate to the secondary produced water is 1:2-1:3, and the membrane pressure is 3-4 MPa.

[0014] Preferably, during the third membrane concentration process, the copper ion concentration in the tertiary concentrated liquid is 2 to 9 g / L, and the copper ion concentration in the tertiary produced water is 0.1 to 0.3 g / L.

[0015] Preferably, during the third membrane concentration process, the flow rate ratio of the tertiary concentrated liquid to the tertiary produced water is 1:2 to 1:3, and the membrane pressure is 2 to 3 MPa.

[0016] Preferably, during the pretreatment of the dilute copper chloride solution, at least one of a pleated filter element, a cotton core and a silicon carbide filter element is used for filtering and removing impurities, and the pore sizes of the pleated filter element and the silicon carbide filter element are controlled at 0.1 to 5 um.

[0017] Preferably, the secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid are returned to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.

[0018] The beneficial effect lies in that the copper chloride dilute solution membrane concentration method provided by the present application mainly selects suitable nanofiltration membranes and reverse osmosis membranes, and reasonably matches and designs the number and position of the nanofiltration membranes and the reverse osmosis membranes, and then performs multiple membrane concentrations on the pretreated copper chloride dilute solution, so that copper chloride can be efficiently intercepted at a relatively low membrane pressure, and the copper ions in the copper chloride dilute solution are increased from 0.5 to 3 g / L to more than 20 g / L, so that it can directly enter the electrolytic deposition system to recover cathode copper, thereby solving the problems that the nanofiltration membrane is difficult to intercept copper chloride, the reverse osmosis membrane has a high pressure to intercept copper chloride, and the problem of copper loss in the cleaning water after acid etching, thereby achieving the purpose of protecting the environment and reducing costs and increasing efficiency. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0020] The following embodiments are only used to illustrate the present invention, but are not limited to the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the protection scope of the present invention.

[0021] In the examples of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0022] Source of raw materials:

[0023] The cleaning water is collected from the circuit boards after acid etching by Longyu Electronic Technology Co., Ltd. in Meizhou, Guangdong Province.

[0024] Nanofiltration membrane, Veolia INDUSTRIAL NF1 8040F35, was purchased from Beijing Shengda Weixin Technology Development Co., Ltd.;

[0025] Reverse osmosis membrane was purchased from Hunan Zhiqing Environmental Protection Technology Co., Ltd.

[0026] Example 1

[0027] This embodiment provides a method for concentrating a dilute copper chloride solution through a membrane, comprising:

[0028] Pretreatment of copper chloride dilute solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected to the transfer tank, and the impurities (ink residue, etc.) are removed by filtering with a silicon carbide filter element with a pore size of 0.1um. The washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated copper chloride dilute solution. The redox potential of the pretreated copper chloride dilute solution is 350-450mv, the total organic carbon is less than 50ppm, and the copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent, is 2g / L;

[0029] First membrane concentration: The pretreated copper chloride dilute solution is concentrated through a first-level membrane to obtain a first-level concentrate and a first-level produced water. The first-level membrane includes two nanofiltration membranes and one reverse osmosis membrane. The two nanofiltration membranes and the one reverse osmosis membrane are both arranged in the first membrane tube. The first membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the first-level concentrate, that is, the copper ion concentration of the second-level influent, is 6g / L, and the copper ion concentration in the first-level produced water, that is, the copper ion concentration of the third-level influent, is 0.5g / L. The flow rate ratio of the first-level concentrate to the first-level produced water is 1:2, and the membrane pressure is 1.5Mpa.

[0030] Second membrane concentration: The primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water. The secondary membrane includes two reverse osmosis membranes and one nanofiltration membrane. The two reverse osmosis membranes and one nanofiltration membrane are both arranged in the second membrane tube. The second membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the secondary concentrate is 20g / L, the copper ion concentration in the secondary produced water is 1g / L, the flow rate ratio of the secondary concentrate to the secondary produced water is 1:2, and the membrane pressure is 3Mpa.

[0031] The third membrane concentration: the primary produced water is concentrated through the third membrane to obtain the third concentrated liquid and the third produced water. The third membrane includes a three-core reverse osmosis membrane. The three-core reverse osmosis membrane is arranged in the third membrane tube. The third membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the third concentrated liquid is 2g / L, and the copper ion concentration in the third produced water is 0.1g / L. The flow rate ratio of the third concentrated liquid to the third produced water is 1:2, and the membrane pressure is 2Mpa.

[0032] The secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid return to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.

[0033] Example 2

[0034] This embodiment provides a method for concentrating a dilute copper chloride solution through a membrane, comprising:

[0035] Pretreatment of copper chloride dilute solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected to the transfer tank, and the impurities are removed by filtering with a 5um folded filter element and a 0.1um silicon carbide filter element in turn (ink residue, etc. are removed, and the washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated copper chloride dilute solution. The redox potential of the pretreated copper chloride dilute solution is 350-450mv, and the total organic carbon is less than 50ppm. The copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent, is 6g / L;

[0036] First membrane concentration: The pretreated copper chloride dilute solution is concentrated through a first-level membrane to obtain a first-level concentrate and a first-level produced water. The first-level membrane includes two nanofiltration membranes and one reverse osmosis membrane. The two nanofiltration membranes and the one reverse osmosis membrane are both arranged in the first membrane tube. The first membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the first-level concentrate, that is, the copper ion concentration of the second-level influent, is 9g / L, and the copper ion concentration in the first-level produced water, that is, the copper ion concentration of the third-level influent, is 1.67g / L. The flow rate ratio of the first-level concentrate to the first-level produced water is 1:2.5, and the membrane pressure is 2.2Mpa.

[0037] Second membrane concentration: The primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water. The secondary membrane includes two reverse osmosis membranes and one nanofiltration membrane. The two reverse osmosis membranes and one nanofiltration membrane are both arranged in the second membrane tube. The second membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the secondary concentrate is 23g / L, and the copper ion concentration in the secondary produced water is 3g / L. The flow rate ratio of the secondary concentrate to the secondary produced water is 1:2.5, and the membrane pressure is 3.5Mpa.

[0038] The third membrane concentration: the primary produced water is concentrated through the third membrane to obtain the third concentrated liquid and the third produced water. The third membrane includes a three-core reverse osmosis membrane. The three-core reverse osmosis membrane is arranged in the third membrane tube. The third membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the third concentrated liquid is 5.5g / L, and the copper ion concentration in the third produced water is 0.2g / L. The flow rate ratio of the third concentrated liquid to the third produced water is 1:2.5, and the membrane pressure is 2.5Mpa.

[0039] The secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid return to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.

[0040] Example 3

[0041] This embodiment provides a method for concentrating a dilute copper chloride solution through a membrane, comprising:

[0042] Pretreatment of copper chloride dilute solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected to the transfer tank, and the cotton core, the silicon carbide filter element with a pore size of 5um and the folded filter element with a pore size of 0.1um are used in turn to filter and remove impurities (remove ink residue, etc.), and the washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated copper chloride dilute solution. The redox potential of the pretreated copper chloride dilute solution is 350-450mv, the total organic carbon is less than 50ppm, and the copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent water, is 8g / L;

[0043] First membrane concentration: The pretreated copper chloride dilute solution is concentrated through a first-level membrane to obtain a first-level concentrate and a first-level produced water. The first-level membrane includes two nanofiltration membranes and one reverse osmosis membrane. The two nanofiltration membranes and the one reverse osmosis membrane are both arranged in the first membrane tube. The first membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the first-level concentrate, that is, the copper ion concentration of the second-level influent, is 12g / L, and the copper ion concentration in the first-level produced water, that is, the copper ion concentration of the third-level influent, is 3g / L. The flow rate ratio of the first-level concentrate to the first-level produced water is 1:3, and the membrane pressure is 3Mpa.

[0044] Second membrane concentration: The primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water. The secondary membrane includes two reverse osmosis membranes and one nanofiltration membrane. The two reverse osmosis membranes and one nanofiltration membrane are both arranged in the second membrane tube. The second membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the secondary concentrate is 25g / L, the copper ion concentration in the secondary produced water is 6g / L, the flow rate ratio of the secondary concentrate to the secondary produced water is 1:3, and the membrane pressure is 4Mpa.

[0045] The third membrane concentration: the primary produced water is concentrated through the third membrane to obtain the third concentrated liquid and the third produced water. The third membrane includes a three-core reverse osmosis membrane. The three-core reverse osmosis membrane is arranged in the third membrane tube. The third membrane tube is a three-core membrane tube with a diameter of 8 inches. The copper ion concentration in the third concentrated liquid is 9g / L, and the copper ion concentration in the third produced water is 0.3g / L. The flow rate ratio of the third concentrated liquid to the third produced water is 1:3, and the membrane pressure is 3Mpa.

[0046] The secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid return to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.

[0047] Example 4

[0048] This embodiment provides a method for concentrating a dilute copper chloride solution through a membrane, comprising:

[0049] Pretreatment of copper chloride dilute solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected to the transfer tank, and cotton and a 3um folded filter element are used to filter and remove impurities (remove ink residue, etc.), and the washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated copper chloride dilute solution. The redox potential of the pretreated copper chloride dilute solution is 350-450mv, the total organic carbon is less than 50ppm, and the copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent, is 4.5g / L;

[0050] First membrane concentration: The pretreated copper chloride dilute solution is concentrated through a first-level membrane to obtain a first-level concentrate and a first-level produced water. The first-level membrane includes two nanofiltration membranes and one reverse osmosis membrane. The two nanofiltration membranes and the one reverse osmosis membrane are both arranged in the first membrane tube. The first membrane tube is a three-core membrane tube with a diameter of 9 inches. The copper ion concentration in the first-level concentrate, that is, the copper ion concentration of the second-level influent, is 8.2g / L, and the copper ion concentration in the first-level produced water, that is, the copper ion concentration of the third-level influent, is 1.2g / L. The flow rate ratio of the first-level concentrate to the first-level produced water is 1:2, and the membrane pressure is 1.64Mpa.

[0051] Second membrane concentration: The primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water. The secondary membrane includes two reverse osmosis membranes and one nanofiltration membrane. The two reverse osmosis membranes and one nanofiltration membrane are both arranged in the second membrane tube. The second membrane tube is a three-core membrane tube with a diameter of 15 inches. The copper ion concentration in the secondary concentrate is 24g / L, and the copper ion concentration in the secondary produced water is 5g / L. The flow rate ratio of the secondary concentrate to the secondary produced water is 1:3, and the membrane pressure is 3.7Mpa.

[0052] The third membrane concentration: the primary produced water is concentrated through the third membrane to obtain the third concentrated liquid and the third produced water. The third membrane includes a three-core reverse osmosis membrane. The three-core reverse osmosis membrane is arranged in the third membrane tube. The third membrane tube is a three-core membrane tube with a diameter of 12 inches. The copper ion concentration in the third concentrated liquid is 8.1g / L, and the copper ion concentration in the third produced water is 0.15g / L. The flow rate ratio of the third concentrated liquid to the third produced water is 1:3, and the membrane pressure is 2.4Mpa.

[0053] The secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid return to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.

[0054] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for concentrating a dilute copper chloride solution by membrane, characterized in that: include: Pretreatment of dilute copper chloride solution: After the pickled and etched circuit board is washed with clean water, the washing water is collected in a transfer tank, filtered to remove impurities, and the washing water is collected in a storage tank containing a metal copper block, and then flows out of the storage tank and passes through an activated carbon filter tower to obtain a pretreated dilute copper chloride solution, wherein the pretreated dilute copper chloride solution has an oxidation-reduction potential of 350-450mv and a total organic carbon of less than 50ppm; First membrane concentration: the pretreated copper chloride dilute solution is concentrated through a primary membrane to obtain a primary concentrate and primary produced water, the primary membrane comprises two nanofiltration membranes and one reverse osmosis membrane, and the two nanofiltration membranes and the one reverse osmosis membrane are both arranged in a first membrane tube; Second membrane concentration: the primary concentrate is concentrated through a secondary membrane to obtain a secondary concentrate and secondary produced water, the secondary membrane comprises two reverse osmosis membranes and one nanofiltration membrane, the two reverse osmosis membranes and one nanofiltration membrane are both arranged in the second membrane tube; The third membrane concentration: the primary produced water is concentrated through a tertiary membrane to obtain a tertiary concentrated liquid and tertiary produced water, the tertiary membrane comprises a three-core reverse osmosis membrane, and the three-core reverse osmosis membranes are all arranged in the third membrane tube.

2. The copper chloride dilute solution membrane concentration method according to claim 1, characterized in that: The first membrane tube, the second membrane tube and the third membrane tube are all three-core membrane tubes.

3. The copper chloride dilute solution membrane concentration method according to claim 1, characterized in that: In the first membrane concentration process, the copper ion concentration in the pretreated copper chloride dilute solution, that is, the copper ion concentration of the primary influent water, is 2 to 8 g / L.

4. The copper chloride dilute solution membrane concentration method according to claim 1, characterized in that: During the first membrane concentration process, the copper ion concentration in the primary concentrate, i.e., the copper ion concentration in the secondary inlet water, is 6-12 g / L, and the copper ion concentration in the primary produced water, i.e., the copper ion concentration in the tertiary inlet water, is 0.5-3 g / L.

5. The copper chloride dilute solution membrane concentration method according to claim 1, characterized in that: In the first membrane concentration process, the flow rate ratio of the primary concentrated liquid to the primary produced water is 1:2 to 1:3, and the membrane pressure is 1.5 to 3 MPa.

6. The copper chloride dilute solution membrane concentration method according to claim 1, characterized in that: During the second membrane concentration process, the copper ion concentration in the secondary concentrate is 20-25 g / L, the copper ion concentration in the secondary produced water is 1-6 g / L, the flow rate ratio of the secondary concentrate to the secondary produced water is 1:2-1:3, and the membrane pressure is 3-4 MPa.

7. The method for concentrating a dilute copper chloride solution by membrane according to claim 1, characterized in that: During the third membrane concentration process, the copper ion concentration in the tertiary concentrated solution is 2-9 g / L, and the copper ion concentration in the tertiary produced water is 0.1-0.3 g / L.

8. The method for concentrating a dilute copper chloride solution by membrane according to claim 1, characterized in that: During the third membrane concentration process, the flow rate ratio of the tertiary concentrated liquid to the tertiary produced water is 1:2 to 1:3, and the membrane pressure is 2 to 3 MPa.

9. The method for concentrating a dilute copper chloride solution by membrane according to claim 1, characterized in that: During the pretreatment of the dilute copper chloride solution, at least one of a pleated filter element, a cotton core and a silicon carbide filter element is used for filtering and removing impurities, and the pore sizes of the pleated filter element and the silicon carbide filter element are both controlled at 0.1 to 5 um.

10. The method for concentrating a dilute copper chloride solution by membrane according to claim 1, characterized in that: The secondary concentrated liquid enters the electrolytic deposition system to recover cathode copper, the secondary produced water and the tertiary concentrated liquid are returned to the copper chloride dilute solution pretreatment process, and the tertiary produced water enters the pure water preparation system.