Method for recovering metal from waste printed circuit board and a cell thereof

Patent metadata

Field	Value
Publication number	US-2023416936-A1
Application number	US-202217847301-A
Country	US
Kind code	A1
Filing date	Jun 23, 2022
Priority date	Jun 23, 2022
Publication date	Dec 28, 2023
Grant date	—

Abstract

A metal recovery device for recovering metal in a waste printed circuit board by way of electrodeposition including: a cathode, an anode, and an electrolyte in electrical communication with the cathode and the anode, wherein the electrolyte includes a glycol-based compound and a metal chloride. A method of preparing an electrolyte for use in the same. A method of metal recovery for recovering metal from waste printed circuit board by making use the same.

First claim

1 . A metal recovery device for recovering metal in a waste printed circuit board by way of electrodeposition comprising:
a cathode, an anode, and an electrolyte in electrical communication with the cathode and the anode, wherein the electrolyte comprises a glycol-based compound and a metal chloride.

2 . The metal recovery device according to claim 1 , wherein the glycol-based compound is a petrochemical.

3 . The metal recovery device according to claim 1 , wherein the glycol-based compound is a monomeric glycol.

4 . The metal recovery device according to claim 3 , wherein the monomeric glycol is ethylene glycol.

5 . The metal recovery device according to claim 3 , wherein the monomeric glycol is propylene glycol.

6 . The metal recovery device according to claim 1 , wherein the anode comprises an anode material selected from a group consisting of porous carbon material, metal foam, conductive polymer foam and a combination thereof.

7 . The metal recovery device according to claim 6 , wherein the porous carbon material is selected from a group consisting of reticulated vitreous carbon, carbon nanotube foam, graphene foam, graphite foam, carbon cloth, carbon paper and a combination thereof.

8 . The metal recovery device according to claim 1 , wherein the anode being reticulated vitreous carbon with a porosity from about 10 ppi to about 100 ppi.

9 . The metal recovery device according to claim 1 , wherein depth of the anode submerged in the electrolyte varies with the porosity of the anode.

10 . The metal recovery device according to claim 1 , wherein the cathode comprises a cathode material selected from a group consisting of nickel, copper, iron, nickel foam, copper foam, aluminum foam, carbon cloth, carbon foam, and a combination thereof.

11 . The metal recovery device according to claim 10 , wherein the cathode material is covered by a substantially porous structure.

12 . The metal recovery device according to claim 11 , wherein the substantially porous structure has a porosity from about 100 mesh to about 200 mesh.

13 . The metal recovery device according to claim 11 , wherein the substantially porous structure comprises a material selected from a group consisting of cotton cloth, porous carbon cloth, plastic cloth and a combination thereof.

14 . The metal recovery device according to claim 1 , wherein the electrodeposition is conducted at a current density from about 0.2 mA cm 2 to about 300 mA cm 2 .

15 . The metal recovery device according to claim 1 , wherein the metal comprises heavy metal.

16 . The metal recovery device according to claim 15 , wherein the heavy metal is copper.

17 . The metal recovery device according to claim 1 , wherein the metal chloride is potassium chloride.

18 . The metal recovery device according to claim 1 , wherein the electrolyte further comprises NH 4 Cl.

19 . The metal recovery device according to claim 1 , wherein the electrolyte is reusable for two or more electrodeposition cycles.

20 . The metal recovery device according to claim 19 , wherein sensitivity of the device is between about 50% to about 60% in each electrodeposition cycle.

21 . The metal recovery device according to claim 19 , wherein reuse of the electrolyte increases amount of metal recovered in each electrodeposition cycle.

22 . The metal recovery device according to claim 21 , wherein the device has a sensitivity of about 60% when the electrolyte is being reused for three electrodeposition cycles.

23 . The metal recovery device according to claim 21 , wherein cathodic Faradaic efficiency of the device in each electrodeposition cycle increases with number of cycles the electrolyte being reused.

24 . The metal recovery device according to claim 23 , wherein the cathodic Faradaic efficiency of the device is at about 99%, when the electrolyte is being reused for three electrodeposition cycles.

25 . The metal recovery device according to claim 1 , wherein the electrodeposition cycle has a metal selectivity of at least 50%.

26 . The metal recovery device according to claim 1 , wherein the electrodeposition cycle has a metal recovery from about 26% to about 70%.

27 . A method of preparing an electrolyte for use in the metal recovery device as claimed in claim 1 for recovering metal by way of electrodeposition, comprising the steps of:
a) mixing a glycol-based compound with a metal chloride to form a substantially pH-neutral mixture; and
b) contacting the substantially pH-neutral mixture with a desirable amount of sample to form a slurry.

28 . The method according to claim 27 , further comprising the step of preparing the sample by way of size reduction.

29 . The method according to claim 28 , wherein the size reduction comprising the step of blending the sample to powder form.

30 . The method according to claim 29 , wherein the powder form of the sample is of about 100 mesh to about 200 mesh.

31 . The method according to claim 27 , wherein concentration of the sample in the electrolyte is about 1 mg/L to about 25 mg/L.

32 . A method of metal recovery for recovering metal from waste printed circuit board by making use of the metal recovery device as claimed in claim 1 , comprising the step of:
conducting a first electrodeposition cycle with a current density of about 0.2 mA cm −2 to about 300 mA cm −2 for a cycle.

33 . The method according to claim 32 , wherein the electrodeposition is conducted at room temperature and atmospheric pressure.

34 . The method according to claim 32 , wherein the electrodeposition is conducted for at least 30 min.

35 . The method according to claim 32 , further comprising the step of conducting a second electrodeposition cycle by reusing electrolyte of the first electrodeposition cycle.

36 . The method according to claim 35 , wherein amount of metal collected in the second electrodeposition cycle is higher than amount of metal collected in the first electrodeposition cycle.

37 . The method according to claim 36 , wherein metal being recovered is selected from the group consisting of copper, cadmium, palladium and a combination thereof.

Assignees

• Univ City Hong Kong

Inventors

• Lam Chun Ho

Classifications

• Y02P10/20

  Recycling · CPC title

• C25C1/20

  of noble metals · CPC title

• C25C1/16

  of zinc, cadmium or mercury · CPC title

• C25C1/12

  of copper · CPC title

• C22B7/006

  Wet processes · CPC title