System and Method for Recovering Catalytic Precious Metal from Aqueous Galvanic Processing Solution

Patent metadata

Field	Value
Publication number	US-2018245178-A1
Application number	US-201615754224-A
Country	US
Kind code	A1
Filing date	Aug 15, 2016
Priority date	Aug 19, 2015
Publication date	Aug 30, 2018
Grant date	—

Abstract

A system is provided for recovering catalytic precious metals from aqueous galvanic processing solutions. The system comprises at least one holding tank, and at least one filtration unit, wherein the holding tank holds the galvanic processing solution and the filtration unit comprises ultrafiltration means and wherein the filtration unit is in hydraulic connection with the holding tank. The filtration unit is capable of providing a permeate stream having a reduced concentration of catalytic precious metal relative to the feed of the filtration unit and a concentrate stream with increased concentration of catalytic precious metal relative to the feed of the filtration unit. The system comprises at least one heat-exchanger hydraulically arranged between the holding tank and the filtration unit, being capable to limit the average temperature TRI of the aqueous galvanic processing solution to ≤50° C., preferably ≤45° C., more preferably ≤40° C. prior to entering the filtration unit.

First claim

1 . A system for recovering catalytic precious metals from aqueous galvanic processing solutions, comprising:
d) at least one holding tank, wherein the holding tank holds the galvanic processing solution that contains catalytic precious metal; e) a first filtration unit, wherein the first filtration unit comprises an ultrafiltration means, wherein the first filtration unit is in hydraulic connection with the at least one holding tank, wherein the at least one holding tank provides a feed into the first filtration unit; and f) at least one heat-exchanger hydraulically arranged between the at least one holding tank and the first filtration unit, wherein the at least one heat exchanger is capable of limiting the average temperature T R1 of the aqueous galvanic processing solution to ≤50° C., preferably ≤45° C., more preferably ≤40° C., prior to entering the first filtration unit.

2 . The system according to claim 1 , wherein the first filtration unit provides a permeate stream and a concentrate stream, wherein the permeate stream has a reduced concentration of catalytic precious metal relative to the feed into the first filtration unit and the concentrate stream has an increased concentration of catalytic precious metal relative to the feed into the first filtration unit.

3 . The system according to claim 2 , comprising a second filtration unit comprising an ultrafiltration means, wherein the second filtration unit is fed by the permeate stream of the first filtration unit, and wherein the second filtration unit provides a second permeate stream having a reduced concentration of catalytic precious metal relative to the feed into the second filtration unit and a concentrate stream having an increased concentration of catalytic precious metal relative to the feed into the second filtration unit.

4 . The system according to claim 3 , wherein a second heat exchanger is hydraulically arranged between the first filtration unit and the second filtration unit and wherein the second heat exchanger is capable of limiting the average temperature T R2 of the permeate stream coming from the first ultrafiltration unit to ≤50° C., preferably ≤45° C., more preferably ≤40° C. prior to entering the second filtration unit.

5 . The system according to claim 2 , wherein the system comprises at least one feedback line guiding at least one concentrate stream coming from the filtration unit back to the heat exchanger upstream to the filtering unit from which the concentrate stream descends from.

6 . The system according to claim 4 , further comprising a feed pump to pump the aqueous galvanic processing solution from the holding tank into the heat exchanger and/or a feed pump to pump the aqueous galvanic processing solution from the heat exchanger into the filtration unit, and/or a feed pump to pump the concentrate coming from the second heat exchanger into the filtration unit.

7 . The system according to claim 6 , further comprising a measuring means to provide data that is electronically connected to a control unit, said control unit being electronically connected to one or more feed pumps, and wherein the control unit is capable of controlling at least one of said feed pumps in dependence on data retrieved from said measuring means.

8 . The system according to claim 7 , wherein the measuring means are independently selected from the group consisting of conductivity probe, density probe, temperature probe, filling level probe, IR-absorption probe, UV-VIS-absorption probe, turbidity probe, chloride probe, or combinations thereof.

9 . The system according to claim 1 , wherein the ultrafiltration means has a nominal molecular weight cut-off≤500 kDa, preferably in a range of between ≥0.75 kDa and ≤20 kDa, more preferably in a range of between ≥1 kDa and ≤20 kDa, more preferably in a range of between ≥5 kDa and ≤15 kDa, even more preferably in a range of between ≥2 kDa and ≤8 kDa, and most preferably in a range of between ≥4 kDa and ≤6 kDa.

10 . The system according to claim 3 , wherein the first ultrafiltration means has a different nominal molecular weight cut-off than the second ultrafiltration means, preferably a greater nominal molecular weight cut-off.

11 . The system according to claim 2 , further comprising a means to re-feed the permeate to the holding tank.

12 . The system according to claim 1 , wherein the holding tank is a galvanic process tank selected from the group consisting of a plating tank, an etching tank, an activation tank, and a rinse tank.

13 . A method for recovering catalytic precious metals from aqueous galvanic processing solutions by ultrafiltration, characterized in that the ultrafiltration is performed under isothermal conditions, preferably at a temperature≤50° C., more preferably ≤45° C., most preferably ≤40° C.

14 . The method according to claim 13 , wherein the ultrafiltration has a nominal molecular weight cut-off≤500 kDa, preferably in a range of between ≥0.75 kDa and ≤20 kDa, more preferably in a range of between ≥1 kDa and ≤20 kDa, more preferably in a range of between ≥5 kDa and ≤15 kDa, even more preferably in a range of between ≥2 kDa and ≤8 kDa, and most preferably in a range of between ≥4 kDa and ≤6 kDa.

15 . The method according to claim 13 , wherein prior to the ultrafiltration, the aqueous galvanic processing solution is not subject to any of pH-adjusting pretreatment, oxidation and/or reduction pretreatment, or precipitation pretreatment.

Assignees

• Macdermid Enthone Inc

Inventors

• Goldacker Jens

Classifications

• C22B7/005 Primary

  Separation by a physical processing technique only, e.g. by mechanical breaking · CPC title

• C22B11/046

  from manufactured products, e.g. from printed circuit boards, from photographic films, paper or baths · CPC title

• C22B11/048 Primary

  from spent catalysts · CPC title

• C22B7/009

  General processes for recovering metals or metallic compounds from spent catalysts (for recovering specific metals C22B11/00 - C22B61/00) · CPC title

• Y02P10/20

  Recycling · CPC title