Method and apparatus for converting metal ion in solution to the metal state

• US 20040226407A1
• Filed: 05/14/2004
• Published: 11/18/2004
• Est. Priority Date: 05/14/2003
• Status: Abandoned Application

• Current Assignee: David Ericson
• Original Assignee: David Ericson
• Inventors: Ericson, David
• Application Number:
  US10/845,182
• Publication Number:
  US 20040226407A1
• Time in Patent Office: Days
• US Class Current: 75/711
• CPC Class Codes: C22B 3/42 by ion-exchange extraction
• CPC Class Codes: C23C 18/1617 Purification and regeneration of coating baths
• CPC Class Codes: C23C 18/405 Formaldehyde
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A metal ion conversion process, where the chelation component of a matrix of chemicals forms an electroless solution for converting metal ion to the metal state. The chelated metal complex is repeatedly circulated through a filter. The solution matrix is cycled back continuously through the filter and the metal ion is titrated back (colorimetrically) from various processes containing excess metal ion. The reactants required to complete said ‘electroless’ reaction are repleted continuously as said solution matrix cycles through said filter. The process is repeated continuously until the metal ion is exhausted or to the limit of the filter volume. Any residual metal ion present may then be polished down to acceptable limits by the same means and then resulting solution is discharged or used for further neutralization cycles.

Claims

1. A method for converting metal ions in solution to the metal state comprising the steps of:

(a) providing an initial quantity of reaction solution containing a matrix of chemicals, the reaction solution comprising an electroless solution for said ions including a chelating agent for the ions;

(b) providing a chamber for containing the reaction solution;

(c) delivering the reaction solution to the chamber;

(d) feeding the reaction solution in the chamber through a filter constructed of a polymer treated with a catalyst at a pre-determined filter exposure rate for reducing ions to the metal ground state;

(e) repeating steps (c) to (d) one or more times until ion concentration in the reaction solution is less than or equal to a minimal concentration limit.

2. The method of claim 1, wherein the step of feeding the reaction solution through a filter comprises the subsequent step of replenishing hydroxyl ions and reducer.

3. The method of claim 1, wherein the step of delivering the reaction solution to the chamber comprises the further step of adding an aliquot of aqueous ions to the reaction solution if:

the quantity of reaction solution is less than a pre-determined volume; and

the ion concentration is greater than or equal to a pre-determined additive point.

4. The method of claim 3, wherein the reaction solution is polished if the quantity of reaction solution is equal or greater than the pre-determined volume.

5. The method of claim 1, wherein the ion concentration is determined by an optical element.

6. The method of claim 5, wherein the optical element comprises:

a light emitter chosen from the group consisting of a light emitting diode and a laser;

a wave guide for directing light generated by the light emitter into the reaction solution;

a photo diode for receiving light from the wave guide through the reaction solution; and

a computer with software to interpret light intensity reading from the photo diode as an indication of ion concentration.

7. The method of claim 1, wherein the ions are copper ions;

and the electroless solution comprises EDTA as the chelating agent, and formaldehyde as a reducer.

8. The method of claim 1, wherein the initial quantity of electroless solution is derived by steps which include adding a blank solution to aqueous metal ions thereby chelating all metal ions in the electroless solution.

9. The method of claim 1, further comprising the step of rinsing the metallized copper to remove the residuals salts and EDTA carried forward.

10. The method of claim 1, wherein the catalyst is palladium.

11. The method of claim 1, wherein the filter is constructed of reticulated foam.

12. The method of claim 1, wherein the pre-determined filter exposure rate is above approximately 300 square feet per liter per minute.

13. The method of claim 1, further comprising the step of storing the metal depleted reaction solution for future use as a blank solution.

14. The method of claim 1, wherein the reaction solution is at a temperature between about 90 degrees and 120 degrees Fahrenheit when fed through the filter.

15. An apparatus for converting copper ions in a reaction solution, the reaction solution comprising an electroless solution for said ions including a chelating agent for the ions, to the metal state comprising:

(f) a chamber for containing the reaction solution;

(g) a filter in fluid communication with the chamber providing a catalytic surface for metallic copper deposition from the reaction solution when fed through the filter, the filter surface being a polymer treated with a catalyst; and

(h) a heating element for monitoring and controlling the temperature of the reaction solution when fed through the filter;

(i) a pump element for circulating the reaction solution after flow through the filter to the chamber.

16. The apparatus of claim 15, further comprising elements for replenishing hydroxyl ions reducer, and adding more reaction solution.

17. The apparatus of claim 16, wherein the reaction solution is polished if the quantity of reaction solution is equal or greater than a pre-determined volume.

18. The apparatus of claim 15, further comprising an optical element for determining the ion concentration in the reaction solution, the optical element comprising:

a light emitter chosen from the group consisting of a light emitting diode and a laser;

a wave guide for directing light generated by the light emitter into the reaction solution;

a photo diode for receiving light from the wave guide through the reaction solution; and

a computer with software to interpret light intensity reading from the photo diode as an indication of ion concentration.

19. The apparatus of claim 15, wherein the ions are copper ions;

and the electroless solution comprises EDTA as the chelating agent, and formaldehyde as a reducer.

20. The apparatus of claim 15, wherein the initial electroless solution is derived by steps which include adding a blank solution to aqueous metal ions thereby chelating all metal ions in the electroless solution.

21. The apparatus of claim 15, further comprising an element for rinsing the metallized copper to remove the residuals salts and EDTA carried forward.

22. The apparatus of claim 15, wherein the catalyst is palladium.

23. The apparatus of claim 15, wherein the filter is constructed of reticulated foam.

24. The apparatus of claim 15, wherein the pre-determined filter exposure rate is above approximately 300 square feet per liter per minute.

25. The apparatus of claim 15, wherein the heating element maintains the temperature of the reaction solution when fed through the filter between about 90 degrees and 120 degrees Fahrenheit.

26. A method for converting metal ions in solution to the metal state comprising the steps of:

(j) providing an initial quantity of reaction solution containing a matrix of chemicals, the reaction solution comprising an electroless solution for said ions including a chelating agent for the ions at a temperature between about 90 degrees and 120 degrees Fahrenheit;

(k) providing a chamber for containing the reaction solution;

(l) delivering the reaction solution to the chamber;

(m) feeding the reaction solution in the chamber through a filter constructed of a polymer treated with a catalyst at a pre-determined filter exposure rate for reducing ions to the metal ground state;

(n) repeating steps (c) to (d) one or more times until ion concentration in the reaction solution is less than or equal to a minimal concentration limit.