Electrolytic capacitor containing a valve metal sourced from a conflict-free mine site and a method of forming thereof

• US 10,535,471 B2
• Filed: 09/21/2017
• Issued: 01/14/2020
• Est. Priority Date: 09/22/2016
• Status: Active Grant

• Current Assignee: Kyocera AVX Components Corporation (Kyocera Corporation)
• Original Assignee: AVX Corporation (Kyocera Corporation)
• Inventors: Millman, William A., Loun, Jan
• Primary Examiner(s): Thomas, Eric W
• Assistant Examiner(s): Ramaswamy, Arun
• Application Number:
  US15/710,903
• Publication Number:
  US 20180082794A1
• Time in Patent Office: 845 Days
• Field of Search: 361523, 361528, 361529, 702 2, 29 2503
• CPC Class Codes: G01N 33/24 Earth materials G01N33/42 takes precedence
• CPC Class Codes: H01G 9/0029 Processes of manufacture
• CPC Class Codes: H01G 9/0032 formation of the dielectric layer
• CPC Class Codes: H01G 9/0036 Formation of the solid electrolyte layer
• CPC Class Codes: H01G 9/025 Solid electrolytes H01G11/54 takes precedence
• CPC Class Codes: H01G 9/028 Organic semiconducting electrolytes, e.g. TCNQ
• CPC Class Codes: H01G 9/035 Liquid electrolytes, e.g. impregnating materials H01G11/54 takes precedence
• CPC Class Codes: H01G 9/042 characterised by the material H01G11/22 takes precedence
• CPC Class Codes: H01G 9/048 characterised by their structure H01G11/22 takes precedence
• CPC Class Codes: H01G 9/052 Sintered electrodes
• CPC Class Codes: H01G 9/0525 Powder therefor
• CPC Class Codes: H01G 9/07 Dielectric layers
• CPC Class Codes: H01G 9/145 Liquid electrolytic capacitors H01G11/00 takes precedence
• CPC Class Codes: H01G 9/15 Solid electrolytic capacitors H01G11/00 takes precedence

Abstract

A method of forming an electrolytic capacitor is provided. The method includes obtaining an unverified mineral sample from a mine site, analyzing the unverified mineral sample via quantitative mineralogical analysis and comparing data collected during the quantitative mineralogical analysis for the unverified mineral sample to data in a database that corresponds to quantitative mineralogical analysis collected for verified mineral samples sourced from one or more mine sites from a conflict-free geographic region to determine if the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region. If it is determined that the unverified mineral sample is sourced from one or more mine sites from the conflict-free geographic region, the method then involves converting the unverified mineral sample into an anode for the electrolytic capacitor. The electrolytic capacitor can be a solid electrolytic capacitor or a wet electrolytic capacitor.

Claims

1. A method of forming an electrolytic capacitor, the method comprising:

obtaining an unverified mineral sample from a mine site;

analyzing the unverified mineral sample via quantitative mineralogical analysis and comparing data collected during the quantitative mineralogical analysis for the unverified mineral sample to data in a database that corresponds to quantitative mineralogical analysis collected for verified mineral samples sourced from one or more mine sites from a conflict-free geographic region to determine if the unverified mineral sample is sourced from the one or more mine sites from the conflict-free geographic region, wherein analyzing the unverified mineral sample via quantitative mineralogical analysis comprises performing automated mineralogy testing on the unverified mineral sample and identifying grains for additional testing based on data obtained during automated mineralogy testing, wherein from about 25 grains to about 125 grains are identified for additional testing; and

if it is determined that the unverified mineral sample is sourced from the one or more mine sites from the conflict-free geographic region, converting the unverified mineral sample into an anode for the electrolytic capacitor.

2. The method of claim 1, further comprising rejecting the unverified mineral sample if it cannot be determined that the mineral sample is sourced from the one or more mine sites from the conflict-free geographic region.

3. The method of claim 1, wherein the conflict-free geographic region excludes the Democratic Republic of Congo, Angola, Burundi, Central African Republic, Congo Republic, Rwanda, Sudan, Tanzania, Uganda, and Zambia.

5. The method of claim 1, wherein analyzing the unverified mineral sample via quantitative mineralogical analysis comprises polishing the unverified mineral sample to expose grain interiors present in the unverified mineral sample.

6. The method of claim 1, further comprising performing electron micro probe analysis (EMPA) on the identified grains.

7. The method of claim 6, further comprising performing laser ablation inductively coupled plasma spectrometry (LA-ICP-MS) on the identified grains.

8. The method of claim 7, wherein it is determined that the unverified mineral sample is sourced from the one or mine sites from the conflict-free geographic region if data collected during the automated mineralogy testing, LA-ICP-MS, and/or EMPA for the unverified mineral sample substantially matches data collected during the automated mineralogy testing, LA-ICP-MS, and/or EMPA for one of the verified mineral samples sourced from the one or mine sites from the conflict-free geographic region.

9. The method of claim 1, wherein the unverified mineral sample comprises a valve metal, wherein the valve metal comprises tantalum, niobium, or a combination thereof.

10. The method of claim 9, wherein converting the unverified mineral sample into the anode for the electrolytic capacitor comprises:

separating the valve metal from the unverified mineral sample;

forming the valve metal into a valve metal powder;

pressing the valve metal powder to form the anode; and

sintering the anode.

11. The method of claim 10, further comprising forming a dielectric layer over the sintered anode.

12. The method of claim 1, wherein the electrolytic capacitor is a solid electrolytic capacitor.

13. The method of claim 12, wherein the solid electrolytic capacitor includes a solid electrolyte.

14. The method of claim 13, wherein solid electrolyte includes a conductive polymer or manganese dioxide.

15. The method of claim 1, wherein the electrolytic capacitor is a wet electrolytic capacitor.

16. The method of claim 15, wherein the wet electrolytic capacitor includes a cathode comprising a metal substrate coated with a conductive coating and a fluidic working electrolyte in communication with the anode and the cathode.

17. An electrolytic capacitor formed according to the method of claim 1.

4. The method of 1, further comprising performing one or more chemical assays on the unverified mineral sample, wherein the one or more chemical assays determines the amount of uranium, thorium, or tantalum present in the unverified mineral sample.