Hydrometallurgical process for producing finely divided copper and copper alloy powders

• US 4,778,517 A
• Filed: 05/27/1987
• Issued: 10/18/1988
• Est. Priority Date: 05/27/1987
• Status: Expired due to Fees

• Current Assignee: GTE Products Corporation
• Original Assignee: GTE Products Corporation
• Inventors: Johnson, Walter A., Kopatz, Nelson E.
• Primary Examiner(s): Roy, Upendra
• Application Number:
  US07/054,553
• Time in Patent Office: 510 Days
• Field of Search: 75/0.5 A, 75/0.5 BB, 75/0.5 C, 75/251, 264/10, 264/12, 264/15
• US Class Current: 75/342
• CPC Class Codes: B22F 1/065 Spherical particles

Abstract

A process for producing finely divided spherical copper copper alloy powders comprises forming an aqueous solution of copper and alternatively other metal values forming a reducible metallic material from the solution, reducing the material to metal powder particles, subjecting the metal particles to a high temperature zone to melt a portion of the metal powder particles and to form droplets and cooling the droplets to form an essential spherical metal alloy particles.

Claims

1. A process of forming spherical shaped copper based metallic particles comprising:

(a) forming an aqueous solution containing copper as the major ingredient,

(b) forming a first material having a major portion selected from the group consisting of reducible copper salts, copper oxide and copper hydroxide and mixtures thereof,

(c) reducing said material to form a second material of copper based powder particles by heating said material in a reducing atmosphere at a temperataure above the reducing temperature of the salts but below the melting point of the metals in the particles,

(d) entraining at least a portion of said second material in a carrier gas,

(e) feeding said entrained material and said carrier gas into a high temperature zone and maintaining said second material in said zone for a sufficient time to melt at least about 50% by weight of said second material, and to form droplets therefrom and

(f) cooling said droplets to form a third material of copper based metallic particles having essentially a spherical shape and a majority of said particles having a size less than 20 micrometers.

2. A process according to claim 1 wherein said aqueous solution is an acid solution from the group consisting of hydrochloric, sulfuric and nitric acids solutions.

3. A process according to claim 1 wherein said aqueous solution contains a water soluble acid.

4. A process according to claim 1 wherein said first material from step (b) is subjected to a particle size reduction step prior to the reduction step (c).

5. A process according to claim 1 wherein said high temperature zone is created by a plasma touch.

6. A process according to claim 1 wherein said carrier gas is an inert gas.

7. A process according to claim 1 wherein essentially all of said second material are melted.

8. A process according to claim 1 wherein said solution contains, in addition to copper, at least one additional metal at an alloy forming level and wherein a copper alloy powder particles are formed.

9. A process according to claim 1 wherein the powder particles from step (c) are subjected to a particle size reduction step prior to the entraining step (d).

10. A process according to claim 2 wherein said acid is hydrochloric acid.

11. A process according to claim 2 wherein said first material is formed by evaporation of the water from the solution.

12. A process according to claim 2 wherein said first material is formed by adjusting the pH of the solution to form a solid which is separated from the resulting aqueous phase.