Process for rapid production of colloidal particles

• US 5,704,556 A
• Filed: 09/16/1996
• Issued: 01/06/1998
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Devmar Group Limited
• Original Assignee: Devmar Group Limited
• Inventors: McLaughlin, John R.
• Primary Examiner(s): HUSAR, JOHN
• Application Number:
  US08/716,561
• Time in Patent Office: 477 Days
• Field of Search: 241/21, 241/26, 241/27
• US Class Current: 241/21
• CPC Class Codes: B02C 17/16 Mills in which a fixed container houses stirring means tumbling the charge
• CPC Class Codes: B02C 17/20 Disintegrating members
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/776 Ceramic powder or flake
• CPC Class Codes: Y10S 977/90 having step or means utilizing mechanical or thermal property, e.g. pressure, heat

Abstract

In a process for rapidly producing colloidal particles a feedstock of particles less than a micron in size is provided to a stirred media mill, along with ceramic beads less than 100 microns in size. The mill is filled to a volume in excess of 90%, and operated at tip speeds in excess of 20 meters/second with a residence time less than about two minutes; thereby producing particles having an average particle size less than about 0.1 micron from the feedstock.

Claims

1. A process for rapidly producing colloidal particles, the process comprising

(a) providing a feedstock slurry having an average particle size less than one micron to a stirred media mill, the slurry including from about 5 to 10 percent by weight dispersant;

and a total solids of less than about 50 percent by weight in a low viscosity fluid;

(b) providing ceramic beads less than 100 microns in diameter in the mill;

(c) filling the mill to a volume in excess of 90%;

(d) operating the mill at tip speeds at least 20 meters/sec; and

(e) limiting the residence time to less than about two minutes;

.

thereby producing particles having an average particle size less than about 0.1 micron from the feedstock.

2. A process according to claim 1 wherein the ceramic beads are selected from zircon, glass and yttrium toughened zirconium oxide.

3. A process according to claim 1 wherein the size of the diameter of the ceramic beads is no more than about one hundred times the average particle size of the feedstock particles.

4. A process according to claim 1 wherein the energy consumed by the mill is less than about 100 kilowatt-hour per ton of feedstock.

5. A process for rapidly producing colloidal particles, the process comprising

(a) providing a feedstock slurry having an average particle size less than one micron to a stirred media mill, the slurry including from about 5 to 10 percent by weight dispersant;

and a total solids of less than about 50 percent by weight in a low viscosity fluid;

(b) providing yttrium toughened zirconium oxide ceramic beads less than 100 microns in diameter in the mill;

(c) filling the mill to a volume in excess of 90%;

(d) operating the mill at tip speeds at least 20 meters/sec;

(e) limiting the residence time to less than about two minutes; and

(f) providing less than about 100 kilowatt-hour of energy to drive the mill per ton of feedstock;

thereby producing particles having an average particle size less than about 0.1 micron from the feedstock.