# US 11,078,124 B2 · Systems and methods for making ceramic powders

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- Number: US 11,078,124 B2
- Document ID: US11078124B2
- Status: Granted
- Kind: B2
- Application number: 16/241,517
- Filed: 2019-01-07
- Published: 2019-05-09
- Granted: 2021-08-03
- Earliest claimed: 2016-07-08
- Assignees: Alcoa USA Corp.
- Applicants: Alcoa USA Corp.
- Inventors: James C. McMillen; Lance M. Sworts; Benjamin D. Mosser; Charles Robert Shanta, III
- Web page: https://patentgrep.com/patent/US11078124B2

## CPC

- B01J 4/007: {provided with moving parts}
- C04B 35/626: Preparing or treating the powders individually or as batches {(pigments for ceramics C09C1/0009); preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B}
- B01J 8/085: {Feeding reactive fluids (for solid material, see B01J8/0015)}
- B01J 8/087: {Heating or cooling the reactor}
- B01J 8/10: moved by stirrers or by rotary drums or rotary receptacles {or endless belts}
- B01J 15/00: Chemical processes in general for reacting gaseous media with non-particulate solids, e.g. sheet material; Apparatus specially adapted therefor (B01J19/08 takes precedence)
- C04B 35/56: based on carbides {or oxycarbides (containing free metal binder C22C29/00)}
- C04B 35/58: based on borides, nitrides, {i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides} or silicides {(containing free binder metal C22C29/00)}
- C04B 35/58021: {based on titanium carbonitrides}
- C04B 35/5805: {based on borides}
- C04B 35/58071: {based on titanium borides}
- C04B 35/6261: {Milling}
- C04B 35/62645: {Thermal treatment of powders or mixtures thereof other than sintering}
- C04B 35/6265: {involving reduction or oxidation}
- C04B 35/65: Reaction sintering of free metal- or free silicon-containing compositions {(C04B35/573, C04B35/591 take precedence)}
- C22C 29/00: Alloys based on carbides, oxides, nitrides, borides, or silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides, sulfides {(C22C26/00 takes precedence)}
- C22C 29/02: based on carbides or carbonitrides
- C22C 29/14: based on borides
- B01J 2208/00168: with heat exchange elements outside the bed of solid particles
- B01J 2208/00495: using insulating materials or refractories
- B01J 2208/0053: Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
- B01J 2208/00557: controlling the residence time inside the reactor vessel
- B01J 2208/00814: the particulate material being provides in prefilled containers
- B01J 2208/0092: Perforated plates
- B01J 2219/182: horizontal
- B01J 2219/185: vertical
- B01J 2219/187: inclined at an angle to the horizontal or to the vertical plane
- B01J 2219/192: polygonal
- B01J 2219/1923: square or square-derived
- B01J 2219/1928: hexagonal
- B01J 2219/1943: cylindrical
- C04B 2235/3232: Titanium oxides or titanates, e.g. rutile or anatase
- C04B 2235/3409: Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
- C04B 2235/422: Carbon
- C04B 2235/48: Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
- C04B 2235/6567: Treatment time
- C04B 2235/74: Physical characteristics
- C04B 2235/95: Products characterised by their size, e.g. microceramics
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C22C: ALLOYS (treatment of alloys C21D, C22F)

## Abstract

Systems and methods for making ceramic powders configured with consistent, tailored characteristics and/or properties are provided herein. In some embodiments a system for making ceramic powders, includes: a reactor body having a reaction chamber and configured with a heat source to provide a hot zone along the reaction chamber; a sweep gas inlet configured to direct a sweep gas into the reaction chamber and a sweep gas outlet configured to direct an exhaust gas from the reaction chamber; a plurality of containers, within the reactor body, configured to retain at least one preform, wherein each container is configured to permit the sweep gas to flow therethrough, wherein the preform is configured to permit the sweep gas to flow there through, such that the precursor mixture is reacted in the hot zone to form a ceramic powder product having uniform properties.

## Claims

### Claim 1

A method for carbothermically producing a ceramic powder, the method comprising:
a) preheating at least one container in a staging zone, wherein the at least one container comprises a preform;
(i) wherein the preform comprises a mixture, wherein the mixture comprises a carbon source and at least one of (a) a metal oxide and (b) boric acid;
(ii) wherein the preform comprises a plurality of granules, wherein the wherein the plurality of granules define an inter-granular porosity of the preform, wherein the inter-granule porosity is from 0.1 to 0.6 area fraction of the preform based on cross section area of the preform, wherein the plurality of granules are internally porous defining an intra-granular porosity, and wherein the intra-granule porosity is configured to occupy not greater than 0.6 area fraction of the preform based on cross section area of the preform;
b) moving the at least one container into a reactor body, wherein the reactor body comprises a reaction zone;
c) carbothermically reacting the preform in the reaction zone thereby producing a ceramic powder, wherein the carbothermically reacting comprises reducing, via the carbon of the preform, at least one of the metal oxide and the boric acid of the preform to form the ceramic powder, wherein the ceramic powder comprises ceramic particles, wherein the ceramic particles are selected from the group consisting of metal carbide particles, metal boride particles, metal nitride particles, and combinations thereof; and
d) moving the at least one container from the reactor body to a receiving zone.

### Claim 2 (depends on 1)

The method of claim 1, comprising flowing, during at least the carbothermically reacting step, a sweep gas into the at least one container.

### Claim 3 (depends on 1)

The method of claim 1, wherein the carbothermically reacting step comprises a reaction time, wherein the reaction time is from 0.5 to 12 hours.

### Claim 4 (depends on 1)

The method of claim 1 comprising, prior to the preheating step, forming the preform from a precursor mixture, wherein the precursor mixture comprises the carbon source and at least one of the metal oxide and the boric acid.

### Claim 5 (depends on 4)

The method of claim 4, wherein the forming comprises at least one of: compacting the precursor mixture, molding the precursor mixture, casting the precursor mixture, and extruding the precursor mixture.

### Claim 6 (depends on 5)

The method of claim 5 comprising, after the forming step, processing the preform, wherein the processing comprises at least one of: dehydrating, curing, and demolding of the preform.

### Claim 7 (depends on 1)

The method of claim 1 comprising, after the carbothermically reacting step, deagglomerating the ceramic powder.

### Claim 8 (depends on 1)

The method of claim 1, wherein the metal oxide is titanium dioxide, and wherein the preform comprises the carbon source and the titanium dioxide.

### Claim 9 (depends on 8)

The method of claim 8, wherein the preform comprises the carbon source, the titanium dioxide, and the boric acid.

### Claim 10 (depends on 9)

The method of claim 9, wherein the preform comprises 10-35 wt. % of the carbon source, 20-50 wt. % of the titanium dioxide, and 30-70 wt. % of the boric acid.

### Claim 11 (depends on 1)

The method of claim 1, wherein the ceramic particles are titanium diboride particles and wherein the ceramic powder is a titanium diboride powder.