Calcium lanthanoid sulfide powders, methods of making, and ceramic bodies formed therefrom

Patent metadata

Field	Value
Publication number	US-9809501-B2
Application number	US-69107510-A
Country	US
Kind code	B2
Filing date	Jan 21, 2010
Priority date	Jan 21, 2010
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A method of preparing a fine powder of calcium lanthanoid sulfide is disclosed. The method includes spraying soluble calcium and lanthanoid salts into at least one precipitating solution to form a precipitate comprising insoluble calcium and lanthanoid salts, optionally, oxidizing the precipitate comprising insoluble calcium and lanthanoid salts, and sulfurizing the optionally oxidized precipitate to form a fine powder of calcium lanthanoid sulfide. An alternative method for forming the powder is by flame pyrolysis. The calcium lanthanoid sulfide powder produced by either method can have an impurity concentration of less than 100 ppm, a carbon concentration of less than 200 ppm, a BET surface area of at least 50 m 2 /g, and an average particle size of less than 100 nm.

First claim

The invention claimed is:

1. A method of preparing a fine powder of calcium lanthanoid sulfide comprising:
forming a precipitate comprising insoluble calcium and lanthanoid salts by spraying soluble calcium and lanthanoid salts into at least one bath comprising a precipitating solution while simultaneously applying ultrasonic energy to each bath;
oxidizing the precipitate, wherein the oxidizing of the precipitate comprising insoluble soluble calcium and lanthanoid salts is performed at a temperature of less than 900° C.; and
sulfurizing the oxidized precipitate to form a fine powder of calcium lanthanoid sulfide.

2. The method of claim 1 , further comprising washing the precipitate comprising insoluble calcium and lanthanoid salts with an aprotic solvent.

3. The method of claim 2 , wherein the aprotic solvent comprises at least one of acetone, dioxane, and tetrahydrofuran.

4. The method of claim 1 , wherein the oxidized precipitate is milled to reduce agglomeration of particles.

5. The method of claim 1 , wherein the spraying includes atomizing soluble calcium and lanthanoid salts in solution to form fine droplets of 1-20 μm average size in diameter.

6. The method of claim 1 , wherein the soluble calcium salt is sprayed into a first precipitating solution to form a precipitate comprising an insoluble calcium salt and the soluble lanthanoid salt is sprayed into a second precipitating solution to form a precipitate comprising an insoluble calcium salt.

7. The method of claim 6 , further comprising milling the insoluble calcium salt and insoluble lanthanoid salt together.

8. The method of claim 1 , wherein the precipitating solution includes at least one of an oxalate, oxalic acid, a carbonate, and a bicarbonate.

9. The method of claim 1 , wherein the lanthanoid is selected from lanthanum, gadolinium, and combinations thereof.

10. The method of claim 1 , wherein the fine powder comprises at least one of:
an impurity concentration of less than 100 ppm;
a carbon concentration of less than 200 ppm;
a BET surface area of at least 50 m 2 /g; and
an average particle size of less than 100 nm.

11. A calcium lanthanoid sulfide powder formed by the method of claim 1 .

12. The calcium lanthanoid sulfide powder of claim 11 , comprising at least one of:
an impurity concentration of less than 100 ppm;
a carbon concentration of less than 200 ppm;
a BET surface area of at least 50 m 2 /g; and
an average particle size of less than 100 nm.

13. A method of preparing a fine powder of calcium lanthanoid sulfide comprising:
forming a precipitate comprising insoluble calcium and lanthanoid salts by spraying soluble calcium and lanthanoid salts into at least one bath comprising a precipitating solution while simultaneously applying ultrasonic energy to each bath;
oxidizing the precipitate; and
sulfurizing the oxidized precipitate to form a fine powder of calcium lanthanoid sulfide, wherein the sulfurizing includes heating the oxidized precipitate in the presence of at least one of hydrogen sulfide and carbon disulfide.

14. The method of claim 13 , further comprising washing the precipitate comprising insoluble calcium and lanthanoid salts with an aprotic solvent.

15. The method of claim 13 , wherein the spraying includes atomizing soluble calcium and lanthanoid salts in solution to form fine droplets of 1-20 μm average size in diameter.

16. The method of claim 13 , wherein the soluble calcium salt is sprayed into a first precipitating solution to form a precipitate comprising an insoluble calcium salt and the soluble lanthanoid salt is sprayed into a second precipitating solution to form a precipitate comprising an insoluble calcium salt.

17. The method of claim 13 , wherein the precipitating solution includes at least one of an oxalate, oxalic acid, a carbonate, and a bicarbonate.

18. The method of claim 13 , wherein the lanthanoid is selected from lanthanum, gadolinium, and combinations thereof.

19. A calcium lanthanoid sulfide powder formed by the method of claim 13 .

20. The calcium lanthanoid sulfide powder of claim 19 , comprising at least one of:
an impurity concentration of less than 100 ppm;
a carbon concentration of less than 200 ppm;
a BET surface area of at least 50 m 2 /g; and
an average particle size of less than 100 nm.

Assignees

• Bayya Shyam S
• Kim Woohong
• Sanghera Jasbinder S
• Villalobos Guillermo R
• Aggarwal Ishwar D
• Us Navy

Inventors

• Bayya Shyam S
• Kim Woohong
• Sanghera Jasbinder S
• Villalobos Guillermo R
• Aggarwal Ishwar D

Classifications

• C01F17/38

  sulfur being the only anion, e.g. CaLa2S4 · CPC title

• C01P2006/80

  Compositional purity · CPC title

• C04B2235/9661

  Colour · CPC title

• C01P2006/12

  Surface area · CPC title

• C04B2235/72

  Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics · CPC title