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The synthesis of actinide tetraborides including uranium tetraboride (UB4), plutonium tetraboride (PuB4) and thorium tetraboride (ThB4) by a solid-state metathesis reaction are demonstrated. The present method significantly lowers the temperature required to 850 C. As an example, when UCl4 is reacted with an excess of MgB2, at 850 C., crystalline UB4 is formed. Powder X-ray diffraction and ICP-AES data support the reduction of UCl3 as the initial step in the reaction. The UB4 product is purified by washing water and drying.

Inventors: Anthony J. Lupinetti, Eduardo Garcia, Kent D. Abney
Original Assignee: The United States of America as represented by the United States Department of Energy
Primary Examiner: Wayne A. Langel
Attorneys: Jim C. Durkis, Dickson Kehl, Paul A. Gottlieb
Current U.S. Classification: 423/249; 423/250; 423/251; 423/252; 423/254
International Classification: C01F/1500; C01G/4300; C01G/5600

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Referenced by

Citing PatentFiling dateIssue dateOriginal AssigneeTitle
US6967011Dec 2, 2002Nov 22, 2005The United States of America as represented by the United States Department of EnergyMethod for synthesizing extremely high-temperature melting materials

Claims

1. A method for preparing an actinide boride of an actinide element which comprises the steps of heating a mixture of an oxide of said actinide element with an amount of magnesium diboride such that a metathesis reaction occurs, thereby forming said actinide boride.

2. The method of claim 1, wherein the oxide of said actinide element comprises the dioxide thereof.

3. The method of Claim 1, wherein said actinide element is selected from the group consisting of uranium, plutonium, americium, neptunium, and thorium.

4. The method of claim 2, wherein said actinide element comprises uranium and wherein said actinide boride comprises UB4.

5. The method of claim 1, wherein a low-melting flux is added to said mixture.

6. The method of claim 5, wherein said low-melting flux is selected from the group consisting of potassium chloride, lithium chloride, calcium chloride, sodium chloride, and cesium chloride, and mixtures thereof.

7. The method of claim 2, wherein the amount of magnesium diboride comprises 0.5 molar equivalents of magnesium diboride.

8. The method of claim 7, wherein the amount of magnesium diboride comprises 2.5 molar equivalents of magnesium diboride.

9. The method of claim 1, wherein the mixture is heated to 850 C.

10. The method of claim 9, wherein the mixture is heated to between 350 C. and 850 C.

11. The method of claim 2, wherein the mixture of the dioxide of said actinide element with an amount of magnesium diboride is heated under helium.

12. The method of claim 1, further comprising the steps of washing said actinide boride with water.

13. The method of claim 12, further comprising the step of drying said actinide boride.

14. The method of claim 2, wherein the step of heating a mixture of the dioxide of said actinide element with an amount of magnesium diboride is performed in a vessel selected from the group consisting of quartz, tantalum and tungsten.

15. A method for preparing an actinide boride of an actinide element which comprises the step of heating a mixture of an oxyhalide of said actinide element with an amount of magnesium diboride such that a metathesis reaction occurs, thereby forming said actinide boride.

16. The method of claim 15, wherein the halide of said oxyhalide of said actinide element is selected from the group consisting of chlorine, bromine and iodine.

17. The method of claim 15, wherein said actinide element is selected from the group consisting of uranium, plutonium, americium, neptunium and thorium.

18. The method of claim 17, wherein said oxyhalide is selected from the group consisting of UOCl2, ThOCl2, and PuOCl.

19. The method of claim 15, wherein a low-melting flux is added to dissolve said actinide oxyhalide.

20. The method of claim 19, wherein said low-melting flux is selected from the group consisting of potassium chloride, lithium chloride, calcium chloride, sodium chloride, and cesium chloride, and mixtures thereof.

21. The method of claim 15 wherein the mixture is heated to 850 C.

22. The method of claim 21, wherein the mixture is heated to between 350 C. and 850 C.

23. The method of claim 15, wherein the mixture of the oxyhalide of said actinide element with an amount of magnesium diboride is heated under helium.

24. The method of claim 15, further comprising the steps of washing said actinide boride with water.

25. The method of claim 24, further comprising the step of drying said actinide boride.

26. The method of claim 15, wherein the step of heating a mixture of the oxyhalide of said actinide element with an amount of magnesium diboride is performed in a vessel selected from the group consisting of quartz, tantalum and tungsten.

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