Gallium-containing pseudoboehmite, gallium oxide-alumina composite, and method for producing the same

Abstract

This invention relates to a gallium-containing pseudoboehmite and a gallium oxide-alumina composite. The gallium-containing pseudoboehmite, elementally, contains 0.05 wt%–8.5 wt% gallium and 30.0 wt%–45.0 wt% aluminum. XRD characterization shows diffraction peaks at 2θ angles of 13.1±1°, 27.8±1°, 38.4±1°, 49.3±1°, and 64.7±1°. The preparation method of the gallium-containing pseudoboehmite includes the steps of preparing a gallium-aluminum alloy solution, reacting the gallium-aluminum alloy solution with hot water, and separating the gallium-containing pseudoboehmite. In the gallium oxide-alumina composite, the gallium content, based on oxides, is 0.1 wt%–12.0 wt%, the alumina to gallium oxide mass ratio is 7–1000, the pore volume is 0.35–1.20 mL / g, and the specific surface area is 180–500 m². 2 / g, with a most probable pore size of 4.0-10.0 nm. The gallium-containing pseudoboehmite and gallium oxide-alumina composite obtained by this invention are almost free of impurity elements, have large pore volume and specific surface area, and do not generate wastewater discharge during the preparation process, making the operation simple.

Claims

1. A gallium-containing pseudoboehmite, wherein, The gallium content is 0.15wt%-7.0wt% and the aluminum content is 30.0wt%-45.0wt% by elemental analysis. XRD characterization shows diffraction peaks at 2θ angles of 13.1±1°, 27.8±1°, 38.4±1°, 49.3±1°, and 64.7±1°. The gallium-containing pseudoboehmite contains virtually no elements other than gallium, aluminum, hydrogen, and oxygen.

2. The gallium-containing pseudoboehmite according to claim 1, wherein, The method for preparing gallium-containing pseudoboehmite includes the following steps: (1) Prepare a gallium-aluminum alloy solution under a protective atmosphere; (2) Add the gallium-aluminum alloy solution to hot water, and let it stand after the reaction is complete. The upper layer of the reaction system is a suspension containing gallium-containing boehmite; the temperature of the hot water is not lower than 60°C. (3) Separate the upper suspension in step (2), and dry the obtained solid to obtain gallium-containing pseudoboehmite; the drying conditions include: drying temperature of 100-150℃ and drying time of 4-12 hours.

3. The gallium-containing pseudoboehmite according to claim 2, wherein the protective atmosphere is a gaseous atmosphere that does not react with gallium and aluminum, and the gas is selected from one or more of nitrogen or inert gases.

4. The gallium-containing pseudoboehmite according to claim 2, wherein the gallium-aluminum alloy solution contains 70% to 99% gallium by mass and 1% to 30% aluminum by mass.

5. According to claim 2, the mass ratio of hot water to gallium-aluminum alloy in step (2) is 3:1 to 20:

1.

6. According to claim 5, the mass ratio of hot water to gallium-aluminum alloy in step (2) is 4:1 to 10:

1.

7. The gallium-containing pseudoboehmite according to claim 3, wherein the temperature of the hot water in step (2) is 65℃-100℃.

8. The gallium-containing pseudoboehmite according to claim 3, wherein, The method of adding gallium-aluminum alloy to hot water in step (1) is to add it drop by drop, and the addition is completed in 0.2-10 minutes.

9. The gallium-containing pseudoboehmite according to claim 3, wherein, The gallium-aluminum alloy is added to hot water under stirring conditions, with a stirring speed of 100-1000 rpm.

10. The gallium-containing pseudoboehmite according to claim 3, wherein the method for separating the upper suspension in step (2) in step (3) is centrifugation, filtration or vacuum filtration.

11. According to claim 10, in step (3), after separation, deionized water is used for one or more washing processes.

12. A gallium oxide-aluminum oxide composite, wherein the gallium content (based on oxides) is 0.1 wt%-12.0 wt%, the mass ratio of alumina to gallium oxide is 7-1000, the pore volume is 0.35-1.20 mL / g, and the specific surface area is 180-500 m². 2 / g, with a most probable pore size of 4.0-10.0 nm; the gallium oxide-aluminum oxide composite is essentially free of elements other than aluminum, gallium, hydrogen and oxygen.

13. The gallium oxide-alumina composite according to claim 12, wherein the gallium content, based on oxides, is 0.5 wt%-10.0 wt%; the mass ratio of alumina to gallium oxide is 9-200; the pore volume is 0.45-1.00 mL / g; and the specific surface area is 200-450 m². 2 / g; most probable pore size is 4.5-9.0 nm.

14. The gallium oxide-alumina composite according to claim 12, wherein the gallium content, based on oxides, is 1.0 wt%-8.0 wt%; the mass ratio of alumina to gallium oxide is 11.5-99; the pore volume is 0.50-0.90 mL / g; and the specific surface area is 200-400 m². 2 / g; most probable pore size is 5.0-8.5 nm.

15. A method for preparing the gallium oxide-alumina composite of claim 12, comprising calcining the gallium-containing pseudoboehmite of any one of claims 1-9, wherein the calcination conditions include: The roasting temperature is 500-800℃, and the roasting time is 0.5-12 hours.

16. The preparation method according to claim 15, wherein, The roasting conditions include: a roasting temperature of 550-750℃ and a roasting time of 1-10 hours.

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