Method for preparing flaky aluminum oxide based on liquid metal

Abstract

The invention provides a method for preparing flaky aluminum oxide based on liquid metal. The method comprises the following steps: (1) taking liquid metal, and putting the liquid metal into a crucible; and adding a mixture of uniformly mixed molten salt and an aluminum-containing compound into the crucible; (2) putting the crucible filled with the mixture of the liquid metal, the fused salt and the aluminum-containing compound in the step (1) into a drying box, heating to 100-150 DEG C, and keeping the temperature for 0.5-3 hours to remove moisture in the crucible; and (3) putting the crucible filled with the mixture of the liquid metal, the molten salt and the aluminum-containing compound in the step (2) into a heating furnace, heating to 700-1500 DEG C, preserving heat for 1-5 hours, cooling to 1-30 DEG C above the melting point of the liquid metal, taking out solid matters, grinding and washing to obtain the flaky aluminum oxide. According to the method, the aluminum-containing liquid metal is adopted as a medium, molten salt and aluminum oxide react on the liquid metal medium to generate flaky aluminum oxide, the flaky aluminum oxide is easy to take out, and introduction of impurities is reduced.

Description

technical field [0001] The invention belongs to the technical field of alumina preparation, and in particular relates to a method for preparing flaky alumina based on liquid metal. Background technique [0002] Because of its high hardness and high melting point, alumina is a commonly used material for making refractory materials. Its melting point is 2054°C and its boiling point is as high as 2980°C. As a functional material with excellent performance, flaky alumina inherits all the advantages of ordinary alumina. It has a unique flaky structure, so it has the dual characteristics of micron powder and nanopowder. Flaky alumina is mainly γ-Al in industry 2 o 3 , β-Al 2 o 3 , α-Al 2 o 3 (commonly known as corundum) these three crystal forms; as the temperature increases, its crystal form will change from γ-β-α-Al 2 o 3 Among the three crystal forms, the most stable one is α-Al 2 o 3 , it is the only crystal form that can exist stably at any temperature below the mel...

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Problems solved by technology

[0004] The current preparation methods of flaky alumina include high-temperature sintering method, hydrothermal method, sol-gel method, mechanical method and molten salt method, among which the molten salt method has simple process, uniform composition, good and controllable crystal morphology, Good phase purity has become the main method for the preparation of flaky alumina. In the process of preparing flaky alumina by the molten salt method, high temperature sintering is required, so the crucible generally uses a high temperature resistant ceramic crucible, but in the molten salt method. In the process of alumina, the molten salt is sintered at a high temperature of 1000-1500°C, causing the mixture of molten salt and flaky alumina to stick to the surface of the ceramic crucible, which is inconvenient to take out, and a large amount of sintered mixture will remain on the surface of the crucible

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