A method for preparing flaky alumina based on liquid metal

Abstract

The invention provides a method for preparing flaky alumina based on liquid metal, comprising the following steps: (1) taking liquid metal and placing the liquid metal in a crucible; adding molten salt and aluminum-containing compound mixed into the crucible (2) the crucible of the mixture of liquid metal, molten salt and aluminum-containing compound in step (1) is placed in a drying oven, heated to 100-150 ° C, kept for 0.5-3h, and moisture is removed therein; (3 ) and then place the crucible containing the mixture of liquid metal, molten salt and aluminum-containing compound in a heating furnace and heat it to 700-1500°C, keep it warm for 1-5h, and cool to 1-30°C above the melting point of the liquid metal , take out the solid matter, grind and wash with water to obtain flaky alumina. The method of the invention adopts aluminum-containing liquid metal as a medium, and reacts molten salt and alumina on the liquid metal medium to form flaky alumina, which is easy to take out and reduces the introduction of impurities.

Description

technical field [0001] The invention belongs to the technical field of alumina preparation, and in particular relates to a method for preparing sheet alumina based on liquid metal. Background technique [0002] Alumina is a commonly used material for making refractories because of its high hardness and high melting point. 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 micro-powder and nano-powder. Flake alumina is mainly γ-Al in the 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 be changed from γ-β-α-Al 2 O 3 In turn, among the three crystal forms, the most stable is α-Al 2 O 3 , it is the only crystal form that can exist stably at any temperature below the...

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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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