Preparation method of high-purity aluminum oxide for growth of sapphire monocrystalline

Abstract

The invention relates to a preparation method of a high-purity aluminum oxide, in particular to a preparation method of high-purity aluminum oxide for growth of sapphire monocrystalline. The method includes: grinding high-purity ammonium aluminum sulfate to obtain ammonium aluminum sulfate precursor powder uniform in particle size, heating according to different temperature sections, pyrolyzing to remove by-products, and sintering to obtain high-purity aluminum oxide uniform in particle size. According to the method, the high-purity ammonium aluminum sulfate is ground to obtain ammonium aluminum sulfate raw material powder, dewatering is completed at a low temperature, ammonia gas is removed at a moderate temperature, the temperature is further increased to enable the raw materials to be decomposed completely, and the high-purity aluminum oxide is obtained by means of sintering at 1000-1050 DEG C. The aluminum oxide prepared by the method is low in pyrolysis temperature and high in purity, tail gases such as SO3 and NH3 can be recovered directly, and consequently environment pollution is reduced, by-products are used reasonably, and production cost is reduced.

Description

technical field [0001] The invention relates to a preparation method of high-purity alumina, in particular to a preparation method of high-purity alumina used for growing sapphire single crystal. Background technique [0002] High-purity alumina has excellent properties such as high strength, high hardness, wear resistance, high temperature resistance, and chemical corrosion resistance. Important materials for devices, etc. As we all know, the current LED chips mostly use sapphire single crystal as the substrate, and high-performance chips have strict requirements on the substrate. High quality and purity. Alumina is used as a raw material for preparing sapphire single crystals, and its purity has a direct impact on the crystal quality of sapphire single crystals. There are also many ways to prepare high-purity alumina. For example, the improved Bayer method was adopted in the early stage, and ammonium metaaluminate was used as raw material to obtain high-purity aluminum ...

AI Technical Summary

Problems solved by technology

However, the above methods all have problems such as complex operation process and many production links involved in the process.

Another commonly used method is the high-temperature pyrolysis of ammonium aluminum sulfate. This method does not require the participation of other raw materials, and alumina powder can be obtained only through simple pyrolysis, but there are high sintering temperatures and the presence of SO 3 by-products etc.