Modified gamma-Al2O3 and processing method thereof

Abstract

The invention discloses a method for processing modified gamma-Al2O3. Sodium aluminate, a dispersing agent, a modifier and pseudo-boehmite washing liquor are mixed, and a mixture A is obtained; the mixture A is sequentially subjected to sedimentation, ageing and roasting, and the modified gamma-Al2O3 product is obtained, wherein roasting is carried out for 2 h to 40 h at the temperature of 90 DEGC to 170 DEG C, and then roasting is carried out for 1 h to 4 h at the temperature of 600 DEG C to 900 DEG C. According to the process, industrial aluminum hydroxide is adopted as the raw material, steam heating and high alkali concentration dissolving out are adopted, a sodium aluminate solution is generated, diluting, filtering and purifying are carried out, the sodium aluminate solution and salpeter solution to which a modifying agent is added are subjected to coprecipitation, and pseudo-boehmite is obtained. The pseudo-boehmite is subjected to ageing, washing, adhesive water and crystal water high-temperature removal and smashing and levigating, and then qualified modified aluminum oxide is obtained. The process raw material cost is low, the production process is environmentally friendly, the product is good in high temperature resisting performance, sewage generated in the project can be adopted as water for an aluminum oxide producing system of an aluminum oxide plant, no waste water is drained out, and the advantages are more obvious.

Description

technical field [0001] The invention relates to the technical field of alumina processing, in particular to modified γ-Al 2 o 3 and its processing method. Background technique [0002] Modified γ-Al 2 o 3 It can be used as a catalyst carrier for automobile exhaust purification, and it is one of the most widely used catalyst powders. However, γ-Al 2 o 3 The problem of thermal stability of γ-Al is still perplexing people for a long time, especially in the presence of high temperature and water vapor, metastable γ-Al 2 o 3 It is prone to phase change and sintering, and develops into a thermodynamically stable α phase and large particles, which greatly reduces the specific surface area and leads to the deactivation of the supported catalyst. Therefore for γ-Al 2 o 3 Modification is carried out to maintain its low-temperature activity, so as to ensure that the automobile exhaust gas purification catalyst can have good catalytic reaction activity for a long time. [0003...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to provide a modified γ-Al 2 o 3 And its processing method, to solve the existing technology is mainly to use large specific table, low sodium, low iron, low silicon pseudo-boehmite as raw material, through the modifier to prepare new catalyst powder materials, there is a high cost of raw materials, The ammonia water used in production has a great impact on the environment, and the product has poor high temperature resistance and other obvious shortcomings.

Images