A kind of preparation method of pseudo-boehmite

Abstract

The invention discloses a preparation method of pseudo-boehmite. The method comprises the following steps: (1) bottom water is added into a pressure zone and a reaction zone of a reactor, a stabilizing agent is added into bottom water in the reaction zone, and gelling temperature is adjusted; (2) an aqueous solution of alkaline aluminate is added into the reactor from the upper part of the reaction zone, at the same time CO2 permeates from a semi-permeable membrane at the lower part of the reaction zone into the reaction zone, CO2 and the aqueous solution of alkaline aluminate are neutralized for carrying out a sol forming reaction, when the concentration of the aluminium hydroxide sol to be generated reaches 5-15g / 100ml, a pressure pump pumps water in the pressure zone into a reaction zone through a semi-permeable membrane, the sol concentration is kept in a concentration range, and the reaction is continuously carried out for a period of time; (3) after the reaction ends, ultrasonic vibration at the bottom is started, pH value of the reactor is adjusted, temperature is rapidly raised to a aging temperature, after aging, filtering, washing and drying are carried out, the pseudo-boehmite is obtained. The pseudo-boehmite is prepared by a semi-permeable membrane penetration mode, and the obtained pseudo-boehmite has the advantages of high purity, high crystallization degree, and uniform particle size distribution; and the pseudo-boehmite is suitable for preparing carriers of hydrotreatment catalysts and catalysts for wax oil, heavy oil and other inferior raw materials.

Description

technical field [0001] The invention relates to a method for preparing pseudo-boehmite, in particular to a method for preparing pseudo-boehmite with high purity and high crystallinity. Background technique [0002] At present, industrial aluminum hydroxide is mainly prepared by industrial routes such as acid dissolution and reprecipitation with ammonia water or other alkalis. This method has complex production process, requires anti-corrosion equipment and consumes expensive chemical raw materials. In China, the cost of hydrolysis of organoaluminum compounds produced by other industrial by-products is much lower. Moreover, the pseudo-boehmite currently prepared in China has the disadvantages of high impurity content, uneven particle size distribution, low crystallinity, and unsatisfactory pore structure. [0003] CN85100161A discloses a carbonation process (CO 2 method) to produce pseudo-boehmite, which uses the intermediate product-industrial sodium aluminate solution as...

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Problems solved by technology

[0005] At present, pseudo-boehmite is mostly prepared by neutralization and gelation. During the preparation process, the concentration of pseudo-boehmite sol is constantly increasing, which can easily cause the sol to quickly aggregate into a gel, resulting in the formation of amorphous pseudo-boehmite. Formation, and its particle size distribution is uneven, low crystallinity, high impurity content and other shortcomings

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