Method for preparing nano magnalium hydrotalcite and equipment thereof

Abstract

The invention relates to a method for preparing nanometer magnalium hydrotalcite and equipment thereof. The method comprises the following reaction steps: a magnalium mixed salt solution is prepared; an ammonium hydrogen carbonate solution is prepared; two mixed solutions are simultaenosuly added into a static mixer and have chemical reaction to generate magnalium hydrotalcite microcrystal; and the magnalium hydrotalcite microcrystal grows through a curing reactor to obtain a nanometer magnalium hydrotalcite product. The method uses ammonium bicarbonate to replace the prior sodium hydroxide or urea as a precipitator, adopts the static mixer for liquid-liquid two-phase coprecipitation reaction and carries out the coprecipitation reaction of the magnalium salt solution and the ammonium hydrogen carbonate solution so as to separate the reaction and the ripening and control the generation and growth conditions of the microcrystal respectively. The method and the equipment overcome the disadvantages thatcrystal grains are too small and granules are uneven; and the whole dimension of the crystal grains and the dimension of the granules are difficult to control in the prior art, thereby preparing a magnalium hydrotalcite powder body with even distribution of nanometer dimension and granularity. The method can also reduce the production cost of the magnalium hydrotalcite and simultaneously simplify the production flow.

Description

technical field [0001] The invention relates to a method and equipment for preparing nano-magnesium-aluminum hydrotalcite, in particular to a method for preparing nano-hydrotalcite by using ammonium bicarbonate as a precipitating agent and equipment for implementing the method. Background technique [0002] Hydrotalcite (HT for short), Mg 6 Al 2 (OH) 16 CO 3 4H 2 O, whose structure is similar to brucite Mg(OH) 2 , by MgO 6 Octahedrons share edges to form a layered structure, and the Mg on the layer 2+ Can be Al within a certain range 3+ Isomorphic substitution, such that Mg 2+ 、Al 3+ , OH - layer has a positive charge. Interlayer with exchangeable anion CO 3 2- Balanced with the positive charges on the laminates, the entire structure is electrically neutral. In addition, some water molecules co-exist between the hydroxide layers, which can be removed without destroying the layered structure. [0003] Under certain conditions, the Mg in the hydrotalcite composi...

AI Technical Summary

Problems solved by technology

Since the mixing of salt and alkali in the reactor is achieved by stirring, the mixing is not sufficient, the reaction interface is small, there is a concentration gradient, and the reaction speed and diffusion speed are slow, so new precipitated particles are formed on the first precipitated particles, and new and old particles Simultaneous existence and growth at the same time, resulting in extremely uneven particle size distribution

The particle size and uniform dispersion performance of synthetic materials are greatly affected

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