Method for preparing 4A zeolite by kaolin crucible melting method

Abstract

The invention discloses a method for preparing 4A zeolite by a kaolin crucible melting method, the method comprises the following steps: uniformly mixing kaolin, sodium hydroxide and aluminum hydroxide, and placing in a ceramic crucible for calcining and activating treatment to obtain an activated product; crushing the obtained activated product, adding a proper amount of distilled water, and mixing to obtain a gelling product; continuously stirring the gelling product at 30-100 DEG C for 2-8 hours, heating to 80-100 DEG C, and carrying out hydrothermal crystallization for 1-4 hours to obtain a crystallized product; and centrifuging the obtained crystallization product at 6000-8000 r / min for 3-10 minutes, washing with distilled water, and finally drying at 80-120 DEG C for 24 hours to obtain the 4A zeolite product. According to the invention, different grades of kaolin raw materials (especially high silica-alumina ratio and more quartz impurities) are matched according to a 4A zeolite gel formula, single-component 4A zeolite can be generated, the application range of low-quality kaolin is widened, and the method is superior to a traditional high-temperature calcination method and an alkali melting method.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a preparation method of zeolite. Background technique [0002] The composition of 4A zeolite is Na 12 al 12 Si 12 o 48 27H 2 O is a three-dimensional skeleton structure compound composed of silicon-oxygen and aluminum-oxygen tetrahedra. It belongs to the cubic crystal system. The diameter of the free hole formed by its 8-membered ring structure is 4.12A, so it is called 4A zeolite. 4A zeolite on Ca 2+ 、H 2 O and other small molecular substances have strong adsorption and exchange capabilities. The detergents with 4A zeolite as the auxiliary agent have the characteristics of no phosphorus, no pollution, no residue, and strong decontamination ability, so they can effectively replace the three polymers that have serious pollution to water bodies. sodium phosphate. In addition, 4A zeolite is also widely used in petroleum cracking and adsorbent industries. [00...

AI Technical Summary

Problems solved by technology

This method uses 4A zeolite as a directing agent, which can improve product quality, but because the directing agent is added before the gel crystallization, it is difficult to disperse evenly in the gel, which affects the calcium exchange capacity index of the product, and because the crystallization There is inconsistency in the chemicalization process, resulting in uneven particle distribution of 4A zeolite products, easy powder sedimentation and other defects

This method uses a large amount of chemical raw materials such as sodium aluminate solution and sodium silicate solution, and requires repeated washing to reduce the pH value, thereby significantly increasing production costs and causing certain pollution to the environment.