Preparation process of molecular sieve
Preparation process of molecular sieve
Fulong molecular sieve
molecular sieve is a kind of aluminosilicate compound with cubic lattice, and its varieties reach dozens of kinds.
The production process of molecular sieve is divided into two stages: one is the synthesis of original molecular sieve powder; the other is the formation of molecular sieve.
Molecular sieves are synthesized using silicon compounds (such as silica sol, sodium silicate, etc.), aluminum compounds (such as activated alumina, aluminum salts, etc.), alkalis (such as sodium hydroxide, etc.) and templates under hydrothermal conditions. The product prepared from this is called the original molecular sieve powder, which is an extremely fine aluminosilicate crystal material with a crystal diameter of about 100 nanometers. It cannot be directly used in the industrial production process. It must be processed into particles of a certain shape and size. Practical value.
Molecular sieves need to be processed into different shapes according to their different uses. There are many molding methods and types, each with its own characteristics.
At present, molecular sieves commonly used in industry have three shapes: strips, spheres and microspheres. Among them, strip and spherical molecular sieves are the most common and are widely used as adsorbents and fixed bed acid catalysts.
Traditional molecular sieve balls are mostly processed by a rolling machine using a rotating molding process. Mainly by sending the raw molecular sieve powder or catalyst powder and appropriate amount of water (or binder) to the rotating pot body container, the pot body rotates clockwise, artificial powder and water are added to make the material tumble and slip inside the pot body , Friction and grinding. Through continuous rolling action, the wetted materials adhere to each other and gradually form spherical particles.
This traditional processing mode is only suitable for the processing of some materials that are easy to form balls, and the materials need to have certain strength and shape retention.
For Cuihua agent, the amount and adjustment of the binder are very important. In addition, there is a certain balance between the moisture content of the raw materials and the supplied moisture, which is more complicated and difficult to adjust. Therefore, the rotational molding method is suitable for the molding of single-component materials or multi-component materials with similar specific gravity. For multi-component materials with relatively large specific gravity, the difference in the specific gravity of each component will cause the difference in centrifugal force when rotating, so it is difficult to obtain a uniform composition of the ball. In the process of rolling the ball, manual control of the input amount of materials is likely to cause poor inter-batch reproducibility of the finished product, reduce the efficiency of the subsequent drying process, and increase the manual labor intensity.
The entire ball making process is controlled and judged by operators based on their experience and technical level. Therefore, there are higher requirements for the technical level of the operators. Secondly, objective human factors limit the quality and performance of the finished product, which often results in the finished ball. The size of the model varies, the density of the sphere is uneven, the surface compression and wear resistance is not high, and the product quality and performance are low. And in the rolling process, the dust pollution is relatively large, which damages the health of the operators and is not conducive to environmental protection. In today's modern production, which has strong market competitiveness, high requirements for product quality and performance, high degree of continuous automation and environmental protection, this traditional rolling ball equipment highlights its shortcomings and cannot meet the needs of modern production .
In modern production, the automatic production line that connects equipment and auxiliary equipment according to the technological sequence to automatically complete all or part of the product manufacturing process plays an important role in industrial production. It can not only make the production management of the workshop organized, but also Improve labor productivity, stabilize and improve product quality, and improve labor conditions, reduce production costs, and have significant economic benefits in ensuring production balance.
From the mixing of the original powder, mixture, silica sol, and purified water of the molecular sieve in the early stage, to the forming of the ball, to the later drying process, it can also be completed by the equipment of the automated production line. The entire production line has a high degree of automation, realizing "stable, accurate and fast" continuous production, greatly improving productivity, reducing labor, and improving the production environment. These functions are respectively composed of mixing equipment, refining equipment, ball making equipment, screening equipment, drying equipment and the linkage of equipment such as lifting and transmission.