A kind of hole-protecting drying method of porous material

Abstract

A pore-protecting drying method for porous materials relates to porous materials. Mix the displacing agent, pore-protecting agent and hydrous porous material gel in a drying kettle, heat the drying kettle to boiling, and use a water separator to separate the water, and continue heating after most of the water in the hydrous porous material can be replaced , to obtain a dry solid product. The used displacing agent is cheap, easy to recycle, simple and easy to control the process, mild operating conditions; the prepared porous material has excellent performance. On the basis of conventional low-boiling azeotropic distillation, a small amount of pore-preserving agent is added to achieve pore-protecting drying, so as to obtain high-pore-volume silica and other porous materials efficiently and economically.

Description

Technical field [0001] The invention relates to a porous material, in particular to a pore protection drying method of the porous material. Background technique [0002] Nano-porous materials are widely used in petrochemical, coating industry, rubber industry, daily necessities manufacturing and other industries. For example, porous silica materials can be used in coatings, adsorbents, thermal insulation materials and other fields. Its characteristic parameter pore volume is an important indicator of its performance: the higher the pore volume of silica as a matting agent, the greater the matting performance of the coating. it is good. At present, the industry mainly uses sodium silicate and sulfuric acid as raw materials, adopts the sol-gel method, combined with spray drying to prepare silica powder. Sol-gel method can obtain large pore volume silica hydrogel, but due to the existence of surface tension in the drying process, spray drying can easily cause the pores to collapse...

AI Technical Summary

Problems solved by technology

Supercritical drying can completely eliminate surface tension and protect holes well, but this method has high equipment cost, complicated process, and high-pressure environment, which limits its industrial-scale application; freeze-drying can eliminate surface tension, but this method is also expensive. It is difficult to process large batches; azeotropic distillation and drying is to use organic solvents and water in the gel to azeotropically bring out water to achieve drying. For example, in the patent CN101585540, n-butanol and water binary azeotrope are used to dry silica. Under a certain degree of vacuum (vacuum degree 0.03MPa), the highest pore volume is 2.5cm 3 / g of large pore volume products

[0004] Although the binary azeotropic distillation and drying of n-butanol and water in the patent CN101585540 can obtain better results, the effect of the prepared product is still limited, such as the pore volume is difficult to break through, and the azeotropic temperature is relatively high. Big loss, high cost

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