Hole-protecting drying method for porous material

Abstract

A hole-protecting drying method for a porous material relates to a porous material. The method comprises the steps: mixing a displacer, a hole protector and a water-containing porous material gel in a drying kettle; heating the drying kettle; raising the temperature till the mixture is boiled; dividing water by using a water konckout vessel; and after most of water in the water-containing porous material is to be dispalced, continuously heating the mixture to obtain a dried solid product. The used displacer is low in price, easy to recover, simple and easy to control process and relatively mild in operating condition; the prepared porous material is excellent in performance. Based on conventional low-boiling-point azeotropic distillation, a small amount of the pore protector is added to realize hole-protecting drying so as to efficiently and economically obtain high pore volume silicon dioxide and other porous materials.

Description

technical field [0001] The invention relates to porous materials, in particular to a pore-protecting drying method for porous materials. Background technique [0002] Nanoporous materials are widely used in petrochemical industry, 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. The characteristic parameter pore volume is an important indicator affecting its performance: the higher the pore volume of silica as a matting agent, the better the matting performance of the coating. good. At present, the industry mainly uses sodium silicate and sulfuric acid as raw materials to prepare silica powder by sol-gel method combined with spray drying. The sol-gel method can obtain silica hydrogel with large pore volume, but due to the existence of surface tension in the drying process, spray drying can easily cause pore collaps...

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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