Fundamental Researches Of Sepiolite,Diatomite And Zeolite As Humidity Control Building Materials

Humidity is a physical quality, which influence the comfort of humanbeing's job and life. At present, air conditioning is usually used to control indoor air humidity, but it's not good for environment protection and enegy conservation. Therefore, producing inorganic intelligent humidity-control material, which is green and economical, is one of the main developments of building materials to control indoor humidity. In this paper, the testing and assessment methods about humidity control material have been put forward, and systematic research has been carried out on the capability of humidity adsorption and desorption of three environmental mineral materials (sepiolite, diatomite, zeolite), their morphology and structure also has been detected by SEM and XRD observations.It is founded out through experiments that maximum humidity adsorption mass changes of sepiolite reaches 5.64% at 25 ℃ , 75%RH and maximum humidity desorption mass changes reach 2.39% at 25℃, 35%RH, which is better than zeolite and diatomite in the same condition whose quantity is 2.0% and 0.5% around . In the same condition, the ability of mixture samples change with the proportion of sepiolite. The sample of high proportion of sepiolite has a strong water adsorption and desorption ability, the percent of maximum humidity adsorption and desorption mass changes of sepiolite reach 4.20%, 2.05% separately. We found out that the main principle of humidity regulating materials is adsorption and desorption of H2O by the pores and channels in the material. In this paper, the humidity control ability of materials has been analyzed bu the theory of capillary effect and solid surface adsorption.A number of samples of plank form mineral composite materials have been made from these mineral materials and white cement in different proportions. Firstly, humidity adsorption and desorption experiments have been made to test the capability of humidity adsorption-desorption of different kinds of samples; Secondly, the samples were laid in high humidity and low humidity vessels respectively in respect to test the capability of humidity adsorption and desorption of the different kinds of samples. The results show that: the capability of moisture adsorption-desorption of humidity-control material has been improved after mixed with white cement by the aperture structure matching and surface active points increasing, the percent of maximum humidity adsorption or desorption mass changes amount to 8.07% or 3.26% respectively; while the samples were in the over-higher and over-lowerhumidity vessels, the inner humidity changes of the vessels became even and stabilized between 40% and 60% in a comparably short time. Experimental results show that the sample compounded by sepiolite and white cement(sepiolite:white cement =3:2) takes on sound humidity control ability which could regular the humidity of the experimental vessel in a scope of 44%~54%.Above experiments establish a sound foundation for developing air humidity control material.