Method of manufacturing dehumidifier element

A method of manufacturing a dehumidifier element comprising the steps of:

• (a) alternately laminating a flat sheet and a corrugated sheet of low density papers, the main constituent of the papers being inorganic fiber selected from the group consisting of ceramic fiber, glass fiber, rock fiber, carbon fiber, slag fiber and mixtures of not less than two of said fibers, to form a honeycomb matrix having many small channels;
• (b) heating the matrix to a temperature of 200.degree.-500.degree. C. to remove organic substances contained in the matrix and to decrease the density of sheets;
• (c) impregnating the matrix with an aqueous solution of sodium silicate water glass;
• (d) heating and drying the impregnated matrix so that the sodium silicate water glass becomes hydrated water glass or half-solid state water glass;
• (e) soaking the matrix in an aqueous solution of metal sulphate selected from the group consisting of aluminum sulphate and magnesium sulphate to react with the sodium silicate water glass to form silicate hydrogel on the sheets in the matrix and in the apertures between fibers in the sheets;
• (f) washing and drying the matrix to change the silicate hydrogel into silicate aerogel and to obtain the dehumidifier element;
• (g) cooling the aqueous solution of metal sulphate to precipitate and remove sodium sulphate, which is produced as a by-product of the reaction with the sodium silicate water glass and is dissolved in the aqueous solution of metal sulphate;
• and
• (h) adding sodium silicate to the aqueous solution of sodium silicate after the reaction and adding additional metal sulphate to the aqueous solution of metal sulphate after reaction to prepare the solution to repeat said steps (c) to (e) for a next dehumidifier element to be manufactured.