| 摘要 |
PROBLEM TO BE SOLVED: To provide a silica gel having a controlled structure and improved characteristics such as pressure loss and to provide its manufacturing method. SOLUTION: An aqueous solution of sodium silicate is prepared in step 1-1, to which a strong acid ion exchange resin is added to a desired pH in step 1-2 so as to sufficiently remove Na ion. A tubular cell containing the silica sol is inserted into liquid nitrogen at a specified insertion speed by using a constant speed motor in step 2-1. In this step, the pore diameter of the honeycomb structure is controlled by controlling the insertion speed and the temperature of the coolant. The sample in a frozen state is subjected to low temperature ageing for a specified time in step 2-2. The cell is put into a temperature controlled tank at 50°C and rapidly thawed in step 3-1 and kept in the temperature controlled tank for a specified time to carry out high temperature ageing. Then the sample is cleaned with t-butanol in step 3-2 to replace a minute amount of water in the sample with t-butanol. The sample is freeze-dried at -10°C in step 3-3. COPYRIGHT: (C)2005,JPO&NCIPI
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