time was measured by using a ags 500d mechanical tester shimadzu co ltd kyoto japan after the specimens were dry the measured dry specimen compressive strength is listed table 7 the procedures of example 7 were repeated by using sugar ki c 17 h 33 coona and c 13 h 27 cooh instead of kcl the immersion time was 14 days in deionized water in the cases where the c 17 h 33 coona and c 13 h 27 cooh were used the cpc blocks were further immersed in ethanol for additional four days the conditions and the results are listed in table 8 it can be seen from table 8 that various powders which are soluble in water can be used in the preparation of a porous cpc block according to the method of the present invention to a setting solution of 1m phosphoric acid solution ph 5 89 the nd cpc powder from preparative example 3 was added in a liquid powder ratio l p ratio of 0 4 i e 4 ml liquid 10 g powder while stirring kcl powder in a ratio of kcl powder cpc by volume of 2 was mixed to the resulting mixture by stirring intensively the resulting paste was filled into a cylindrical steel mold having a length of 12 mm and a diameter of 7 mm and was compressed with a gradually increased pressure until a maximum pressure of 3 5 mpa was reached the maximum pressure was maintained for.