摘要 |
A granular material having a high strength and a large BET specific surface area composed of porous particles comprising calcium oxide and calcium hydroxide wherein the calcium oxide is contained in an amount of 30 to 80 weight % based on a total amount of the calcium oxide and calcium hydroxide and the porous particles have a BET specific surface area of 40 m 2 /g or more, or composed of porous particles comprising calcium oxide, magnesium oxide, calcium hydroxide, and magnesium hydroxide wherein a ratio of an amount of magnesium to a total of an amount of calcium and an amount of magnesium is in the range of 0.05 to 0.80, a total hydroxide content in the whole particles is in the range of 1 to 20 weight % and the porous particles have a BET specific surface area of 50 m 2 /g or more. |