title: Fabrication of microporous calcite block from calcium hydroxide compact under carbon dioxide atmosphere at high temperature.
abstract: Effects of carbonation temperature and compacting pressure on basic properties of calcite block were studied using Ca(OH)2 compact made with 0.2-2.0 MPa and their carbonation at 200-800ºC for 1 h. Microporous calcite was obtained only when carbonated at 600ºC using Ca(OH)2 compact made with 0.2 MPa even though thermogravimetry analysis showed that calcite powder was stable up to 920ºC under CO2 atmosphere. CaO formed by carbonation at 700ºC and 800ºC is thought to be caused by the limited CO2 diffusion interior to the Ca(OH)2 compact. Also, unreacted Ca(OH)2 was found for Ca(OH)2 compact prepared with 0.5 MPa or higher pressure even when carbonated at 600ºC. As a result of high temperature carbonation, crystallite size of the calcite, 58.0 nm, was significantly larger when compared to that of calcite prepared at room temperature, 35.5 nm. Porosity and diametral tensile strength of the microporous calcite were 39.5% and 6.4 MPa.
authors.affiliation: Department of Biomaterials, Faculty of Dental Science, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Otsu
authors.forename: Kanji
authors.initials: K
authors.lastname: Tsuru
authors.forename: Michito
authors.initials: M
authors.lastname: Maruta
authors.forename: Melvin L
authors.initials: ML
authors.lastname: Munar
authors.forename: Shigeki
authors.initials: S
authors.lastname: Matsuya
authors.forename: Kunio
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D001031:Apatites / Q000737:chemistry; D018786:Bone Substitutes / Q000138:chemical synthesis*; D002119:Calcium Carbonate / Q000138:chemical synthesis*; D002126:Calcium Hydroxide / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D003460:Crystallization; D006358:Hot Temperature; D016062:Porosity; D011312:Pressure; D013718:Tensile Strength; D013818:Thermogravimetry
chemical_list: D001031:Apatites; D018786:Bone Substitutes; D002245:Carbon Dioxide; C030782:carboapatite; D002119:Calcium Carbonate; D002126:Calcium Hydroxide