@article{oai:air.repo.nii.ac.jp:00002090,
 author = {WAJIMA, TAKAAKI},
 issue = {2},
 journal = {Clay science},
 month = {Jun},
 note = {Diatomite has different properties depending on the origin of the deposit and the collection site. In order to obtain a material suitable for silica supply, modification of diatomite using acid leaching after thermal treatment was investigated. Four types of diatomite, white and gray from deposits of marine origin in Takanosu, and white and yellow from lacustrine deposits in Shonai, were used. The samples were calcined at 300-1100℃ for 24h, and then stirred in 5M HCl solution at 80℃ for 1h. There are not notable changes of amorphous phase in diatomite at 300-900℃, while amorphous silica was transformed into cristobalite, which was low solubility in basic solution, after calcining at 1100℃. The removal of Al via acid leaching was the highest at 500-700℃, while those of Fe, Mg and Ca were almost constant at 300-900℃. The removal of Al from lacustrine diatomite was higher than that from marine one. Diatomites via acid leaching after calcination at 700℃ contains higher Si and lower impurities than raw diatomite, and have the almost same solubility of silica into alkali solution.},
 pages = {55--60},
 title = {MODIFICATION OF JAPANESE NATURAL DIATOMITE TO SUPPLY SILICA INTO ALKALI SOLUTION USING THERMAL TREATMENT AND ACID LEACHING},
 volume = {14},
 year = {2009}
}