US 7,399,268 B2
Method for treatment of arsenic-contaminated soil
Toru Ida, Kobe (Japan); Hiroshi Murakami, Kobe (Japan); and Yutaka Inada, Kobe (Japan)
Assigned to Kabushiki Kaisha Kobe Seiko Sho, Hyogo (Japan)
Filed on Dec. 02, 2005, as Appl. No. 11/291,822.
Claims priority of application No. 2004-364404 (JP), filed on Dec. 16, 2004.
Prior Publication US 2008/0139867 A1, Jun. 12, 2008
Int. Cl. B09C 1/06 (2006.01)
U.S. Cl. 588—256  [588/412; 588/320] 10 Claims
OG exemplary drawing
 
1. A method for treatment of arsenic-contaminated soil which comprises heating arsenic-contaminated soil at 200 to 700° C. in the presence of air or oxygen thereby converting trivalent inorganic arsenic compounds and organoarsenic compounds in the arsenic-contaminated soil into pentavalent inorganic arsenic compounds which are readily soluble in water; and mixing the heated soil with a calcium compound and water into a mixture thereby converting said pentavalent inorganic arsenic compounds into calcium arsenate compounds,
wherein 100 parts by weight of the heated soil is mixed with 3 to 20 parts by weight of the calcium compound and 10 to 70 parts by weight of the water.