| 摘要 |
PROBLEM TO BE SOLVED: To prevent leaching out of arsenic from arsenic-containing soil over a long period and facilitate utilization of the soil as recycle soil. SOLUTION: A soil improver is prepared from a calcium salt, e.g. gypsum, and an oxidizing agent, e.g. potassium permanganate, and/or a pH-adjusting agent, e.g. calcium carbonate and mixed with arsenic-containing soil. The calcium of the calcium salt and the V-valent arsenic form an only slightly soluble compound to prevent leaching out of arsenic. The oxidizing and pH-adjusting agents convert the III-valent arsenic incapable of forming an only slightly soluble compound with calcium into the V-valent arsenic and prevent the time-lapse change of the V-valent to the III-valent arsenic. More specifically, the oxidizing agent controls, for a long period, the occurrence of a reducing atmosphere in soil which serves as circumstances which allow arsenic to change to the III-valent state and thereby stabilizes the preventing effect on leaching out of arsenic over a long period. COPYRIGHT: (C)2006,JPO&NCIPI |
