To provide a method by which, in a smelter where an arsenic sulfide precipitate and a larger amount of decoppered electrolytic slime than the amount of the precipitate are generated as nonferrous smelting intermediate products, treatment is enabled without keeping a fixed blending ratio between the materials, and to provide a method for increasing a fraction of arsenic leached as pentavalent arsenic in a leaching step in the method.
The method for treating arsenic includes: an oxidation leaching step of carrying out oxidation leaching of mixed slurry of the nonferrous smelting intermediate products; a liquid regulation step of adding an oxidizing agent to the resulting leachate so as to oxidize arsenic to pentavalent arsenic; and a crystallization step of converting the arsenic in the resulting regulated liquid to scorodite crystals. The leaching step includes: a first step of leaching where elemental sulfur is added to the mixed slurry at the beginning of reaction and leaching is carried out at ≥50°C and pH 1.0-2.0 while adding an oxidizing agent; a second step of leaching where the pH is adjusted to ≥2.0 by alkali addition and leaching is carried out while adding the oxidizing agent to the mixed slurry; and a third step of leaching where the addition of the oxidizing agent is stopped and stirring is carried out.
SATO YUSUKE
MIKAMI HIRONOBU
TAGUCHI RYOICHI
KUBO SHOJI
MATSUMOTO MASAYOSHI
| JP2008239412A | 2008-10-09 | |||
| JP2008150659A | 2008-07-03 | |||
| JP2008150658A | 2008-07-03 | |||
| JP2008222525A | 2008-09-25 | |||
| JP2008200635A | 2008-09-04 |
| WO2008114833A1 | 2008-09-25 |
Hitoshi Kiyono