| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a low-scaling method for removing arsenic from a sulfur dioxide-contg. solution through neutralizing the solution resulting from scrubbing the flue gas from a smelting facility comprising such a process that an aqueous solution containing iron, arsenic and sulfur dioxide is brought into an oxidation reactor where an oxidation is carried out, and a seed crystal for precipitate is added to the solution which is then neutralized with a calcium- contg. base to effect deposition of precipitate, part of which is then circulated. SOLUTION: This method for removing arsenic from a sulfur dioxide-contg. solution comprises the following process: an acidic gas-scrubbed stream 10 from a smelting facility is brought into a sedimentation thickener 12, whereas an overflow stream 20 with high concentrations of arsenic, iron and sulfur dioxide into an oxidation tank 22; the air 26 in the oxidation tank 22 is agitated with a mixer 24 to completely oxidize the arsenic, iron and sulfur dioxide before neutralization; the resultant solution is transferred to an adjustment tank 32 where the solution is agitated with a mixer 34 followed by addition of a seed crystal; the resultant solution is transferred to a 1st neutralization tank 42 where a calcium-contg. base 44 is added to the solution and the resulting neutralization product is precipitated; the slurry 60 thus neutralized is allowed to flow into a sedimentation thickener 62; and part 36 of the neutralized flow 64 downstream of the sedimentation thickener 62 is circulated into the adjustment tank 32.</p> |
