| 摘要 |
<p>PURPOSE:To obtain a desired concentration of dilute sulfuric acid by a manufacturing method of dilute sulfuric acid for industrial purpose from sulfurous acid-lean waste gas, in which conc. sulfuric acid is circulated inside a nitric acid process sulfuric acid manufacturing apparatus. CONSTITUTION:A waste gas containing a small amount (2vol% or less) of sulfurous acid gas is passed through a wet dust collector and then introduced into a nitric acid process sulfuric acid manufacturing apparatus, where the sulfurous acid is converted into sulfuric acid by absorption, etc., during passage through the desulfurizing tower 1, the manufacturing towers 2 and 3, and the nitric acid-arresting towers 4-6, and then held in nitrose circulating inside the apparatus. In this case, a more than 90wt% conc. industrial sulfuric acid is added as a circulating acid to at least one tower of the denitrifying tower 1, the sulfuric acid-manufacturing towers 2 and 3, and the nitric acid-arresting towers 4-6, whereby, while measuring the concentration of acid circulating in each tower, a 60-80wt% industrial dilute sulfuric acid can be desirably manufactured.</p> |
