Rates of autoxidation of sulphur (IV) in aqueous suspensions of limestone. powder: Implications for scrubber chemistry

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:arial;mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="">The kinetics of autoxidation of sulphur (IV) in acetate buffered aqueous suspensions of limestone powder in the condition [S(IV) ≤1 x 10³ mol dm^-3 obey the rate law which is first order in each of [limestone] and [S(IV)] and inverse first order in [H⁺]. On the other hand, in the condition [S(IV)] > 1 x 10^-3 mol dm^-3 a different kinetics rate law which is first order in [limestone], second order in [S (IV)] and inverse first order in [H⁺] is obeyed. The calculations indicate that a slurry containing 1.0 g dm^-3limestone will remove 90% of dissolved aqueous SO₂ (1 x 10^-3 mol dm^-3) in less than a minute at <i>p</i>h 6 and 40^oC.</span>