Sơ đồ phản ứng:
\(S\xrightarrow{{}}S{O_2}\xrightarrow{{}}S{O_3}\xrightarrow{{}}{H_2}S{O_4}\xrightarrow{{}}N{a_2}S{O_4}\xrightarrow{{}}BaS{O_4}\)
\(S + {O_2}\xrightarrow{{{t^o}}}S{O_2}\)
\(2S{O_2} + {O_2}\xrightarrow{{{V_2}{O_5},{t^o}}}2S{O_3}\)
\(S{O_3} + {H_2}O\xrightarrow{{}}{H_2}S{O_4}\)
\(2NaOH + {H_2}S{O_4}\xrightarrow{{}}N{a_2}S{O_4} + 2{H_2}O\)
\(Ba{(OH)_2} + N{a_2}S{O_4}\xrightarrow{{}}BaS{O_4} + 2NaOH\)