Oleum prodn. by thermal decomposition of steel sulphate - esp. from pickling plant or titanium di:oxide mfr., using dry gas contg. oxygen and ferric oxide catalyst

摘要

In the prodn. of oleum and absorption of SO3 in oleum, metal sulphates are decomposed at 520-600 degrees C with dry gas contg. O2 in the presence of Fe2O3, the SO3 formed is absorbed in oleum and the residual gas is used for indirect heating of the cracking gas to 800-1000 degrees C after intermediate combustion. The process allows the use of metal sulphates obtd. in large amts. in pickling plants and in the mfr. of TiO2 for oleum prodn. Pref. the oxidising gas contains >=15 vol.% O2 and the temp. of the cracking gas flowing in counter-current to the goods to be decomposed is reduced to ca. 350-400 degrees C.