This question is way beyond my area of expertise. From what I have read on this subject, I suspect whether you have a corrosion problem or not will depend on the operating temperatures, concentrations, and what other chemical species are present. I have one reference that indicates that a high silica refractory type is resistant to sulfur vapors (SO2 and O2) as long as the temperature is greater than 600° C. For further information, I suggest you consult a reference on this subject such as Carniglia, Stephen C. and Barna, Gordon L., “Handbook of Industrial Refractories: Technology Principles,Types, Properties and Applications,” Noyes Publications, 1992; Harbison-Walker, “Modern Refractory Practice,” Fifth Edition, 1992; or Plibrico-Japan, “Technology of Monolithic Refractories,” English Edition, 1984.