Abstract: A highly efficient apparatus for burning sulfur to sulfur dioxide and generating sulfurous acid comprises a primary sulfur-burning chamber, a sulfur feed tank closely coupled to the primary chamber, a secondary sulfur-burning chamber, and an absorption tower. Air is introduced to the primary chamber under turbulent, high-velocity flow conditions. Gas passes through the secondary chamber under turbulent flow conditions. The apparatus is capable of converting sulfur to sulfur dioxide at a rate in excess of 25 pounds of sulfur per hour per square foot of surface area of the molten pool of sulfur in the primary chamber.