Abstract: Apparatus for producing an acid compound wherein an aqueous medium is pumped through a first reactor into which ammonia is injected. The first reactor comprises a venturi with a mixing deflector in the throat of the venturi. The ammonia is introduced to the first reactor via an inclined fitting proximate to the deflector. The aqueous ammonia medium is caused to flow through a second reactor downstream from the first reactor wherein sulfuric acid is injected and mixed with the aqueous ammonia medium resulting in an exothermic reaction between the ammonia and sulfuric acid under high temperatures and pressures. The sulfuric acid inlet of the second reactor comprises an inclined fitting which extends into the second reactor to form a baffle to facilitate mixing of the sulfuric acid and the aqueous ammonia mixture. The ammonia/sulfuric acid mixture then flows into a vat wherein the temperature and pressure of the compound are reduced.