Abstract: Contaminated sulfuric acid which may contain water, organic compounds and inorganic salts is converted to almost pure concentrated sulfuric acid by passing the acid through a Pauling plant and distilling the concentrated contaminated acid.Addition of nitric acid improves the decomposition of organic compounds and ammonium salts of the contaminated acid.

Abstract: A continuous process is provided which has the primary purpose of removing NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 from the subject gas mixtures and the secondary purpose of producing (NH.sub.4).sub.2 SO.sub.4 and iron oxide for industrial uses. The gas mixture which contains tar and other condensible vapors, NH.sub.3, H.sub.2 S, HCN, and (CN).sub.2 together with small volumes of gas from the ammonia still of the system, and gas from a system H.sub.2 SO.sub.4 plant, is contacted in a single three-stage reaction chamber in the presence, if need be, of a tar solvent, additional NH.sub.3, and the reagent Fe(OH).sub.2, which itself is a product of a concurrent reaction between NH.sub.3 and FeSO.sub.4. The unpurified gas mixture's condensible vapors are largely prevented from condensing by maintaining a steady, elevated temperature, while the mixture is essentially freed of HCN, (CN).sub.2, NH.sub.3, and H.sub.2 S in the reactor before the gas mixture passes through a primary gas cooler.

Abstract: A method for preparing anhydrous nitric acid comprising extracting an aqueous mixture of nitric acid and sulfuric acid with methylene chloride to yield a solution of anhydrous nitric acid in methylene chloride. The anhydrous nitric acid can be isolated from the methylene chloride by distillation or crystallization. Alternatively, the anhydrous solution of nitric acid in methylene chloride may be used directly. The methylene chloride extract of the nitric acid-sulfuric acid mixture is a useful nitrating agent.

Abstract: Two-step-process for regenerating dilute sulfuric acid which may contain organic and inorganic impurities such as heavy metal salts. In the first step the impure acid is distilled in vacuo and in the second step concentrated in a Pauling apparatus.