CS208337B1 - Sulfuric acid purification process - Google Patents

Abstract

The invention relates to the purification of sulfuric acid, which is formed during nitration and oxidation processes, by adsorption.

Description

208 337 1

Sulfuric acid, which is eliminated by nitrating, oxidizing, sulfonating proesters, has a concentration of 20-80%. It contains organic substances, nitric acid, nitrogen oxides, inorganic sulphates and the like. Such sulfuric acid is used in the production of mineral fertilizers (superphosphates, ammonium sulfate, and the like) in metallurgy to remove metal oxides. Procedures are known to remove impurities from the sulfuric acid used. Nitrogen oxides are removed in denitration plants or removed from sulfuric acid by acetylene. According to NOR Patent No. 120,184, nitrogen oxides are removed from the used sulfuric acid by urea or other carbamides. Sulfuric acid by weight concentration of 70% after nitroassay processes, is concentrated in a Pauling apparatus, oxidizing organic, impurities with sulfuric acid, or wetting, purifying the sulfuric acid used by phenol extraction is described in the Soviet Certificate No. 316 648. Extraction of organic impurities with fatty, The removal of organic matter from sulfuric acid in the presence of iron sulphates or by the medium is described in the Soviet & compounds containing a fluorine is described in FIG. Alkali sulphates and sulphates of heavy metals are separated from dilute sulfuric acid by concentrating sulfuric acid to a concentration of 96% to 93%. Diluted sulfuric acid is used to produce calcium sulfate, barium sulfate, zinc sulfate and the like. Organic matter is removed from spent sulfuric acid by an organic solvent that is not mixed with the acid mixture. In common practice, at least two extractions are required, both of which are associated with the usual problems of emulsification and processing in order to substantially reduce the content of organic compounds. The phase separation of organic materials in the spent acid mixture, even at a higher extraction rate, usually requires a high organic content higher than can be tolerated by sulfuric acid suitable for reuse. The organics are removed from the acid by distillation with steam, whereupon sulfuric acid is quenched with water, resulting in a concentration of sulfuric acid.

The above drawbacks are avoided by the purification of sulfuric acid containing 3-methyl-4-nitrphenol, 3-methylphenol and its nitroso- and sulfoderivatives, nitric acid, nitrogen oxides and alkali sulphates as impurities. 3-methylphenol, 3-methyl-4-nitrophenol, 3-methylphenol and its nitroso and sulfoderivatives are adsorbed by silicates with adsorbent active sites which are separated after adsorption from the sulfuric acid. In the second adsorption step, 3-methyl-4-nitrophenol, 3-Qistylphenol and its nitrososulfoderivatives are optionally adsorbed with activated carbon, which is separated after adsorption from the sulfuric acid.

The 3-methyl-4-nitrophenol content of 3-methylphenol derivatives is 1 to 100%. Activated bentonite is used from the adsorbent active silicates.

Sulfuric acid is separated after separation of the adsorbent by evaporation of water to a concentration of 90 to 98%. The crystallized / alkaline sulphates are separated from the sulfuric acid. An advantage of the process of the invention is. purification of waste sulfuric acid resulting from the production of nitro- and sulfoderivatives 3-methylphenol. SpSsob is technically good manageable and easy. The resulting diluted HgSO4 finds application in the production of superphosphate, or after concentration it can be used for routine use.

Claims (5)

EXAMPLE 1 100 ml of used sulfuric acid with a concentration by weight of 31.3% HgSO4, 1.4% of dicarbonate, 0.12% of nitrogen oxides titrated with aluminic acid, 3.2% of Na @ + + ions are added to the flask. 0.14% of 3-methyl-4-nitrophenol and 0.11% of 3-methylphenol and jehonitroso and sulfoderivatives. 3 g of activated bentonite was added to the acid. After 15 min, the adsorbent was filtered off. The sulfuric acid obtained contained 0.06% of 3-methyl-4-nitrophenyl and 0.04% of 3-methylphenol and its nitroso-, sulfoderivatives. EXAMPLE 2 The procedure is as in Example 1, except that 1 g of activated charcoal is added after the adsorbent is separated. After 24 hours, charcoal was filtered off actively from the acid solution. The content of 3-methyl-4-nitnophenol was 0.01% and 3-methylphenol and its nitrososulfoderivatives were 0.005%. Example 3 The procedure is the same as in Example 1, except when 2 absorption steps were used. The amount of solidity in the second absorption stage was also 3 g. After separation of the adsorbent in the second stage, the sulfuric acid had a mass concentration of 0.02% of 3-methyl-4-nitrophenol and 0.02% of 3-methylphenol and its nitroso and sulfoderivatives. Example 4 The procedure is the same as in Example 1, only fine-grained silica gel is used instead of activated bentonite and the time is 24 hours. After filtration of the silica gel, the content of 3-methyl-4'-nitrophenol was 0.10% and the content of 3-methylphenol and its derivatives was 0.09%. EXAMPLE 5 The procedure is the same as in Example 4, except that the adsorption with activated charcoal has been converted 2 times; Water was distilled from the sulfuric acid by rectification. The crystallized NaBSO4 was filtered off. The obtained sulfuric acid had a concentration by weight of 95.6% and contained 0.1% Na + - ions. Sulfuric acid was virtually organic-free. The invention can be used to purify sulfuric acid used in the production of 3-methyl-4-nitrophenol. The sulfuric acid used has not been used and drained into wastewater. . BEFORE M. T Tlil L E Z U 1. A method of purifying sulfuric acid comprising 3-methyl-4-nitrophenol, 3-methylphenol and its nitroso and sulfodivatives, nitric acid, nitrogen oxides and alkaline sulphates as impurities, characterized in that 3-methyl-4-nitrophenol, 3 The methylphenol and the nitroso-and sulphodivatives adsorb the silicates with adsorbent active compounds which are adsorbed from the sulfuric acid. 208 337 3 2. The process according to claim 1, wherein in the second adsorbent step, 3-methyl-4-nitrophenol, 3-ethylphenol and its nitroso-sulfoderivatives are admixed with activated carbon which is separated after adsorption from the sulfuric acid. 1 3. A method according to (1) and (2), wherein the weight content of 3-methyl-4-nitro-phenol in the 3-methylphenol derivative is 1 to 100%. 4. The method of claim 1, wherein activated bentonite is used as the silicate with adsorbent activated sites. 5. The process of claim 1, wherein the sulfuric acid is concentrated to 90-98% by weight after separation of the adsorbent by evaporation of the water and the crystallized alkaline sulphates are separated from the sulfuric acid. Printed by Jihočeské tiskárny, n. P., České Budějoviceprovoz 11 Český Krumlov Price: 2,40 Kčs