Sulfuric acid

Industrial Uses

Metallurgy and petroleum industry

Used in the metallurgical industry and metal processing In the metallurgical industry, especially the production of non-ferrous metals. For example, when refining copper, zinc, cadmium, and nickel by electrolysis, the electrolyte requires the use of sulfuric acid. The refining of certain precious metals requires sulfuric acid to dissolve and remove other metal inclusions. Before cold rolling, cold drawing and stamping processing in the steel industry, the iron oxide on the steel surface must be removed with sulfuric acid. In the ferrous metallurgical enterprise sector, the steel that needs to be pickled generally accounts for about 5% to 6% of the total steel production, and the pickling of each ton of steel consumes about 98% of 30 to 50kg of sulfuric acid.

In the production process of petroleum products such as gasoline and lubricating oil in the petroleum industry, concentrated sulfuric acid refining is required to remove sulfur-containing compounds and unsaturated hydrocarbons. Each ton of crude oil refining requires about 24kg of sulfuric acid, and each ton of diesel refining requires about 31kg of sulfuric acid. The preparation of activated clay used in the petroleum industry also consumes a lot of sulfuric acid.

In concentrated nitric acid, concentrated sulfuric acid is used as the dehydrating agent; in the chlor-alkali industry, concentrated sulfuric acid is used to dry chlorine, hydrogen chloride, etc.; in the inorganic salt industry, such as cryolite, borax, trisodium phosphate, disodium hydrogen phosphate, lead sulfate, Sulfuric acid is used in the preparation of zinc sulfate, copper sulfate, ferrous sulfate and other sulfates. The preparation of many inorganic acids such as phosphoric acid, boric acid, chromic acid (sometimes also referred to as CrO3), hydrofluoric acid, chlorosulfonic acid; organic acids such as oxalic acid, acetic acid, etc. also often requires sulfuric acid as raw material. In addition, the coking chemical industry (using sulfuric acid to react with ammonia in coke oven gas to produce ammonium sulfate as a by-product), electroplating industry, tanning industry, pigment industry, rubber industry, paper industry, paint industry (preparation of organic solvents), and industrial explosives and lead-acid battery manufacturing, etc., all consume considerable amounts of sulfuric acid.

It can be used as hard water softener, ion exchange regenerant, pH adjuster, oxidant and detergent. It can also be used in the manufacture of chemical fertilizers, pesticides, dyes, pigments, plastics, chemical fibers, explosives and various sulfates. It is widely used in petroleum refining, non-ferrous metal smelting, steel pickling, tanning process, coking industry, light textile industry, and national defense industry. Strong acidic cleaning corrosive agent. It is mainly used for silicon wafer cleaning in the integrated circuit manufacturing process.

Solve the problems of people’s basic necessities, food, housing and transportation

The viscose yarn used in the production of chemical fibers, which is familiar to the people, requires the use of a mixture of sulfuric acid, zinc sulfate, and sodium sulfate as the coagulation bath for viscose spinning. For every 1 ton of viscose fiber produced, 1.2 to 1.5 tons of sulfuric acid are consumed. For every 1 ton of vinylon short fiber produced, 230kg of 98% sulfuric acid is consumed. For every 1 ton of capron monomer produced, 1.6 tons of 20% oleum are consumed. In addition, a considerable amount of sulfuric acid is also used in the production of chemical fibers such as nylon, acetate fiber, and polyacrylonitrile fiber.

It is used to produce polymer compounds other than chemical fibers to produce plastics and other polymer compounds, and it plays an increasingly important role in the national economy. For every 1 ton of epoxy resin produced, 2.68 tons of sulfuric acid are needed. For every 1 ton of polytetrafluoroethylene produced, 1.32 tons of sulfuric acid is needed; for the production of organic silicone gum, silicone oil, styrene-butadiene rubber and nitrile-butadiene rubber, etc. , also use sulfuric acid.

There are almost no dyes (or intermediates thereof) used in the dye industry that can be prepared without the use of sulfuric acid. The preparation of azo dye intermediates requires a sulfonation reaction, and the preparation of Aniline dye intermediates requires a nitration reaction, both of which require the use of large amounts of concentrated sulfuric acid or fuming sulfuric acid. Therefore, some dye factories have sulfuric acid workshops to meet needs.

The production of synthetic detergents for daily necessities requires the use of fuming sulfuric acid and concentrated sulfuric acid. Plasticizers for plastics (such as phthalic acid anhydride and phthalic acid ester) and nitrocellulose, the raw material for celluloid products, all require sulfuric acid to prepare. The manufacture of cellophane and parchment also requires the use of sulfuric acid. In addition, production sectors such as the textile printing and dyeing industry, enamel industry, hardware industry, soap industry, and artificial flavoring industry also need to use sulfuric acid.

Sulfuric acid is required for the sulfonation reaction in the preparation process of sulfa drugs in the pharmaceutical industry and the nitration reaction in the preparation process of the powerful fungicide nitrofurazone. In addition, the preparation of many antibiotics, commonly used drugs such as aspirin, caffeine, vitamin B2, vitamin B12 and vitamin C, certain hormones, isoniazid, mercury bromide, saccharin, etc., all do not require the use of sulfuric acid.

Agriculture Uses

soil improvement

In agricultural production, sulfuric acid is increasingly used to improve calcareous soil with high pH. Over the past 20 years, the production of urea-sulfuric acid fertilizers has increased significantly and is widely applied to soils in the western states of the United States. Injecting sulfuric acid into dairy farm lakes and changing the pH of the lake water can solve several air and water quality problems caused by raising livestock in captivity. When sulfuric acid is applied to agricultural soil and water, its main function is to dissolve carbonates and bicarbonates of calcium and magnesium. . These calcium and magnesium salts then replace the exchangeable sodium salts, which are subsequently removed by leaching with water. When carbonates and bicarbonates are broken down, the sulfuric acid reacts with more inert materials, releasing plant nutrients such as phosphorus and iron. Simply lowering the pH of the soil can cause changes in the solubility of many elements, increasing their effectiveness to plants. Applying sulfuric acid to calcareous soils with high pH values ​​will result in stronger plants and increased harvests.

Fertilizer production

The production of ammonium sulfate (commonly known as ammonium sulfate or fertilizer powder) and superphosphate (commonly known as superphosphate lime or calcium superphosphate) used in the production of fertilizers consumes a large amount of sulfuric acid.

Many pesticides used in the production of pesticides use sulfuric acid as raw materials. For example, copper sulfate and zinc sulfate can be used as plant fungicides, thallium sulfate can be used as rodenticide, and ferrous sulfate and copper sulfate can be used as herbicides. The production of the most common pesticides, such as 1059 Emulsion (45%) and 1605 Emulsion (45%), requires the use of sulfuric acid.