Sulfuric acid is one of the most important compounds made by the chemical industry. It is used to make, literally, hundreds of compounds needed by almost every industry.

Uses of sulfuric acid

By far the largest amount of sulfuric acid is used to make phosphoric acid, used, in turn, to make the phosphate fertilizers, calcium dihydrogenphosphate and the ammonium phosphates. It is also used to make ammonium sulfate, which is a particularly important fertilizer in sulfur-deficient.

It is widely used in metal processing for example in the manufacture of copper and themanufacture of zinc and in cleaning the surface of steel sheet, known as "pickling", prior to it being covered in a thin layer of tin, used to make cans for food.

It is also used to make caprolactam, which is converted into polyamide 6 and in themanufacture of titanium dioxide, used, for example, as a pigment.

Amongst its many other uses is in the manufacture of hydrofluoric acid and phenol with propanone all of which are used in many industries.

Sulfuric acid is one of the most important industrial chemicals. More of it is made each year than is made of any other manufactured chemical; more than 40 million tons of it were produced in the United States in 1990. It has widely varied uses and plays some part in the production of nearly all manufactured goods. The major use of sulfuric acid is in the production of fertilizers, e.g., superphosphate of lime and ammonium sulfate. It is widely used in the manufacture of chemicals, e.g., in making hydrochloric acid, nitric acid, sulfate salts, synthetic detergents, dyes and pigments, explosives, and drugs. It is used in petroleum refining to wash impurities out of gasoline and other refinery products. Sulfuric acid is used in processing metals, e.g., in pickling (cleaning) iron and steel before plating them with tin or zinc. Rayon is made with sulfuric acid. It serves as the electrolyte in the lead-acid storage battery commonly used in motor vehicles (acid for this use, containing about 33% H₂SO4 and with specific gravity about 1.25, is often called battery acid).

Sodium sulfate is the sodium salt of sulfuric acid. When anhydrous, it is a white crystalline solid of formula Na₂SO₄ known as the mineral thenardite; thedecahydrate Na₂SO₄·10H₂O is found naturally as the mineral mirabilite, and in processed form has been known as Glauber's salt or, historically, salt mirabilis since the 17th century. With an annual production of 6 million tones, it is a majorcommodity chemical product.

Use in Soaps and Detergents 
A large amount of sodium sulfate has been used in powdered detergents as filler. However, sodium sulfate use has begun declining as well; the need for filler has gone down, due to the trend toward using concentrated liquid detergents instead of bulkier powder formulas. It is still used in carpet powders and window defrosting applications. 
Textiles 
Approximately 100,000 tons of sodium sulfate is utilized annually for dyeing textiles. It does not corrode the stainless steel vessels as sodium chloride (which can also be used in this manner) does. Sodium sulfate is a leveling agent, reducing negative chargers on the fibers, which allows the dyes to penetrate evenly. Sodium sulfate is a by-product of rayon production. 
Wood Pulp 
One notable use for sodium sulfate compound is in the Kraft process, also known as the sulfate process, of wood pulp manufacturing which is widely used to make paper products and building supplies .The technology involves impregnating wood chips with sodium sulfate; the wood is heated, causing a reduction of the sodium sulfate into sodium sulfide. This breaks the bond in the cellulose of the wood, making it malleable and able to be extruded. 
Glass 
Sodium sulfate is used in the glass industry as well. Sodium sulfate prevents scum formation by the molten glass during refining, and also fluxes the glass. The compound also acts as a fining agent in molten glass, removing small air bubbles and imperfections during the blowing and casting processes. 
Drying and Thermal Storage 
In the laboratory, sodium sulfate is often used as an inert drying compound for organic materials. It removes water from compounds reliably at temperatures below 30° C (86° F). Another main use of sodium sulfate is in thermal storage. It has been utilized as a solar heat storage component, because it has a high heat storage capacity and does not change from a solid to a liquid until 90 ° F (32 ° C). Sodium sulfate is used to store heat in thermal tiles, and put into cells surrounded by solar-heated water, as well as in some computer-cooling and insulating applications.