The use of the sulfuric acid chemical industry

The use of the sulfuric acid chemical industry

Industrial grade hydrochloric acid is an important inorganic chemical product, widely used in dyestuff, medicine, food, printing and dyeing, leather, metallurgy and other industries. Hydrochloric acid can be used to make chlorides such as zinc chloride (zinc chloride is a welding flux), and can also be used to extract metals such as radium, vanadium, tungsten, and manganese from ores to make chlorides. With the development of organic synthesis industry, hydrochloric acid (including hydrogen chloride) is more widely used. For example, it is used to hydrolyze starch to make glucose, to make hydrochloride of various organic pharmaceuticals such as quinine hydrochloride (to treat malaria), etc. In the flame reaction, the platinum wire is usually washed with dilute hydrochloric acid (because the chloride has a low melting and boiling point and evaporates quickly after burning, which has little effect on the experiment). When diluting hydrochloric acid, inject concentrated hydrochloric acid into water to prevent the water from boiling. , liquid splash. (Reason: The density of water is lower than that of hydrochloric acid, and it will float on it. When it is diluted, a lot of heat is released to make the water boil.) At the same time, it is stirring to dissipate heat. the



It is used as toilet cleaner and rust remover in daily life.

(1) Hydrometallurgy for rare metals

For example, when smelting tungsten, firstly mix scheelite (calcium tungstate ore) with sodium carbonate, and roast in air (800℃～900℃) to generate sodium tungstate.

(2) Used in organic synthesis

For example, at a temperature of 180°C to 200°C and a mercury salt (such as HgCl2) as a catalyst, hydrogen chloride and acetylene undergo an addition reaction to form vinyl chloride, which is then polymerized into polyvinyl chloride under the action of an initiator. .

(3) Used in bleaching and dyeing industry

For example, acid washing of cotton cloth after bleaching and neutralization of residual alkali after mercerizing of cotton cloth should use hydrochloric acid. In the printing and dyeing process, some dyes are insoluble in water and need to be treated with hydrochloric acid to make soluble hydrochloride before they can be used.

(4) For metal processing, for example, pre-plating treatment of steel parts, first wash with caustic soda solution to remove oil stains, and then soak in hydrochloric acid; before metal welding, it is necessary to apply a little hydrochloric acid on the weld, etc. Hydrochloric acid can dissolve metal oxides to remove rust. In this way, the metal surface can be plated firmly and welded firmly.

(5) Used in the food industry. For example, when making chemical soy sauce, soak the steamed bean cake and other raw materials in a solution containing a certain amount of hydrochloric acid and keep it at a certain temperature. Hydrochloric acid has a catalytic effect and can promote the hydrolysis of complex proteins. After a certain period of time, amino acids with umami taste will be produced, and then neutralized with caustic soda (or soda ash) to obtain amino acid sodium. The principle of making monosodium glutamate is similar to this.

(6) Hydrochloric acid is a strong acid used in the production of inorganic drugs and organic drugs. Both react to produce hydrochloride. Therefore, hydrochloric acid is used in the production of many inorganic drugs. In medicine, many organic drugs, such as novocaine and thiamine hydrochloride (preparation of vitamin B1), are also made from hydrochloric acid.