Application of 1. in chemical industry
2. Application in dye industry
Raw materials commonly used in dye industry, such as caustic soda, soda ash and chlorine gas, are directly produced from salt, while hydrochloric acid, sodium sulfide and sodium hydrosulfite are chemical products made from salt through deep processing. In addition, it directly consumes a lot of salt. Therefore, besides chlor-alkali industry, dye industry is one of the industries closely related to salt industry. Moreover, almost every step in the dye production process consumes a certain amount of salt.
3. Application in metallurgical industry
Salt is used as a chlorinating roasting agent and quenching agent in metallurgical industry, and also as a desulfurizing agent and clarifying agent for treating metal ores. Steel products and rolled steel products can be immersed in salt solution to harden their surfaces and remove oxide films. Salt chemical products are needed for pickling of strip steel and stainless steel, baking AIDS such as aluminum smelting and electrolytic decomposition of sodium metal, as well as refractory materials in smelting.
4. Application in building materials industry
Soda soda made of salt is the main raw material for producing glass. In addition, in order to eliminate bubbles in glass melt, a certain amount of fining agent must be added, and salt is also a component of commonly used fining agent, and the amount of salt is about 1% of glass melt.
General coarse pottery, ceramic tiles and jars need salt as glazing agent. The salt consumption per cubic meter of pottery is 0.5 ~ 3 kg.
In order to improve the performance of enamel glaze, it is necessary to add some enamel additives before enamel coating. Salt is a kind of enamel additive, which is used for surface glaze to increase the strength of powder blank and improve the ability of resisting nicking and wear after enamel is made. The maximum amount of salt per 100 kg glaze slurry is 0.3 kg.
5. Application in machinery industry
In casting, salt can be used as an excellent binder for molding sand in non-ferrous metal and alloy casting. At high temperature, salt can soften the casting core, thus preventing the occurrence of hot cracks in the casting. Compared with organic adhesives, salt produces the least harmful gas at high temperature.
Salt bath furnace is the most commonly used heating equipment for heat treatment of steel mechanical parts or tools. Compared with box furnace heating, salt bath furnace has many advantages, such as easy temperature control, uniform heating, fast heating speed, local heating, long and thin workpiece is not easy to bend, and can avoid oxidation and decarbonization. At the same time, as a common catalyst in carburizing chemical heat treatment, ideal results can also be obtained by quenching with brine during heat treatment.
When ferrous metals, copper and copper alloys are strongly pickled before electroplating, salt is needed.
6. Application in petroleum industry
In the process of oil well drilling, in order to protect the integrity of rock salt layer cores, salt should be added to the mud as a stabilizer, and barium sulfate, a salt chemical product, should be used to increase the weight of drilling mud and as a regulator. In petroleum refining, salt is used as dehydrating agent to remove water mist from gasoline. In the process of kerosene refining, salt is used as the filter layer to remove impurities. There are also many salt chemical products widely used in petroleum industry, such as: some oil-soluble organic acid barium salts can be used as accelerant for gasoline combustion to promote gasoline complete combustion; Magnesium oxide, magnesium hydroxide and magnesium carbonate can be added to fuel oil as ash modifiers to prevent high temperature corrosion of vanadium compounds; The hardness of boron nitride made from boron is equal to that of diamond, and its stability is better than that of diamond at high temperature of 1500- 1600℃, so it can be used as superhard material to produce oil drilling bits.