Salt also is added to secure the soil and to provide firmness to the foundation on which highways are built. Salt brine and sulfuric acid are used to coagulate an emulsified latex made from chlorinated butadiene. In rubber manufacture, salt is used to make buna, neoprene and white rubber types. In tanning and leather treatment, salt is added to animal hides to inhibit microbial activity on the underside of the hides and to attract moisture back into the hides. The chlorine dioxide process, which originated in Germany after World War I, is becoming more popular because of environmental pressures to reduce or eliminate chlorinated bleaching compounds.
It also is used to make sodium chlorate, which is added along with sulfuric acid and water to manufacture chlorine dioxide, an excellent oxygen-based bleaching chemical. In the pulp and paper industry, salt is used to bleach wood pulp. It is also used in processing aluminium, beryllium, copper, steel and vanadium. One of its main roles is to provide the positive ion charge to promote the absorption of negatively charged ions of dyes. In textiles and dyeing, salt is used as a brine rinse to separate organic contaminants, to promote "salting out" of dyestuff precipitates, and to blend with concentrated dyes to standardize them. Salt is also used to increase the curing of concrete in cemented casings. Whenever a drill hits a salt formation, salt is added to the drilling fluid to saturate the solution in order to minimize the dissolution within the salt stratum. It is used to flocculate and increase the density of the drilling fluid to overcome high downwell gas pressures. In oil and gas exploration, salt is an important component of drilling fluids in well drilling. Sodium chloride is heavily used, so even relatively minor applications can consume massive quantities. These methods listed provide procedures for analyzing sodium chloride to determine whether it is suitable for its intended use and application.
The standard is named ASTM E534-13 and is the standard test methods for chemical analysis of sodium chloride. Sodium chloride has an international standard that is created by ASTM International. In the Mannheim process, sodium chloride is used for the production of sodium sulfate and hydrochloric acid. Sodium carbonate, in turn, is used to produce glass, sodium bicarbonate, and dyes, as well as a myriad of other chemicals. Sodium chloride is used in the Solvay process to produce sodium carbonate and calcium chloride. Sodium hydroxide is extensively used in many different industries enabling production of paper, soap, and aluminium etc. Some applications of chlorine include PVC thermoplastics production, disinfectants, and solvents. Other technologies are under development due to the high energy consumption of the electrolysis, whereby small improvements in the efficiency can have large economic paybacks.
Each of those uses a different method to separate the chlorine from the sodium hydroxide. This electrolysis is conducted in either a mercury cell, a diaphragm cell, or a membrane cell. It is the starting point for the chloralkali process, the industrial process to produce chlorine and sodium hydroxide, according to the chemical equation 2 NaCl + 2 H 2 O → e l e c t r o l y s i s Cl 2 + H 2 + 2 NaOH
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