Caustic soda or sodium hydroxide or lye is that chemical from which it is impossible to get rid of. May be only heard the name in your chemistry classes during experiments with bases, but just have a look on the labels of cleaning agents you are using at your home. They may bear Lye, isn’t it?
Caustic soda plays a vital role in chemical manufacturing process as a raw material used in manufacturing textiles, dyes, refinery, paper and other industries. Used in wide range of applications in different industries, Lye acts as a strong base formed with a solution of Sodium Hydroxide in water i.e. NaOH in H2O.
Basically it is a natural co-product of chlorine production. As per the chemistry law, for every tonne of chlorine produced, caustic soda about 1100 kg also produced together with hydrogen about 285 kg.
The manufacturer of sodium hydroxide typically supplies concentrated solution or pure lye to such manufacturers that make soap, detergent, paper and pulp, bleach and other cleaning agents, biodiesel, textiles and garments.
Despite the fact that caustic soda is an important alkali base, it is one of the most hazardous substances in chemistry that must be handled with utmost care. Therefore it is necessary for chemical manufacturers and buyers to know the proper storage and usage of the substance. For example in laboratory, precautions should be applied while handling hazardous chemicals. Caustic soda is like a corrosive chemical that can burn your skin upon exposure, therefore wearing gloves is imperative.
Solid form of compound needs more precautions to avoid eye exposure and fumes inhalation. So it’s good to wear goggles and mask while working with this. The substance is generally incompatible with other materials that may react energetically with them. For example- a single water drop when pour on pellets of caustic soda, it release enough heat to turn water into steam by an explosive exothermal reaction.
Manufacturers can produce lye in number of ways including Mercury Cell Process (where mercury is used to reduce the sodium cations to sodium metal which then react with H2O to form NaOH (base)), Membrane Cell Process (where a membrane is used as a barrier between anode and cathode reaction chamber and through this only water molecules and sodium ions can pass. In this way a high grade lye is produced by an efficient system with low steam and electricity) and Diaphragm Cell Process (where a permeable diaphragm and a steel cathode is used as a barrier and a sodium chloride and water solution is put into the anode chamber, by which dilute caustic brine solution leaves the chamber and requires a purification process to separate the concentrated solution).
