Anhydrous Caustic Soda (sodium hydroxide) is produced by multi-stage evaporation process and transformed into the solid state either as micro spherical particles called Prills (Pearl) or as Caustic Soda Solid (Fused).
- Prills (Caustic Soda Prills)
- Solid (Caustic Soda Solid [Fused])
- Highly hygroscopic and deliquescent (soluble in the moisture absorbed from the atmosphere).
- Odourless, non-combustible and has no explosive limit.
- Reacts with carbon dioxide present in the air to form sodium carbonate.
- Reacts exothermically with metals such as lead, zinc, aluminium (to form sodium aluminate NaAlO2), magnesium and other metals, resulting in the evolution of hydrogen gas.
- Reacts with many acids to form the sodium salt of the acid anion plus water for example with hydrochloric acid to form sodium chloride.
- Reacts with methanol to form sodium methoxide, a powerful base used for the production of many metal carboxylates used in the coatings industry and for the production of biodiesel
Caustic Soda in the form of Prill’s offer distinct advantages over flakes, as shown below:
- Uniform and optimum size of prills facilitate good blending characteristics in dry mix formulation and possess excellent free-flow properties.
- Prills are hard and crush resistant hence do not easily break down into irritant dust. Low irritant dust means low moisture absorption, greatly reduces the risk of caking and operator safety.
- Prills dissolve faster needing only a shorter period of agitation.
- Prills being denser than flakes, occupy less space for the same weight of Caustic. This permits optimum utilization of storage facilities and minimal transport cost in shipping.