Caustic Soda Definition

Caustic Soda, also known as Sodium Hydroxide (NaOH) and lye is an important chemical with wide applications in many industries throughout the world. The term caustic soda was derived from its chemical properties that is corrosive and caustic. They are an alkaline with considerably high pH (around 14) and because of that they are often used in the oil field as pH controller in drilling mud. Caustic soda in its pure form are a waxy, white solid and they are readily capable to absorb water to form aqueous solutions.

Caustic Soda Usage

Caustic soda is mainly used in the chemical and food industry, but they are also used in some other industries such as aluminum and paper industry. Caustic soda are used to make candles, soaps, rubber bleaching and detergents, tiles, cosmetics, batteries, polymers, and many more. For the food industry, they are used in the process of making soft drinks, alcohols and sugars. They are also used in the pulping process in paper industry.

For the oil & gas industry, they are used to maintain or increase pH in drilling mud (lubricant in drilling operations). Increasing pH with caustic soda precipitates magnesium (Mg2+) and suppresses calcium (Ca2+) in high-hardness waters such as seawater, reduces corrosion, and neutralizes acid gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S).

Caustic Soda Specifications and Properties

Caustic soda doesn’t have any taste, color and odor. However, due to its corrosive property, it can irritate and injure anyone who come in contact to it. It can also damage materials such as leathers, animal skins, some metals like aluminum, magnesium, copper, brass, zinc, silver and iron. Caustic soda can also react with air and this in turn will reduce its quality and also the surrounding air quality. To increase its shelf life, it should be kept in dry place far from moisture.

In terms of specifications, different types of caustic soda have different specifications. However, nearly all of them have same alkalinity, which is around 14 pH. This makes them suitable as an alkaline agent and pH controller in chemical solutions. Caustic soda also have good solubility in water, which is about 110 gram in 100 gram water at 20 degC. This made them a better options compared to other minerals. Caustic soda’s boiling point is 1390 degC and this made them favorable in oil well drilling operations and is widely used as an additive in drilling mud.

Caustic Soda Precautions

Care must be observed when handling caustic soda. Caustic soda and solutions containing more than 5% caustic soda is a strongly corrosive substance. Persons who handle caustic soda should learn about related laws and regulations (such as the Poisonous and Deleterious Substance Control Law), its properties, and precautions on handling; and should observe them to ensure safety. Caustic soda reacts with some metals and it necessary to avoid contact with them. It can also react with organic and inorganic materials such as paraffin compositions, strong acids, some plastics and precautions must be made to avoid contact between them. Caustic soda is soluble in water but the chemical reaction that happen is an exothermic reaction, where heat is produced.