Product Description
Caustic soda flakes, commonly known as sodium hydroxide flakes, are a strong inorganic alkali with the chemical formula NaOH. The product appears as white, semi-transparent flake solids. Industrial-grade material may exhibit slight coloration due to trace impurities. It is odorless and highly hygroscopic, readily absorbing moisture from the air. When handled, it produces a characteristic slippery sensation. Sodium hydroxide flakes dissolve easily in water, releasing a significant amount of heat and forming a strongly alkaline solution. As a fundamental inorganic chemical raw material, caustic soda flakes are widely used in pulp and paper, textiles, dyeing, petroleum refining, water treatment, metallurgy, and detergent manufacturing industries.
Chemical Properties of Caustic Soda Flakes
Strong Alkalinity. Caustic soda flakes exhibit extremely strong alkalinity. They readily react with acids in neutralization reactions to form salts and water. The product can corrode materials such as glass, ceramics, and aluminum. It reacts with fats and oils through saponification to produce sodium salts of higher fatty acids (the primary component of soap) and glycerol. In addition, it reacts with non-metal oxides such as carbon dioxide to form corresponding sodium salts and water; excess carbon dioxide can further react to produce sodium bicarbonate.
High Corrosiveness. Sodium hydroxide is highly corrosive to human tissues, including skin, mucous membranes, and eyes, and contact may result in severe burns. It also reacts with certain metals, such as aluminum and zinc, generating hydrogen gas and posing potential safety hazards. Furthermore, it can corrode or degrade organic materials such as textiles and paper upon prolonged exposure.
Deliquescent Nature. The product readily absorbs moisture from the air and undergoes deliquescence, gradually dissolving into a sodium hydroxide solution. It also absorbs carbon dioxide from the atmosphere, forming sodium carbonate and potentially affecting product purity. Therefore, airtight storage in a dry environment is essential to maintain quality and stability.
Excellent Solubility. Sodium hydroxide flakes are highly soluble in water, releasing a significant amount of heat during dissolution. The resulting aqueous solution is strongly alkaline, with a pH value of ≥13. The product is also soluble in polar organic solvents such as ethanol and glycerol, but insoluble in non-polar solvents like ether and acetone. At 20°C, its solubility reaches approximately 109 g per 100 mL of water, and solubility increases further as temperature rises.
(1) Industrial Applications
Chemical Industry. A fundamental raw material for the production of detergents, soaps, synthetic fatty acids, dyes, plastics, agrochemicals, and a wide range of chemical intermediates.
Pulp & Paper and Textile Industries. Used in pulp cooking and bleaching processes in paper manufacturing. In the textile industry, it serves as a desizing agent, scouring agent, and mercerizing agent for cotton fabrics, improving strength, luster, and dyeing performance.
Metallurgy. Applied in the digestion of bauxite for alumina production (aluminum refining) and in various metal surface treatment processes.
Petroleum Industry. Utilized in petroleum refining to remove acidic components such as hydrogen sulfide and improve product quality.
Water Treatment. Used to neutralize acidic wastewater and regulate pH levels in industrial and municipal water treatment systems.
Other Uses. Functions as an alkaline drying agent in laboratory applications and serves various other industrial purposes.
(2) Food-Grade Applications
Food Processing. Used as an acidity regulator, peeling agent (e.g., for citrus fruits and peaches), container cleaning agent, as well as a decolorizing and deodorizing agent in food production processes.
Specialized Applications. Applied in the production of preserved eggs, soaking of dried seafood products, edible oil refining, and the manufacture of food flavors and fragrances.