Caustic Soda
Applications
Caustic Soda (Sodium Hydroxide) is a highly alkaline and versatile industrial chemical widely used across multiple manufacturing and processing industries. Due to its strong cleaning ability, pH-control properties, and chemical reactivity, caustic soda plays a critical role in many industrial applications.
Chemical Industry
Used as a basic raw material in the manufacture of chemicals, soaps, detergents, solvents, and industrial intermediates.
Soap & Detergent Industry
Extensively used in soap making, detergent production, and cleaning formulations for saponification and effective grease removal.
Paper & Pulp Industry
Applied in pulping and bleaching processes to remove lignin and improve paper quality and brightness.
Textile Industry
Used in textile processing, dyeing, and mercerization of cotton fabrics to improve strength, luster, and dye absorption.
Water Treatment
Used for pH adjustment, water purification, and wastewater treatment in municipal and industrial plants.
Aluminum & Metallurgical Industry
Used in bauxite processing for the production of alumina and for surface cleaning of metals.
Oil & Gas Industry
Applied in petroleum refining and oil processing to remove acidic components and impurities.
Food Industry (Food Grade Caustic Soda)
Used under controlled conditions for food processing, cleaning, peeling of fruits and vegetables, and equipment sanitation.
Pharmaceutical Industry
Used in drug manufacturing and formulation processes for pH regulation and chemical synthesis.
| Sr No. | Characteristics | Requirements (On 100% basis) | Requirements (47.5% Caustic Lye)* | Requirements (32% Caustic Lye)* | Average Quality (32% Caustic Lye) | Average Quality (47.5% Caustic Soda Lye) |
| 1 | Sodium Hydroxide (as NaOH) Percent by mass, min. | 99.5% | 47.5% | 32% | 32% | 47.5% |
| 2 | Sodium Carbonate (as Na2CO3) Percent by mass, max. | 0.40 | 0.19 | 0.13 | 0.13 | 0.19 |
| 3 | Chlorides (as NaCl) ppm, max. | 1000 | 475 | 320 | 30 | 50 |
| 4 | Sulphates (as Na2SO4) ppm, max. | 1000 | 475 | 320 | N.D. | N.D. |
| 5 | Silicates (as SiO2) ppm, max. | 200 | 96 | 64 | 08 | 10 |
| 6 | Iron (as Fe) ppm, max. | 20 | 9.5 | 6.4 | 1.0 | 2.0 |
| 7 | Copper (as Cu) ppm, max. | 2 | 0.95 | 0.64 | N.D. | N.D. |
| 8 | Manganese (as Mn) ppm, max. | 1 | 0.48 | 0.32 | N.D. | N.D. |
| 9 | Chlorates and Perchlorates (as NaClO3) ppm, max | 10 | 4.8 | 3.2 | – | – |
| 10 | Matter Insoluble in water Percent by mass, max. | 0.05 | 0.024 | 0.016 | Nil | Nil |
Note: N.D. = Not Detectable. *Requirement of 47.5% and 32% Caustic Soda Lye is derived from the specification of 100% Caustic Soda Lye.