Caustic Soda
Description
Caustic Soda (Sodium Hydroxide) is a highly corrosive, odorless, non-flammable white solid. It is usually produced as shiny pellets or flakes, which are highly water-soluble, making a slippery solution. The 50% solution is slightly viscous. Caustic Soda is a general purpose industrial chemical used extensively by process industries.
Properties
| Parameter | Unit | Quantity |
|---|
| Molecular weight | g/mol | 40 |
Melting point
crystallization begins | °C | 12-15 |
| Specific gravity | °C, 20°C/20°C | 1.53 |
| Specific heat | (cal/gm/°C), 40°C-90°C | 0.766 |
| CAS number | 1310-73-2
14014-06-3 (2H)
12179-02-1 (monohydrat) |
| IUPAC name | Sodium hydroxide |
Specifications
Caustic Soda (Diaphragm)
| Parameter | Unit | Quantity | Test Method |
|---|
| Sodium hydroxide | wt % | 49.5 - 51.5 | HC - 269 |
| Sodium chloride | wt % | 1.05 max. | HC - 435 |
| Sodium chlorate | ppm, wt | 2000 max. | HC - 282 |
| Sodium carbonate | ppm, wt | 2000 max. | HC - 267 |
| Sodium sulfate | ppm, wt | 500 max. | HC - 204 |
| Iron | ppm, wt | 9 max. | ASTM E-291 |
| Appearance | Visual | Clear to Hazy | VISUAL |
Caustic Soda ((Membrane)
| Parameterth> | Unit | Quantity | Test Method |
|---|
| Sodium hydroxide | wt % | 49.5 - 51.5 | ASTM E-291 |
| Sodium chloride | ppm, wt | 200 max. | ASTM E-291 |
| Sodium chlorate | ppm, wt | 50 max. | HC - 282 |
| Sodium carbonate | ppm, wt | 2000 max. | ASTM E-291 |
| Sodium sulfate | ppm, wt | 200 max. | ASTM D-501 |
| Iron | ppm, wt | 2 max. | ASTM D-1068 |
Note:
- ASTM : American Society for Testing and Materials.
- HC : Houston Chemical Method Series.
Hazards and safety
Caustic Soda is highly corrosive to skin tissue and the eyes and
must be handled with care. Appropriate warnings, safety showers
and eyewash stations must be located in all areas where Caustic
Soda is stored or used. It is highly recommended that Caustic
Soda be handled only by trained personnel wearing long sleeve
clothing and equipped with protective eye goggles, rubber gloves,
body apron, respirator and other safety equipment as required.
Additionally, personnel who handle Caustic Soda need to know that
considerable heat will be generated when water is added to the
caustic solution.
Applications
Caustic Soda is a highly versatile chemical. Included among its many applications are the following: acid neutralization, bleaching in paper making and cotton processing, petroleum refining, production of alumina from bauxite, manufacturing synthetic fabrics such as rayon, production of soaps and detergents, and also manufacturing food products.
Storage and handling
Caustic Soda is normally handled and stored in iron or steel containers and at temperatures above 15°C and below 55°C. At temperatures higher than 55°C, the caustic solution may pick up iron, which could cause it to deteriorate in time due to caustic embattlement. Stainless steel, nickel and Monel 400 are recommended for handling Caustic Soda in higher temperatures. It is also good practice to tore Caustic Soda in higher temperature conditions in tanks lined with an organic metal. At temperatures below 15°C, a Caustic Soda solution will start to freeze. If the ambient temperature falls below 15°C, a source of heating for the caustic tank is required. A small low-pressure steam coil inside the tank is adequate for keeping the caustic solution within recommended temperature ranges.