How to properly dissolve caustic soda flakes

Sodium hydroxide (NaOH), also known as caustic soda, is an alkali that saponifies acids and fats in the process of making soap.

 

At room temperature, it is a white, crystalline, odorless powder that absorbs moisture from the air. It is soluble in water and ethanol but insoluble in ether. When dissolved in water or neutralized with an acid, caustic soda releases a large amount of heat, enough to ignite combustible materials and the aqueous solution known as lye.

 

Caustic soda can be found in liquid or solid form (e.g., flakes, granules or micropearls.) Both forms have the same chemical formula and the same applications; therefore, they are interchangeable.

 

Granulated caustic soda is the form that has the largest contact area due to its small particle size, and therefore is the easiest to dissolve.

 

It is also possible to obtain 50% caustic soda, but it must be crystal clear, because if it is cloudy, it has absorbed CO2 (carbon dioxide) from the air and has formed sodium carbonate.

Before working with caustic soda, it is important to use a surgical mask to avoid inhaling it. Latex or gardening-type gloves should also be used, as well as safety glasses.

 

The steps are:

 

- According to directions, place the the amount of water that will be used in a Pyrex-type flask (because the temperature will rise.) Ideally, the water should be cold.

- Measure the caustic soda (flakes or pearls) and add it to the water, taking care to do this neither too fast nor too slow. The soda should be sprinkled because it will sink to the bottom quickly. Always add the soda to the water, never vice versa.

- Using a Teflon-type spoon, stir slowly without shaking or whisking. A hard layer will form at the bottom and the solution will become cloudy. This is normal. Never use a shaker or blender for soda.

- Let the solution stand for a few minutes, then continue stirring and gradually everything will dissolve and the solution will become clearer. The final state of the solution will always be clear.

- The soda should be prepared just before use at the temperature recommended. It should not be allowed to cool. If it cools completely, it will absorb carbon dioxide from the surrounding environment and will form a layer of sodium carbonate that will cloud the solution.

Caustic soda is used primarily in the following areas: manufacturing industries including cotton, synthetics, plastics, textiles and soaps; organic and inorganic chemistry industries (in the manufacture of sodium compounds); the food industry; water treatment; the agricultural industry; etc.

 

It is used in the manufacture of paper, textiles, detergents, synthetics, explosives, dyes and petroleum products; in the processing of cotton textiles; and, in laundry, bleaching, oxidation, electroplating, and electrolyte removal. Other uses include absorbing acid gases such as carbon dioxide or sulfur dioxide.

 

Caustic soda is used as a raw material in the production of sodium hypochlorite, as well as in all types of textiles (finishing and dressing, obtaining cellulose fibers from the viscose process, etc.) It is used as a surfactant and detergent  in the paper and pulp, and oil and gas industries.

 

Industria Química del Istmo S.A. de C.V. (IQUISA) is a producer and seller of chlorine, sodium hypochlorite, hydrochloric acid, muriatic acid, and liquid and solidified caustic soda. These are used in various applications in the chemical industry, as well as in water purification and the manufacture of cleaning products for the home.

 

For more information about caustic soda granules, flakes or liquid, click here and contact them.

 

To learn more IQUISA, click here

 

Sources:

http://es.wikipedia.org/wiki/Hidr%C3%B3xido_s%C3%B3dico

http://www.monografias.com/trabajos15/hidroxido-sodio/hidroxido-sodio.shtml

http://www.pinsapo.com/modules.php?name=News&file=article&sid=328

http://www.dgdc.meh.es/Informes%20SGC/N05035INFWEB.pdf