Food grade products are used in the food industry as acid neutralizer, as peeling agent for citrus, peaches, etc., and as detergent for empty bottles, empty cans and other containers, as well as decolorant and deodorant.

When sodium hydroxide is used as basic reagent, it can be used as neutralizing agent, matching masking agent, precipitating agent, precipitation masking agent, absorber of small amount of carbon dioxide and water, and color developer for determination of ketone steroids in thin-layer analysis, etc. It is widely used in the manufacture of all kinds of sodium salts, soaps, paper pulp, finishing of cotton fabrics, silk, viscose fibers, regeneration of rubber products, cleaning of metals, electroplating, bleaching, etc. It is also used as detergent for empty bottles and cans, as well as deodorant.

Applications

In the metallurgical industry, it is often necessary to convert the active ingredients in the ore into soluble sodium salts in order to remove the insoluble impurities, therefore, it is often necessary to add soda ash (which is also a flux), and sometimes caustic soda is also used. For example, in the smelting process of aluminum, used in the preparation of cryolite and bauxite treatment, are to use soda ash and caustic soda.

Another example is the smelting of tungsten, but also the first concentrate and soda ash roasted into soluble sodium tungstate, and then by acid precipitation, dehydration, reduction and other processes to produce powdered tungsten. In the chemical industry, the production of sodium metal, electrolysis of water are used caustic soda.

Many inorganic salt production, especially the preparation of some sodium salts (such as borax, sodium silicate, sodium phosphate, sodium dichromate, sodium sulfite, etc.) are to use caustic soda or soda ash. Synthetic dyes, drugs and organic intermediates also use caustic soda or soda ash.

Reference: Baidu Encyclopedia - Sodium Hydroxide, Baidu Encyclopedia - Caustic Soda Solution