Application range and use of sodium hydroxide

Application range and use of sodium hydroxide

YANGZHOU EVERBRIGHT CHEMICAL CO.LTD.

Caustic soda tablet is a kind of caustic soda, chemical name sodium hydroxide, is a soluble alkali, extremely corrosive, can be used as acid neutralizer, with masking agent, precipitating agent, precipitation masking agent, color agent, saponification agent, peeling agent, detergent and so on

Very versatile. Common uses of caustic soda tablets are summarized as follows:

1, papermaking:

papermaking raw materials are wood or grass plants, these plants in addition to cellulose, but also contains a considerable amount of non-cellulose (lignin, gum, etc.). Flake alkali is used for delignification, and the fiber can only be obtained by removing the lignin from the wood. The non-cellulose component can be dissolved by adding dilute caustic soda solution, so that cellulose as the main component of pulp can be prepared.

2, refined petroleum:

After the petroleum products are washed with sulfuric acid, some acidic substances must be washed with tablet alkali solution, and then washed to obtain refined products.

3. Textile:

cotton and linen fabrics are treated with concentrated sodium hydroxide (caustic soda) solution to improve fiber properties. Artificial fibers such as artificial cotton, artificial wool, rayon, etc., are mostly viscose fibers, they are made of cellulose (such as pulp), caustic soda, carbon disulfide (CS2) as raw materials, made of viscose, by spinning, condensation.

4, printing and dyeing:

cotton fabric with alkaline solution treatment, can remove covered in cotton fabric wax, grease, starch and other substances, while increasing the mercerization color of the fabric, so that dyeing more uniform.

5, making soap:

the main component of soap is the sodium salt of advanced fatty acids, usually made of oil and alkali tablets as raw materials through saponification reaction. In addition to high fatty acid salts, soap also contains rosin, water glass, spices, dyes and other fillers. Structurally, the higher fatty acid sodium contains a non-polar hydrophobic part (hydrocarbon group) and a polar hydrophilic part (carboxyl group). The hydrophobic group has oleophilic properties. During washing, the grease in the dirt is stirred and dispersed into small oil droplets, and after contact with the soap, the hydrophobic group (hydrocarbon group) of the higher fatty acid sodium molecules is inserted into the oil droplets, and the oil molecules are bound together by van der Waals forces. The hydrophilic group (carboxyl group), which is easily dissolved in water, is extended outside the oil drop and inserted into the water. The main ingredient of soap is NaOH, but NaOH is not soap. Its aqueous solution is greasy and can be used as soap. Soap is an emulsifier. The principle is the saponification reaction CH3CO0CH2CH3+NaOH=CH3COONa+CH3CH2OH, and CH3COONa is the active ingredient in soap.

6, chemical industry:

make metal sodium, electrolytic water are to use tablets of alkali. The production of many inorganic salts, especially the preparation of some sodium salts (such as borax, sodium silicate, sodium phosphate, sodium dichromate, sodium sulfite, etc.) are used in tablet alkali. It is also used in the synthesis of dyes, drugs and organic intermediates.

7, metallurgical industry:

often to transform the active component of the ore into soluble sodium salt, in order to remove the insoluble impurities, therefore, often need to add alkali tablets. For example, in the smelting process of aluminum, the preparation of cryolite and the treatment of bauxite are used.

8, the use of lime to improve the soil：

in the soil, because the organic matter in the decomposition process will produce organic acids, weathering of minerals may also produce acidic substances. In addition, the use of inorganic fertilizers such as ammonium sulfate, ammonium chloride, etc., will also make the soil acidic. Applying the right amount of lime can neutralize the acid in the soil, make the soil suitable for crop growth, and promote the propagation of microorganisms. After the increase of Ca2+ in the soil, it can promote the condensation of soil colloid, which is conducive to the formation of aggregates, and at the same time, it can supply the calcin required for plant growth.

9. Alumina production :

NaOH solution is heated to dissolve alumina in bauxite and obtain sodium aluminate solution. After the solution is separated from the residue (red mud), the temperature is lowered, aluminum hydroxide is added as crystal seed, after a long time of stirring, sodium aluminate is decomposed into aluminum hydroxide, washed, and calcined at 950~1200℃, the finished aluminum oxide is obtained. The solution after precipitation of aluminum hydroxide is called mother liquor, which is evaporated and concentrated and recycled. Due to the different crystalline structures of diaspore, diaspore and diaspore, their solubility in caustic soda solution is very different, so it is necessary to provide different dissolution conditions, mainly different dissolution temperatures. The diaspore type bauxite can be dissolved at 125~140C, and the diaspore type bauxite can be dissolved at 240~260℃ and the addition of lime (3~7%).

10, ceramics:

caustic soda in the ceramic manufacturing role has two points: first, in the firing process of ceramics, caustic soda as a diluent. Second, the surface of the fired ceramic will be scratched or very rough, and after cleaning with caustic soda solution, the ceramic surface will be smoother.

11, disinfection:

the virus protein denaturation. These are mainly used for cleaning and disinfecting bottles in the wine industry.

12, in addition to wastewater:

strong sodium oxide to adjust the ph value, sewage treatment, so that resources recycling.

13, chemical preparations, industrial additives：

Tablet alkali is mainly used in the pharmaceutical industry to alkalize solutions or adjust the pH value of pharmaceutical solutions.

14, electroplating, tungsten refining.：

Alkali tablets in metal plating as electroplating solution, play the role of conductor!

15, manufacture silk, manufacture rayon cotton.

16. Leather industry (Introduction of two uses of alkali tablets)：

(1) For the recycling process of tannery waste ash liquid, soak and add sodium sulfide aqueous solution in the existing expansion process

Between the two steps of lime powder soaking treatment, the use of 30% sodium hydroxide solution with tare weight 0.3-0.5% is increased to make the skin fiber fully expanded to meet the process requirements and improve the quality of semi-finished products.
(2) As an alkaline medium and a neutralizer, add the amount of water to the reactor, and then heat up to 90 ° C through steam, stir while adding polyvinyl alcohol, and then cool down to 80 ° C after the polyvinyl alcohol is completely dissolved. After stirring, add hydrochloric acid in a trickle, continue to stir for 20 to 30 minutes, and add the formula amount of formaldehyde water. Keep it warm at 78~80℃, allow it to react for 40~50 minutes, add the configured 10% sodium hydroxide solution for neutralization, cool it down to 60~70℃, then add the formula urea for amino treatment, and filter the glue solution through the yarn net for reserve use.

17, polyester chemical industry：

used for the manufacture of formic acid, oxalic acid, borax, phenol, sodium cyanide and soap, synthetic fatty acids, synthetic detergent, etc.

18, textile printing and dyeing industry：

used as cotton desizing agent, boiling agent, mercerizing agent and reduction dye, Haichang blue dye solvent.

19, smelting industry：

used to manufacture aluminum hydroxide, aluminum oxide and metal surface treatment agent.

20, instrument industry,：

used as acid neutralizer, decolorizing agent, deodorizing agent.

21, adhesive industry：

used as starch gelatinizer, neutralizer.

22, manufacture phosphate, manufacture manganate.

23. Regeneration of old rubber.

24, can be used as citrus, peach peeling agent and decolorizing agent, deodorant.

25, tablet alkali is also used in pesticide manufacturing.