Sodium hydroxide (Sodium hydroxide)

1. Strong alkaline, solid caustic soda has strong hygroscopicity. It is easily soluble in water and exothermic when dissolved. The aqueous solution is alkaline and has a smooth feeling; it is extremely corrosive and has a corrosive effect on fibers, skin, glass, ceramics, etc. It reacts with metal aluminum and zinc, non-metal boron and silicon to release hydrogen; it reacts with halogens such as chlorine, bromine, and iodine; it neutralizes with acids to form salt and water. Staff should be well protected, if accidentally touch the skin and eyes, should be immediately rinsed with plenty of water. The working environment should have good ventilation conditions. Easy to moisture, soluble in water, ethanol, glycerol (glycerol). The aqueous solution has a smooth feeling and generates high heat when dissolved in water. When operating, wear protective goggles and rubber gloves. Be careful not to splash on the skin or eyes. In case of touching skin, it can be washed with 5% ~ 10% magnesium sulfate solution, then rinse with a large amount of water, and rinse with boric acid water and a large amount of water into eyes.

2. Stable stability

3. Prohibition of strong acids, flammable or combustibles, carbon dioxide, peroxides, water

4. Avoid contact with humid air

5. Polymerization harms non-polymerization

6. Decomposition product sodium oxide

Basic chemical raw materials, used as high purity reagent, are widely used in chemical industry, metallurgy, papermaking, petroleum, textile, daily chemical industry and other departments.; Used for acid calibration in analysis; Mainly used for viscose rayon, synthetic fiber, dye intermediate, rubber regeneration, fabric bleaching and dyeing, paper making, soap making..

Production in industry caustic soda has two methods: causticization and electrolysis. The causticization method is divided into soda ash caustic method and soda ash caustic method according to different raw materials; The electrolytic method can be divided into diaphragm electrolysis method and ion exchange membrane method.

1. Soda ash caustic method: soda ash and lime are respectively converted into soda ash solution and ash into lime milk. Causticizing reaction is carried out at 99~101 ℃, and the causticized solution is clarified, evaporated and concentrated to more than 40%, liquid caustic soda is prepared. The concentrated solution is further boiled and solidified to produce solid sodium hydroxide finished products. Causticized mud is washed with water, which is used to convert alkali. The reaction equation is as follows:

2. Caustic soda caustic soda caustic soda after crushing, dissolving (or alkali brine), after clarification, add lime milk to be causticized at 95 ~ 100℃, caustic liquor after clarification, evaporation and concentration to about 46% of NaOH concentration, the clear liquid is cooled and boiled further after salt evolution. Solid sodium hydroxide finished products are made. The causticized mud is washed with water, which is used to dissolve the Trona. Its

the diaphragm electroboat method adds soda ash, caustic soda and barium chloride concentrate to remove impurities such as calcium, magnesium and sulfate ions, and then adds sodium polyacrylate or causticized bran into the clarification tank to accelerate precipitation, after sand filtration, hydrochloric acid is added to neutralization, brine is preheated and sent to electrolysis, electrolyte is preheated, evaporated, divided into salt and cooled to prepare liquid caustic soda, and solid sodium hydroxide finished product is obtained after further boiling. Salt mud washing water is used to convert salt. Its

3. The ion exchange membrane method refines the raw salt after salt conversion according to the traditional method, filters the primary salt water through microporous sintered carbon tubular filter, and then performs secondary refining through chelated ion exchange resin tower, the content of calcium and magnesium in the brine is reduced to less than 0.002%, and the secondary refined brine is electrolyzed to generate chlorine in the anode chamber, na + in the brine of the anode chamber enters the cathode chamber and cathode chamber through Ionic screen protector for 0H to generate sodium hydroxide, and H + directly discharges on the cathode to generate hydrogen. In the electrolysis process, add a proper amount of high purity hydrochloric acid to the anode chamber to neutralize the back-moving OH-, and add the required pure water to the cathode chamber. The concentration of high purity caustic soda generated in the cathode chamber is 30%~ 32%(mass), which can be directly used as liquid alkali product or further concentrated to produce the finished caustic soda of the peripheral body. Its

purification method of sodium hydroxide: Impurities contained in sodium hydroxide usually include iron, sodium chloride, silicate, carbonate, etc. Take 100g industrial sodium hydroxide dissolved in 1L anhydrous ethanol (excluding acetaldehyde), filter in dry air without carbon dioxide and moisture, remove impurities such as chloride, carbonate, silicate, and concentrate filtrate to remove ethanol, the generated solid sodium ethoxide are separated with concentration. Washing with pure absolute ethanol for several times and heating under reduced pressure for a long time to remove the residual ethanol, sodium hydroxide with a purity of about 99.8% is obtained.

Electrolytic method and causticization method are adopted. Electrolytic method is divided into Mercury electrolytic method and diaphragm electrolytic method. Mercury electrolysis salt after adding soda ash, caustic soda and barium chloride to remove tungsten, magnesium, sulfate and other impurities. After clarification, sand filtration, addition of hydrochloric acid, and then preheating, electrolysis. Membrane electrolysis is to salt salt, add soda ash, caustic soda and barium chloride, remove tungsten, magnesium and sulfate