potassium nitrate

inorganic compound

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This entry is made by Compilation and application of scientific encyclopedia entries of "Science Popularization China" to examine.

Potassium nitrate is a kind of inorganic compound , commonly known as Gunite or Soil nitrate ， chemical formula Is KNO 3， It's potassium Nitrate , colorless transparent rhombic crystal or rhombic crystal or white powder, odorless, salty and cool. It absorbs little moisture in the air and is not easy to agglomerate, Soluble Soluble in water liquid ammonia and glycerol , insoluble in Anhydrous ethanol and Ether 。

Potassium nitrate is a chlorine free nitrogen and potassium compound fertilizer with high solubility. Its effective components, nitrogen and potassium, can be quickly absorbed by crops without chemical residues. As fertilizer, it is suitable for vegetables, fruits and flowers, and some chlorine sensitive crops (such as potatoes, strawberries, beans, cabbage, lettuce, peanuts, carrots, onions, blueberries, tobacco, apricots, grapefruit, avocados, etc.).

Potassium nitrate is Strong oxidant , and organic compound Contact can cause burning and blast With toxic and irritating odor^{[6 ]} 。 Therefore, potassium nitrate should be stored in a cool and dry place, away from kindling and heat sources. Never store and transport together with reducing agents, acids, combustible materials and metal powders.^[1]

Listed in the List of Explosive Hazardous Chemicals^[3] , and Control according to the Measures for Public Security Management of Explosive Hazardous Chemicals^[4] 。

Chinese name: potassium nitrate
Foreign name: Potassium nitrate
Alias: Soil nitrate; Gunite; Saltpeter; Saltpetre
chemical formula: KNO three
molecular weight: one hundred and one point one zero
CAS login number: 7757-79-1
EINECS login number: 231-818-8
Melting point: 334 ℃
Water solubility: Easily soluble in water, soluble in glycerin, insoluble in absolute ethanol, ether

Density: 2.109 g/cm³
Appearance: Colorless transparent rhombic or triangular crystal system particles or white powder
Flash point: 400 ℃
Application: Used in the manufacture of fireworks, gunpowder, matches, medicine, and glass industry
Security description: S7；S17；S24/25；S26；S36；
Hazard symbol: O
Hazard description: R8
UN dangerous goods number: one thousand four hundred and eighty-six

catalog

nine Operation, disposal, storage and transportation
ten security information
▪ Safety terminology
▪ Risk terminology

Development History

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Structural formula of potassium nitrate

70% of the world's potassium nitrate is used for agriculture. Israel and the United States have the largest output, accounting for about three quarters of the world's total, and Chile ranks third. In 1995, the total capacity of potassium nitrate in the world was about 900000 tons per year, of which the output of direct method accounted for about 75%. The current production capacity of potassium nitrate in China was about 60000 tons per year, and the capacity under construction was also 60000 tons per year, of which about 80% was used in industrial sectors.^[2]

Physical and chemical properties

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physical property

Melting point: 334 ℃

flash point ：400℃

Density: 2.109g/cm three^{[5 ]}

Character: colorless transparent prismatic or white particles or crystalline powder. It tastes spicy, salty and cool. Slight deliquescence, less deliquescence than sodium nitrate.

Solubility : Easily soluble in water, insoluble in anhydrous ethanol and ether. It absorbs heat when dissolved in water, and the solution temperature decreases.

chemical property

1. Can participate in redox reaction:

(Black powder reaction) Note that sulfur and potassium nitrate in this reaction are oxidants.

2. Oxidizing in acid environment:

3. Heat and decompose to generate oxygen:

4. The product can cause combustion and explosion by contacting with organic matter, phosphorus and sulfur or heating by impact.

5. Identification method:

Determine according to OT-42 method.

Potassium identification test (1T-27) was positive (with 10% sample solution).

The nitrate identification test (IT-23) was positive (with 10% sample solution).

6. Content analysis:

Accurately weigh about 0.4g of the sample (pre dried at 105 ℃ for 4h) and dissolve it into 300mL of water in a 500mL round bottom flask. After adding 3g of Devada alloy powder and 15mL of 40% sodium hydroxide solution, connect the splash proof ball and condenser with the flask. Put 50mL of 0.1mol/L sulfuric acid into the receiver, leave it for 2h, distill it until 250mL of distillate, titrate the excess sulfuric acid with 0.1mol/L sodium hydroxide, and use three drops of methyl red methylene blue test solution (TS-150) as the indicator. At the same time, carry out blank test and make necessary corrections. Each milliliter of 0.1mol/L sulfuric acid is equivalent to 10.11mg of potassium nitrate (KNO ≮).

Toxicological data

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Acute toxicity: LD fifty : 3750mg/kg (rat by mouth)

Other harmful effects: the substance may be harmful to the environment and has accumulation in groundwater.

application area

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Potassium nitrate is the raw material for making black powder, such as mine powder, fuse, firecracker, etc. It is also used in fireworks to produce purple sparks. Mechanical heat treatment is used as salt bath for quenching. The ceramic industry is used to manufacture porcelain glaze and color medicine. Used as glass clarifying agent. It is used to manufacture glass shells of automobile lamps, optical glass picture tubes, etc. The pharmaceutical industry is used to produce penicillin potassium salt and rifampicin. Used for making cigarette paper. Used as a catalyst. Mineral processing agent. It is used as a compound fertilizer for crops and flowers. Potassium nitrate is also a colouring agent allowed in China. In meat products, it is reduced to potassium nitrite due to bacterial action, which plays the role of color protection and bacteriostasis. According to Chinese regulations, it can be used in meat products. The maximum use amount is 0.5g/kg, and the residue amount shall not exceed 0.03g/kg. Industrial potassium nitrate is also widely used in the manufacturing process of reinforced glass.

Protective measures

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Engineering control: the production process is closed and ventilation is strengthened. Provide safety shower and eyewash equipment.

Respiratory system protection: It is recommended to wear a hood type electric air supply filter type dust respirator when it may be exposed to dust.

Eye protection: protection has been made in respiratory system protection.

Body protection: wear polyethylene gas protective clothing.

Hand protection: wear neoprene gloves.

Other protection: smoking, eating and drinking are prohibited at the work site. After work, take a shower and change clothes. Keep good hygiene habits.

First aid measures

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Skin contact: Take off contaminated clothes immediately, and wash with plenty of flowing water for at least 15 minutes. Get medical attention.

Eye contact: immediately lift the eyelid, and thoroughly flush it with a large amount of flowing water or physiological saline for at least 15 minutes. Get medical attention.

Inhalation: quickly leave the site to a place with fresh air. Keep the respiratory tract unobstructed. If breathing is difficult, give oxygen. If breathing stops, perform artificial respiration immediately. Get medical attention.

Ingestion: Rinse with water and drink milk or egg white. Get medical attention.

Fire fighting measures

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Hazardous characteristics: strong oxidant. In case of combustible fire, it can promote the fire. There is a risk of combustion and explosion when contacting or mixing with organic substances, reducing agents, combustibles such as sulfur, phosphorus, etc. During combustion and decomposition, toxic nitrogen oxide gas is released. It decomposes under heat and gives off oxygen.

Hazardous combustion products: nitrogen oxides, nitrite dust.

Extinguishing method: firefighters must wear gas masks and full body fire-fighting clothes to extinguish the fire in the upwind direction. Misty water and sand. Do not spray water directly onto molten materials to avoid serious flowing fire or severe boiling splash.

Leakage emergency treatment

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Isolate the leakage contaminated area and restrict access. It is recommended that emergency personnel wear dust masks (full face masks) and gas suits. Do not touch the leakage directly. Do not allow the leakage to contact with organics, reducing agents and inflammables.

Small amount of leakage: wash with a large amount of water, and put the diluted washing water into the waste water system.

Large amount of leakage: covered with plastic cloth and canvas. Then collect and recycle or transport to waste disposal site for disposal.

Operation, disposal, storage and transportation

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Precautions for operation: close operation and strengthen ventilation. Operators must be specially trained and strictly abide by the operating procedures. It is recommended that operators wear hood type electric air supply filter type dust respirator, polyethylene gas suit and neoprene gloves. Keep away from kindling and heat sources, and smoking is strictly prohibited in the workplace. Keep away from flammable and combustible materials. Avoid dust generation. Avoid contact with reducing agents, acids and active metal powders. Load and unload gently during transportation to prevent damage to packaging and containers. Fire fighting equipment and leakage emergency treatment equipment of corresponding types and quantities shall be provided. Empty containers may leave harmful substances.

Precautions for storage: store in a cool, dry and well ventilated warehouse. Keep away from kindling and heat sources. The storage temperature shall not exceed 30 ℃, and the relative humidity shall not exceed 80%. It shall be stored separately from reducing agents, acids, combustible (combustible) materials and active metal powder, and mixed storage is strictly prohibited. The storage area shall be equipped with appropriate materials to contain leakage.

Packaging method: two layers of plastic bags or one layer of plastic bags outside gunny bags, plastic woven bags, latex cloth bags; Composite plastic woven bag outside the plastic bag (polypropylene three in one bag, polyethylene three in one bag, polypropylene two in one bag, polyethylene two in one bag); Ordinary wooden case outside screw mouth glass bottle, plastic bottle or plastic bag; Screw mouth glass bottle, iron cap pressure mouth glass bottle, plastic bottle or ordinary wooden case outside metal bucket (can).

Precautions for transportation: during railway transportation, the dangerous goods shall be loaded in strict accordance with the dangerous goods loading table in the Dangerous Goods Transportation Rules of the Ministry of Railways. It shall be transported separately, and the container shall not leak, collapse, fall or be damaged during transportation. The transport vehicles shall be equipped with corresponding types and quantities of fire-fighting equipment. It is strictly prohibited to transport together with acids, inflammables, organics, reducing agents, spontaneous combustion materials, inflammables in wet conditions, etc. During transportation, the speed should not be too fast, and forced overtaking is not allowed. Transport vehicles shall be thoroughly cleaned before and after loading and unloading. It is strictly prohibited to mix with organic substances, combustibles and other impurities.