Hydrofluoric acid (English: Hydrofluoric Acid) is an aqueous solution of hydrogen fluoride gas, a clear, colorless, smoky corrosive liquid with a strong pungent odor. The melting point is -83.3°C, the boiling point is 19.54°C, the flash point is 112.2°C, and the density is 1.15g/cm3. Easily soluble in water and ethanol, slightly soluble in ether.
Because the bonding ability between hydrogen atoms and fluorine atoms is relatively strong, and there are hydrogen bonds between hydrogen fluoride molecules in the aqueous solution, so that hydrofluoric acid cannot be completely ionized in water, so in theory, low-concentration hydrofluoric acid is a weak acid. It is highly corrosive and can strongly corrode metals, glass and silicon-containing objects. Inhalation of vapor or contact with skin can cause incurable burns. The laboratory generally uses fluorite (the main component is calcium fluoride) and concentrated sulfuric acid to prepare it, and it needs to be sealed in a plastic bottle and stored in a cool place.
Pathogenesis
Hydrogen fluoride is irritating and corrosive to clothing, skin, eyes, respiratory tract, digestive tract mucosa, and fluoride ions can combine with calcium and magnesium ions when entering the blood or tissues, making it insoluble or slightly soluble calcium fluoride and magnesium fluoride. Larger ones can directly block blood vessels and directly or indirectly affect the functions of the central nervous system and cardiovascular system, leading to hypocalcemia and hypomagnesemia syndrome. Fluoride ions can also combine with hemoglobin to form fluorohemoglobin and inhibit succinate dehydrogenase. Causes a decrease in oxygenation and affects cellular respiratory function. In addition, hydrofluoric acid can cause obvious burns at the contact site, dehydration and dissolution of tissue proteins, and can quickly penetrate the stratum corneum, penetrate deep tissues, dissolve cell membranes, and cause tissue liquefaction. In severe cases, it can reach the periosteum and bone, making bones Calcium fluoride forms a slow-healing ulcer. Inhalation of high concentrations of vapor or percutaneous absorption can cause pulmonary edema.
Hazard protection
Health hazards: It has a strong corrosive effect on the skin. The skin is flushed and dry at the beginning of the burn. The wound was pale, necrotic, and then purple-black or gray-black. Deep burns or improper treatment can form deep ulcers that are difficult to heal and damage the periosteum and bone. This product burns with severe pain. Eye contact with high concentrations of this product can cause corneal perforation. Bronchitis, pneumonia, etc. may occur when exposed to its vapor. Chronic effects: irritation of the eyes and upper respiratory tract, or epistaxis, and decreased sense of smell. There may be tooth erosion. Skeletal X-ray abnormalities and industrial fluorosis are rare.
Combustion and explosion hazard: This product is non-flammable, highly corrosive, and highly irritating, which can cause burns to the human body.
Skin contact: Take off contaminated clothing immediately, rinse with plenty of running water for at least 15 minutes and seek medical attention.
Eye contact: Lift the eyelid immediately, and rinse thoroughly with plenty of running water or saline for at least 15 minutes. Seek medical attention.
Inhalation: Quickly leave the scene to a place with fresh air. Keep the airway unobstructed. Oxygen is given when breathing is difficult, artificial respiration is not allowed, it may cause the person undergoing artificial respiration to inhale hydrogen fluoride gas. Give 2-4% sodium bicarbonate solution nebulized inhalation. Seek medical attention.
Ingestion: Rinse mouth with water, drink milk or egg white. Seek medical attention.
Hazardous characteristics: This product is non-flammable, but it can react with most metals to generate hydrogen and cause an explosion. It burns immediately in case of H blowing agent. Very corrosive.
Hazardous combustion products: hydrogen fluoride.
Extinguishing method: Extinguishing agent: water spray, foam.
Urgent treatment
Emergency treatment: Small spill: mix with sand, dry lime or soda ash. It can also be washed with a large amount of water, and the washing water is diluted and put into the waste water system. A large number of leaks: build a dike or dig a pit for storage. Use a pump to transfer to a tanker or a special collector for recycling or transport to a waste disposal site for disposal.
Operation precautions: Airtight operation, pay attention to ventilation. The operation is as mechanized and automated as possible. Operators must undergo special training and strictly abide by the operating procedures. It is recommended that operators wear self-priming filter gas masks (full face masks), wear rubber acid and alkali resistant clothing, and rubber acid and alkali resistant gloves. Prevent the vapor from leaking into the air in the workplace. Avoid contact with alkalis, active metal powders, and glass products. When handling, load and unload with care to prevent damage to packaging and containers. Equipped with leakage emergency treatment equipment. Empty containers may be harmful residues.
Storage precautions: Store in a cool, ventilated warehouse. Keep away from fire and heat sources. The storage temperature does not exceed 30℃, and the relative humidity does not exceed 85%. Keep the container tightly closed. It should be stored separately from alkalis, active metal powders, and glass products, and avoid mixed storage. The storage area should be equipped with leakage emergency treatment equipment and suitable storage materials. Monitoring method: ion selective electrode method; fluorine reagent-lanthanum salt colorimetry method
Engineering control: Airtight operation, pay attention to ventilation. Be as mechanized and automated as possible. Provide safety shower and eyewash equipment.
Respiratory protection: Wear a self-priming filter gas mask (full face mask) or air respirator when you may be exposed to its smoke. During emergency rescue or evacuation, it is recommended to wear an oxygen respirator.
Eye protection: Respiratory protection has been used for protection.
Body protection: Wear rubber acid and alkali resistant clothing.
Hand protection: Wear rubber acid and alkali resistant gloves.
Other protections: Smoking, eating and drinking are prohibited at the work site. After work, take a shower. Store clothes contaminated by poisons separately and wash them for later use. Maintain good hygiene.
Main purpose: Used as analytical reagent, preparation of high-purity fluoride, glass etching and electroplating surface treatment, etc.
Incompatible materials: strong alkali, active metal powder, glass products.
Waste disposal method: Neutralize with excess lime in water, and the precipitated sediment is landfilled or recycled, and the supernatant is diluted and discharged Into the wastewater system.
 
 
Packaging method: Put it in a lead bucket or a special plastic container, and then put it in a wooden box. Fill the gaps with non-combustible materials; put them in plastic bottles, special bakelite, rubber or lead containers, seal them tightly, and then put them into solid wooden boxes. The wooden box is lined with non-combustible materials, the net weight of each box does not exceed 20 kg, and the package of 3 to 5 kg is limited to 4 bottles per box.
Leak handling
Leakage: Quickly evacuate personnel from the leaked contaminated area to a safe area, and isolate them, strictly restrict access. It is recommended that emergency personnel wear self-contained positive pressure respirators and wear acid-alkali-proof overalls. Do not directly touch the leakage. Cut off the source of leakage as much as possible to prevent entry into restricted spaces such as sewers and flood drains.
Small leakage: Mix with sand, dry lime or soda ash. It can also be washed with a lot of water, and the washing water is diluted and put into the waste water system.
Large leaks: construct dikes or dig pits for storage; use pumps to transfer to tank trucks or special collectors for recovery or transportation Dispose of at the waste disposal site.
Fire fighting method
Flammability: non-combustible
Extinguishing agent: water mist, foam.
Precautions for fire fighting: Firefighters must wear oxygen breathing apparatus and full protective clothing. Ingestion
1. If the patient is about to lose consciousness, has lost consciousness or has spasms, do not feed anything by mouth. 2. 　 Rinse mouth thoroughly with cold water. 3. 　 Do not induce vomiting. 4. 　 Let the patient drink 240-300ml of 10% calcium gluconate solution to dilute the substance in the stomach. 5. 　 If the patient vomits spontaneously, let the patient move forward to avoid inhaling the vomit. 6. Give the patient water repeatedly. 7. Get medical attention.