Industrial Hydrofluoric Acid

Hydrofluoric acid is a liquid form of hydrogen fluoride. It is extremely strong and can corrode bones and penetrate muscles. Craftsmen must be careful when using it. However, it can transform metal and stone, so all kinds of craftsmen rely on its skills. Its uses are as follows: 1. Jade carving Glassware may need to be carved and engraved. Hydrofluoric acid can corrode its surface, making it hazy like fog and translucent like gauze. The carving marks on the back of a mirror and the scales of a measuring instrument are all attacked with this acid. 2. Metallurgy The refining of aluminum requires cryolite as a medium, and hydrofluoric acid is the key to making this stone. In addition, the purification of uranium ore and the cleaning of stainless steel also rely on the power of this acid. 3. The transformation of grease In order to transform heavy petroleum oil into light oil, its quality must be cracked. Hydrofluoric acid is a catalyst that helps pyrotechnic fractionation to obtain gasoline, diesel and other products. 4. The wonder of medicine and stone Fluorine can be used as medicine to strengthen teeth and bones. Hydrofluoric acid is the beginning of the production of fluoride. However, it is very poisonous, so craftsmen must use lead or rubber containers to prevent it from leaking. 5. Electrical Works Semiconductor chips use silicon as the base material. Hydrofluoric acid can etch silicon into tiny lines, making the circuits densely packed like ant holes, thus creating the sophisticated devices of today.

Hydrofluoric acid is extremely fierce, corroding gold and penetrating bones, and boiling when it comes into contact with water. However, it is needed in industry, so it must be stored carefully. The method is as follows: 1. Selection of containers Hydrofluoric acid should not be stored in glass or ceramics, for fear of corrosion. It should be stored in lead cans, polytetrafluoroethylene (PTFE) containers, or steel drums lined with rubber or wax grease to avoid leakage. 2. Cool and avoid light This acid is afraid of heat, and it will evaporate when it comes into contact with the sun, so it should be stored in a cool and ventilated place, away from stoves and scorching sun. Water mist should be prepared in the warehouse to prevent acid gas from spreading and hurting people. 3. Isolate water vapor Hydrofluoric acid will boil violently when it comes into contact with water, so the storage container must be sealed to prevent moisture from entering. It should also be protected from rain and dew during transportation to avoid accidental stimulation. 4. Keep away from other objects It should not be stored together with alkali (such as lime, caustic soda) and metal powder, for fear of attacking each other and producing high-temperature toxic smoke. Also stay away from organic matter to avoid unexpected changes. 5. Leakage prevention A pool of lime or calcium carbonate should be set up in the warehouse. If acid leaks, it can be quickly poured in to neutralize its toxicity. Craftsmen who approach it must wear a gel suit and a mask, and prepare calcium gluconate gel to prevent skin contact and first aid.

Hydrofluoric acid is the most poisonous of all acids. It corrodes bones and flesh, and disrupts meridians when it enters the blood. Therefore, craftsmen who use it should be as if they are standing on the edge of an abyss or walking on thin ice. The precautions are listed as follows: 1. Protective equipment The face shield is indispensable - you must wear a gas mask to protect your eyes and nose to prevent acid mist from invading your lungs. The rubber suit must be tightly wrapped - wear acid-resistant gloves (made of fluororubber), aprons, and boots, and do not expose your skin. The best strategy is to keep the air flowing - if you are in a closed place, you should set up an exhaust fan to disperse the acid gas to prevent accumulation and injury. 2. Handling method Avoid spilling when transferring liquid - use a special siphon or plastic dropper to take acid to avoid splashing. Dilution must be slow - if you want to dilute it, you must add acid to water, and it cannot be reversed to avoid boiling and burning the skin. Choose the material of the utensils carefully - polytetrafluoroethylene or lead dishes are recommended for containers, and glass and ceramics must be worn when they are encountered. 3. First aid techniques Wash away the skin quickly if it gets on the skin. If the acid stains the skin, rinse with clean water for half a minute (15 minutes), then apply calcium gluconate gel to slow down the bone-eroding poison. Irrigate the eyes quickly if they get into the eyes. Lift the eyelids and rinse them. Seek medical help immediately. If you delay, you will go blind. Don’t induce vomiting if you swallow it by mistake. Drink milk or aluminum hydroxide gel to protect the internal organs. Seek medical help immediately. 4. Disposal of residual acid Don’t pour out the residual liquid recklessly. It must be neutralized with lime milk or calcium carbonate. Wait until it is inert before discarding it. Put it in a separate place for dirty utensils. After use, the utensils must be soaked in alkaline water and cleaned. Do not mix with ordinary utensils. 5. Things to avoid It is a big taboo to use it alone. Two people must work together, one to handle it and the other to watch it. It can be saved in case of sudden changes. Don’t get close to fireworks. Acid gas will explode when it meets fire. Candles, wax and electric fire are prohibited in the warehouse. Keep away from food and drink. Don’t bring water into the workshop to prevent acid poison from entering the throat and intestines.

1. Observe its shape and color Top quality - clear as water, slightly hazy (mist-like), without suspended residue. Substandard - yellowish green, or turbid, this is caused by iron and sulfur impurities, the etching material is impure. Inferior - turbid like pulp, or with precipitation, such acid should never be used for precision work. 2. Measure its concentration The power of hydrofluoric acid lies in the amount of hydrogen fluoride (HF), which is usually measured in percentage or Baume (°Bé): Commonly used in industry - mostly 40% to 70%, too concentrated is easy to volatilize, too dilute is weak. Electronic grade fine acid - needs to reach more than 49%, and the impurities are very small, it can be used to etch wafers. 3. Check its impurities Iron (Fe) - if it contains too much iron, the acid will be yellowish, and it is easy to leave residues when etching metal. The iron content of top quality acid should be <0.005%. Sulfate (SO₄²⁻) - If there is too much of this substance, the acidity will be unstable, and the inferior acid may exceed 0.02%. Fluorosilicic acid (H₂SiF₆) - It is often impurity in acid, the best one should be less than 1%, if it is too much, it will not etch glass effectively. 4. Classification Commercially available hydrofluoric acid can be divided into three grades according to purity: Industrial grade - used for cleaning metals and petrochemical catalysts, HF content ≥ 40%, slightly more impurities. Reagent grade - used in laboratories, HF is pure, in accordance with GB/T 620-2011. Electronic grade - used for semiconductor etching, impurities must be less than 0.1ppm, so as not to damage the micro-chip. 5. Test its effectiveness To know the strength of the acid, you can try it with the following method: Glass etching test - drop acid on a glass slide, fog marks will appear in a moment, the faster the stronger, the slower the inferior. Test the purity of aluminum sheet - soak the aluminum for a while, take it out and observe it. If the surface is smooth and has no black spots, the acid is pure; if there are stains, it contains sulfur and iron filth.

1. The harm of soil erosion Soil decay - When acid seeps into the ground, it will attack the calcium and magnesium in the soil, making the hard soil soft and loose, losing all its fertility, and preventing crops from growing. Root veins wither - When grass and trees are exposed to it, their roots rot, branches and leaves wither, and they die within three days. Toxic accumulation is difficult to eliminate - Fluoride ions sink into the soil and do not dissipate for years. Even if they are neutralized with lime, it is difficult to restore the original state. 2. The harm of sewage Rivers and lakes are poisoned - If acid flows into streams, fish gills will be corroded, shrimps and crabs will die suddenly, and all aquatic creatures will die. Wells and springs contain filth - Fluoride seeps down and mixes with groundwater. When people and animals drink it, they will have black teeth and brittle bones at the least, and paralysis and death at the worst. Algae and water plants will not grow - Wherever acid water goes, duckweed and algae will turn into mud, and water insects will have no place to live, and it will eventually become a dead pool. 3. Disasters caused by toxic gases Acid mist fills the sky - if acid gas leaks out and drifts with the wind, mulberry and hemp will wither and bees and butterflies will fall to the ground wherever they pass. Rain and dew contain evil - acid mist condenses in the clouds and falls as toxic rain, corroding rubble, rusting copper and iron, and the ears of crops in the fields will be empty when it encounters it. Choking and death of people and animals - if farmers inhale it by mistake, their throats and lungs will ulcerate; if birds touch it, their feathers will fall and their meat will rot. 4. Methods to prevent filth Storage and leakage prevention - the acid storage should be built with corrosion-resistant bricks, and a lime pool should be set up underneath to neutralize the leak. Waste liquid inertness - the residual acid must be poured with slaked lime (calcium hydroxide) and wait until it solidifies into calcium fluoride before it is discarded in a special tomb. Plants as whistles - pine and cypress should be planted around the acid plant. If the tips are withered and the leaves are brown, it means that toxic gases have occurred and should be checked and blocked as soon as possible. 5. Lessons from the past In the past, a country in the West had an acid plant that was abandoned, causing bones to float in the streams for hundreds of miles, and crops to not grow for ten years. Therefore, "The Works of Nature" says: "A sharp blade can chop wood, but it can also cut legs; a strong drug can save lives, but it can also take lives." Today, those who use hydrofluoric acid should follow the example of Dayu in controlling floods, guide its benefits and block its harm, so as not to disappoint the kindness of heaven and earth in giving birth to humans.