Ammonium acid fluoride chemical properties what is

Ammonium fluoride, also known as ammonium hydrogen fluoride ($NH_4HF_2 $), is an important chemical substance with unique chemical properties.

Ammonium hydrogen fluoride is in the form of a white crystalline powder and is corrosive. It is easily deliquescent and will gradually decompose in the air due to moisture absorption, emitting hydrogen fluoride gas. This gas has a pungent odor and has a strong irritating and corrosive effect on the human respiratory tract, eyes and skin. Therefore, extra caution and protective measures should be taken when operating.

From the perspective of chemical activity, ammonium hydrogen fluoride is acidic and can neutralize with alkali substances. When reacted with sodium hydroxide, sodium fluoride, water and ammonia gas are formed. This reaction is a typical acid-base neutralization, following the chemical law of acid-base reaction. At the same time, because it contains fluoride ions, it can also react with a variety of metal ions to form corresponding metal fluoride precipitation. For example, when it encounters calcium ions, insoluble calcium fluoride precipitation will be formed. This property is often used in analytical chemistry and industrial wastewater treatment to remove calcium ions from the solution.

Under heating conditions, ammonium hydrogen fluoride is unstable and will decompose to produce ammonia, hydrogen fluoride gas and water. This decomposition reaction is a type of thermal decomposition reaction, and the decomposition temperature is relatively low, starting to decompose at about 125 ° C. This thermal decomposition property can be used to prepare hydrogen fluoride gas in some specific industrial production processes, providing raw materials for related chemical production.

Ammonium hydrogen fluoride has a high solubility in water. When it dissolves, it will ionize, resulting in ammonium ions ($NH_4 ^ + $) and hydrogen fluoride ions ($HF_2 ^ - $). This ionization process is affected by factors such as temperature and pH of the solution. And its aqueous solution is acidic due to hydrolysis of hydrogen fluoride ions, showing the general properties of acidic solutions, such as turning purple litmus test solution red.

In short, the chemical properties of ammonium hydrogen fluoride make it widely used in many fields such as chemical industry, metallurgy, electronics, etc. However, due to its corrosiveness and toxicity, it is necessary to strictly follow safe operating procedures when using it.

Ammonium acid fluoride uses

Ammonium acid fluoride (Ammonium acid fluoride) is widely used, and can be used as a flux in the field of metallurgy. During ore smelting, it can reduce the melting point of ore and make metal extraction more smooth, just like the key to opening the door of ore smelting, helping metals to precipitate from the complex structure of ore.

In chemical production, it is also an important raw material. Preparation of many fluorine-containing compounds, fluoride of normalylate participates in the reaction. Just like the cornerstone of building a chemical building, through various chemical reactions, fluorine-containing products with different characteristics can be constructed and used in many fields.

In the electronics industry, ammonium acid fluoride can be used in etching processes. In the production of printed circuit boards for electronic components, it can accurately etch away unwanted metal parts, just like a skilled craftsman carefully crafted to ensure that the circuit board circuit is accurate and correct, laying the foundation for the normal operation of electronic products.

In addition, it also contributes to wood corrosion protection. It can penetrate into the interior of the wood, inhibit the growth of microorganisms, and protect the wood from moth and decay. For example, by covering the wood with a strong protective armor, the service life of the wood can be extended, so that the wood products can serve people's lives and production for a long time.

Ammonium acid fluoride in storage and transportation

Ammonium acid fluoride, when storing and transporting, all precautions must be detailed.

The first word storage, this is a matter of vital importance. Ammonium acid fluoride is active and easy to react with other things, so it must be stored in a dry, cool and well-ventilated place. If it is in a humid place, water vapor is easy to attach to it, causing it to deliquescent and deteriorate, losing its original properties. And it must be kept away from fire and heat sources, because it is heated or decomposable, releasing harmful gases and endangering the surroundings. It should also be stored separately from alkalis and oxidants. If these numbers meet it, they are prone to violent reactions and risk accidents.

As for transportation, it should not be ignored. Before loading the vehicle, it is necessary to carefully check whether the container is intact to prevent leakage. During transportation, make sure that the vehicle runs smoothly, avoid bumps and vibrations, and avoid packaging damage. In case of high temperature weather, it is advisable to choose a cool time in the morning and evening for transportation, and the vehicle must be equipped with shading facilities to avoid direct sunlight to maintain the stability of ammonium acid fluoride. Transport personnel should also be familiar with emergency response methods. If there is a leak, they can quickly take correct measures to reduce damage hazards. During loading and unloading, the operation should be gentle, and it is strictly forbidden to drop or press, and the packaging should be intact to ensure the safety of storage and transportation, so as to avoid accidents.

Ammonium acid fluoride production method

Ammonium acid fluoride, that is, ammonium hydrogen fluoride, is prepared as follows:
First take an appropriate amount of hydrofluoric acid and place it in a special reactor. Dilute with water to an appropriate concentration, usually according to the scale of the reaction and subsequent product requirements, control the concentration of hydrofluoric acid within a certain range.
Then, slowly pass ammonia into the reactor containing hydrofluoric acid. This process requires strict temperature control. Because the reaction between ammonia and hydrofluoric acid is an exothermic reaction, if the temperature is too high, it is not conducive to product formation. Generally, the temperature is maintained between 0 and 20 ° C. The ammonia rate also needs to be precisely controlled. If it is too fast, it is easy to cause the reaction to go out of control, and if it is too slow, it will affect the production efficiency. < Br > When the pH value of the solution reaches a specific range, about 3-4, it can be determined that the reaction is roughly completed. The resulting mixture at this time contains ammonium hydrogen fluoride and some impurities.
Then, the mixture is transferred to the crystallization equipment, and the crystallization of ammonium hydrogen fluoride is promoted by means of cooling and cooling or vacuum evaporation. When cooling down, the temperature should be gradually reduced to 0-5 ° C. For vacuum evaporation, it is necessary to control the pressure and temperature to allow the water to evaporate moderately, so as to facilitate crystallization.
After crystallization is completed, use a filtration equipment to separate the crystal from the mother liquor. After that, wash the crystal with an appropriate amount of cold water or a specific organic solvent to remove impurities attached to the surface.
Finally, the washed crystals are placed in a drying equipment and dried at a suitable temperature and pressure to remove the residual moisture and finally obtain a pure ammonium hydrogen fluoride product. The entire production process requires high reaction conditions, equipment accuracy and operating specifications, so as to ensure the quality and yield of the product.

Ammonium acid fluoride on the environment and human impact

Ammonium fluoride, also known as ammonium hydrofluoride ($NH_4HF_2 $), has a significant impact on both the environment and the human body.

In the environment, if released into the atmosphere, it will mix with water vapor and drop fluoride-containing acid rain. Where this acid rain passes, the soil composition gradually changes, the fertility is damaged, and the roots on which plants depend for survival are destroyed. And water bodies are not immune. Fluoride dissolves into it, causing chaos to the water ecological balance and threatening the survival of aquatic life. Over time, the structure and function of the entire ecosystem are severely damaged, and the biodiversity is greatly reduced.

As for the human body, ammonium hydrofluoride is highly corrosive. If it is accidentally touched with the skin, it will sting and turn red in the light, and the skin and flesh will fester in the severe case, and it will be difficult to heal and leave scars. If the volatile gas enters the eyes, the tissue of the eyes will be eroded, vision may be damaged, and even blindness. If the volatile gas is inhaled, the respiratory tract will bear the brunt, causing cough, asthma, breathing difficulties and other diseases. Over time, lung function will also be damaged, which will seriously affect the human body's respiratory circulation and endanger life and health.

Therefore, the production, use and disposal of ammonium hydrofluoride need to be cautious, and proper protection and environmental protection measures should be taken to reduce its harm to the environment and people.