ammonium chloride brief introduction

ammonium chloride(Chemical formula: NH4Cl) Colorless cubic crystals or white crystals, with a salty and cool taste with a slight bitterness. Easy to dissolve in water and liquid ammonia, and slightly soluble in alcohols; But insoluble in acetone and ether. The aqueous solution is weakly acidic, and the acidity increases when heated. Due to the coordination of ammonium ions, ammonium chloride solution is corrosive to metals, especially copper.

ammonium chloride Basic information

ammonium chloride Numbering system

ammonium chloride Physical and Chemical Properties

Appearance and characteristics:

White crystalline solid

Density:

one point five two

Boiling point:

100 °C750 mm Hg

Melting point:

340 °C (subl.)(lit.)

Refractive index:

one point six four two

Water solubility:

soluble

Stability:

Stable. Incompatible with strong acids, strong bases.

Storage conditions:

Warehouse ventilation, low temperature drying

Steam density:

1.9 (vs air)

Steam pressure:

1 mm Hg ( 160.4 °C)

security information

• RTECS：

• BP4550000

Safety instructions:

S22-S36-S26

Hazard category code:

R22; R36

WGK Germany：

one

Customs code:

two billion eight hundred and twenty-seven million one hundred and one thousand

Dangerous goods transportation code:

UN 9085

Dangerous goods signs:

Xn

Hazard description:

H302; H319; H411

Danger signs:

GHS07, GHS09

Hazard prevention instructions:

P273; P305 + P351 + P338

Signal words:

Warning

Production method and purpose

Production method

1. The gas-liquid synthesis method introduces hydrogen chloride gas from the bottom of a turbulent absorption tower, which comes into contact with the circulating mother liquor sprayed at the top of the tower to generate saturated ammonium chloride mother liquor. The saturated ammonium chloride mother liquor flows into the reactor and undergoes neutralization reaction with ammonia gas to generate a saturated ammonium chloride solution. Sent to the cooling crystallizer and cooled to 30-45 ℃ to precipitate supersaturated ammonium chloride crystals. Send the ammonium chloride solution from the upper part of the crystallizer to the air cooler for cooling and circulate it to the crystallizer; The lower crystal slurry is thickened by a thickener and then centrifuged to obtain the finished product of ammonium chloride. The reaction equation is as follows: The mother liquor separated by centrifugation is sent to the turbulent absorption tower for recycling.

2. Double decomposition method: First, the ammonium chloride mother liquor is added to the reactor and heated to 105 ℃. Then, ammonium sulfate and salt are added, and the double decomposition reaction is carried out at 117 ℃ to generate ammonium chloride solution and sodium sulfate crystals. The sodium sulfate is separated by filtration, and the saturated ammonium chloride solution is sent to the cooling crystallizer for cooling to 32-35 ℃ to precipitate crystals. After filtration, the crystals are washed with four different concentrations of ammonium chloride solutions (15-17 ° B é, 11-12 ° B é, 10 ° B é, 9.5-10 ° B é) to control Fe<0.008% and SO42-<0.001%. After washing to a qualified level, the crystals are adjusted into a slurry again with ammonium chloride solution and sent to a centrifuge for separation and dehydration. Hot air drying produces industrial ammonium chloride products. The reaction equation is as follows: the mother liquor is sent to the decomposition reactor for recycling. Sodium sulfate separated by filtration is used to produce sodium sulfate powder.

3. The recrystallization method involves adding crude ammonium chloride into a solvent, dissolving it in steam, filtering it, cooling and crystallizing the filtrate, centrifuging and drying it to obtain industrial ammonium chloride products. The mother liquor separated by centrifugation is returned to the dissolution vessel for use. The recrystallization method involves adding industrial grade ammonium chloride into a solvent already filled with distilled water, dissolving it through heating, and purifying and filtering the solution with arsenic and heavy metal removal agents to remove impurities such as arsenic and heavy metals. The filtrate is then cooled, crystallized, centrifuged, and dried to produce finished edible ammonium chloride products.

4. Add 200kg of distilled water to every 100kg of industrial ammonium chloride, stir and heat to dissolve, then add ammonium sulfide, stir thoroughly, let it settle and clarify, and filter out the precipitated impurities (As2S3Pbs); Add ammonium oxalate (or 8-hydroxyquinoline) and barium nitrate sequentially to the solution to remove Ca2+Mg2+SO

4 2-HPO42- and other impurity ions; Add hydrogen peroxide and heat to boiling, then add activated carbon and ammonium carbonate, adjust the pH to 12 with ammonia water, and concentrate appropriately (supplement ammonia water to maintain alkalinity). While hot, filter with two layers of glass cloth and a layer of filter paper in between to remove impurities such as water-insoluble substances, calcium oxalate, barium sulfate, barium phosphate, and iron hydroxide. The finished product is obtained by cooling, crystallization, spin drying, and drying the filtrate. The amount of reagents added to remove impurities should be determined based on the impurity content in the raw materials. The crystallization mother liquor can be recycled, but generally not more than four times.

5. Under cooling conditions (using ice or cold water), add a small amount of chemically pure hydrochloric acid with a relative density of 1.12 to chemically pure ammonia water (with a relative density of 0

In 91), completely neutralize it: If the solution is acidic, add a small amount of ammonia water to make the solution alkaline, then heat it to boiling, filter while hot, concentrate and evaporate the filtrate until there is a crystalline film, cool the crystallization (if necessary, use ice water to cool), dry, and obtain ammonium chloride reagent. If high-purity hydrochloric acid, high-purity ammonia water, and conductive water are used, high-purity ammonium chloride can be obtained.

6. The one-step heating method sends the alkali mother liquor to an evaporator and heats it to boiling (≥ 110 ℃) for concentration. Stop heating when NH4Cl crystals precipitate, then add BaCl2 to remove SO2-4 and KMnO4 to remove iron. Just clarify, you can keep warm and filter while it's hot (≥ 100 ℃). A large amount of salt crystals and other water-insoluble substances are filtered out, and the filter residue is sent to the salt tank for salt recovery. The filtrate is sent to the crystallizer for cooling and crystallization. The crystallized ammonium chloride is sent to a centrifuge for spin drying and washed with an appropriate amount of water to remove residual mother liquor between crystals, then dried and packaged. It can also be produced by the reaction of hydrogen chloride and ammonia, or by the gas-phase synthesis method of ammonia gas obtained from coking reacting with hydrogen chloride, or by the double decomposition method of ammonium sulfate and salt, as well as the by-products of the combined alkali method.

use to

Mainly used for dry batteries, rechargeable batteries, ammonium salts, tanning, electroplating, precision casting, pharmaceuticals, photography, electrodes, adhesives, yeast nutrients, and dough improvers. Ammonium chloride, also known as brine sand, is a quick acting nitrogen chemical fertilizer with a nitrogen content of 24% to 25%. It is a physiologically acidic fertilizer. It is suitable for crops such as wheat, rice, corn, rapeseed, etc., especially for cotton and linen crops, it has the effect of enhancing fiber toughness and tensile strength and improving quality. However, due to the nature of ammonium chloride and if applied incorrectly, it often has some adverse effects on soil and crops. Usually ammonium nitrate is used.