AR Magnesium Oxide

Introduction

White amorphous powder. The relative density is 3.26~3.43. Odorless, tasteless and non-toxic. Soluble in acid and ammonium salt solution, insoluble in water and ethanol. Strong refraction in the visible and near ultraviolet range. When exposed to air, it is easy to absorb moisture and carbon dioxide and gradually become basic magnesium carbonate, which combines with water to form magnesium hydroxide, which is slightly alkaline reaction, and the pH of the saturated aqueous solution is 10.3. But it is very soluble in dilute acid, very slightly soluble in pure water, and its solubility is increased due to the presence of carbon dioxide. It is a mild catalyst. Relative density (d254) 3.58. Melting point 2852 ?. Boiling point 3600?.

 

Chemical formula: MgO

 

Relative molecular mass: 40.30

 

Quality standard: chemical industry standard HG/T2679-2006.

 

Ionic equation:

 

MgO+2H+=Mg2++H2O

 

MgO+2NH4+=Mg2++2NH3?+H2O

 

Use

 

Analytical pure magnesium oxide is mainly used in the reagent industry and other chemicals or intermediates, and fluorescent grade magnesium oxide is mainly used as raw materials for trichromatic phosphors and other types of light bodies.

 

Manufacturing process

 

1.gas phase method

 

The high-purity metal magnesium and oxygen are reacted to form crystal nuclei, and then the particles continue to grow to obtain high-purity micropowder magnesium oxide. The crude raw material containing 80% by weight or more of magnesium oxide is dissolved in an inorganic acid (sulfuric acid, hydrochloric acid, nitric acid) at a molar ratio of 1:2 to prepare a magnesium salt of the inorganic acid. Refined to remove impurities, pressurized and heated in an oxygen atmosphere, washed with water, dehydrated, dried, and heated at 1100 ° C for 1 hour to obtain high-purity magnesium oxide.

 

The magnesium hydroxide calcination method uses the magnesium sulfate solution that has been removed and purified as the raw material, and pure ammonia water is used as the precipitant to add Mg(OH)2 to the magnesium solution to precipitate Mg(OH)2. The purity of Mg(OH)2 is then dried and calcined to obtain high-purity magnesia.

 

The calcined bitter earth powder is subjected to water separation to remove impurities and then precipitate into magnesium slurry, and then through digestion, drying and calcination, magnesium hydroxide is dehydrated to form magnesium oxide. Its MgO+H2O?Mg(OH)2Mg(OH)2?MgO+H2O;

 

2.Brine-ammonium bicarbonate method

 

The brine is reacted with ammonium bicarbonate to generate basic magnesium carbonate, which is then aged, washed, dehydrated, dried, calcined, and then purified and heat treated after being crushed to obtain silicon steel grade magnesium oxide.

 

3.Carbonization

 

Dolomite is calcined, digested and carbonized to obtain basic magnesium carbonate, and then thermally decomposed, calcined, pulverized, and air-selected to obtain light magnesium oxide. That

 

MgCO3·CaCO3?MgO+CaO+2CO2?

 

(MgO+CaO)+2H2O?Mg(OH)2+Ca(OH)2

 

Mg(OH)2+Ca(OH)2+3CO2?Mg(HCO3)2+CaCO3+H2O5

 

Mg(HCO3)2+H2O?4MgCO3·

 

Mg(OH)2·5H2O+6CO2?4MgCO3·

 

Mg(OH)2 5H2O?5MgO+4CO2?+6H2O

 

The ammonium bicarbonate method removes impurities from the mother liquor (magnesium ion content is about 50g/L) after seawater salt making, and then mixes it with ammonium bicarbonate in an appropriate proportion to carry out precipitation reaction, and then undergo centrifugal dehydration, drying, calcination, crushing and classification, After packaging, the finished product of light magnesium oxide is obtained. That

 

5MgC12+10NH4HCO3+H2O?4MgCO3·

 

Mg(OH)2 5H2O+10NH4CI+6C02?

 

4MgCO3·Mg(OH)2·5H2O?5MgO+4CO2?+6H2O

 

 

Precautions Safety Measures

 

Respiratory protection: Workers are advised to wear dust masks.

 

Eye Protection: Use a safety face shield if necessary.

 

Protective Clothing: Wear tight-sleeved overalls and long rubber shoes.

 

Hand Protection: Wear protective gloves.

 

Route of entry: inhalation, ingestion.

 

Health Hazards: Magnesium casting heat is caused by inhalation of magnesium oxide fumes. Symptoms include a metallic taste in the mouth, thirst, dry throat, loss of appetite, chest tightness, dry cough, headache, dizziness, sore limbs, high fever and aversion to cold. Large amounts of magnesium oxide dust can block sebaceous ducts and cause skin pimples and eczema.

 

Extinguishing method: non-combustible. Extinguishing media available around the fire.

 

Others: Smoking, eating and drinking are strictly prohibited at the work site. After work, shower and change. Pay attention to personal hygiene.

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