What are the preparation methods of magnesium oxide?

The mainstream preparation method of magnesium oxide

1. Magnesite calcination method (most commonly used in industry)

1. Crushing and screening magnesite ore

2. Low temperature calcination at 700~950 ℃ → Light magnesium oxide

3. High temperature calcination above 1500 ℃ → heavy heavy burning of magnesium oxide

Advantages: Low cost, large output, universal fire-resistant building materials

2. Magnesium extraction method from brine/seawater

Using salt lake brine, seawater, and underground brine as raw materials

-Precipitation of magnesium hydroxide by adding alkali to brine

-High purity magnesium oxide obtained by high-temperature calcination after filtering and washing with water

Advantages: extremely high purity, suitable for pharmaceuticals, electronics, and high-end chemicals

3. Carbonization method of dolomite

Raw material: Dolomite ore

Calcination → Digestion → Carbonization → Separation and Purification → Calcination of Finished Products

Mostly used for producing lightweight magnesium oxide, with readily available raw materials

4. Magnesium hydroxide calcination method

First, prepare magnesium hydroxide powder, and then dehydrate it through high-temperature decomposition

$\ ce {Mg (OH) 2 \ xlongequal {\ text {high temperature}} MgO+H2O ↑}$

The product has high activity and few impurities, specifically designed for rubber and flame retardant applications

5. Chemical synthesis method (fine and high-purity)

Magnesium salts such as magnesium chloride and magnesium nitrate react with alkali to precipitate, refine and calcine

Produce nano magnesium oxide and high-purity active magnesium oxide for scientific research, catalysts, and ceramics

6. Gas phase synthesis method

Preparation of ultrafine nano magnesium oxide by gas-phase reaction

Mostly used in high-end new materials and electronics fields, with high cost

brief summary

-Large quantity and cheap: calcination of magnesite ore

-High purity: brine method

-High activity: Calcination of magnesium hydroxide

-Ultra fine high-end: chemical synthesis/gas-phase method