1. Metal treatment

• Separator in Annealing: Magnesium oxide is applied as a coating on steel sheets to prevent them from fusing together during the annealing process, especially in the finish annealing stage. This is crucial for maintaining the integrity of the metal sheets and preventing damage.
• Flux for Removing Impurities: In steelmaking, Magnesium oxide acts as a basic flux to remove acidic impurities like silicon, phosphorus, and sulfur. This helps improve the quality and properties of the steel.
• Deoxidizer: Magnesium is added to heat-resistant nickel-chrome alloys to completely deoxidize and desulfurize them. This improves their mechanical properties and hot forming capabilities.
• Insulating Layer: Magnesium oxide reacts with silicon dioxide on the surface of electrical steel to form a magnesium silicate insulating base. This insulation is important for the electrical performance of the steel.
• Furnace Lining: Magnesium oxide is a key component of furnace linings, particularly in basic oxygen furnaces (BOF) where it withstands high temperatures and helps remove impurities.
• Corrosion Protection: Magnesium oxide coatings can protect magnesium alloys from corrosion by preventing the transfer of corrosive ions to the metal surface.

2. Construction

• Fireproofing: Magnesium oxide ability to withstand high temperatures makes it a key component in fire-resistant building materials, such as cement and drywall.
• Magnesium Phosphate Cement: Similar to Sorel cement, Magnesium oxide can also be combined with acid phosphate salts to create magnesium phosphate cements, which are used as rapid-hardening repair cements.
• Shrinkage Compensation: In certain applications, Magnesium oxide has been used to compensate for shrinkage in concrete, like in concrete dams.
• Cladding and Panels: Magnesium oxide is used in cladding systems and insulated panels, offering a sustainable and durable alternative to conventional building materials.

3. Pharmaceuticals

• Antacid: Magnesium oxide is used alone or in combination with other ingredients as an antacid to relieve indigestion.
• Mineral Supplement: It's used in mineral supplements to address magnesium deficiencies, which are crucial for nerve and muscle function.
• Magnesium Salts: Magnesium oxide is a key component in producing various magnesium salts, which are used in different pharmaceutical applications.

4. Polymers & Resins

• Rubber Compounding: In rubber, Magnesium oxide is used as a curative agent to form ionic bonds with the polymer chains, and it can also act as an acid acceptor. This helps to control the cure rate and maintain product consistency.
• Antidegradant Packages: Magnesium oxide is often included in antidegradant packages for high-performance polymers, such as HNBR, to protect them from degradation.
• Catalyst and Support: Magnesium oxide is used as a catalyst and a support for other catalyst species in various chemical reactions, including those involving polymers.

5. Performance Chemicals

• Catalysis: Magnesium oxide, particularly in its nanoparticle form, serves as a catalyst in many chemical reactions due to its basic properties and ability to enhance surface area.
• Intermediate: Magnesium oxide is a crucial intermediate in the production of magnesium metal through reduction processes, particularly when combined with other materials like ferro-silicon.
• Neutralization of Acids: Magnesium oxide basic nature allows it to neutralize acids, forming salts and water, which is a useful property in some chemical syntheses and industrial processes.

6. Water Treatment

• pH Neutralization: Magnesium oxide's basic nature allows it to neutralize acidic water, which can be caused by industrial waste or natural factors. Acidic water can corrode pipelines and is detrimental to human health, so MgO helps to maintain a neutral or slightly alkaline pH, which is optimal for many organisms involved in wastewater treatment.
• Heavy Metal Removal: MgO helps remove heavy metals like lead, arsenic, and cadmium by forming insoluble hydroxide precipitates, effectively trapping these toxic elements from the water and reducing their environmental and health risks.
• Water Softening: Hard water, with its high calcium and magnesium content, can cause scale buildup in pipelines, reducing the efficiency of industrial equipment. MgO helps in softening hard water by reacting with these ions and reducing their concentration, improving water quality for both domestic and industrial uses.