Magnesia Briquetting Advances Boost Industrial Efficiency

Light-burned magnesium oxide, also known as caustic calcined magnesia, is produced by calcining magnesite (MgCO₃) at temperatures between 700-900°C. Unlike dead-burned magnesia (calcined at temperatures above 1000°C), light-burned magnesium oxide typically exhibits excellent reactivity. This versatile material finds applications across multiple industries including ceramics, enamel production, refractory crucibles and bricks manufacturing. It serves as a polishing agent, binder, filler in coatings and paper products, as well as an accelerator and activator in chloroprene and fluorine rubber production.

In pharmaceutical applications, light-burned magnesium oxide functions as an antacid and mild laxative for treating conditions like hyperacidity, gastric ulcers, and duodenal ulcers. Within the chemical industry, it serves as a catalyst and raw material for magnesium salt production.

Light-burned magnesium oxide typically exists as fine powder, which presents numerous challenges during transportation, storage, and application. Dust dispersion not only causes environmental pollution but also increases material loss. Furthermore, powdered magnesium oxide proves difficult to use directly in certain industrial applications, such as serving as a slag conditioner in steelmaking processes. Pelletizing light-burned magnesium oxide offers significant advantages:

• Improved transportation and storage: Pelletized magnesium oxide has higher density and smaller volume, facilitating easier handling and transportation while reducing storage space requirements.
• Reduced dust pollution: The pelletizing process effectively controls dust dispersion, improving working conditions and minimizing environmental impact.
• Enhanced utilization efficiency: Pelletized magnesium oxide experiences less material loss during application, improving overall utilization rates.
• Optimized process performance: For certain applications, pelletized magnesium oxide better meets technical requirements. In steelmaking, for example, pellets offer easier addition and more uniform dissolution rates.

Roller press pelletizers represent the ideal equipment for light-burned magnesium oxide pelletization, capable of producing qualified pellets regardless of raw material purity. With their powerful compression capability and stable performance, these machines ensure pellet strength and quality.

The dry pelletizing process for light-burned magnesium oxide, conducted with near-zero moisture content, offers notable economic advantages. This method has low moisture content requirements for raw materials, accommodates dry materials from various sources, and imposes no special demands on particle size distribution. These characteristics have made dry pelletizing technology increasingly prominent in the magnesium oxide industry.

In roller press systems, fine magnesium oxide particles are compressed under sufficiently high pressure to form pellets with adequate strength. This process can operate independently or combine with other techniques, such as soda activation processes, to produce magnesium oxide pellets with specific properties.

The primary production process for light-burned magnesium oxide pellets includes:

1. Feeding: A forced feeder uniformly delivers light-burned magnesium oxide powder into the pelletizer.
2. Compression: The powder undergoes high-pressure compaction between two counter-rotating parallel rollers to form pellets.
3. Conveying: A conveyor belt transports the formed pellets to subsequent processing stages.
4. Screening (optional): This optional step removes substandard pellets and fines to ensure product quality.
5. Packaging (optional): Another optional step packages qualified pellets for storage and transportation.

Roller speed and pressure levels critically influence pellet quality. Given the stringent quality requirements for light-burned magnesium oxide pellets, high-pressure pelletizers are typically employed.

Light-burned magnesium oxide pellets boast broad application prospects, primarily including:

1. Steelmaking slag conditioner: In steel production, these pellets regulate slag basicity, promote desulfurization and dephosphorization, and improve steel quality.
2. Intermediate product for high-purity magnesium oxide production: The pellets serve as intermediate products that undergo further calcination and purification to yield high-quality magnesium oxide.

Producing qualified pellets requires high-pressure pelletizing equipment. Several factors influence pelletizing effectiveness:

• Material characteristics: The reactivity, particle size distribution, and moisture content of light-burned magnesium oxide all affect pellet quality. Generally, higher reactivity magnesium oxide forms stronger pellets more easily. Uniform particle size distribution enhances pellet density, while improper moisture levels negatively impact results.
• Equipment selection: High-pressure pelletizers provide sufficient compression for pellet strength. Roller geometry and dimensions also affect quality, as does feeder stability for uniform material distribution.
• Process parameters: Compression pressure, roller speed, and feed rate require optimization based on material properties for optimal pelletizing results.

Pellet density depends on magnesium oxide type and compression pressure among other factors. Generally, density is influenced by:

• Compression pressure: Higher pressure increases density, though excessive pressure may cause pellet cracking or deformation.
• Particle size: Finer particles fill voids more effectively, enhancing density.
• Moisture content: Appropriate moisture lubricates particles and improves compaction, though excessive moisture reduces pellet strength.

While theoretically any particle size can be pelletized, uniform particle size distribution yields better results. Excessively coarse or fine particles may compromise pellet strength and density. Typically, finer particles improve compaction but may generate dust, requiring careful size selection based on specific conditions.

Typically, light-burned magnesium oxide pellets form without binders through high-pressure compaction. However, specific applications may require binders to enhance strength or modify properties. Common options include:

• Inorganic binders: Such as water glass, lime, or cement, offering cost-effectiveness and high-temperature resistance.
• Organic binders: Including starch, molasses, or carboxymethyl cellulose, providing strong adhesion and easy dispersion.