I. The Role of High-Purity Magnesium Oxide in Cellulose Acetate
Cellulose acetate raw materials require dissolution during processing. While they do not dissolve in common solvents, they are soluble in magnesium acetate. In the production of cellulose acetate, a magnesium acetate solution of a specific concentration is typically prepared through the reaction between magnesium oxide (MgO) and an acetic acid solution. Additionally, sulfuric acid is used as a catalyst throughout the reaction process, and magnesium oxide is required as a “terminator” (neutralizing agent) once the reaction is complete.
Cellulose acetate is a critical component of cigarette filters due to its excellent moisture absorption and adsorption properties. The Y-shaped cross-section of the monofilament provides a large specific surface area, which effectively reduces smoke, tar, and suspended particles generated during combustion. Because of the high acidity levels within cellulose acetate, magnesium oxide must be added to neutralize the acid and achieve the desired filtration efficiency.
II. Quality Requirements for High-Purity Magnesium Oxide in Production
1. High Activity and Rapid Temperature Rise
The primary use of magnesium oxide is the preparation of the magnesium acetate solution. This requires the MgO to have high reactive activity, ensuring a fast reaction rate and a rapid temperature rise when mixed with the acetic acid solution to complete the process efficiently.
2. MgO Content Greater than 99%
High purity with minimal impurities facilitates the filtration of the magnesium acetate solution. It prevents impurities from being introduced into the cellulose acetate, thereby ensuring the final product quality is not compromised.
3. Particle Size No Finer than 96 Mesh
Controlling the particle size serves two purposes:
- It prevents fine MgO powder from generating excessive dust during feeding, which can adhere to the walls of vent pipes, leading to pollution or equipment failure.
- It prevents fine particles from floating on the surface of the acetic acid solution, which would result in an uneven reaction.
4. Iron Content (as Fe2O3) Not Exceeding 0.08%
The production of cellulose acetate requires high whiteness in the final product. Therefore, it is essential to minimize components like iron that can negatively affect the whiteness and aesthetic quality of the material.
5. Bulk Density Not Less than 0.65 g/cm³
The requirement for bulk density is primarily to ensure that the magnesium oxide can be successfully added to the acetic acid solution. This avoids issues where light and fine dust fail to submerge or mix properly, which would hinder the reaction process and cause difficulties in the subsequent filtration stage.
6. Chloride Ion (Cl−) Content Less than 0.02%
Since the equipment used in cellulose acetate production is made of stainless steel, high levels of chloride ions can accelerate equipment corrosion. Consequently, the chloride content in all raw and auxiliary materials must be strictly controlled.
The production of cellulose acetate demands rigorous standards for high-purity magnesium oxide. Zehui independently develops high-purity magnesium oxide with stringent quality control at every stage. Our products meet the specialized needs of cellulose acetate production and can be customized to fulfill the specific requirements of different customers.