Oxygen absorbents, as chemical agents that effectively remove oxygen from confined environments, are widely used in food preservation, pharmaceutical packaging, and electronic component protection. Their production process involves multiple stages, including raw material preparation, mixing and reaction, molding and drying, and quality inspection. Each step requires strict control to ensure the stability and reliability of the product's performance.
Raw Material Preparation
The main components of oxygen absorbents typically include reduced iron powder, activated carbon, sodium chloride (or calcium chloride), and auxiliary materials such as diatomaceous earth. Reduced iron powder is the core reactant, achieving oxygen absorption through an oxidation reaction with oxygen; activated carbon disperses the iron powder and promotes gas diffusion; sodium chloride or calcium chloride acts as a catalyst, accelerating the oxidation process of iron; and diatomaceous earth is used to regulate the reaction rate and improve the physical properties of the mixture.
In the raw material preparation stage, all raw materials must undergo rigorous screening and pretreatment. Iron powder must meet purity standards to avoid impurities affecting reaction efficiency; activated carbon needs activation treatment to improve adsorption performance; other auxiliary materials must be accurately weighed according to proportions to ensure that the final product's oxygen absorption capacity meets standards.
Mixing and Reaction
Raw material mixing is one of the key steps in the production of oxygen absorbers. Weighed iron powder, activated carbon, sodium chloride, and diatomaceous earth are added to a mixing device according to a specific ratio and mechanically stirred to ensure uniform distribution. During mixing, the speed and time must be controlled to avoid over-stirring, which could lead to particle agglomeration or premature reaction initiation.
Some production processes employ a step-by-step mixing strategy, where activated carbon and sodium chloride are premixed before adding iron powder and other additives to optimize reactivity. Uniformly mixed raw materials are typically in a loose powder form, possessing good air permeability and reaction contact area, laying the foundation for subsequent reactions.
Shaping and Drying
The mixed raw materials need to be shaped according to application requirements. Common shaping methods include tableting, granulation, or direct filling into breathable packaging bags. Tableting is suitable for oxygen absorbers requiring a fixed shape, while granulation improves flowability and filling uniformity. For small-scale packaging applications, directly filling the mixed powder into breathable non-woven bags is more common.
If the shaped oxygen absorber contains some moisture, it needs to be dried to extend its shelf life and ensure reaction stability. Drying temperature is typically controlled within the range of 40–60℃ to prevent premature oxidation of the iron powder due to high temperatures. The dried product must be stored in a sealed container to prevent moisture absorption and ensure optimal performance.
Quality Testing and Packaging
Finished oxygen absorbers undergo rigorous quality testing, including oxygen absorption capacity testing, reaction rate determination, and moisture content analysis. Oxygen absorption capacity is assessed by simulating oxygen consumption in a closed environment to ensure compliance with industry standards; reaction rate testing verifies the product's effectiveness under target temperature and humidity conditions; and moisture content must be strictly controlled to a low level to prevent deterioration during storage.
Qualified products are sealed in aluminum-plastic composite bags or packaging materials with oxygen barrier properties to prevent the entry of external moisture and oxygen, which could lead to premature failure. Some high-end products also include humidity or oxygen indicators for users to visually monitor the absorber's status.
The production process of oxygen absorbers integrates multiple disciplines, including materials science, chemical engineering, and quality control. Its core lies in ensuring the stability and efficiency of the iron-based reaction system. Through rigorous raw material selection, precise proportioning control, and standardized production management, reliable and versatile oxygen absorbent products are ultimately produced to meet the preservation and protection needs of various industries. In the future, with increasingly stringent environmental regulations, low-energy-consumption and biodegradable oxygen absorbent production processes will become a key focus of research and development, further driving technological advancements in this field.
