In the traditional aluminum anodizing process, the use of chromic acid and chromate is a major environmental problem. Since chromium compounds are difficult to degrade in the environment, they will cause serious pollution to soil, water bodies, etc., and are also harmful to human health. Therefore, the research and development of chromium-free anodizing processes has become an important research direction. At present, researchers are actively developing new electrolyte systems based on phosphoric acid and sulfuric acid mixed electrolytes, organic acids, inorganic acids and additives. These chromium-free processes are expected to be widely used in the future to meet increasingly stringent environmental protection requirements.
The wastewater generated during the aluminum anodizing process contains a large amount of heavy metal ions (such as aluminum ions), acids, alkalis and organic matter (such as dyes), etc. If directly discharged, it will cause great damage to the environment. Therefore, the development of green wastewater treatment technology has become an inevitable trend. Among them, biological treatment technology is one of the hot spots. By screening and cultivating specific microorganisms, organic matter in wastewater can be effectively degraded. In addition, membrane separation technology is also developing. Membrane technologies such as ultrafiltration and reverse osmosis can efficiently separate heavy metal ions and organic matter in wastewater, thereby achieving standard discharge of wastewater.
In order to reduce the energy consumption of the anodizing process, it has become an important direction to continue to develop and apply new power supply technologies. For example, compared with traditional DC power supplies, high-frequency pulse power supplies can obtain the same quality of oxide film at a lower average current density, thereby reducing power consumption. In addition, intelligent power management systems are also being developed, which can automatically adjust parameters such as current density and voltage according to the growth of the oxide film to improve the efficiency of electric energy utilization.
During the anodizing process, the temperature of the electrolyte has a significant effect on the growth rate and quality of the oxide film. Therefore, it has become an important trend to use efficient heating and cooling systems to stabilize the temperature of the electrolyte. For example, the use of heat pump technology to achieve electrolyte heating and cooling can greatly save energy compared to traditional electric heating and refrigeration equipment.
Sealing treatment is an important step to improve the corrosion resistance, wear resistance and anti-pollution ability of anodized films. Traditional sealing processes, such as nickel salt sealing and chromate sealing, are limited in application due to environmental protection issues. Therefore, the development of environmentally friendly sealing processes has become an important direction. For example, the use of new sealing processes such as nickel-free sealing agents and rare earth salt sealing can not only improve the sealing quality, but also reduce environmental pollution.
The quality of the anodized film layer is affected by a variety of process parameters, such as electrolyte concentration, temperature, current density, oxidation time, etc. These parameters are interrelated, and a slight change in any parameter may lead to changes in film thickness, hardness, porosity and other properties. Therefore, the use of advanced control technology and equipment to accurately control these process parameters to ensure the stability of film quality is an important trend in the development of aluminum anodizing technology.
In the aluminum anodizing process, the treatment of waste electrolytes, waste residues and other wastes is also an important environmental issue. By comprehensively recycling and utilizing these wastes, not only can environmental pollution be reduced, but also the recycling of resources can be achieved. For example, recycling waste electrolytes can reduce the preparation cost of new electrolytes; harmless treatment of waste residues can reduce environmental pollution.
Under the background of environmental protection requirements, the development trend of aluminum anodizing process shows multiple directions, such as chromium-free, green wastewater treatment, application of new power supply technology, application of efficient heating and cooling system, environmental protection improvement of sealing process, precise control of process parameters, comprehensive recycling and circular economy, etc. The realization of these trends will help promote the sustainable development of aluminum anodizing process.
