There are many methods for sheet metal surface treatment, common including spraying, electroplating, oxidation, sandblasting and so on. These methods can improve the appearance of sheet metal products, improve corrosion resistance and wear resistance. However, these surface treatment methods in the implementation process, often produce a variety of pollutants, causing adverse effects on the environment.

Environmental problems in sheet metal surface treatment

Air pollution
(1) During the spraying process, a large number of volatile organic compounds (VOCs) will be produced. VOCs is an important precursor to the formation of ozone and fine particulate matter (PM2.5), which is of great harm to atmospheric environmental quality and human health.
(2) During the plating process, some toxic and harmful gases will be produced, such as chlorine gas and hydrogen chloride. If these gases are discharged directly into the atmosphere without effective treatment, they will cause serious harm to the surrounding environment and human health.

Water pollution
(1) During the plating process, a large amount of wastewater containing heavy metal ions will be produced, such as chromium, nickel, copper, etc. If these heavy metal ions are discharged directly into water without effective treatment, they will cause toxicity to aquatic organisms and destroy ecological balance.
(2) During the spraying process, some wastewater containing organic matter such as pigments and resins will be produced. If the wastewater is discharged directly into the water body without effective treatment, it will cause the eutrophication of the water body and affect the water quality.

Solid waste pollution
(1) Sheet metal surface treatment process, will produce some waste slag, waste paint slag, waste plating solution and other solid waste. If these solid wastes are piled up or landfilled without effective treatment, they will occupy land resources and pollute soil and groundwater.
(2) Some expired or invalid coatings, plating solutions and other chemicals, if discarded without effective treatment, will also cause pollution to the environment.

Causes of environmental problems

1. Backward technology
The technology used by some sheet metal surface treatment enterprises is relatively backward, the equipment is obsolete, the energy consumption is high in the production process, and the emission of pollutants is large. For example, some small electroplating enterprises still use the traditional electroplating process and lack effective pollution treatment facilities, resulting in the discharge of wastewater, waste gas and waste residue is difficult to meet environmental protection standards.
2. Weak environmental awareness
Some enterprises do not pay enough attention to environmental protection issues and lack environmental awareness. They only focus on economic benefits, ignoring the importance of environmental protection. In the production process, in order to reduce costs, they are often reluctant to invest in the construction of environmental protection facilities and technological transformation.
3. Inadequate supervision
At present, there are still some shortcomings in the environmental supervision of the sheet metal surface treatment industry. The law enforcement efforts of the regulatory authorities are not enough, and the penalties for illegal emission enterprises are small, resulting in some enterprises having a fluke mentality and are not willing to actively take environmental protection measures.

Measures to solve environmental problems in sheet metal surface treatment

Promote environmental protection technology
(1) Promote the use of environmentally friendly coatings and plating solutions. Environmentally friendly coatings and plating baths have the characteristics of low VOCs content and low heavy metal content, which can effectively reduce the emission of pollutants.
(2) Promote the use of advanced surface treatment technologies, such as powder spraying, electrophoretic coating, ion coating, etc. These technologies have the advantages of high efficiency, energy saving and environmental protection, and can replace traditional surface treatment methods.

Strengthen enterprise environmental awareness
(1) Enterprises should strengthen environmental protection training for employees and improve their environmental awareness. Let employees realize the importance of environmental protection work, consciously abide by environmental laws and regulations, and actively participate in environmental protection actions.
(2) Enterprises should increase investment in environmental protection and build perfect pollution control facilities. Ensure that the discharge of waste water, waste gas and waste residue meets environmental protection standards and reduces environmental pollution.

Strengthen environmental supervision
(1) The regulatory authorities should strengthen the environmental supervision of the sheet metal surface treatment industry and increase law enforcement. Enterprises that violate the law should be seriously investigated and punished in accordance with the law, and their illegal costs should be increased.
(2) Establish and improve the environmental monitoring system, and strengthen the monitoring and evaluation of sheet metal surface treatment enterprises. Discover and solve environmental protection problems in time to ensure that the environmental protection work of enterprises is implemented.