Foundry exhaust gas treatment: how to effectively reduce harmful emissions?

1、 Source control
Source control is the primary step in reducing harmful emissions from foundries. Improving production processes is one of the core strategies. By introducing advanced casting technology and equipment, optimizing the parameter settings of key processes such as melting, casting, and cooling, the amount of exhaust gas generated can be effectively reduced. For example, by using electromagnetic induction melting technology, energy consumption and exhaust emissions can be reduced through precise control of melting temperature and time. At the same time, promote the use of automated and intelligent production lines, reduce the uncertainty caused by manual operations, and further improve production efficiency and environmental protection levels.
The use of environmentally friendly materials is also an important means of source control. In the casting process, the selection of raw materials is directly related to the content of harmful substances in the exhaust gas. We should actively use low volatility and low toxicity raw materials, such as environmentally friendly casting sand and harmless binders, to reduce the generation of harmful substances in exhaust gas from the source. For harmful substances that cannot be completely avoided, their concentration in exhaust gas can be reduced and their pollution to the environment can be alleviated by optimizing the formula and ratio.
Strengthening equipment maintenance is also an essential aspect that cannot be ignored. During long-term operation, casting equipment may experience an increase in exhaust emissions due to wear and aging. Regular maintenance and overhaul of casting equipment should be carried out to ensure that the equipment is in good operating condition. This includes replacing worn parts, cleaning dust and oil stains, adjusting equipment parameters, etc., to reduce exhaust gas generated due to equipment failure or aging.

2、 Waste gas treatment technology
Exhaust gas treatment technology is a key link in reducing harmful emissions from foundries. In terms of physical methods, activated carbon adsorption method is widely used due to its high efficiency and economic characteristics. Activated carbon has strong adsorption capacity and can adsorb various harmful substances in exhaust gas, such as organic solvents, heavy metal ions, etc. By regularly replacing or regenerating activated carbon, its good adsorption performance can be maintained to ensure the effectiveness of exhaust gas treatment.
The wet washing method is another commonly used physical treatment technique. This method uses a water spray device to dissolve dust and harmful substances in the exhaust gas into water, achieving the goal of purifying the exhaust gas. The wet scrubbing method is easy to operate and cost-effective, suitable for treating exhaust gases containing large amounts of dust and soluble harmful substances. However, it should be noted that wet washing methods may generate secondary pollution, such as improper wastewater treatment, which can cause secondary pollution to the environment. Therefore, when using wet washing method, it is necessary to ensure the completeness and normal operation of wastewater treatment facilities.
In terms of chemical methods, acid-base neutralization and catalytic combustion are two commonly used treatment techniques. The acid-base neutralization method involves spraying an acid-base solution into the exhaust gas to neutralize acidic or alkaline substances and convert them into harmless substances. This method is suitable for treating exhaust gases containing acidic or alkaline substances, and has the advantages of high treatment efficiency and easy operation. However, the acid-base neutralization method may generate a large amount of waste liquid, which needs to be properly treated to avoid secondary pollution to the environment.
Catalytic combustion is an efficient exhaust gas treatment technology that uses catalysts to oxidize harmful substances in exhaust gas at lower temperatures and convert them into harmless substances. This method has high purification efficiency and is suitable for treating high concentration and difficult to degrade exhaust gases. However, catalytic combustion requires a certain amount of energy consumption, and the cost of catalyst regeneration and replacement is relatively high. Therefore, when choosing catalytic combustion method, factors such as treatment efficiency, operating costs, and environmental benefits should be comprehensively considered.
In terms of biological methods, biofiltration tower and biofilm method are two commonly used treatment techniques. The biological filtration tower utilizes the biodegradation of microorganisms to convert organic matter in exhaust gas into harmless substances. This method has the advantages of high processing efficiency, low operating costs, and environmental friendliness. However, biological filtration towers have certain requirements for the temperature and humidity of exhaust gases, and the growth and reproduction of microorganisms require a certain amount of time. Therefore, when using a Foundry fume exhaust gas treatment, the stability of exhaust gas parameters and the growth environment of microorganisms should be ensured.
The biofilm rule is to cultivate microorganisms on biofilms and use their metabolic activities to remove harmful substances from exhaust gases. This method has the advantages of high processing efficiency, small footprint, and simple operation and maintenance. However, the biofilm method also has certain requirements for the temperature and humidity of the exhaust gas, and the cost of replacing and regenerating the biofilm is relatively high. Therefore, when choosing the biofilm method, factors such as treatment efficiency, operating costs, and environmental benefits should be comprehensively considered.

3、 Combination process
Combining various waste gas treatment methods such as physical, chemical, and biological methods can form a more efficient and economical waste gas treatment process. The advantage of combination technology lies in the ability to fully utilize the advantages of various treatment methods, achieve complementary advantages, and achieve the best exhaust gas treatment effect.
For example, physical methods can be used to remove particulate matter and soluble harmful substances from exhaust gas, followed by chemical methods to treat the remaining acidic or alkaline substances, and finally biological methods can be used to remove organic matter and other difficult to degrade substances. This combination process can ensure the effectiveness of exhaust gas treatment and reduce operating costs.
In practical applications, the selection of composite processes should be comprehensively considered based on factors such as the composition, concentration, and emission requirements of the exhaust gas. Meanwhile, it is also necessary to pay attention to the mutual influence and synergistic effect between various processing methods to ensure the stability and reliability of the combined process.

4、 Management and Monitoring
Management and monitoring are important measures to ensure the effectiveness of exhaust gas treatment in foundries. Firstly, a comprehensive exhaust gas treatment system should be established, including processes such as exhaust gas collection, transportation, treatment, and discharge. The exhaust gas collection system should ensure that the exhaust gas can be completely collected and transported to the treatment equipment; The exhaust gas treatment system should select appropriate treatment methods based on the composition and concentration of the exhaust gas; The exhaust emission system should ensure that the treated exhaust gas can meet the emission standards and be safely discharged.
Regular monitoring and analysis of exhaust gas should be conducted to understand its composition, concentration, and emission situation. Monitoring data can be used to evaluate the effectiveness of exhaust gas treatment, identify potential problems, and develop improvement measures. At the same time, monitoring data can also be used as the basis for law enforcement inspections by environmental protection departments to ensure the compliance of exhaust emissions from foundries.
We should also strengthen employee training and environmental awareness education. Through training and education, enhance employees' awareness of the importance of waste gas treatment, ensuring that they understand the correct methods and operating procedures for waste gas treatment. At the same time, employees can be encouraged to actively participate in waste gas treatment work, provide improvement suggestions and recommendations, and jointly promote the continuous improvement and optimization of waste gas treatment work in the foundry.

5、 Other measures
In addition to the above measures, other measures can be taken to further reduce harmful emissions from the foundry. For example, resource recycling is an effective means of reducing emissions. In the process of exhaust gas treatment, it is possible to consider recovering the thermal energy or useful substances in the exhaust gas, such as using the waste heat in the exhaust gas for heating or power generation. This can not only reduce energy consumption and costs, but also minimize the environmental pollution caused by exhaust emissions.
Green production is also an important way to reduce harmful emissions from foundries. By promoting green production technology, optimizing production processes and process parameters, and improving resource utilization efficiency, measures can be taken to reduce the amount of waste gas generated from the source and reduce its pollution to the environment. At the same time, it is also possible to encourage foundry enterprises to adopt a circular economy model, achieve resource reuse, and reduce and dispose of waste in a harmless manner.