in the process of die casting production, the melting and heat preservation of die casting alloy, preheating of die casting, coating spraying, working of die casting machine, cleaning of die casting and other links will all produce smoke and dust, harmful gases, oil drops, oil pollution, noise and thermal radiation, etc. When the amount of these pollutants exceeds the national or local standards, it will have an impact or pollution on the environment. In order to ensure a good production environment in the workshop and the health of workers, effective control measures must be taken. 1. Main pollutants in the die casting workshop and their impact on the environment 1. Pollutants and pollution sources The main pollutants in the die casting workshop and their workplaces, 2. Impact of main pollutants on the environment and human body The main pollutants in the die casting workshop are discharged into the atmosphere, water bodies and surrounding environment, and all kinds of wastes are discharged directly without treatment. If they exceed the national or local discharge standards, they will cause environmental pollution and harm to human body. Influence of pollutants on the environment and human body II. Control and treatment measures of pollutants The treatment of all kinds of pollution in die casting workshop is a highly comprehensive technology. First of all, when designing the new workshop, new materials, new processes and new equipment that do not produce or produce less pollutants should be adopted as much as possible. The second is to carry out cleaner production in existing production workshops. The so-called clean production is a comprehensive measure to control pollution in the whole process of industrial production with energy saving, consumption reduction and pollution reduction as the goal, and with management and technology as the means, so as to minimize the production and discharge of pollutants. The third is to adopt various effective methods to control all kinds of pollutants, reduce pollutant emissions and improve the working environment of the workshop. 1. Control of air pollutants 1) Switch the melting furnace and holding furnace of fuel oil to gas furnace or electric furnace with less air pollution. 2) The flux with less harmful gas is selected to reduce the harmful gas generation in the smelting process. 3) Smoke exhaust devices shall be used as far as possible at the refining and slag cleaning places of melting equipment and above the holding furnace, and the shape of smoke exhaust devices shall be determined according to different furnace types and process operation requirements. Generally, the wind speed at the hood mouth of umbrella-shaped smoke exhaust hood is about 1.5m. 4) An oil smoke filter is installed above the die casting machine, and the smoke generated during die casting is sucked by the oil smoke filter and filtered. 5) The equipment for shot peening, shot blasting, grinding and polishing shall be provided with a dust removal device or an exhaust device, and the spraying place shall be provided with an oil mist separation device. 6) Sulfur dioxide, hydrogen chloride, hydrogen fluoride and other harmful gases can be absorbed by liquid spraying device or activated carbon adsorption device. 7) Strengthen workshop ventilation measures. Workshop ventilation includes natural ventilation and mechanical ventilation. Natural ventilation is the use of wind pressure or hot air pressure for natural ventilation, which requires that the location and orientation of the workshop, the process layout in the workshop, the skylight design and the spacing between workshops should all be conducive to natural ventilation. Mechanical ventilation is to install a ventilator on the roof or wall of the workshop to strengthen the ventilation of the workshop. 2. Treatment of wastewater 1) Treatment of oily wastewater Typical treatment process of single oily wastewater: oily wastewater in die casting workshop is often mixed with residual liquid of excessive spraying release agent, and it is often concentrated with mechanical processing, painting and domestic wastewater in large-scale product factories. The treatment process is complicated, and the typical process flow is as follows: 2) Wet dust removal wastewater is treated by sedimentation tank. Under the action of gravity, suspended particles with density greater than wastewater settle at the bottom of the tank, while particles with density less than wastewater float. 3) Cooling water The main feature of cooling water is thermal pollution, and there are no other pollutants. Generally, it can be recycled after being cooled by the cooling tower. 3. Noise Prevention The noise in the die casting workshop mainly comes from the operation sound of mechanical equipment, the impact sound of castings and materials, the combustion sound of the combustion furnace, the current sound of induced current, and the noise of hydraulic and pneumatic equipment. Noise pollution is a kind of physical contamination. When the noise source stops outputting noise, the pollution disappears immediately, leaving no pollutants. However, if the noise in the workplace exceeds the allowable standard, it will also do harm to people's hearing and health. Noise prevention and control is mainly to control the sound source, the propagation path of sound and protect the receiver. 1) Reduce noise in process design ① Choose low-noise die casting machines, trimming machines and other equipment, and adopt low-noise new processes and technologies. (2) when transporting materials, minimize the impact of materials and reduce the material drop. (3) When designing the workshop process, the high-noise section and the low-noise section should be arranged separately. ④ Equipment with strong vibration should not be arranged on the steel structure platform. 2) Sound insulation ① The offices, control rooms, studios, lounges, etc. located in high-noise areas should be treated with sound insulation, and the doors, windows and walls of the rooms should be provided with sound insulation components to keep the noise out of the room and reduce the impact of noise on the indoor environment. (2) For some high-noise equipment, noise enclosures and barriers can be used to block the spread of noise. 3) Noise elimination A muffler is installed on the compressed air discharge pipeline, which can effectively reduce air noise. 4) Vibration isolation and vibration isolation devices, such as springs and damping cushions, can be installed for equipment with large vibration isolation, such as vibration machines. 5) Personal protection Personal protection is the most effective and economical method in many occasions, and the common method is to wear ear protectors. Ear protectors are divided into earplugs, earmuffs and sound insulation helmets according to different structures. Ear protectors