With the increasing pressure on resources and the environment in our country, government departments have proposed the goals of “achieving sustainable development, building a resource-saving and environmentally friendly society” and “ensuring a 20% reduction in energy consumption and a 10% reduction in total emissions of major pollutants as determined in the Eleventh Five Year Plan”. In China, casting plays a very important role in the machinery manufacturing industry, with casting production ranking first in the world for six consecutive years. There are over 27000 casting enterprises, among which, except for a few large enterprises with advanced casting technology, excellent production equipment, and basic environmental protection measures, most casting enterprises still have outdated manufacturing technology, outdated production equipment, and environmental protection issues that have not been put on the work schedule.
The foundry industry in our country is facing serious challenges in environmental protection. According to reports, 80% to 95% of China’s casting factories mainly use manual molding, and less than 5% of the total number of blast furnaces are equipped with effective environmental protection facilities. Over 80% of casting enterprises have harsh on-site environments, poor working conditions, backward manufacturing technology, and extensive production methods. From the perspective of the structure of the casting industry, enterprises have both casting sub fields or workshops subordinate to the host production plant, as well as professional casting plants and a large number of township casting plants. In terms of production level and scale, there are both large foundries with high mechanization, advanced technology, and an annual output of tens of thousands of tons of castings, as well as small foundries with simple equipment, manual operation, outdated technology, and an annual output of over a hundred tons of castings. In recent years, due to the impact of energy, environmental factors, and labor prices, the production of castings in developed Western industrial countries has decreased, and they have gradually turned to developing countries to purchase general castings, while also exporting high-quality castings with high technological content and high added value to developing countries. Currently, the acceleration of global economic globalization provides both opportunities and challenges for the development of China’s foundry industry. The demand for Chinese castings in both international and domestic markets is showing a sustained growth trend.
Casting equipment, casting sand processing molding
Casting equipment, casting sand processing molding
Based on the current level of casting technology and the main problems in China, this article explores effective ways to achieve “green and environmentally friendly casting” from the following aspects:
1.The development of green manufacturing standards for the foundry industry includes fundamental technologies such as product design theory and methods, material application technology, manufacturing processes and equipment technology, testing technology, automation technology, etc. These are interrelated, interdependent, and indispensable components of the foundry industry’s survival and development Design green castings and casting processes to ensure the “inherent green quality” of casting products and production processes, and optimize the environmental properties of castings throughout their entire lifecycle at the source Considering the important influencing factors of direct consumption of energy, resources, and emission of pollutants and waste, green casting technology and process equipment technology are adopted to convert raw and auxiliary materials (inputs) into castings (useful outputs), thereby achieving true “green and environmentally friendly casting” production Replace traditional raw materials and their application technologies with clean and environmentally friendly raw materials and their application technologies; ④ Adopting advanced, fast and accurate detection and control technology, optimizing the casting production process, eliminating or reducing casting waste, improving casting yield, reducing energy consumption and pollution caused by untimely or inaccurate detection, and achieving “green and environmentally friendly casting”; ⑤ Adopting applicable and effective end of pipe treatment technologies to reduce the discharge of pollutants into the environment. In addition to proposing technical requirements for the above aspects, it is also necessary to combine with the national conditions of China’s foundry industry, so that enterprises can adopt the best governance plan (low-cost, high-efficiency) to achieve final emissions that meet national environmental standards.
2. Starting from various aspects such as casting technology, molding materials, and casting equipment
The current situation of environmental protection in China’s foundry industry is worrying. Efforts can be made to promote environmental protection in the foundry industry from various aspects such as casting technology, molding materials, and casting equipment: ① Casting technology and molding materials: Sand casting is the main method of casting technology, accounting for 80% to 90% of the entire casting production. In casting production, dust pollution, air pollution, and solid pollution caused by the molding materials of sand casting are the most serious. Therefore, in order to achieve green and clean production in sand casting, green inorganic binders should be used as much as possible, and the amount of binders added should be reduced as much as possible (preferably without binders). This is very beneficial for solving the problem of recycling old sand and will greatly reduce the pressure on the environment. Among the various methods of sand casting currently involved, the lost foam casting and V-method casting using adhesive free dry sand molding, as well as the water glass sand casting with adhesive, are the most likely to achieve “green and environmentally friendly casting” production processes. The adhesive free lost foam casting is known as the “new casting technology of the 21st century” and “green engineering in casting” Casting equipment: Currently, most of China’s cast iron parts are melted and produced using blast furnaces, which use clean and long-life refractory materials, high-efficiency hot air continuous blast furnaces, and iron liquid enclosed transportation, pouring, and mold treatment technologies to reduce the amount of metal oxidation and slag generation; Adopting the recommended measures of the International Council for Casting Environment Control for pre purification treatment of furnace materials can reduce the emission of dust during the smelting process; The use of water-cooled granulation slag technology can make slag a highly efficient building material; Comprehensively utilize the exhaust gas from the blast furnace. In addition, in casting production, process equipment that generates dust and noise, such as transportation, screening, cleaning, and sand dropping equipment, can be improved from the product structure to reduce or eliminate dust.
3. Developing new technologies for resource utilization of waste gases to protect the ecological environment and maximize resource conservation has become an urgent goal pursued by foundry workers in various countries. Therefore, when China’s foundry enterprises build or carry out technological transformation, they should also coordinate the comprehensive reuse of waste. This can be done from the following aspects: ① When designing transformation plans, first consider increasing investment in environmental protection, and it is recommended that environmental protection investment account for more than 15% of the total investment; ② Adopting advanced casting equipment that is mechanized, automated, and enclosed to achieve environmental protection goals; ③ Adopting clean production processes to improve the working environment; ④ Develop new technologies for resource utilization of foundry waste by referring to the waste disposal methods of foreign foundry enterprises; ⑤ Adhere to the principles of reduction, reuse, and recycling in the circular economy.
Green and environmentally friendly casting “is a manifestation of the social sustainable development strategy in the manufacturing industry. Starting from the production capacity, technological level, product quality level, energy consumption and raw materials, casting technology talents, quality management level, and emissions of waste sand, waste gas, dust, waste residue, noise, etc. of China’s casting industry, drawing on the achievements of foreign theoretical research and practice, and based on the basic characteristics, existing problems, and basic requirements of environmental protection design of China’s casting industry and casting technology level, basic standards for environmental protection design of different production links in the casting production process are established as the goals of new construction, renovation, expansion, and technological transformation projects of China’s casting enterprises. The behavior of casting production enterprises is standardized, and environmental protection is vigorously promoted to achieve” green and environmentally friendly casting “, Enhance the technological level of China’s foundry industry to meet the needs of rapid development of the national economy.
Post time: Feb-10-2025