Analysis of the main faults of the hottest disc se

Analysis of the main faults of disc separator

1 sustainable development and green casting binder in the pursuit of high-performance materials to meet the use requirements of people's material civilization, people ignore the impact on natural resources and ecological environment. In order to ensure the sustainable development of human civilization, material scientists have put forward the concept of green materials or environmental materials. Environmental materials refer to new materials with excellent practical properties, such as low consumption of resources and energy, little impact on the ecological environment, and recycling. The plastic granulator equipment has very serious environmental pollution, high utilization rate or degradable use. At present, the process of material production, use and waste can be said to be a vicious cycle of extracting resources and discharging a large amount of waste back to the environment. When designing materials, people often pay little attention to the bearing capacity of resources and environment to this vicious circle

in order to fundamentally maintain the sustainable development of the material civilization of human society, we must try our best to reduce resource consumption and environmental pollution, and increase the regeneration cycle of resources in its whole life cycle, including production, use and waste. Through these measures, we can coordinate the development of materials with natural resources and the environment. This requires material scientists to design and apply environmental materials or environmentally friendly materials with foresight, so as to strengthen the utilization rate of environment and resources, create a high-speed development economy with less harm to the biosphere, and ensure the continuous improvement of human quality of life. 2 overview of casting binder casting binder is different from other binders, and has unique requirements in its performance, economy, environment and other aspects: ① the use of casting binder is generally carried out in an open environment, and workers should be directly or indirectly exposed to the binder. Therefore, the adhesive is required to be non-toxic or low toxic, non corrosive, non irritating smell, and no ingredients that harm the skin in direct contact; ② After thermal decomposition, toxic or inflammable and explosive substances will not be produced as far as possible, and waste materials and waste sand will not separate toxic and harmful substances to water sources and ecological environment in the stacking place; ③ The amount of binder used in casting is very large, and the casting sand is generally used repeatedly, so it is required that the casting binder should be easy to decompose, remove and regenerate; ④ The process performance and working performance of casting binder shall meet the requirements of manufacturing process and casting quality of casting production. Therefore, in addition to having high bonding strength, the molding sand made with this binder is also required to have a certain usable time, good fluidity of molding sand, and easy to produce sand mold and sand core with dense surface, clear outline and stable size; It should have the comprehensive high-temperature performance of obtaining high-quality castings, and the air evolution of molding sand should be low to reduce the tendency of pores in castings; ⑥ The binder should be easy to store and transport, cheap and good. Of course, it is impossible to hope that a binder can perfectly meet all the above requirements, but a good binder should be able to meet most of the above requirements, and the deficiencies do not hinder its normal use. At present, there are many kinds of casting binders used at home and abroad, which can be summarized into two categories: clay for green sand and synthetic resin binder for chemical sand

using clay bonded quartz sand as molding material to produce castings has a long history. In modern foundry industry, clay sand Wet mold is the most important casting process. Clay sand dry mold has a trend of being phased out because of its long molding cycle, large drying equipment and high energy consumption

chemical binders are developing fastest, especially synthetic resins and sodium silicate. Various binders used in production have been commercialized and serialized. After the 1950s, foreign countries began to use CO2 sodium silicate sand instead of foundation size to produce various medium and large castings instead of clay sand according to the shape and foundation drawing, so as to improve the molding and core making efficiency and casting quality, and achieved good results. This process was once popularized and applied rapidly. However, due to the high residual strength and poor collapsibility of sodium silicate sand, the project has been supported by the "hundred talents plan" project of the Chinese Academy of Sciences and cooperative enterprises, which brings great difficulties to sand cleaning and old sand regeneration. By the late 1960s, various resin binder systems represented by furan resin sand were emerging in endlessly. Resin sand has high production efficiency and high core strength, which is suitable for batch automatic production. However, this kind of method requires high skills of operators and high environmental pollution. The development trend of synthetic resin is mainly considered from three aspects: modification, environmental protection and energy saving. The modification includes the improvement of resin adhesion, the improvement of resin moisture absorption resistance, the improvement of collapsibility, the reduction of gas evolution, and the reduction of the requirements for the grade of raw sand. In order to protect the environment, research and develop the low toxic and harmless bonding agent system for imported products in the United States, such as sodium polyacrylate/co2 method, alkaline phenolic resin/co2 method and oxygen reducing resin/so2 method. The purpose of adopting cold box method and self hardening non drying method is to save energy

from the basic situation of the current development of molding materials, each binder system has its advantages and limitations, and it is impossible for a certain binder to dominate the world. In general, the development direction of casting binder is that there is no lack of materials, will not cause casting defects and environmental pollution, and can ensure the full regeneration of sand. Green casting binder and molding (core) process green technology is a technology based on environmental value and utilizing the full potential of modern science and technology. There are many sources of pollution in foundry production, one of which is molding materials. In addition to a large amount of discarded waste sand and dust discharged into the air, core sand binder is the main source of harmful or toxic substances. Therefore, there is great potential to treat the pollution of the foundry industry from the perspective of molding materials. It is imperative to design and apply green molding materials, green adhesives and green molding (core) technology

unfortunately, almost every commonly used organic resin binder system contains harmful substances. However, natural physical binders such as clay, animal protein, starch and inorganic chemical binders such as sodium silicate and phosphate are green binders without harmful substances. 3.1 clay

over the past few decades, the technological progress in clay green sand is manifested in a deeper understanding of the properties of clay green sand and the bonding mechanism of clay; The testing method and monitoring method of molding sand performance are continuously improved; The use of clay green sand in mass production solves many problems that make it suitable for various high-speed and high-pressure molding conditions. The additives in clay sand have achieved a lot in improving the properties of molding sand and the quality of castings. With the continuous development of molding technology and related equipment, the task facing foundry workers is to strengthen the research on clay sand and improve its quality control (control) under production conditions, so as to better adapt to new workers