Application of Phosphate Inorganic Binders in Foundry Industry
In recent years, with the implementation of a series of new environmental protection policies, higher requirements have been placed on the environmental management methods of foundry companies and the occupational health and safety of employees. The pollution control technology and facilities of foundry enterprises during the production process are still relatively backward. Especially in areas with developed foundry enterprises, the pollution to the environment caused by the production process is very serious. Some companies' exhaust gas treatment is insufficient or even discharged directly without treatment, which brings a great crisis to the ecological environment; some casting sites are filled with smoke, which brings great disease risks to the health of employees. Under such realistic conditions, there is an urgent need for environmentally friendly binders, and phosphate inorganic binders have emerged.
Advantage:
The inorganic binder has good environmental performance and does not emit waste water, waste gas and solid waste during the production and synthesis stage. It is non-toxic, odorless and dust-free during all stages of the casting application process, such as sand mixing, molding or core making, and pouring. Sand molds (cores) have good high temperature resistance and collapse properties, and can be widely used in cast iron and cast steel. It can effectively reduce gas phase pollutants by more than 90%, and has great potential to contribute to the green production of foundry enterprises.
1. Low cost
1. It is a green and pollution-free material with high strength and environmental protection much better than organic resin.
2. Its dispersibility is better than that of silicate inorganic binders, and it is called "inorganic resin".
3. Its waste sand can also be regenerated by dry method to achieve energy saving and resource reuse.
4. Compared with other inorganic binders, due to its unique properties, it has been widely used in many fields, such as: refractory materials, casting, inorganic coatings, etc.
Questions:
The main problems that need to be solved in theory and practice with phosphate inorganic binders are:
1. There is a lack of systematic research on the ingredients and composition of phosphate binders suitable for casting, and insufficient understanding of the bonding and curing mechanisms of phosphate inorganic binders and the structure of phosphate adhesive films.
2. The stability problem of phosphate inorganic binders remains unresolved. A good adhesive should be able to be stored for at least half a year and remain a uniform and transparent solution without precipitating.
3. Hygroscopicity problem of phosphate inorganic binder molding sand. During the storage process of the casting mold or sand core, the strength is reduced and the gas generation is increased due to the absorption of moisture in the air.
