Ceramsite Sand work with Alkaline sodium silicate in the Foundry
Ceramsite sand is also called Foundry ceramic sand. It gets advantages such as a special spherical shape, high sand strength, high refractory temperature, and low thermal expansion rate. Therefore, it is suitable for lost foam, no-bake sand, and investment casting. Ceramsite is also an excellent foundry sand work with Alkaline sodium silicate binder. It archives many advantages and gains higher economic benefits.
The modified ester hardened Alkaline sodium silicate is an advanced binder than traditional Alkaline sodium silicate. It can improve the collapsibility of molding sand and core sand. In the meantime, it improves the dimensional accuracy of castings. Especially for steel castings and high manganese steel castings, improve the quality and fineness of the surface. Its main advantages include the following:
The amount of binder added is low. Thus the hardening speed is flexible.
The molding sand has good technical performance and good air permeability in winter weather.
The casting quality and dimensional accuracy are high, and the molding sand has good thermoplasticity and low gas generation. It can prevent casting cracks and porosity defects.
Non-irritating, no harmful gas. So it is friendly to operators.
However, the modified ester hardening Alkaline sodium silicate process has its inevitable disadvantages:
For organic resin binders, the improvement of sand collapsibility is not obvious.
It is difficult to make sand recycled. There will get harmful liquid recycled by wet regeneration, and the recovery effect of dry regeneration is low.
Ceramsite works well with modified ester hardened Alkaline sodium silicates. It replaced silica sand as molding sand and core sand. Usually, ceramsite sand 30-50 mesh replaces silica sand 20-40 mesh. It can effectively improve the collapsibility of molding sand and improve the recycling rate of used sand. The specific advantages are as follows:
- Reduce the consumption of Alkaline sodium silicates binder and curing agent. For the same amount of binder added, the strength of ceramsite sand is 30% higher than that of silica sand.
- The particle shape of the ceramsite sand is spherical. So the molding sand is of good fluidity. It can avoid the defect of poor collapsibility in the Alkaline sodium silicates casting process.
- The refractoriness of ceramsite sand is high. It is resistant to high temperatures up to 1800℃. Moreover, its advantages are more obvious when producing large castings with thick walls and many hot joints. The use of ceramsite sand can significantly reduce the defects of sticky sand and iron-clad sand.
- Ceramsite sand is neutral sand with PH values 7-8. That feature can meet the production of castings of various materials. Silica sand is acidic, so it always gets chemical sticky sand when producing basic castings such as high manganese steel. The neutral characteristics of ceramsite sand make it difficult to chemically react with the alloy in the molten metal. As a result, it prevents chemical sand sticking on steel castings.
- Easy to recycle and regenerate. The hardness of ceramsite sand is much higher than that of silica sand, and it is basically not broken during mechanical regeneration. Thereby, the recovery rate of used sand can be improved, the cost can be saved, and the discharge of solid waste can be reduced. Even without wet regeneration, dry regeneration can be recycled dozens of times.
- Improve the surface quality of castings. Foundry ceramic sand contacts the surface of casting with points instead of a surface. So it can effectively improve the surface quality of the casting.