Why does Ceramic sand replace silica sand?
Ceramic sand is more and more acceptable and popular in the Lost Foam foundry to replace silica sand. Silica sand (quartz sand) is easy to get at a low cost. But its two major drawbacks. The first one is high expansion coefficient lead to low casting accuracy. The second problem is severe sand sticking on the surface of the casting, making it difficult to clean the defects.
Silica sand generates various homogeneous and heterogeneous crystals at different temperatures, resulting in significant volume changes. On the other hand, silica sand has a low refractory temperature of about 1400 ℃. Some parts of the casting (such as holes, grooves, and areas with concentrated hot spots) are severely bonded with sand. Then it makes cleaning to tough work. The above disadvantages are particularly serious in the production of large steel castings.
However, ceramic sand can overcome these problems and greatly improve the quality of castings with the following aspects：
1. The coefficient of thermal expansion is small, and the performance can be comparable to that of zircon sand. When used to prepare molding sand, castings will not produce expansion defects;
2. The sand particles are spherical, with good fluidity, easy compaction, and good breathability
3. The surface is smooth and the structure is dense, allowing the adhesive to cover evenly
4. Ceramic sand is a neutral material that can be used as both acid and alkali binders
5. Good recycling and regeneration performance, high cost-effectiveness
6. High fire resistance and easy to collapse
7. High thermal conductivity, good stability, and no cracking
8. Wide application range including lost foam casting, and no-bake sand casting.
It is a good choice to use Ceramic sand for lost foam casting. The use of ceramic sand for casting not only greatly improves the quality of castings, but also facilitates sand cleaning.