special low-expansion sands

We also stock alternative substrates with reduced thermal expansion characteristics compared with pure silica sand. These can be used in our own coated sand products or supplied direct to the customer’s foundry for use with alternative binders.

The choice of which low-expansion material to use depends on the degree of the problem and the relative cost of the special sand. We have the knowledge and experience to help you make this choice effectively. Within our own coated sand products we also have the facility to blend special low-expansion sands and silica sands where practical.

Our portfolio of low-expansion sands can be broken down into:

J-Sand:
A range of modified quartz products with high feldspar content – suitable for use in iron or aluminium castings showing low to moderate levels of expansion-related defects. J-Sand offers the following benefits:

• competitive price
• low bulk density
• average refractoriness, pH (acid demand), expansion characteristics, grain shape
• available in a range of grain sizes

D-Sand:
A range of highly refractory synthetic ceramic bead products offering very low expansion characteristics – used predominantly with iron and steel castings and especially in thin section complex cores where expansion-related defects are common. D-Sand offers the following benefits:

• highly refractory
• excellent bonding performance (unique)
• round grained, good packing
• excellent flowability into coreboxes
• low density
• suitable also for greensand and lost foam
• combines high permeability with good surface finish

Zircon:
Available as a coated sand product of 110 AFS, Zircon offers the following benefits:

• very low thermal expansion
• highly refractory
• high heat capacity and thermal conductivity (chilling effect on sand)
• high density resists flotation
• good grain shape and produces strong cores / moulds
• low acid demand
• resists penetration

For further information please call +44 (0)1270 752 400 or 0845 357 4040 or email sales@sibelco.co.uk