Bentonite For Foundry

Bentonite is the essential bonder used in foundry (Metal Casting ).In foundry,there are several kinds of proper Bentonite depending on the quality of casts. Choosing proper Bentonite for foundry, the factory can not only guarantee the cast quality but also reduce the cost. Bentonite could hold back sand inclusion, scar over, spalling, collapsing because of its good plasticity. Our company can provide Calcium Bentonite and Sodium Bentonite in a long time. Because of its excellent properties, it is often used as a favorabl bond in nonferrous mental foundry, especially used in casting steel and casting iron , resulting in remarkably improving moulding surface more clean and precise.

Bentonite for foundry working principle
Bentonite serves as an economical bonding material in the molding processes associated with the metal casting industry. Bentonite, when mixed with foundry molding sands, forms a pliable bond with the sand granules. Impressions are formed into the face of the bentonite/sand mixtures. Molten metal is pored into the impressions at temperatures exceeding 2,800 F. The unique bonding characteristics of bentonite insures the durability of the mold during these high temperatures. Once the process is complete, the bentonite/sand mold can then be broken away from the casting face and reused.

Sort Item Indicators	Sodium Bentonite	Calcium Bentonite
Wet Compression Strength	≥0.05	≥0.048
Colloid Index ( ml/15g)	>93	55-70
Blue Absorption (g/100g)	≥38	≥38
Moisture %	≤10	≤10
Expansion multiple (ml/g)	≥20	≥12
Heat-humidity Tensile Strength (g/cm2)	>30	>10
Granularity 200Holes	95	95
PH value	>7	>7
Montmorillonite content (%)	70-90	70-90