Bentonite powders and bentonite clays for foundry sands meet the requirements of the State Branch Standards 28177-89 Bentonite forming clays. Common Technical Conditions. The quality properties are presented in following table.

The basic parameters Unit Mark P1T1 P2T1 P2T2 S2T1 S3T1 Breaking point on compression, not less Pa 9x104 9x104 9x104 7x104 7x104 Breaking point in fractured condensation zone of the moisture, not less Pa 0,28x104 0,24x104 0,2x104 0,2x104 0,15x104 Thermal stability, not less unit 0,6 0,7 0,3-0,6 0,7 0,6 Mass fraction of montmorillonite, not less % 70 70 70 70 70 Mass fraction of carbonates, not more % 12 12 12 12 12 Mass fraction of iron in terms of Fe2O3, not more % 1,7 1,7 1,7 1,7 1,7 Colloidality, not less % 70 70 70 70 70 Factor of the water absorbing, not less unit 7,0 7,0 7,0 7,0 7,0 Mass fraction of sulphur, not more % 0,03 0,03 0,03 0,03 0,03 Base cation exchange, meq/100 g of dry clay, not less mg 65 65 65 65 65 Mass fraction of moisture % 6,0 - 10,0 6,0 - 10,0 6,0 - 10,0 6,0 - 10,0 6,0 - 10,0 Sieve residue with mesh size, not more 0,4 mm 0,16 mm % 3,0 10,0 3,0 10,0 3,0 10,0 3,0 10,0 3,01 0,0