55 lbs Bag - Assay Borax Anhydrous

55 lbs - Borax Anhydrous - (Sodium Tetraborate Anhydrous) - Lab / Assay Grade Other common names include: Sodium Borate, Sodium Tetraborate, Borax, Calcined Borax, Dehydrated Borax, Pyrobor Sold by the Each (55 lbs) Bag For use as an assaying flux (or flux thinner) for melting or smelting gold and other precious metals. Analysis / Specification Boric Oxide (B2O3) - 68.5% min Equivalent Borax (Na2B4O7) - 99.0% Sodium Oxide (Na2O) - 30.5% min Sulfate as SO4 - 150 ppm max Total Iron (Fe) - < 50 ppm US Sieve No. +12 - 2% max CAS 1330-43-4