Potassium Fluoroborate: Spec: Assay: 99% min Cl: 0.01% max Free acid: 1% max K2SiF6: 1% max Moisture: 0.5% max Heavy metal (Pb): 0.5% max Packing: in 25kg composite bags or plastic woven bags or 500/1000kg bag Application: Welding flux, sand-casting of aluminum and magnesium, grinding aid in resinoid grinding wheels; flux for soldering and brazing, electrochemical processes and chemicals.