... ,relative density is 1.63,melting point is 34.6.USE: used as a fire-prevention agent for fabric,timber,and paper ... ,also as water softening agent for boiler,food additive,buffering agent,solder, ... .10.05Heavy metals, as Pb. % max-----0.001Arsenic,as As. % max-----0.0003Fluoride,as F. % max-----0.002Sulfate,as SO4 % max-----0.25Chloride,as Cl. % max ...