... acidic.5. Quality standard:(FCC-IV) INDEXESFCC-IVAssay(As Ca),%15.9-17.7Pb, ≤%0.0002As, ... ≤%0.0003Heavy metals(As Pb), ≤%0.0015Fluoride, ≤%0.005Residue on ignition, ... 56. Usage: In food industry, it is used as leavening agent, dough regulator, buffer, modifier, solidification agent ... and ventilative warehouse; Kept away from moisture and poisonous substances. Handled with care.