... or yellow powdercrystallization point:≥ 78.3ºC(excellent grade),≥78.0ºC(first level) ,≥77.5º ... C(qualified level)invalatile substance:≤ 0.04 (excellent grade), ≤ 0.06 (first level),≤ 0.08 (qualified ... level)ash:≤ 0.01(excellent grade),≤0.01(first level),≤0.02(qualified level) ... and additive of concrete Top grade Industrial naphthalene flakes,crude naphthalene,technical naphthalene,