Quality standard: Item Index High-grade product Ⅰ High product Ⅱ Appearance White powder White powder Bromine content % ≥ 81.5 81.5 Whiteness ≥ 90 88.0 Volatilization% ≤ 0.05 0.05 Grain size um ≤ 3.0 5.0 Melting point ≥ 345 ℃ 345 ℃