Copper Oxide Purity:99%, Production following the state standards used in producing glass,ceramic,fire works, etc. Copper Oxide Item Standard I Standard II CuO , % ≥9998Muriatic acid insoluble substance ≤ ,%0.050.20Cl , % ≤0.020.20SO 4 , % ≤0.050.20water-insoluble , % ≤0.010.10Residue on sieve (150um ) ≤ ,% 0.10Residue on sieve (300um ) ,≤ %0.10 Copper Oxide