In nature, sulfide minerals form oxidized minerals under the action of oxygen in air or water and ions in water. Oxidation usually occurs in the upper part of the deposit, and the thickness of the oxide layer can reach 10 ~ 50m according to different geological conditions. Ores can be divided into oxidized ores, sulfide ores and mixed ores according to the oxidation rate of ores (referring to the percentage of a metal in the oxidized mineral state). Generally, more than 30% of the oxidation rate is oxidized ore, and less than 10% is sulfide ore, and there are mixed ore between the two. The main minerals of non-ferrous metal oxide ore are copper oxide, lead oxide and zinc oxide ore.

Copper oxide (CuO) is a black oxide of copper, slightly neutral, slightly hygroscopic. The relative molecular weight is 79.545, the density is 6.3 ~ 6.9 g/cm, and the melting point is 1026. Insoluble in water and ethanol, soluble in acid, ammonium chloride and other solutions, slowly soluble in ammonia solution, can react with a strong base, so how to preserve is very important. Be sure to pay attention to storage; Store in a cool, ventilated place. Keep away from fire and heat. It should be stored separately from reducing agents, alkali metals and edible chemicals, and should not be mixed. Storage areas should be equipped with suitable materials to prevent leakage.

It is often believed that the role of copper oxide is "step oxygen release", that is, potassium nitrate, barium nitrate, bismuth oxide, copper oxide in their respective temperature ranges will be thermal decomposition to release oxygen, so that the bright beads reignite, producing more flash. This view is shared by some. However, iron oxide and manganese dioxide were used in the white flash formula last year. The first group still left bismuth oxide and copper oxide, but added iron oxide and manganese dioxide. The second group removed bismuth oxide and copper oxide and added only iron oxide and manganese dioxide. No difference in flicker frequency was found between the two groups. Therefore, the role of copper oxide and bismuth oxide in "step oxygen release" was temporarily overthrown.

Therefore, some experts still believe that copper oxide and bismuth oxide play the role of light screen, that is, emit a small amount of light blue-green light, effectively blocking some visible stray light. Makes the white flash effect look brighter. At the same time, as far as possible do not use blue light agent instead of copper oxide. The blue agent contains chloride ions, which will make barium nitrate emit green light, and turn yellow after mixing with white, which has a certain influence on the overall light color effect.