Ammonium Salt - Malachite - Sodium Sulfide Catalyzed Oxidation Mechanism Discussed

When we entered the21th century, our country has developed rapidly in the science and technology development. The consumption of resources is large, some resources even in the extreme shortage degree. China's copper demand is more than a domestic copper metal production, to overseas resources dependence is more and more big. The copper resources in China, there are quite part to oxide copper, because of the oxide copper ore nature, it is difficult to get good dressing indexes, and to reduce the copper recycling, caused serious waste of resources. Therefore, we need to find more reasonable and effective oxide copper flotation process.In the oxide copper processing, the most commonly used method is sulfide-xanthates flotation, which is a method of first adding the sodium sulfide, then adding xanthates as collector for flotation.The sodium sulfide is a kind of unstable material, which has the hygroscopicity, and in natural conditions are easy to oxidation. Trace material in the water play certain catalytic role.The transition metal salts, such as copper, iron, cobalt, manganese, nickel, etc can be greatly accelerated the oxidation of sulfides. Oxide copper belong to soluble minerals, so it also can oxide the sodium sulfide.In the oxide copper sulfide-xanthates flotation, the sodium sulfide plays an important role.When add appropriate dosage, we can get good flotation index, but the sodium sulfide excessive,the remnants of sulfur ion in the pulp can produce inhibition,go against the flotation. But at the same time or in to join the sodium sulfide with the same amount of ammonium sulfate can remove the inhibition, speed up the curing speed, still can make vulcanization film is more stable, density, promote the oxide copper flotation, and industrial practice has been confirmed.In this paper, on the basis of catalytic oxidation of the sodium sulfide, according to the promoting function of inorganic ammonium salt in the oxide copper sulphidizing flotation process, the tracking measurement of the concentration of S2-and pH,main is the oxide copper-the sodium sulfide system and oxide copper-inorganic ammonium salt-the sodium sulfide system of the change of the S2-and pH were studied.The results of the study show that, in the oxide copper flotation sulfide, except the sodium sulfide of activation of oxide copper, forming copper sulfide film outside, still happen complex oxidation reaction, the oxidation process including two process, first it is S2-oxidized to in elemental sulfur, second it is elemental sulfur oxidized to high price sulfur, the two processes, progressive exist between the relationship, and the oxidation process and system pH value there is a close relationship; The ammonium sulfate in the oxide copper sulphidizing flotation process on mineral surface cleaning, improves the activity of the mineral surface, which not only promotes the vulcanization process, also accelerated the divalent sulfur ion oxidation, which is ammonium sulfate promotes the oxidation of copper sulfide flotation is important reason.