A Preliminary Study On The Mechanism Of Azurite Ammonium Salt-enhanced Sulfidation Flotation

Azurite is one of the important copper oxide minerals.It has similar structure and chemical composition with malachite.However,due to the less extensive distribution of malachite,the research on azurite is not as much as that on malachite.In this paper,azurite is taken as the research object to explore the micromechanism of azurite sulfide strengthening by ammonium salt,which will become an important supplement to the theory of copper oxide flotation and better guide the industrial practice.In this paper,the flotation behavior of azurite and the enhanced sulfidization mechanism of azurite under the action of ammonium salt were systematically studied,and the enhanced curing effect of ammonium salt was confirmed by modern analysis and detection methods.Meanwhile,the migration path of ammonium ions was determined by solution chemical calculation.Flotation tests show that,although the dosage of xanthate is increased from1×10^-5mol/L to 2×10^-4mol/L by 20 times,the floatability of azurite can only reach9.36%,and the natural floatability is poor.Although the addition of Na₂S can significantly improve the floating property of azurite,it is vulnerable to the limitation of sodium sulfide dosage.When sodium sulfide is used in excess,it can have an inhibitory effect.However,the flotation rate of azurite in ammonium salt-sodium sulphide-xanthate flotation system is 81%when the amount of sodium sulphide-xanthate is 1×10^-4mol/L with the same amount of xanthate,which is nearly10 percentage points higher than the flotation rate of 62.9%in sodium sulphide-xanthate flotation system,indicating significant activation effect.The research results of sulfide mechanism in azurite flotation show that under the driving force of the difference in the solubility of azurite and covellite,sodium sulfide can achieve the purpose of sulfide by the solid-liquid multiphase reaction of S^2-with the surface of azurite to generate Cu S crystal.Related analysis and solution chemical calculation results show that the direct sulfide mineral surface generated by the copper sulfide product for covellite(syn-Cu S),to anticipate,the crystal without ammonium ion crystal is poorer,stability is not high,easy to fall off in pulp,this is covellite sulfide flotation directly direct cause is difficult to achieve the desired effect.In the process of azurite sulfide,ammonium ions complexed Cu²⁺dissolved on the surface of the mineral into[Cu(NH₃)_n]²⁺in the pulp,and then reacted with HS^-to release S^2-and Cu²⁺.Under the attraction of van der Waals force on the surface of the mineral,Cu blue crystals were aggregated on the surface of azurite through REDOX reaction.Compared with direct sulfide,The slurry system pretreated by ammonium ions can slow down the direct impact of S^2-,create a more suitable growth environment for Cu S crystals,and make the covering layer of sulfide products larger,more stable and better crystallized,thus reducing the formation of colloidal copper sulfide in the residual liquid.