Study On The Effect Of Small Molecule Depressants In Copper-Molybdenum Separation

Molybdenite is the main source of molybdenum extraction in the industry,which is mainly associated with copper sulfide minerals in porphyry copper ore,due to the low grade of copper and molybdenum,to maximize the recovery of copper and molybdenum,mixed flotation is usually used to obtain chalcopyrite-molybdenite mixed concentrate and then separate.However,the floatability of chalcopyrite and molybdenite is good,and the separation of chalcopyrite-molybdenite mixed concentrate needs to consume a significant amount of depressants,resulting in high cost or even loss of molybdenum separation.To develop efficient depressants for chalcopyrite-molybdenite separation,the effects of five organic small molecule depressants containing–SH or–NH₂ on the flotation behavior of chalcopyrite and molybdenite were explored through single mineral and artificial mixed ore flotation experiments,and the depression of depressants on chalcopyrite and molybdenite adsorbed with butyl xanthate（BX）on the surface were studied.Adsorption mechanism of these five depressants on the surface of chalcopyrite and molybdenite was discussed by adsorption capacity test,Zeta potential test,X-ray photoelectron spectroscopy（XPS）and Ultraviolet-visible（UV-vis）spectrometer test.The results of single mineral and artificial mixed ore flotation experiment results show that these five organic small molecule depressants can achieve highly selective separation of chalcopyrite and molybdenite under low dosage conditions.Among them,the dosage of DH containing only–NH₂ is significantly higher than other reagents containing–SH,and the depressant containing only–NH₂ has a weak depression effect on chalcopyrite under weak alkaline conditions.According to the adsorption capacity test,Zeta potential test and XPS test results,it is inferred that these five organic small molecule depressants depress it by selective adsorption on the chalcopyrite surface,and the–SH in the depressant molecule can have strong chemisorption with the copper oxide on the chalcopyrite surface,while–NH₂ is mainly electrostatically adsorbed on the surface of chalcopyrite through–NH₃⁺generated by protonation,so the depressant containing–SH has a significantly stronger depression effect on chalcopyrite than the depressant containing–NH₂ alone.Surface adsorption of butyl xanthate（BX）will further narrow the difference in the floatability of chalcopyrite and molybdenite,increase the difficulty of chalcopyrite-molybdenite separation,while the surface adsorption of BX will hinder the adsorption of depressants on the surface of minerals,resulting in weak depression and poor separation effect.H2O2 can oxidize and decompose BX and accelerate the oxidation of mineral surface.However,using H₂O₂ alone to separate chalcopyrite-molybdenite mixed concentrate has problems such as long flotation time and large dosage.Adding a small amount of H₂O₂ can regulate the oxidation behavior of chalcopyrite-molybdenite mixed concentrate with BX adsorbed on the surface,promote selective adsorption of depressants,and achieve molybdenite suppression and chalcopyrite flotation.The chalcopyrite-molybdenite mixed concentrate was separated under the conditions of H₂O₂concentration of 4×10^–4 mol/L,AMT concentration of 30 mg/L at p H 7,and a rough selection of molybdenite concentrate with a Mo grade of 41.38%and a recovery of 84.26%was obtained.The results of UV-vis spectroscopy and adsorption capacity test showed that H₂O₂ would decompose part of BX,but the main reason for the separation of copper and molybdenum was that H₂O₂accelerated the oxidation of mineral surface and provided more adsorption sites for the adsorption of depressants.Organic small molecule depressants effectively solve the problem of large dosage of chalcopyrite-molybdenite separation depressants,providing a new reference for the development of chalcopyrite-molybdenite separation depressants.And the regulation of oxidant can enhance the separation effect of organic small molecule depressants on chalcopyrite and molybdenum with BX adsorbed on the surface,which provides a new idea for the separation of chalcopyrite and molybdenite,and has certain guiding significance for the field of chalcopyrite-molybdenite separation.