Study On The Behavior Of Pyrite In Flotation Of Carlin-type Gold Deposits In Acidic Syste

Pyrite is the main gold-bearing mineral in Carlin-type gold deposits,and gangue minerals are dolomite,quartz and calcite.In the acidic flotation system,dolomite and calcite alkaline gangue minerals are easily dissolved,and it is inevitable that the ion concentration and pulp p H change have a great influence on flotation.The research on the flotation of Carlin-type gold ore in acid system can open up the application prospect for the utilization of preoxidized acid wastewater in Carlin-type gold ore enterprises,and provide a theoretical basis for the flotation of Carlin-type gold ore in acid system.In this paper,the influence of metal ions on the floatability of pyrite,quartz,dolomite and calcite based on acidic system was studied.On this basis,the flotation test of Carlin-type gold ore was carried out,and the flotation mechanism of Fe²⁺on the surface of pyrite and dolomite was studied.The effects of Fe²⁺,Fe³⁺,Cu²⁺,Ca²⁺and Mg²⁺on the floatability of pyrite,quartz,dolomite and calcite were studied by pure mineral flotation test.The results show that Cu²⁺,Fe²⁺and Fe³⁺have activation effect on pyrite flotation,while Ca²⁺and Mg²⁺have inhibition effect in the acidic system with butyl xanthate.Low concentration of Cu²⁺and Fe²⁺can activate dolomite,while Ca²⁺,Mg²⁺and Fe³⁺have little effect on dolomite flotation.The flotation of Cu²⁺and Fe³⁺activated quartz was inhibited at low ion concentration and inhibited at high ion concentration.Ca²⁺,Mg²⁺and Fe²⁺have a certain inhibitory effect on quartz.Cu²⁺,Ca²⁺,Fe²⁺and Fe³⁺can activate calcite in a certain concentration range,and high concentration of Mg²⁺inhibits the flotation of calcite.The acid flotation process of Carlin type gold ore was studied.The flotation conditions were optimized by single factor and response surface method,and the influence of interaction between factors on flotation was studied.The results show that the degree of influence on the recovery rate of sulfur concentrate is:grinding fineness>reaction time>H₂SO₄dosage;the effect on sulfur grade is:reaction time>grinding fineness>H₂SO₄dosage.The interaction between H₂SO₄dosage and reaction time has the most significant effect on the recovery and grade of sulfur concentrate.The open-circuit flotation process of one roughing,two cleaning and two scavenging is adopted.The grinding fineness of-0.075 mm is 92%,the dosage of H₂SO₄is 1 kg/t,the dosage of activator Cu SO₄is 300 g/t,the dosage of butyl xanthate and ammonium dibutyl dithiophosphate is 200 g/t and 100 g/t,and the dosage of 2#oil is 60 g/t.The grade and recovery of sulfur concentrate are 26.13%and 64.64%,respectively.The gold grade is 17.98%,and the recovery rate is 54.08%.The flotation mechanism of Fe²⁺on pyrite and dolomite was investigated by means of butyl xanthoxanthate adsorption determination,Zeta potential determination,infrared spectrum and X-ray photoelectron spectroscopy.The results show that adding Fe²⁺to the system increases the adsorption capacity of pyrite and dolomite surface to butyl xanthate,and increases the mineral surface potential.When p H=5,butyl xanthate was chemically adsorbed on the iron lattice of pyrite surface with xanthan ions.The addition of Fe²⁺helps xanthate oxidize to double xanthate on the surface of pyrite,which increases the surface hydrophobicity of pyrite.Fe²⁺hydrates under acidic conditions to form Fe OH⁺,which is absorbed on the surface of dolomite and positively charged.Xanthanate anion is electrostatic adsorbed to activate dolomite flotation.