Study On Double Reverse Flotation Of Desilication Of Micro-fine Phosphate Ore

In this paper,AWL and BWL of low grade calcareous–siliceous phosphate rock with fine particle insertion in two typical phosphate mining areas in guizhou was investigated by double reverse flotation.The effects of grinding fineness,pulp concentration,air volume and and reagent system on flotation indexes were systematically studied from three aspects of flotation process exploration,flotation process optimization,and flotation process verification.The mechanism of collector AY onto quartz and collophane was preliminarily discussed by means of contact angle,surface tension,Zeta potential,and FTIR.The research results provide a basis for the flotation practice of this type phosphate rock.The research results provide a basis for the flotation practice of this type phosphate rock.The following main conclusions:XRD analysis shows that the useful minerals of AWL and BWL are fluorapatite,and the gangue minerals are mainly dolomite and quartz.AWL phosphate is observed by microscope,the associated relationship between useful minerals and gangue minerals is more complex and tightly embedded.The results of laser particle size analysis show that the size distribution of the two is not uniform,the content of fine grain is more,and the content of coarse grain is less.Chemical composition analysis shows that the contents of P₂O₅,MgO and SiO₂ in AWL phosphate are18.72%,3.12%and 25.86%,respectively.The contents of P₂O₅,MgO and SiO₂ in BWL phosphate are 24.49%,2.81%and 17.20%,respectively.The content of P₂O₅ in AWL phosphate is lower than that of BWL phosphate,and all of the two belong to low grade calcareous–siliceous phosphate.In the exploration experiment,the grinding fineness is-0.075 mm 79.45%,pulp concentration is 27%,air volume is 0.10 m³/h,pulp pH is 3.5（H₂SO₄ dosage is 5.0 kg/t）,and the AY dosage is0.5 kg/t,and the test process of"one roughing,one concentration and one scavenging"is used to obtain the grade and recovery of P₂O₅ in concentrate are 26.65%and 58.27%,the content of MgO and SiO₂ is 1.99%and 18.36%,and the removal rate of SiO₂ is 44.22%.In the optimization experiment,the grinding fineness is-0.075 mm 75.86%,Adding 5.0 kg/t H₂SO₄ and 0.6 kg/t GJBW for roughing selection,and the dosage of H₂SO₄ and AY is 2.0 kg/t and 0.4 kg/t for concentration selectionand,and the test process of"one roughing and one concentration"is used to obtain the grade and recovery of P₂O₅ in concentrate are 26.70%and 73.87%,the content of MgO and SiO₂ is 1.43%and 19.22%,and the removal rate of SiO₂ is 51.97%.The optimized double reverse flotation process for the treatment of AWL phosphate can get better flotation index by contrasting exploratory test and optimization test.BWL phosphate experimental results show that the grinding fineness of-0.075 mm content accounted for 78.08%,adding 7.5 kg/t mixed acid（sulphuric acid and phosphoric acid volume ratio is 2:1）and 0.3 kg/t GJBW for roughing selection,and the dosage of mixed acid and AY is 7.5 kg/t and 0.4 kg/t for concentration selection,via the double reverse flotation test procedure,final flotation phosphate concentrate with P₂O₅ grade of30.27%,recovery rate is 84.42%was obtained and the content of MgO and SiO₂ is 1.10%and13.37%,and the removal rate of SiO₂ is 31.36%.Compared with the results of double reverse flotation test of BWL phosphate,the process has a certain feasibility for low grade calcareous–siliceous phosphate rock.The orthogonal test results show that there is interaction between the mixed acid,collector GJBW and AY,which has a significant effect on the flotation index of AWL concentrate,and has little effect on the flotation index of BWL concentrate.The collophane and quartz have strong hydrophilicity,poor floatability.The floatability of the collophane and quartz is greatly improved after the action of AY.Contrasting the wetting contact angle of quartz and collophane after the action of AY,it is found that the flotation separation of collophane and quartz by AY is still limited.The surface tension of solution decreases with concentration of collector AY increases,it is also affected by pH value,and in a certain range,surface tension of solution decreases with the decrease of pH.The surface electronegativity of quartz is stronger than collophane with the increase of pH,and AY is more easily adsorbed onto the surface of quartz.The cationic collector AY can realize flotation separation of collophane and quartz under weak acid conditions.The collector AY has no obvious adsorption onto collophane,and the adsorption of AY onto quartz is mainly physical adsorption and strong adsorption under weak acid condition.