Effects of stirring speed and time, pH and sodium oleate concentration on the shear hydrophobic flocculation of ultrafine Anshan hematite with sodium oleate as the surfactant were discussed. The results show that thes...Effects of stirring speed and time, pH and sodium oleate concentration on the shear hydrophobic flocculation of ultrafine Anshan hematite with sodium oleate as the surfactant were discussed. The results show that these parameters significantly affect the shear hydrophobic flocculation of ultrafine hematite. The optimum conditions for the flocculation are： stirring speed 1 400 r/min, flocculation time 20 min, pH 9 and sodium oleate concentration 3.94×10-4 mol/L; the flotation recovery of hematite flocs is remarkably high compared with non flocculated ultrafine hematite. According to the extended DLVO theory, the total interaction potential of Anshan ultrafine hematite was determined. The calculation results indicate that the hydrophobic flocculation state of the ultrafine hematite-sodium oleate system is mainly dominated by electric double layer repulsive interaction potential and hydrophobic interaction potential. A mechanical agitation is required to impart particles a kinetic energy to overcome potential barrier between them due to the existence of electric double layer repulsive interaction potential. Those particles further approach to form flocs due to the significant increase of the hydrophobic interaction potential.展开更多
Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related ...Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related to the particle size, and that an excessive content of fine particles(<18 μm) impacted the recovery of coarse particles. When hydrophobic flocculation pretreatment was used, the recovery of fine cuprite in sulfidation-flotation increased from 60.3% to 86.3% under optimum conditions(pH 9.5; sodium oleate concentration, 2 × 10^(-4) mol×L^(-1); stirring time, 6 min; stirring speed, 1600 r×min^(-1)). The laser particle size analysis and optical microscopy results indicate that hydrophobic flocculation pretreatment effectively reduces the content of fine cuprite, and augments the apparent particle size in the pulp. We performed the Derjaguin–Landau–Verwey–Overbeek(DLVO) theory and extended DLVO theory calculations to further support the interpretation of the results.展开更多
The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid（SPA） was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based part...The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid（SPA） was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force（stirring speed） and stirring time played significant roles in flocculation. The isoelectric point（IEP） and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.展开更多
基金Project (20062026) supported by Natural Science Foundation of Liaoning Province, China
文摘Effects of stirring speed and time, pH and sodium oleate concentration on the shear hydrophobic flocculation of ultrafine Anshan hematite with sodium oleate as the surfactant were discussed. The results show that these parameters significantly affect the shear hydrophobic flocculation of ultrafine hematite. The optimum conditions for the flocculation are： stirring speed 1 400 r/min, flocculation time 20 min, pH 9 and sodium oleate concentration 3.94×10-4 mol/L; the flotation recovery of hematite flocs is remarkably high compared with non flocculated ultrafine hematite. According to the extended DLVO theory, the total interaction potential of Anshan ultrafine hematite was determined. The calculation results indicate that the hydrophobic flocculation state of the ultrafine hematite-sodium oleate system is mainly dominated by electric double layer repulsive interaction potential and hydrophobic interaction potential. A mechanical agitation is required to impart particles a kinetic energy to overcome potential barrier between them due to the existence of electric double layer repulsive interaction potential. Those particles further approach to form flocs due to the significant increase of the hydrophobic interaction potential.
基金financially supported by the National Natural Science Foundation of China (Nos. 51374079 and 51504053) the Hundred, Thousand and Ten Thousand Talent Project of Liaoning Province (No. 2014921014)the Postdoctoral Science Foundation of China (No. 2015M571324)
文摘Hydrophobic flocculation pretreatment was performed to assess its effect on the recovery of fine cuprite in sulfidation-flotation. The results of the micro-flotation experiment showed that cuprite recovery is related to the particle size, and that an excessive content of fine particles(<18 μm) impacted the recovery of coarse particles. When hydrophobic flocculation pretreatment was used, the recovery of fine cuprite in sulfidation-flotation increased from 60.3% to 86.3% under optimum conditions(pH 9.5; sodium oleate concentration, 2 × 10^(-4) mol×L^(-1); stirring time, 6 min; stirring speed, 1600 r×min^(-1)). The laser particle size analysis and optical microscopy results indicate that hydrophobic flocculation pretreatment effectively reduces the content of fine cuprite, and augments the apparent particle size in the pulp. We performed the Derjaguin–Landau–Verwey–Overbeek(DLVO) theory and extended DLVO theory calculations to further support the interpretation of the results.
基金Projects(51474254,51774332,51320105006) supported by the National Natural Science Foundation of ChinaProject(NCET-13-0595) supported by the Program for New Century Excellent Talents in University,ChinaProjects(2017zzts579,2017zzts379) supported by the Fundamental Research Funds for the Central Universities of China
文摘The hydrophobic flocculation flotation of rutile fines in the presence of styryl phosphonic acid（SPA） was investigated by flotation tests, zeta-potential measurement, optical microscope observation, laser-based particle size analysis, adsorption measurements and DLVO theory. The flotation tests indicated that rutile fines could be flocculated by SPA, and pH, shear force（stirring speed） and stirring time played significant roles in flocculation. The isoelectric point（IEP） and zeta-potential in whole range all moved to negative values as SPA was added according to the results from zeta-potential measurement. It was demonstrated that the primary reason for above was chemical adsorption. The laser-based particle size results showed the particle size at a stirring speed of 1800 r/min and 1000 mg/L SPA was the largest in all experiments. Furthermore, using the optical microscope observation and flotation tests, it was important for flotation of rutile fines to produce the flocculant. In the light of above-mentioned facts, floc flotation of rutile fines could be induced in the form of chemical adsorption by SPA to increase particle size. The data calculated from DLVO theory also indicated that chemical adsorption was the main reason for the formation of flocculant.
