A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surf...A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.展开更多
Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and ...Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and high collector dosage.In order to address these issues,CGFS sample taken from Shaanxi,China was used as the study object in this paper.A new process of size classification-fine grain ultrasonic pretreatment flotation(SC-FGUF)was proposed and its separation effect was compared with that of wholegrain flotation(WGF)as well as size classification-fine grain flotation(SC-FGF).The mechanism of its enhanced separation effect was revealed through flotation kinetic fitting,flotation flow foam layer stability,particle size composition,surface morphology,pore structure,and surface chemical property analysis.The results showed that compared with WGF,pre-classification could reduce the collector dosage by 84.09%and the combination of pre-classification and ultrasonic pretreatment could increase the combustible recovery by 17.29%and up to 93.46%.The SC-FGUF process allows the ineffective adsorption of coarse residual carbon to collector during flotation stage to be reduced by pre-classification,and the tightly embedded state of fine CGFS particles is disrupted and surface oxidizing functional group occupancy was reduced by ultrasonic pretreatment,thus carbon and ash is easier to be separated in the flotation process.In addition,some of the residual carbon particles were broken down to smaller sizes in the ultrasonic pretreatment,which led to an increase in the stability of flotation flow foam layer and a decrease in the probability of detachment of residual carbon particles from the bubbles.Therefore,SCFGUF could increase the residual carbon recovery and reduce the flotation collector dosage,which is an innovative method for carbon-ash separation of CGFS with good application prospect.展开更多
Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well...Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface.The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment.展开更多
基金Projects 50274036 supported by the National Natural Science Foundation of China11531Z02 by the Educational Committee of Heilongjiang Province2009RFXXG030 by the Special Foundation of Harbin Bureau of Science and Technology
文摘A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.
基金supported by the National Natural Science Foundation of China(No.52374279)the Natural Science Foundation of Shaanxi Province(No.2023-YBGY-055).
文摘Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and high collector dosage.In order to address these issues,CGFS sample taken from Shaanxi,China was used as the study object in this paper.A new process of size classification-fine grain ultrasonic pretreatment flotation(SC-FGUF)was proposed and its separation effect was compared with that of wholegrain flotation(WGF)as well as size classification-fine grain flotation(SC-FGF).The mechanism of its enhanced separation effect was revealed through flotation kinetic fitting,flotation flow foam layer stability,particle size composition,surface morphology,pore structure,and surface chemical property analysis.The results showed that compared with WGF,pre-classification could reduce the collector dosage by 84.09%and the combination of pre-classification and ultrasonic pretreatment could increase the combustible recovery by 17.29%and up to 93.46%.The SC-FGUF process allows the ineffective adsorption of coarse residual carbon to collector during flotation stage to be reduced by pre-classification,and the tightly embedded state of fine CGFS particles is disrupted and surface oxidizing functional group occupancy was reduced by ultrasonic pretreatment,thus carbon and ash is easier to be separated in the flotation process.In addition,some of the residual carbon particles were broken down to smaller sizes in the ultrasonic pretreatment,which led to an increase in the stability of flotation flow foam layer and a decrease in the probability of detachment of residual carbon particles from the bubbles.Therefore,SCFGUF could increase the residual carbon recovery and reduce the flotation collector dosage,which is an innovative method for carbon-ash separation of CGFS with good application prospect.
基金financially supported by the National Key Research and Development Program of China (No. 2021YFC2903202)the National Natural Science Foundations of China (Nos. 51974366, 52174267, 52174270 and 52004250)+2 种基金the China Postdoctoral Science Foundation (No. 2020M680100 and 2020TQ0279)the Postdoctoral Research Grant in Henan Province (No. 202003025)the State Key Laboratory of Mineral Processing and Co-innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources。
文摘Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface.The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment.
