A new method of testing frother performance was proposed. Four parameters were tested: maximum foam volume, foam half-life, gas-liquid ratio and mean foam rise velocity. Among them the former two parameters indicate ...A new method of testing frother performance was proposed. Four parameters were tested: maximum foam volume, foam half-life, gas-liquid ratio and mean foam rise velocity. Among them the former two parameters indicate frother's foaming ability and foam stability respectively, and the latter two indicate water carrying ability and foam viscosity, respectively. The performance of four frothers in a two-phase (solution-air) system was tested and batch flotation tests on a copper ore were carried out. By analyzing frother performance in a two-phase system and comparing with the flotation results, correlation between them was found. Higher-copper concentrate grade was obtained by frothers with weak water carrying ability and low foam viscosity. And frothers with strong foaming ability and stable foam tend to obtain higher copper recovery.展开更多
The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation reco...The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors.When butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate.At the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline conditions.But Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector.By the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the collector.Using sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is established.At pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).展开更多
In conventional chromite beneficiation plant, huge quantity of chromite is used to loss in the form of tailing. For recovery these valuable mineral, a gravity concentrator viz. wet shaking table was used.Optimisation ...In conventional chromite beneficiation plant, huge quantity of chromite is used to loss in the form of tailing. For recovery these valuable mineral, a gravity concentrator viz. wet shaking table was used.Optimisation along with performance prediction of the unit operation is necessary for efficient recovery.So, in this present study, an artificial neural network(ANN) modeling approach was attempted for predicting the performance of wet shaking table in terms of grade(%) and recovery(%). A three layer feed forward neural network(3:3–11–2:2) was developed by varying the major operating parameters such as wash water flow rate(L/min), deck tilt angle(degree) and slurry feed rate(L/h). The predicted value obtained by the neural network model shows excellent agreement with the experimental values.展开更多
The effect of a modified ester collector named as BL on the flotation of chalcopyrite at low temperatures was investigated by micro-flotation tests,contact angle measurements,adsorption experiments,laser particle size...The effect of a modified ester collector named as BL on the flotation of chalcopyrite at low temperatures was investigated by micro-flotation tests,contact angle measurements,adsorption experiments,laser particle size analysis,cryogenic transmission electron microscopy(Cryo-TEM)and Fourier transform infrared(FTIR)analyses.Micro-flotation tests proved that the collecting ability of BL for chalcopyrite was significantly better than that of N,N-diethyl dithiocarbamate propiononitrile ester(ester-105)at low temperatures.Combined with laser particle size,Cryo-TEM and FTIR analyses,it was found that the particle size of BL in water was smaller than that of ester-105,and the distributed density of BL was higher than that of ester-105 at low temperatures,indicating that BL dispersed well at low temperatures.Therefore,BL was more easily adsorbed on the chalcopyrite surface and improved the surface hydrophobic degree of chalcopyrite,which were also confirmed by the contact angle measurements and adsorption experiments.展开更多
To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of...To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of species was determined in terms of relative density, frequency and importance value for each species. The study reveals variations in performance of species; for example in terms of importance values, Acacia polyacantha (33.5%), Toona ciliata (21.4%), Acacia sieberana (9.9%), Bauhinia thonningii (9.1%) and Peltophorum africanum (8.3%) were the most dominant species. The dominance of these species on tailings dams demonstrates tolerance to railings dams conditions. The study recommends that emphasis must be placed on these species in re-vegetating tailings dams.展开更多
Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance(grade and recovery) is a consequence of the...Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance(grade and recovery) is a consequence of the quality and quantity of the solid particles collected from the pulp phase, transported into the froth phase, and surviving as bubble-particle aggregates into the overflow. This work will focus on studying these phenomena and will incorporate the effects of particle hydrophobicities in the 3-phase system. Solids are classed as either hydrophilic non-sulphide gangue(e.g. silica, talc), hydrophilic sulphide(e.g. pyrite), or hydrophobic sulphide(e.g. sphalerite). Talc is a surface-active species of gangue that has been shown to behave differently from silica(frother adsorbs on the surface of talc particles). Both are common components of ores and will be studied in detail. The focus of this work is to investigate the role of solids on pulp hydrodynamics, froth bubble coalescence intensity, water overflow rate with solids present, and in particular, the interactions between solids, frother and gas on the gas dispersion parameters. The results show that in the pulp zone there is no effect of solids on bubble size and gas holdup; in the froth zone, although hydrophilic particles solely do not effect on the water overflow rate, hydrophobic particles produce higher intensity of rates on water overflow and bubble coalescence, and many be attributed to the water reattachment.展开更多
A dish/stifling solar thermal electricity system consists of two parts: a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was es...A dish/stifling solar thermal electricity system consists of two parts: a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.展开更多
基金Project(51174229)supported by the National Natural Science Foundation of China
文摘A new method of testing frother performance was proposed. Four parameters were tested: maximum foam volume, foam half-life, gas-liquid ratio and mean foam rise velocity. Among them the former two parameters indicate frother's foaming ability and foam stability respectively, and the latter two indicate water carrying ability and foam viscosity, respectively. The performance of four frothers in a two-phase (solution-air) system was tested and batch flotation tests on a copper ore were carried out. By analyzing frother performance in a two-phase system and comparing with the flotation results, correlation between them was found. Higher-copper concentrate grade was obtained by frothers with weak water carrying ability and low foam viscosity. And frothers with strong foaming ability and stable foam tend to obtain higher copper recovery.
基金Project(50774094) supported by the National Natural Science Foundation of China
文摘The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was studied.It is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different collectors.When butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl dithiocarbamate.At the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline conditions.But Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the collector.By the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the collector.Using sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is established.At pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).
文摘In conventional chromite beneficiation plant, huge quantity of chromite is used to loss in the form of tailing. For recovery these valuable mineral, a gravity concentrator viz. wet shaking table was used.Optimisation along with performance prediction of the unit operation is necessary for efficient recovery.So, in this present study, an artificial neural network(ANN) modeling approach was attempted for predicting the performance of wet shaking table in terms of grade(%) and recovery(%). A three layer feed forward neural network(3:3–11–2:2) was developed by varying the major operating parameters such as wash water flow rate(L/min), deck tilt angle(degree) and slurry feed rate(L/h). The predicted value obtained by the neural network model shows excellent agreement with the experimental values.
基金financial supports from the National Natural Science Foundation of China(No.52074206)the Talent Science and Technology Fund of Xi’an University of Architecture and Technology,China(No.ZR19062)+4 种基金the Open Foundation of State Key Laboratory of Mineral Processing,China(No.BGRIMM-KJSKL-2021-19)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2021JQ-507)the Special Research Project of Shaanxi Education Department,China(No.21JK0731)the Key Program for International S&T Cooperation Projects of Shaanxi Province,China(No.2021KWZ-16)the Natural Science Foundation of Qinghai Province,China(No.2021-ZJ-975Q)。
文摘The effect of a modified ester collector named as BL on the flotation of chalcopyrite at low temperatures was investigated by micro-flotation tests,contact angle measurements,adsorption experiments,laser particle size analysis,cryogenic transmission electron microscopy(Cryo-TEM)and Fourier transform infrared(FTIR)analyses.Micro-flotation tests proved that the collecting ability of BL for chalcopyrite was significantly better than that of N,N-diethyl dithiocarbamate propiononitrile ester(ester-105)at low temperatures.Combined with laser particle size,Cryo-TEM and FTIR analyses,it was found that the particle size of BL in water was smaller than that of ester-105,and the distributed density of BL was higher than that of ester-105 at low temperatures,indicating that BL dispersed well at low temperatures.Therefore,BL was more easily adsorbed on the chalcopyrite surface and improved the surface hydrophobic degree of chalcopyrite,which were also confirmed by the contact angle measurements and adsorption experiments.
文摘To facilitate the development of the basis for the selection of plants for re-vegetating tailings in Zambia, an as sessment of the performance of tree species growing on tailings dams was conducted. The performance of species was determined in terms of relative density, frequency and importance value for each species. The study reveals variations in performance of species; for example in terms of importance values, Acacia polyacantha (33.5%), Toona ciliata (21.4%), Acacia sieberana (9.9%), Bauhinia thonningii (9.1%) and Peltophorum africanum (8.3%) were the most dominant species. The dominance of these species on tailings dams demonstrates tolerance to railings dams conditions. The study recommends that emphasis must be placed on these species in re-vegetating tailings dams.
基金financially supported by the Chair in Mineral Processing at McGill University, under the Collaborative Research and Development program of NSERC (Natural Sciences and Engineering Research Council of Canada) with industrial sponsorship from Vale, Teck Cominco, Xstrata Process Support, Agnico-Eagle, Shell Canada, Barrick Gold, COREM, SGS Lakefield Research and Flottec
文摘Froth flotation is a widely used process of particle separation exploiting differences in surface properties. It is important to point out that overall flotation performance(grade and recovery) is a consequence of the quality and quantity of the solid particles collected from the pulp phase, transported into the froth phase, and surviving as bubble-particle aggregates into the overflow. This work will focus on studying these phenomena and will incorporate the effects of particle hydrophobicities in the 3-phase system. Solids are classed as either hydrophilic non-sulphide gangue(e.g. silica, talc), hydrophilic sulphide(e.g. pyrite), or hydrophobic sulphide(e.g. sphalerite). Talc is a surface-active species of gangue that has been shown to behave differently from silica(frother adsorbs on the surface of talc particles). Both are common components of ores and will be studied in detail. The focus of this work is to investigate the role of solids on pulp hydrodynamics, froth bubble coalescence intensity, water overflow rate with solids present, and in particular, the interactions between solids, frother and gas on the gas dispersion parameters. The results show that in the pulp zone there is no effect of solids on bubble size and gas holdup; in the froth zone, although hydrophilic particles solely do not effect on the water overflow rate, hydrophobic particles produce higher intensity of rates on water overflow and bubble coalescence, and many be attributed to the water reattachment.
文摘A dish/stifling solar thermal electricity system consists of two parts: a dish solar concentrator and a Stifling engine. For optimizing the system, in this paper, the mathematical model for concentrator design was established and the effects of those design parameters of concentrator, such as the size and intensity of the focal point, the receiver temperature, on the efficiency of the Stifling engine and output power were numerically simulated. The results of the simulation revealed a close relationship between power and efficiency because of power losses, and there was a maximum for the engine efficiency and power with increasing solar radiation because there was a peak value of system efficiency with increasing receiver temperature. So, in view of our Stifling engine, the 450 rim angle and 6m focal length are optimal design for concentrator and the 800℃receiver temperature is best.