The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to b...The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.展开更多
Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-b...Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-bon were discussed.The results showed that phosphoric acid activation assisted by mechanochemical process can slightly improve the adsorption performance of the prepared activated carbon.The iodine,methylene blue adsorption value and the specific surface area of the prepared activated carbons increased from 840.16 mg/g,168 mg/g and 1229.246 m/g to 947.51 mg/g,195 mg/g,and 1265.373 m2/g,respectively.Compared with conventional phosphoric acid activation,the activated carbon produced by mechanochemical process has greater adsorption capacity.展开更多
The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders wer...The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders were investigated. The results show that the increase of mass ratio of phosphoric acid to aluminum hydroxide, the decrease of mass concentration of phosphoric acid and prolongation of mixing time are favorable to the improvement of thermal stability of aluminum hydroxide; when the mass ratio of phosphoric acid to aluminum hydroxide is 5:100, the mass concentration of phosphoric acid is 200 g/L and the mixing time is 10 min, the initial temperature of loss of crystal water in aluminum hydroxide rises from about 192.10 to 208.66 ℃, but the dry modification results in the appearance of agglomeration and macro-aggregate in the modified powders, and the oil absorption of modified powders becomes higher than that of original aluminum hydroxide.展开更多
Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to st...Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to study the luminescence characteristics,energy gap,and thermal stability in detail.CaAlSiN_(3)∶Eu^(2+) exhibits an extended emission band when stimulated with 450 nm blue light,which is caused by the 4f65d to 4f7 transition of Eu^(2+).Similar⁃ly,CaAlSiN_(3)∶Mn^(2+) displays a wide emission band centered at 628 nm,which results from Mn^(2+)’s transition from 4T1(4G) to 6A1(6S).When the ions of Mn^(2+)were combined into CaAlSiN_(3)∶Eu^(2+),the photoluminescence intensity of Eu^(2+ )was greatly boosted because there was energy transfer and co-emission between Mn^(2+) and Eu^(2+).Beyond that,CaAlSiN_(3)∶Eu^(2+),Mn^(2+) emerges with splendid thermostability and high quantum efficiency,the quenching temperature surpasses 300℃,and the internal quantum efficiency is determined to be around 84.9%.The white LED was pack⁃aged with a combination of CaAlSiN_(3)∶Eu^(2+),Mn^(2+),LuAG∶Ce3+ and a blue chip.At a warm white-light corresponding color temperature(3009 K) with CIE coordinates(0.4223,0.3748),the color rendering index Ra has reached 93.2.CaAlSiN_(3)∶Eu^(2+),Mn^(2+) would have great application potential as a red-emitting phosphor for white LEDs.展开更多
A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)...A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)∶Eu^(3+)can produce red mechanoluminescence,and importantly,it shows good repeatability.The mechanoluminescence of Ca_(5)Ga_(6)O_(14)∶Eu^(3+) results from the piezoelectric field generated inside the material under stress,rather than the charge carriers stored in the traps,which can be confirmed by the multiple cycles of mechanoluminescence tests and heat treatment tests.The mechanoluminescence color can be turned from red to green by co-doping varied concentrations of Tb^(3+),which may be meaningful for encrypted letter writing.The encryption scheme for secure communication was devised by harnessing mechanoluminescence patterns in diverse shapes and ASCII codes,which shows good encryption performance.The results suggest that the mechanoluminescence phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+),Tb^(3+)may be applied to the optical information encryption.展开更多
Solvent extraction experiments were conducted from acidic solutions containing germanium（IV） and other metal ions, such as Ga3＋, Fe3＋, Zn2＋ and Fe2＋ in hydrometallurgical process of zinc. The purpose of this wor...Solvent extraction experiments were conducted from acidic solutions containing germanium（IV） and other metal ions, such as Ga3＋, Fe3＋, Zn2＋ and Fe2＋ in hydrometallurgical process of zinc. The purpose of this work was to enhance the efficiency of the extraction and stripping processes and the selectivity of germanium and other metals, while making the method as simple as possible. Germanium was recovered from sulfuric acid, using di-（2-ethylhexyl） phosphoric acid （P2O4） as an extractant, tributyl phosphate （TBP） as modifier diluted in sulfonate kerosene and stripped by NaOH aqueous solution. Extraction studies were carried out under different acid concentrations and solvent concentrations, and optimized conditions were determined. The numbers of stages required for extraction and stripping of metal ions were determined from the McCabe-Thiele plot. The results show that the extracting and stripping efficiencies are 94.3% and 100%, respectively, through two-stage extraction and two-stage strip. Moreover, the synergistic effect of TBP on the system P2O4/kerosense/Ge4＋ is revealed with respect to the extraction of germanium.展开更多
A hydrometallurgical process for tungsten extraction and recovery from scheelite is reported.The technology includes leaching scheelite using phosphoric acid as chelating agent in nitric acid solutions,extracting tung...A hydrometallurgical process for tungsten extraction and recovery from scheelite is reported.The technology includes leaching scheelite using phosphoric acid as chelating agent in nitric acid solutions,extracting tungsten by solvent extraction and reusing leaching agent.In the leaching process,affecting factors,such as temperature,leaching time,nitric acid and dosage of phosphoric acid,were examined on recovery of tungsten.Results show that more than 97%of tungsten could be extracted under conditions of leaching temperature of 80-90°C,HNO3 concentration of 3.0-4.0 mol/L,liquild-to-soild ratio of 10:1,H3PO4 dosage of 3 stoichiometric ratio and leaching time of 3 h.Solvent extraction was then employed for the W recovery from the leachate with a organic system of 40%(v/v)N235,30%(v/v)TBP,and 30%sulfonated kerosene.Approximately 99.93%of W was extracted and ammonium tungstate solution containing 193 g/L W was obtained with a stripping rate of 98.10%under the optimized conditions.展开更多
The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractam and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio （Vσ/Va） o...The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractam and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio （Vσ/Va） of 1.0：1.0, initial pH of 2.0 and stirring speed of 200 r/min. The results show that 75% zinc can be extracted from the zinc sulfate solution when the concentration of zinc is 18.7 g/L after being settled for 10 min. 88.60% zinc can be stripped by 196 g/L sulfuric acid, and zinc ion can be separated from ferric ion.展开更多
In the industrial process of producing the strong phosphoric acid(SPA),clarification of the solution is essential to the ultimate product.However,the large viscosity of sediment and the induced interface interaction r...In the industrial process of producing the strong phosphoric acid(SPA),clarification of the solution is essential to the ultimate product.However,the large viscosity of sediment and the induced interface interaction result in difficulties when the SPA is clarified.CFD numerical methodology was applied to simulate internal flow field and performance of the low speed scraper based on Mixture solidliquid two-phase flow model.Sediment deposition was generated by loading solid particles at the bottom of clarifying vessel.The moving mesh and RNG k-εmodel were used to simulate the rotational turbulent flow in clarifying tank.Variables studied,amongst others,were the scraper rotation speed and the mounting height,which could affect the solid suspension height.Features of flow field and solid volume fraction distribution in computational domain were presented and analyzed.The numerical reports of the scraper torque and velocities of inlet and outlet filed were obtained.It seems the torque value of rotatio-nal axis and particle suspending height augment with an increasing rotating speed.Meanwhile,a high revolving speed is good for the deposition discharge.The particle fraction distribution in meridional surface and horizontal surface at fixed rotation speed were analyzed to determine the corresponding optimal installation height.The simulating results reflect the flow field is marginally stirred by the scraper and proper working parameters are obtained,in which case the comprehensive properties of the scraper and the clarifying tank are superior.展开更多
Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive ...Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.展开更多
Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature hi...Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature higher than 1300℃ and for to 10 h. Microwave assisted sintering could reduce the activation energy and enhance the diffu- sion rate, thus greatly improved the sintering. Moreover, the influence of Si3N4 content on phase formation, morphol- ogy, absorption, and quantum efficiency, and photoluminescence properties of phosphors were studied. As a result, the Ba3Si6OI2N2：Eu^2＋ samples sintered by microwave assisted sintering method have a higher phase purity and photo- luminescence intensity under ultraviolet excitation as compared with samples sintered in the conventional tube furnace The proposed method is a potential preparation method for the oxynitride phosphors with strong photoluminescence and high phase purity.展开更多
Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its prop...Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.展开更多
To investigate the performance of organic and inorganic phosphorous on growth of Roselle （Hibiscus sabdariffa L.）, an experiment was carried out at Newly Developmental Farm （NDF）, Horticulture Section, the univers...To investigate the performance of organic and inorganic phosphorous on growth of Roselle （Hibiscus sabdariffa L.）, an experiment was carried out at Newly Developmental Farm （NDF）, Horticulture Section, the university of Agriculture Peshawar, Pakistan, during 2012. The experiment was laid out in a Randomized Complete Block Design （RCBD） with split plot arrangement and replicated three times. The chemical fertilizer Single Super Phosphate （SSP） was used as inorganic source of phosphorus, while Organic Phosphate （OP） from organic product produced by Niha corporation containing 20% organic mineralized P205, was used as the source of organic phosphorous. Both the sources of fertilizer were applied at the rate of 10, 20, 30 40 and 50 kg. hm2 and control. The statistical analysis of data revealed that both the sources and levels of phosphorus significantly affected most of the growth parameters of Roselle except germination percentage and survival percentage. Plant height （112.09 era）, numbers of leave plant1 （177.87）, numbers of branch plant1 （4.08）, leaf areas （126.60 cm2）, days to flowering （142.83）, fresh flower weight （2.56 g）, fresh calyx weight （1.70 g）, dry calyx weight （0.43 g）, numbers of calyces （94.10）, numbers of root plant-1 （11.03）, root length （22.67 cm） and root weight （27.50 g） were observed in plants fertilized with organic source of phosphorous. Phosphorous levels significantly affected all of the parameters except germination percentage and survival percentage. The maximum plant height （124.39 cm）, numbers of branches （5.32）, numbers of leave plantl （204.89）, leaf areas （148.14 cm2）, fresh flower weight （3.32 g）, fresh calyx weight （2.04 g）, dry calyx weight （0.51 g）, numbers of calyces （105.30）, numbers of root plant-1 （12.78）, root length （24.50 cm） and root weight （29.94 g） were observed in plants fertilized with 40 kg. hm-2 phosphorous and the maximum numbers of days to flowering （148.17） were observed in the control plants. It was concluded from the experimental results that organic phosphorous at the rate 40 kg. hm2 would be used for better production of Roselle under agro-climatic condition of Peshawar.展开更多
YxVO4∶0.01Dy3+ and Y0.99-xVO4∶0.01Dy3+,xBi3+ phosphors were synthesized by chemical co-precipitation method.Their crystal structure,micromorphology and photoluminescence(PL) properties were investigated by X-ray dif...YxVO4∶0.01Dy3+ and Y0.99-xVO4∶0.01Dy3+,xBi3+ phosphors were synthesized by chemical co-precipitation method.Their crystal structure,micromorphology and photoluminescence(PL) properties were investigated by X-ray diffraction(XRD),scan electron microscopy(SEM) and spectrofluorometer.YxVO4∶0.01Dy3+ and Y0.99-xVO4∶0.01Dy3+,xBi3+ phosphors have a broad excitation band from about 250 to 350 nm including a strongest peak at about 310 nm.Under its excitation,the emission spectra exhibits two sharp peaks,one of which centered at about 483 nm for 4F9/2→6H15/2 transition of Dy3+ and the other at about 574 nm due to the 4F9/2→6H13/2 transition of Dy3+.For YxVO4∶0.01Dy3+(x=0.94,0.97,0.99,1.01,1.03) phosphor,with increasing value of x,the body color of phosphor changes from yellow to white and the strongest peak in the excitation spectra shifts a little to shorter wavelength.It is detrimental to luminous intensity when Y3+ content deviates stoichiometric ratio.For Y0.99-xVO4∶0.01Dy3+,xBi3+(x=0.01,0.05,0.1,0.15,0.2,0.25) phosphor,the samples have extraneous bismuth vanadium oxide phase except for the major tetragonal zircon structure when x≥0.20.With increasing value of x,the band edge in the excitation spectra shifts to longer wavelength,the excitation intensity and luminous intensity increase early and decrease late.When the value of x is 0.01,the intensities increase evidently.In addition,the influence of Y3+ or Bi3+ on the color temperature of emission and micromorphology of YVO4∶Dy3+ is slight.展开更多
An advanced sludge reduction process, i.e. sludge reduction and phosphorous removal process, was developed. The results show that excellent sludge reduction and biological phosphorous removal can be achieved perfectly...An advanced sludge reduction process, i.e. sludge reduction and phosphorous removal process, was developed. The results show that excellent sludge reduction and biological phosphorous removal can be achieved perfectly in this system. When chemical oxygen demand ρ（COD） is 332 - 420 mg/L, concentration of ammonia p（NH3-N） is 30 - 40 mg/L and concentration of total phosphorous p（TP） is 6.0 -9.0 mg/L in influent, the system still ensures ρ（COD）〈23 mg/L, ρ（NH3-N）〈3.2 mg/L and ρ（TP）〈0. 72 mg/L in effluent. Besides, when the concentration of dissolved oxygen ρ（DO） is around 1.0 mg/L, sludge production is less than 0. 140 g with the consumption of 1 g COD, and the phosphorous removal exceeds 91 %. Also, 48.4% of total nitrogen is removed by simultaneous nitrification and denitrification.展开更多
基金Projects(41472278,41202220)supported by the National Natural Science Foundation of ChinaProject(20120022120003)supported by the Research Fund for the Doctoral Program of Higher Education,China+1 种基金Project(2652012065)supported by the Fundamental Research Funds for the Central Universities,ChinaProject supported by Beijing Higher Education Young Elite Teacher Program,China
文摘The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.
文摘Activated carbon was prepared from bamboo by mechanochemical process with phosphoric acid as activating agent.The effects of milling time on the adsorption property and porous structure of the obtained activated car-bon were discussed.The results showed that phosphoric acid activation assisted by mechanochemical process can slightly improve the adsorption performance of the prepared activated carbon.The iodine,methylene blue adsorption value and the specific surface area of the prepared activated carbons increased from 840.16 mg/g,168 mg/g and 1229.246 m/g to 947.51 mg/g,195 mg/g,and 1265.373 m2/g,respectively.Compared with conventional phosphoric acid activation,the activated carbon produced by mechanochemical process has greater adsorption capacity.
基金Project(06SK2011) supported by the Science and Technology Program of Hunan Province, China
文摘The dry modification of aluminum hydroxide powders with phosphoric acid and the effects of modification of technological conditions on thermal stability, morphology and oil absorption of aluminum hydroxide powders were investigated. The results show that the increase of mass ratio of phosphoric acid to aluminum hydroxide, the decrease of mass concentration of phosphoric acid and prolongation of mixing time are favorable to the improvement of thermal stability of aluminum hydroxide; when the mass ratio of phosphoric acid to aluminum hydroxide is 5:100, the mass concentration of phosphoric acid is 200 g/L and the mixing time is 10 min, the initial temperature of loss of crystal water in aluminum hydroxide rises from about 192.10 to 208.66 ℃, but the dry modification results in the appearance of agglomeration and macro-aggregate in the modified powders, and the oil absorption of modified powders becomes higher than that of original aluminum hydroxide.
文摘Eu^(2+) and Mn^(2+) co-activated CaAlSiN_(3) red phosphors were produced using the solid-state reaction tech⁃nique in a N2 environment.Excitation spectra,emission spectra,and diffuse reflection spectra were used to study the luminescence characteristics,energy gap,and thermal stability in detail.CaAlSiN_(3)∶Eu^(2+) exhibits an extended emission band when stimulated with 450 nm blue light,which is caused by the 4f65d to 4f7 transition of Eu^(2+).Similar⁃ly,CaAlSiN_(3)∶Mn^(2+) displays a wide emission band centered at 628 nm,which results from Mn^(2+)’s transition from 4T1(4G) to 6A1(6S).When the ions of Mn^(2+)were combined into CaAlSiN_(3)∶Eu^(2+),the photoluminescence intensity of Eu^(2+ )was greatly boosted because there was energy transfer and co-emission between Mn^(2+) and Eu^(2+).Beyond that,CaAlSiN_(3)∶Eu^(2+),Mn^(2+) emerges with splendid thermostability and high quantum efficiency,the quenching temperature surpasses 300℃,and the internal quantum efficiency is determined to be around 84.9%.The white LED was pack⁃aged with a combination of CaAlSiN_(3)∶Eu^(2+),Mn^(2+),LuAG∶Ce3+ and a blue chip.At a warm white-light corresponding color temperature(3009 K) with CIE coordinates(0.4223,0.3748),the color rendering index Ra has reached 93.2.CaAlSiN_(3)∶Eu^(2+),Mn^(2+) would have great application potential as a red-emitting phosphor for white LEDs.
文摘A novel self-recoverable mechanoluminescent phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+) was developed by the high-tem-perature solid-state reaction method,and its luminescence properties were investigated.Ca_(5)Ga_(6)O_(14)∶Eu^(3+)can produce red mechanoluminescence,and importantly,it shows good repeatability.The mechanoluminescence of Ca_(5)Ga_(6)O_(14)∶Eu^(3+) results from the piezoelectric field generated inside the material under stress,rather than the charge carriers stored in the traps,which can be confirmed by the multiple cycles of mechanoluminescence tests and heat treatment tests.The mechanoluminescence color can be turned from red to green by co-doping varied concentrations of Tb^(3+),which may be meaningful for encrypted letter writing.The encryption scheme for secure communication was devised by harnessing mechanoluminescence patterns in diverse shapes and ASCII codes,which shows good encryption performance.The results suggest that the mechanoluminescence phosphor Ca_(5)Ga_(6)O_(14)∶Eu^(3+),Tb^(3+)may be applied to the optical information encryption.
基金Project(50774094)supported by the National Natural Science Foundation of China
文摘Solvent extraction experiments were conducted from acidic solutions containing germanium（IV） and other metal ions, such as Ga3＋, Fe3＋, Zn2＋ and Fe2＋ in hydrometallurgical process of zinc. The purpose of this work was to enhance the efficiency of the extraction and stripping processes and the selectivity of germanium and other metals, while making the method as simple as possible. Germanium was recovered from sulfuric acid, using di-（2-ethylhexyl） phosphoric acid （P2O4） as an extractant, tributyl phosphate （TBP） as modifier diluted in sulfonate kerosene and stripped by NaOH aqueous solution. Extraction studies were carried out under different acid concentrations and solvent concentrations, and optimized conditions were determined. The numbers of stages required for extraction and stripping of metal ions were determined from the McCabe-Thiele plot. The results show that the extracting and stripping efficiencies are 94.3% and 100%, respectively, through two-stage extraction and two-stage strip. Moreover, the synergistic effect of TBP on the system P2O4/kerosense/Ge4＋ is revealed with respect to the extraction of germanium.
基金Project(51334008) supported by the National Natural Science Foundation of China
文摘A hydrometallurgical process for tungsten extraction and recovery from scheelite is reported.The technology includes leaching scheelite using phosphoric acid as chelating agent in nitric acid solutions,extracting tungsten by solvent extraction and reusing leaching agent.In the leaching process,affecting factors,such as temperature,leaching time,nitric acid and dosage of phosphoric acid,were examined on recovery of tungsten.Results show that more than 97%of tungsten could be extracted under conditions of leaching temperature of 80-90°C,HNO3 concentration of 3.0-4.0 mol/L,liquild-to-soild ratio of 10:1,H3PO4 dosage of 3 stoichiometric ratio and leaching time of 3 h.Solvent extraction was then employed for the W recovery from the leachate with a organic system of 40%(v/v)N235,30%(v/v)TBP,and 30%sulfonated kerosene.Approximately 99.93%of W was extracted and ammonium tungstate solution containing 193 g/L W was obtained with a stripping rate of 98.10%under the optimized conditions.
基金Project(50774094) supported by the National Natural Science Foundation of China
文摘The extraction of zinc from zinc sulfate solution was investigated, using 20% saponified D2EHPA as an extractam and 260^# sulfonate kerosene as a diluent. The solution was stirred for 8 min at phase ratio （Vσ/Va） of 1.0：1.0, initial pH of 2.0 and stirring speed of 200 r/min. The results show that 75% zinc can be extracted from the zinc sulfate solution when the concentration of zinc is 18.7 g/L after being settled for 10 min. 88.60% zinc can be stripped by 196 g/L sulfuric acid, and zinc ion can be separated from ferric ion.
基金Graduate Research and Innovation Program in Jiangsu Province(KYZZ16_0286)
文摘In the industrial process of producing the strong phosphoric acid(SPA),clarification of the solution is essential to the ultimate product.However,the large viscosity of sediment and the induced interface interaction result in difficulties when the SPA is clarified.CFD numerical methodology was applied to simulate internal flow field and performance of the low speed scraper based on Mixture solidliquid two-phase flow model.Sediment deposition was generated by loading solid particles at the bottom of clarifying vessel.The moving mesh and RNG k-εmodel were used to simulate the rotational turbulent flow in clarifying tank.Variables studied,amongst others,were the scraper rotation speed and the mounting height,which could affect the solid suspension height.Features of flow field and solid volume fraction distribution in computational domain were presented and analyzed.The numerical reports of the scraper torque and velocities of inlet and outlet filed were obtained.It seems the torque value of rotatio-nal axis and particle suspending height augment with an increasing rotating speed.Meanwhile,a high revolving speed is good for the deposition discharge.The particle fraction distribution in meridional surface and horizontal surface at fixed rotation speed were analyzed to determine the corresponding optimal installation height.The simulating results reflect the flow field is marginally stirred by the scraper and proper working parameters are obtained,in which case the comprehensive properties of the scraper and the clarifying tank are superior.
基金Project(2006BAB02A03)supported by the National Key Technology Research and Development ProgramProject(08MX16)supported by Mittal Scientific and Technological Innovation Projects of Central South University during 2008
文摘Physical-chemical properties of phosphorous gypsum, proportion and cemented mechanism of slurry with gypsum as aggregate were studied to remove the harms of gypsum pile, combining with difficult problems of excessive mined-out gobs, enormous ore body under roadway and low recovery ratio of Yongshaba Mine, Kaiyang Phosphor Mine Group, Guizhou Province, China. An appropriate backfill system and craflwork were designed, using shattering milling method to crush gypsum, double-axles mixing and strong activation mixing way to mix slurry, cemented slurry and mullock backfill alternately process. The results show that gypsum is fit for backfilling afterwards by adding fly ash, though it is not an ideal aggregate for fine granule and coagulate retardation. The suggested dosage （the mass ratio of cement to fly ash to gypsum） is 1：1：6-1：1：8 with mass fraction of solid materials 60%-63%. Slurry is transported in suspend state with non-plastic strength, and then in concretion state after backfilling. The application to mine shows the technology is feasible, and gypsum utilization ratio is up to 100%. Transportation and backfill effect is very good for paste-like slurry and drenching cemented slurry into mullock, and the compressive strength and recovery ratio are 2.0 MPa and 82.6%, respectively, with the maximum subsidence of surface only 1.307 mm. Furthermore, the investment of system is about 7 × 10^6 yuan （RMB）, only 1/10 of that of traditional paste backfill system.
文摘Eu^2＋-doped Ba3Si6012N2 green phosphors were prepared by microwave assisted sintering method at 1275℃ for 4 h, while the counterparts using conventional solid-state reaction method were synthesized at temperature higher than 1300℃ and for to 10 h. Microwave assisted sintering could reduce the activation energy and enhance the diffu- sion rate, thus greatly improved the sintering. Moreover, the influence of Si3N4 content on phase formation, morphol- ogy, absorption, and quantum efficiency, and photoluminescence properties of phosphors were studied. As a result, the Ba3Si6OI2N2：Eu^2＋ samples sintered by microwave assisted sintering method have a higher phase purity and photo- luminescence intensity under ultraviolet excitation as compared with samples sintered in the conventional tube furnace The proposed method is a potential preparation method for the oxynitride phosphors with strong photoluminescence and high phase purity.
基金Projects(51178172,51308076)supported by the National Natural Science Foundation of ChinaProject(13JJ4107)supported by Hunan Provincial Natural Science Foundation,ChinaProject(K1207026-31)supported by Changsha Planning Project of Science and Technology,China
文摘Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.
文摘To investigate the performance of organic and inorganic phosphorous on growth of Roselle （Hibiscus sabdariffa L.）, an experiment was carried out at Newly Developmental Farm （NDF）, Horticulture Section, the university of Agriculture Peshawar, Pakistan, during 2012. The experiment was laid out in a Randomized Complete Block Design （RCBD） with split plot arrangement and replicated three times. The chemical fertilizer Single Super Phosphate （SSP） was used as inorganic source of phosphorus, while Organic Phosphate （OP） from organic product produced by Niha corporation containing 20% organic mineralized P205, was used as the source of organic phosphorous. Both the sources of fertilizer were applied at the rate of 10, 20, 30 40 and 50 kg. hm2 and control. The statistical analysis of data revealed that both the sources and levels of phosphorus significantly affected most of the growth parameters of Roselle except germination percentage and survival percentage. Plant height （112.09 era）, numbers of leave plant1 （177.87）, numbers of branch plant1 （4.08）, leaf areas （126.60 cm2）, days to flowering （142.83）, fresh flower weight （2.56 g）, fresh calyx weight （1.70 g）, dry calyx weight （0.43 g）, numbers of calyces （94.10）, numbers of root plant-1 （11.03）, root length （22.67 cm） and root weight （27.50 g） were observed in plants fertilized with organic source of phosphorous. Phosphorous levels significantly affected all of the parameters except germination percentage and survival percentage. The maximum plant height （124.39 cm）, numbers of branches （5.32）, numbers of leave plantl （204.89）, leaf areas （148.14 cm2）, fresh flower weight （3.32 g）, fresh calyx weight （2.04 g）, dry calyx weight （0.51 g）, numbers of calyces （105.30）, numbers of root plant-1 （12.78）, root length （24.50 cm） and root weight （29.94 g） were observed in plants fertilized with 40 kg. hm-2 phosphorous and the maximum numbers of days to flowering （148.17） were observed in the control plants. It was concluded from the experimental results that organic phosphorous at the rate 40 kg. hm2 would be used for better production of Roselle under agro-climatic condition of Peshawar.
基金Supported by Shaanxi provincial project of special foundation of key disciplines(101-00X902)Young People Foundation of Xi’an University of Technology(101-210920)
文摘YxVO4∶0.01Dy3+ and Y0.99-xVO4∶0.01Dy3+,xBi3+ phosphors were synthesized by chemical co-precipitation method.Their crystal structure,micromorphology and photoluminescence(PL) properties were investigated by X-ray diffraction(XRD),scan electron microscopy(SEM) and spectrofluorometer.YxVO4∶0.01Dy3+ and Y0.99-xVO4∶0.01Dy3+,xBi3+ phosphors have a broad excitation band from about 250 to 350 nm including a strongest peak at about 310 nm.Under its excitation,the emission spectra exhibits two sharp peaks,one of which centered at about 483 nm for 4F9/2→6H15/2 transition of Dy3+ and the other at about 574 nm due to the 4F9/2→6H13/2 transition of Dy3+.For YxVO4∶0.01Dy3+(x=0.94,0.97,0.99,1.01,1.03) phosphor,with increasing value of x,the body color of phosphor changes from yellow to white and the strongest peak in the excitation spectra shifts a little to shorter wavelength.It is detrimental to luminous intensity when Y3+ content deviates stoichiometric ratio.For Y0.99-xVO4∶0.01Dy3+,xBi3+(x=0.01,0.05,0.1,0.15,0.2,0.25) phosphor,the samples have extraneous bismuth vanadium oxide phase except for the major tetragonal zircon structure when x≥0.20.With increasing value of x,the band edge in the excitation spectra shifts to longer wavelength,the excitation intensity and luminous intensity increase early and decrease late.When the value of x is 0.01,the intensities increase evidently.In addition,the influence of Y3+ or Bi3+ on the color temperature of emission and micromorphology of YVO4∶Dy3+ is slight.
基金Project (50278101) supported by the National Natural Science Foundation of China Project( CSTC, 2005AB7030)supported by Chongqing Key Technologies Research and Development Program
文摘An advanced sludge reduction process, i.e. sludge reduction and phosphorous removal process, was developed. The results show that excellent sludge reduction and biological phosphorous removal can be achieved perfectly in this system. When chemical oxygen demand ρ（COD） is 332 - 420 mg/L, concentration of ammonia p（NH3-N） is 30 - 40 mg/L and concentration of total phosphorous p（TP） is 6.0 -9.0 mg/L in influent, the system still ensures ρ（COD）〈23 mg/L, ρ（NH3-N）〈3.2 mg/L and ρ（TP）〈0. 72 mg/L in effluent. Besides, when the concentration of dissolved oxygen ρ（DO） is around 1.0 mg/L, sludge production is less than 0. 140 g with the consumption of 1 g COD, and the phosphorous removal exceeds 91 %. Also, 48.4% of total nitrogen is removed by simultaneous nitrification and denitrification.
