The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geop...The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geopolymers with compressive strength of 38.8 MPa were prepared by using phosphate tailings as the main raw material,fly ash as the active silicon-aluminum material,and water glass as the alkaline activator.The solid content of phosphate tailings and fly ash was 60%and 40%,respectively,and the water-cement ratio was 0.22.The results of XRD,FTIR,SEM-EDS and XPS show that the reactivity of phosphate tailings with alkaline activator is weak,and the silicon-aluminum material can react with alkaline activator to form zeolite and gel,and encapsulate/cover the phosphate tailings to form a dense phosphate tailings-based geopolymer.During the formation of geopolymers,part of the aluminum-oxygen tetrahedron replaced the silicon-oxygen tetrahedron,causing the polycondensation reaction between geopolymers and increasing the strength of geopolymers.The leaching toxicity test results show that the geopolymer has a good solid sealing effect on heavy metal ions.The preparation of geopolymer from phosphate tailings is an important way to alleviate the storage pressure and realize the resource utilization of phosphate tailings.展开更多
Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means o...Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means of the ferron-timed spectroscopy method. Furthermore,the effect of n(P)/n(Fe),alkalization degree,pH value,and PPFS dosage on the removal rate of eutrophic water turbidity and chl-a and ζ-potential of products were also investigated. The experimental results show that the best n(P)/n(Fe) of flocculation effect in stable product of PFFS is 0.3; the best alkalization degree of flocculation effect is 0.2,while the n(P)/n(Fe) is 0.3. Under the neutral and subalkalic (pH value is 7-8) conditions,PPFS achieves the best processing efficiency. PPFS has more excellent turbidity and higher chlorophyl removal rate by studying treatment eutrophic water in comparison with PFS.展开更多
Applying spent lithium iron phosphate battery as raw material,valuable metals in spent lithium ion battery were effectively recovered through separation of active material,selective leaching,and stepwise chemical prec...Applying spent lithium iron phosphate battery as raw material,valuable metals in spent lithium ion battery were effectively recovered through separation of active material,selective leaching,and stepwise chemical precipitation.Using stoichiometric Na2S2O8 as an oxidant and adding low-concentration H2SO4 as a leaching agent was proposed.This route was totally different from the conventional methods of dissolving all of the elements into solution by using excess mineral acid.When experiments were done under optimal conditions(Na2S2O8-to-Li molar ratio 0.45,0.30 mol/L H2SO4,60℃,1.5 h),leaching efficiencies of 97.53% for Li^+,1.39%for Fe^3+,and 2.58% for PO4^3−were recorded.FePO4 was then recovered by a precipitation method from the leachate while maintaining the pH at 2.0.The mother liquor was concentrated and maintained at a temperature of approximately 100℃,and then a saturated sodium carbonate solution was added to precipitate Li2CO3.The lithium recovery yield was close to 80%.展开更多
The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with ...The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V （vs SCE）. The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca（H2PO4）2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.展开更多
The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on co...The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.展开更多
The solubilization of hardly soluble aluminum phosphate （AlPO4） by specific Penicillium spp. isolated from wheat rhizospheric soils was investigated in Pikovskaya agar and liquid medium, respectively. Most of the Pe...The solubilization of hardly soluble aluminum phosphate （AlPO4） by specific Penicillium spp. isolated from wheat rhizospheric soils was investigated in Pikovskaya agar and liquid medium, respectively. Most of the Penicillium isolates except P. sirnplicissimum AP 11 and P. variabile AP 15 developed clear transparent zone around the colony margin in plate assays. Results of broth assays show that the Penicillium isolates can efficiently solubilize aluminum phosphate in Pikovskaya liquid medium, and vary in their capabilities to release soluble phosphate from aluminum phosphate. All the isolates exhibit different abilities to lower the pH and increase the titratable acidity in the broth compared to the control. HPLC analysis shows that most of the isolates except the species of P. aurantiogriseum can excrete different concentrations of organic acids, including gluconic acid, citric acid, oxalic acid, malic acid and tartaric acids, in the broth. The release of soluble phosphate by the isolate P. oxalicum AP2, which is the best solubilizer of aluminum phosphate among the isolates, is accompanied by a significant drop of pH and an obvious rise of titratable acidity during 7 d of aluminum phosphate-solubilizing experiments. The effects of temperature, initial pH, concentration of aluminum phosphate and shaking speed on aluminum phosphate solubilization by P. oxalicum AP2 were also investigated, and the maximum contents of soluble phosphate released are recorded at temperature 30 ℃, initial pH 6, aluminum phosphate concentration 20 g/L, and shaking speed 160 r/min.展开更多
Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation m...Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation mechanism of the fine cassiterite was investigated by adsorbance determination,electrophoretic mobility measurements and Fourier transform infra-red(FT-IR) spectrum checking.Results of the flotation experiments show that with SHA as a collector,the collecting performance is remarkably impacted by the pulp pH value as the floatability of cassiterite varies sharply when the pH changes,and flotation with SHA gives distinct maximum at about pH 6.5.Additionally,the floatability of cassiterite is determined by using SHA and TBP as collectors.The range of pulp pH for good floatability is broadened in the presence of TBP as auxiliary collector,and the utilization of TBP improves the recovery of cassiterite modestly.Moreover,the optimum pH value for cassiterite flotation is associated with adsorbance.The results of FT-IR spectrum and the electrophoretic mobility measurements indicate that the adsorption interaction between the collectors and the cassiterite is dominantly a kind of chemical bonding in the form of one or two cycle chelate rings due to the coordination of carbonyl group,hydroxamate and P=O group to the metal tin atoms,where the oxygen atoms contained in carbonyl group,hydroxamate and P=O group of the polar groups have the stereo conditions to form five-membered rings.In addition,the adsorption interactions of SHA and TBP on the surfaces of cassiterite are also dominated by means of hydrogen bonds.展开更多
The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pr...The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.展开更多
The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A co...The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A complex alkali resistant phosphate surfactant with good permeability was prepared.The wettability of surfactants was investigated by measuring the immersion time,sinking time and capillary effects of nature cotton grey fabric in NaOH solutions.The surfactivity of the surfactants was characterized by measuring the surface tension.The effect of the complex on the surface appearance of cotton grey fabric was also investigated with a scanning electron microscope(SEM) .The results show that all the surfactants exhibit good wettability for cotton grey fabric in 0.5-5.0 mol/L of NaOH solutions,the complex system exhibits better wettability in 5.0-7.0 mol/L of NaOH solutions,in comparison with either corresponding single surfactant component employed,and wettability is well correlative with the surfactivities of the surfactant.SEM images indicate that the cotton grey fabric is well wetted by the alkaline surfactant solution and the quality of fabric is improved.展开更多
Leaching soluble phosphorus from rock phosphate containing pyrites by Acidithiobacillus ferrooxidans (A.f.) is feasible, and the reaction mechanism is as follows. Pyrites are oxidized by A.f. to produce H_2SO_4 and Fe...Leaching soluble phosphorus from rock phosphate containing pyrites by Acidithiobacillus ferrooxidans (A.f.) is feasible, and the reaction mechanism is as follows. Pyrites are oxidized by A.f. to produce H_2SO_4 and FeSO_4; the rock phosphate is decomposed by H_2SO_4, forming soluble phosphorus compounds; and Fe2+ from FeSO_4 is oxidized to Fe^3+, providing energy for the growth of A. f.. In this process, as H_2SO_4 is produced in the reaction, an acidic condition in the culture medium is formed, which benefits the growth of A. f. and aids both continuous oxidation of pyrites and leaching of soluble phosphorus from rock phosphate. The fraction of phosphorous leached can reach the largest in the presence of 1.0 g/L Fe^3+, 200 mg/L Mg^2+ and 400 mg/L NH_4^+. The optimal technological parameters on the fraction of phosphorous leached are as follows: the volume fraction of inocula of A. f., the mass ratio of pyrites to rock phosphate and the pH value are in ranges of 5%-25%, 3:1-5:1 and 1.8-2.2, respectively.展开更多
Phosphate is widely used to immobilize cadmium(Cd)and lead(Pb)in soils through the insoluble metal phosphate precipitation.However,an increase in the phosphorus content of the environment can cause new pollution.In th...Phosphate is widely used to immobilize cadmium(Cd)and lead(Pb)in soils through the insoluble metal phosphate precipitation.However,an increase in the phosphorus content of the environment can cause new pollution.In this study,five slow-release phosphate amendments(SRPAs)were synthesized and their characteristics including BET,SEM,FTIR,swelling ratio,and thephosphorus release were determined.The results show that SRPA was a sphere with a network structure with a specific surface area of 5 to 7.18 m^(2)/g andcontained phosphate,hydroxyl,carboxyl and other functional groups.Among five SRPAs,S3 sample showed good performance for phosphate release.Phosphate release from SRPA was well fitted with Ritger-Peppas model with constant n between 0.45 and 0.85,indicating that the phosphate release was in accordance with non-Fickian diffusion.As compared with monocalcium phosphate(MCP),SRPA application led to a lower concentration of water-soluble phosphorus in the soil sample and higher remediation efficiencies of Cd and Pb.The remediation efficiencies of water-soluble Cd and Pb in soil with SRPA were 97.1%and 97.9%,respectively.The remediation efficiencies of bioavailable Cd and Pb were 71.85%and 76.47%,respectively.The results of Tessier extraction showed that the exchangeable and carbonatebound fractions of Cd and Pb in the soil sample after SRPA application significantly reduced,while the residual fraction increased,indicating the stability of heavy metals increased.展开更多
Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) an...Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.展开更多
Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its ...Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its active sites after adsorbing water, but the remaining was not affected. The reductions of aldehydes and ketones, when promoted by Rb_3PO_4, were allowed at room temperature. The activities of substrates at room temperature followed a descending order of 2,6-dichlorobenzaldehyde> 4-bromobenzaldehyde>benzaldehyde>acetophenone>anisaldehyde>butanone. A new catalytic cycle postulating a six-membered cyclic transition state for the reductions of aldehydes and ketones was proposed. These results exploited the catalytic usage of Rb_3PO_4 and worth in industrial application.展开更多
The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tr...The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium.展开更多
The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, ...The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, magnetic field intensity, pH value and flow-rate of sewage on phosphorus removal rate were investigated. The results show that addition of 200 mg/L Al2（SO4）3·18H2O and 300 mg/L Fe3O4, magnetic field intensity of 200 kA/m, pH value of 4.57.0 and flow-rate of 6.15 cm/s are both efficient and economic technical parameters for removal of phosphate. The pH value has a tremendous effect on the removal of phosphate. In the pH range of （4.5）7.0, more than 95% phosphate can be removed. Theoretical analysis indicates that the solubility of AlPO4 is minimum at pH 4.07.0 and the electrostatic attractive force between AlPO4 and Fe3O4 is maximum at pH 4.5（6.5.）展开更多
Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoel...Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance （PQCI） technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） and X-ray diffraction （XRD）, respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite （HA） is composed of three stages： （1） acidic calcium phosphate dissolution; （2） phase transformation; and （3） HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance （C8）-time curves.展开更多
Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of sl...Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.展开更多
基金Project(202202AG050010)supported by the Yunnan Major Scientific and Technological Projects,ChinaProject(202103AA080007)supported by the Key R&D Project of Science and Technology Department of Yunnan Province,ChinaProject(NECP2023-06)supported by the Open Project Fund of National Engineering and Technology Research Center for Development&Utilization of Phosphorous Resources,China。
文摘The long-term storage of phosphate tailings will occupy a large amount of land,pollute soil and groundwater,thus,it is crucial to achieve the harmless disposal of phosphate tailings.In this study,high-performance geopolymers with compressive strength of 38.8 MPa were prepared by using phosphate tailings as the main raw material,fly ash as the active silicon-aluminum material,and water glass as the alkaline activator.The solid content of phosphate tailings and fly ash was 60%and 40%,respectively,and the water-cement ratio was 0.22.The results of XRD,FTIR,SEM-EDS and XPS show that the reactivity of phosphate tailings with alkaline activator is weak,and the silicon-aluminum material can react with alkaline activator to form zeolite and gel,and encapsulate/cover the phosphate tailings to form a dense phosphate tailings-based geopolymer.During the formation of geopolymers,part of the aluminum-oxygen tetrahedron replaced the silicon-oxygen tetrahedron,causing the polycondensation reaction between geopolymers and increasing the strength of geopolymers.The leaching toxicity test results show that the geopolymer has a good solid sealing effect on heavy metal ions.The preparation of geopolymer from phosphate tailings is an important way to alleviate the storage pressure and realize the resource utilization of phosphate tailings.
基金Project(20777095) supported by the National Natural Science Foundation of ChinaProject(CSTC, 2006AB7055) supported by Chongqing Science and Technology Commission of ChinaProject(708071) supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education,China
文摘Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means of the ferron-timed spectroscopy method. Furthermore,the effect of n(P)/n(Fe),alkalization degree,pH value,and PPFS dosage on the removal rate of eutrophic water turbidity and chl-a and ζ-potential of products were also investigated. The experimental results show that the best n(P)/n(Fe) of flocculation effect in stable product of PFFS is 0.3; the best alkalization degree of flocculation effect is 0.2,while the n(P)/n(Fe) is 0.3. Under the neutral and subalkalic (pH value is 7-8) conditions,PPFS achieves the best processing efficiency. PPFS has more excellent turbidity and higher chlorophyl removal rate by studying treatment eutrophic water in comparison with PFS.
基金Project(Z20160605230001)supported by Hunan Province Non-ferrous Fund Project,China。
文摘Applying spent lithium iron phosphate battery as raw material,valuable metals in spent lithium ion battery were effectively recovered through separation of active material,selective leaching,and stepwise chemical precipitation.Using stoichiometric Na2S2O8 as an oxidant and adding low-concentration H2SO4 as a leaching agent was proposed.This route was totally different from the conventional methods of dissolving all of the elements into solution by using excess mineral acid.When experiments were done under optimal conditions(Na2S2O8-to-Li molar ratio 0.45,0.30 mol/L H2SO4,60℃,1.5 h),leaching efficiencies of 97.53% for Li^+,1.39%for Fe^3+,and 2.58% for PO4^3−were recorded.FePO4 was then recovered by a precipitation method from the leachate while maintaining the pH at 2.0.The mother liquor was concentrated and maintained at a temperature of approximately 100℃,and then a saturated sodium carbonate solution was added to precipitate Li2CO3.The lithium recovery yield was close to 80%.
文摘The influences of pH value, electrolyte temperature and loading time on depositing calcium phosphate coating on pure titanium substrate by electrodeposition process were investigated. The process was carried out with an electrochemical work-station supplying a direct current power at potential of -0.8V （vs SCE）. The electrolyte consists of 7 mmol·L-1 CaCl2·2H2O, 3 mmol·L-1 Ca（H2PO4）2·H2O and 2.5% H2O2. NaOH and HCl solutions were used to adjust pH value. The deposited samples were characterized by X-ray diffraction and scanning electron microscope. The comparison of the deposits obtained at lower and higher pH values demonstrates that the crystallization process at the interface is favoured by high pH value. With temperature increasing, the deposited hydroxyapatite is occasionally of plate-like shape, and the width and the length of the deposited calcium phosphates at 65 ℃ are larger than those at 55 ℃. Therefore, it is confirmed that the morphology and microstructure of electrochemically deposited calcium phosphates can be regulated. Additionally, the coating formed in electrolyte with H2O2 additive is homogeneous and the evolution of H2 bubble can be eliminated.
基金Supported by the Special Agricultural Project of Agricultural Department (200903003)the Agricultural Modernization Project in the Science and Technology Development Plan of Jilin Province (2009-2010) the High-yield Project of Science and Technology Department (2011BAD16B10)
文摘The study was designated to explore the physiological mechanism of cold tolerance enhanced by phosphate in rice. An experiment was conducted to investigate the effects of different levels of phosphate fertilizer on cold tolerance and its related physiological parameters in rice seedings （chilling-sensitive cv. Changbai 9 and chilling-tolerant cv. Jijing 81） under low temperature stress. At the same time, the identification of cold tolerance was conducted. Compared with the normal temperature treatment, the relative chlorophyll content, photosynthesis rate, Fv/Fm and qP decreased and index of unsaturated fatty acid increased in rice under low temperature stress. The effect of chilling-sensitive cultivars was more than that of chilling-tolerant cultivars, more phosphorus fertilizer properly improved seedling quality of rice, slowed relative chlorophyll content dropping degree of rice seeding, increased photosynthesis rate, Fv/Fm, qP and index of unsaturated fatty acids, and enhanced the ability to chilling-tolerant cultivars under low temperature. The effect on chilling-tolerant cultivars was significantly higher than that on chilling sensitive cultivars by applying more phosphorus fertilizer. Phosphate regulated photosynthetic physiology and membrane fluidity to reduce injury by low temperature, and increasd the cold tolerance capacity of rice.
基金Project(51004078) supported by the National Natural Science Foundation of ChinaProject(NCET-11-0965) supported by the Program for New Century Excellent Talents in Universities of China+2 种基金Project(2012FFA101) supported by the National Natural Science Foundation of Hubei Province, ChinaProject(IRT0974) supported by the Program for Changjiang Scholars and Innovative Research Team in Universities of ChinaProject(2011CB411901) supported by the National Basic Research Program of China
文摘The solubilization of hardly soluble aluminum phosphate （AlPO4） by specific Penicillium spp. isolated from wheat rhizospheric soils was investigated in Pikovskaya agar and liquid medium, respectively. Most of the Penicillium isolates except P. sirnplicissimum AP 11 and P. variabile AP 15 developed clear transparent zone around the colony margin in plate assays. Results of broth assays show that the Penicillium isolates can efficiently solubilize aluminum phosphate in Pikovskaya liquid medium, and vary in their capabilities to release soluble phosphate from aluminum phosphate. All the isolates exhibit different abilities to lower the pH and increase the titratable acidity in the broth compared to the control. HPLC analysis shows that most of the isolates except the species of P. aurantiogriseum can excrete different concentrations of organic acids, including gluconic acid, citric acid, oxalic acid, malic acid and tartaric acids, in the broth. The release of soluble phosphate by the isolate P. oxalicum AP2, which is the best solubilizer of aluminum phosphate among the isolates, is accompanied by a significant drop of pH and an obvious rise of titratable acidity during 7 d of aluminum phosphate-solubilizing experiments. The effects of temperature, initial pH, concentration of aluminum phosphate and shaking speed on aluminum phosphate solubilization by P. oxalicum AP2 were also investigated, and the maximum contents of soluble phosphate released are recorded at temperature 30 ℃, initial pH 6, aluminum phosphate concentration 20 g/L, and shaking speed 160 r/min.
基金Project(50774094) supported by the National Natural Science Foundation of ChinaProject(2010CB630905) supported by the National Basic Research Program of China
文摘Two reagents including salicylhydroxamic acid(SHA) and tributyl phosphate(TBP) were tested as collectors either separately or together for electro-flotation of fine cassiterite(<10 μm).Subsequently,the flotation mechanism of the fine cassiterite was investigated by adsorbance determination,electrophoretic mobility measurements and Fourier transform infra-red(FT-IR) spectrum checking.Results of the flotation experiments show that with SHA as a collector,the collecting performance is remarkably impacted by the pulp pH value as the floatability of cassiterite varies sharply when the pH changes,and flotation with SHA gives distinct maximum at about pH 6.5.Additionally,the floatability of cassiterite is determined by using SHA and TBP as collectors.The range of pulp pH for good floatability is broadened in the presence of TBP as auxiliary collector,and the utilization of TBP improves the recovery of cassiterite modestly.Moreover,the optimum pH value for cassiterite flotation is associated with adsorbance.The results of FT-IR spectrum and the electrophoretic mobility measurements indicate that the adsorption interaction between the collectors and the cassiterite is dominantly a kind of chemical bonding in the form of one or two cycle chelate rings due to the coordination of carbonyl group,hydroxamate and P=O group to the metal tin atoms,where the oxygen atoms contained in carbonyl group,hydroxamate and P=O group of the polar groups have the stereo conditions to form five-membered rings.In addition,the adsorption interactions of SHA and TBP on the surfaces of cassiterite are also dominated by means of hydrogen bonds.
基金Project(50778065)supported by the National Natural Science Foundation of China
文摘The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.
基金Project(20573079) supported by the National Natural Science Foundation of China
文摘The wettability,surfactivity and the correlation between wettability and surfactivity of sodium diethylhexylphosphate,sodium diethylhexyl polyoxyethylene phosphate and their complex in NaOH solutions were studied.A complex alkali resistant phosphate surfactant with good permeability was prepared.The wettability of surfactants was investigated by measuring the immersion time,sinking time and capillary effects of nature cotton grey fabric in NaOH solutions.The surfactivity of the surfactants was characterized by measuring the surface tension.The effect of the complex on the surface appearance of cotton grey fabric was also investigated with a scanning electron microscope(SEM) .The results show that all the surfactants exhibit good wettability for cotton grey fabric in 0.5-5.0 mol/L of NaOH solutions,the complex system exhibits better wettability in 5.0-7.0 mol/L of NaOH solutions,in comparison with either corresponding single surfactant component employed,and wettability is well correlative with the surfactivities of the surfactant.SEM images indicate that the cotton grey fabric is well wetted by the alkaline surfactant solution and the quality of fabric is improved.
基金Project(2004CB619200) supported by the State Basic Research Development Program of ChinaProject(Z200515002) supported by the Key Project Foundation of the Education Department of Hubei Province, China
文摘Leaching soluble phosphorus from rock phosphate containing pyrites by Acidithiobacillus ferrooxidans (A.f.) is feasible, and the reaction mechanism is as follows. Pyrites are oxidized by A.f. to produce H_2SO_4 and FeSO_4; the rock phosphate is decomposed by H_2SO_4, forming soluble phosphorus compounds; and Fe2+ from FeSO_4 is oxidized to Fe^3+, providing energy for the growth of A. f.. In this process, as H_2SO_4 is produced in the reaction, an acidic condition in the culture medium is formed, which benefits the growth of A. f. and aids both continuous oxidation of pyrites and leaching of soluble phosphorus from rock phosphate. The fraction of phosphorous leached can reach the largest in the presence of 1.0 g/L Fe^3+, 200 mg/L Mg^2+ and 400 mg/L NH_4^+. The optimal technological parameters on the fraction of phosphorous leached are as follows: the volume fraction of inocula of A. f., the mass ratio of pyrites to rock phosphate and the pH value are in ranges of 5%-25%, 3:1-5:1 and 1.8-2.2, respectively.
基金Projects(2020YFC1808002,2019YFD1100502)supported by the National Key R&D Program of China。
文摘Phosphate is widely used to immobilize cadmium(Cd)and lead(Pb)in soils through the insoluble metal phosphate precipitation.However,an increase in the phosphorus content of the environment can cause new pollution.In this study,five slow-release phosphate amendments(SRPAs)were synthesized and their characteristics including BET,SEM,FTIR,swelling ratio,and thephosphorus release were determined.The results show that SRPA was a sphere with a network structure with a specific surface area of 5 to 7.18 m^(2)/g andcontained phosphate,hydroxyl,carboxyl and other functional groups.Among five SRPAs,S3 sample showed good performance for phosphate release.Phosphate release from SRPA was well fitted with Ritger-Peppas model with constant n between 0.45 and 0.85,indicating that the phosphate release was in accordance with non-Fickian diffusion.As compared with monocalcium phosphate(MCP),SRPA application led to a lower concentration of water-soluble phosphorus in the soil sample and higher remediation efficiencies of Cd and Pb.The remediation efficiencies of water-soluble Cd and Pb in soil with SRPA were 97.1%and 97.9%,respectively.The remediation efficiencies of bioavailable Cd and Pb were 71.85%and 76.47%,respectively.The results of Tessier extraction showed that the exchangeable and carbonatebound fractions of Cd and Pb in the soil sample after SRPA application significantly reduced,while the residual fraction increased,indicating the stability of heavy metals increased.
基金Project(2011AA061002)supported by the High-Tech Research and Development Program of ChinaProject(2010SK2010)supported by the Key Program of Science and Technology of Hunan Province,ChinaProject supported by the Hunan Nonferrous Metals Fund,China
文摘Tributyl phosphate(TBP) was employed for the Bi(Ⅲ) extraction from hydrochloric acid medium.The effects of extraction time and material concentration were examined.The replacement mechanism between the anion(Cl^-) and TBP was proposed for extraction.The results show the species extracted into the organic phase were found to be mainly BiCl_3·x TBP(x=2 or 3).Thermodynamic parameters of the extraction reaction were obtained from the thermodynamics analysis,which illustrates that higher temperatures show a negative effect on the extraction.Extraction isotherm was obtained with 2.16 mol/L TBP for a typical solution containing 0.1 mol/L of bismuth and 1.0 mol/L of hydrochloric acid.About 98.5 % of bismuth has been extracted from the leaching solution under the optimum condition.Moreover,oxalate was explored as a precipitation stripping agent for BiCl_3·x TBP(x=2 or 3) complexes,by which Bi(Ⅲ) was stripped in the form of Bi_2(C_2O_4)_3·7H_2O.A stripping efficiency of 99.3% was obtained in only one stage at the phase ratio of 1 and TBP also could be recycled.Therefore,the method is an efficient,effective and highly selective approach to extract Bi(Ⅲ) and to recover metal bismuth.
基金Project(21576074)supported by the National Natural Science Foundation of China
文摘Rubidium phosphate can be more conveniently obtained by extracting trace Rb+ from the salt lake brine. Rb_3PO_4 was found to be an excellent heterogeneous catalyst for transfer hydrogenation. Rb_3PO_4 lost 70% of its active sites after adsorbing water, but the remaining was not affected. The reductions of aldehydes and ketones, when promoted by Rb_3PO_4, were allowed at room temperature. The activities of substrates at room temperature followed a descending order of 2,6-dichlorobenzaldehyde> 4-bromobenzaldehyde>benzaldehyde>acetophenone>anisaldehyde>butanone. A new catalytic cycle postulating a six-membered cyclic transition state for the reductions of aldehydes and ketones was proposed. These results exploited the catalytic usage of Rb_3PO_4 and worth in industrial application.
基金Project(2004CB619201) supported by the Major State Basic Research and Development Program of ChinaProject(Z200515002) supported by the Key Project Foundation of the Education Department of Hubei Province, China+1 种基金Project(GCP200801) supported by the Open Research Fund of Key Laboratory for Green Chemical Process of Ministry of Education, ChinaProject(Q200811) supported by the Youths Science Foundation of Wuhan Institute of Technology, China
文摘The phosphate solubilizing characteristics of a strain YC, which was isolated from phosphate mines (Hubei, China), were studied in National Botanical Research Institute’s phosphate (NBRIP) growth medium containing tricalcium phosphate (TCP) as sole phosphorus (P) source. The strain YC is identified as Stenotrophomonas maltophilia (S. maltophilia) based upon the results of morphologic, physiological and biochemical characteristics and 16S rRNA sequences analysis. The results show that the strain S. maltophilia YC can solubilize TCP and release soluble P in NBRIP growth medium. A positive correlation between concentration of soluble P and population of the isolate and a negative correlation between concentration of soluble P and pH in the culture medium are observed from statistical analysis results. Moreover, gluconic acid is detected in the culture medium by HPLC analysis. It indicates that the isolate can release gluconic acid during the solubilizing experiment, which causes acidification of the culture medium and then TCP solubilization. S. maltophilia YC has a maximal TCP solubilizing capability when using maltose as carbon source and ammonium nitrate as nitrogen source, respectively, in NBRIP growth medium.
文摘The removal of phosphate from municipal sewage by high gradient magnetic separation using aluminium sulphate as precipitating agent and Fe3O4 as seeding material was studied. The effects of aluminium sulphate, Fe3O4, magnetic field intensity, pH value and flow-rate of sewage on phosphorus removal rate were investigated. The results show that addition of 200 mg/L Al2（SO4）3·18H2O and 300 mg/L Fe3O4, magnetic field intensity of 200 kA/m, pH value of 4.57.0 and flow-rate of 6.15 cm/s are both efficient and economic technical parameters for removal of phosphate. The pH value has a tremendous effect on the removal of phosphate. In the pH range of （4.5）7.0, more than 95% phosphate can be removed. Theoretical analysis indicates that the solubility of AlPO4 is minimum at pH 4.07.0 and the electrostatic attractive force between AlPO4 and Fe3O4 is maximum at pH 4.5（6.5.）
基金Project(2005CB623901) supported by the Major State Basic Research and Development Program of China
文摘Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance （PQCI） technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy （SEM）, Fourier transform infrared （FT-IR） and X-ray diffraction （XRD）, respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite （HA） is composed of three stages： （1） acidic calcium phosphate dissolution; （2） phase transformation; and （3） HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance （C8）-time curves.
基金Project supported by Iran Mineral Processing Research Center(IMPRC)。
文摘Fine particle flotation has been one of the main problems in many mineral processing plants.The bubble particle collision rate is very low for fine particles,which reduces flotation efficiency.Also,the existence of slimes is,generally,detrimental to the flotation process,affecting the selectivity and the quality of the concentrates.Besides,it causes an increase in reagents consumption.Hence,in most of processing plants,some of these particles are transmitted to the tailing ponds to reduce the effects of these problems and increase the selectivity of the process.Esfordi phosphate plant in Iran loses more than 30%of its capacity as particles with d 80 finer than 30μm.These fine particles with 15.9%P_(2)O_(5)content are transferred to tailing dam.Processing of fine particles is very important for phosphate industry from economic and environmental aspects.This study addressed the processing of fine tailings(slimes)from a phosphate ore concentrator via flotation,despite the traditional view that ultrafine particles do not float.Phosphate flotation performances in the presence and absence of nanobubbles(NBs)in both mechanical and column cells were compared according to the metallurgical results of the process.NBs(generated by hydrodynamic cavitation)have interesting and exclusive properties such as high stability,durability and high surface area per volume,leading to increase of their utilization in mining-metallurgy and environmental areas.The results of this study revealed that,in the absence of NBs,a concentrate containing 26.9%P_(2)O_(5)with a recovery of 29.13%was obtained using mechanical cells in comparison to 31.6%P_(2)O_(5)with a recovery of 32.74%obtained using column flotation.In the presence of NBs,the recoveries of the concentrate of the mechanical and column flotation increased to 40.49%and 41.26%with 28.47%and 30.43%P_(2)O_(5)contents,respectively.Comparative study showed that the column flotation was almost more efficient for processing the phosphate ore in the presence of the NBs,and had thicker froth layer compared to the mechanical flotation.
