Several physical and chemical detection methods were used to study the basic properties of sintering dust （ESP dust） collected from Baogang Steel Corporation. The result shows that the major constituents of the ESP ...Several physical and chemical detection methods were used to study the basic properties of sintering dust （ESP dust） collected from Baogang Steel Corporation. The result shows that the major constituents of the ESP dust are KCl, NaCl, Fe2O_3 and Fe3O_4. Water leaching experiment on the sintering dust shows that KCl in the ESP dust can be separated and recovered by water leaching and fractional crystallization. Component analysis of leaching solution indicates that the massive calcium sulfate in the leaching solution should be removed first in order to obtain the pure potassium salt. In order to provide theoretical guidance to inhibit the dissolution of calcium ions from the sintering dust, the water leaching experiment of ESP dust and the dissolution behavior of CaSO_4 in the potassium chloride, sodium chloride, potassium sulfate and their mixed salt solution were studied. It is found that, a lower liquid-solid ratio should be chosen in the leaching process to inhibit the dissolution of calcium sulfate dehydrate. Using sodium carbonate solution as a precipitating agent, the influences of the concentration of sodium carbonate solution, reaction temperature, stirring speed and equilibrium time on the preparation of the spherical calcium carbonate were studied. Spherical calcium carbonate with good dispersing performance and grain size distribution in nanometer range of less than 10 μm was obtained. Furthermore, a potassium recovery process with joint production of spherical calcium carbonate was designed. This process is technically viable and considerable in economic benefit.展开更多
Water leaching of As2O3 from metallurgical dust containing various metals was investigated,serving the purpose of dearsenization and simultaneous metal enrichment especially for indium.Effects of leaching temperature,...Water leaching of As2O3 from metallurgical dust containing various metals was investigated,serving the purpose of dearsenization and simultaneous metal enrichment especially for indium.Effects of leaching temperature,liquid/solid ratio(LSR)and leaching time were studied.It was found that the initial dissolution was very fast but was then so inhibited by the increasingly dissolved As2O3,which makes it difficult to saturate enough arsenic in the leaching solution or in leaching out all the soluble arsenic with excess dosage of water within acceptable time(120 min).Only about 73%of As2O3 was extracted under the optimal conditions investigated.Two-step leaching showed similar trends and was thus unnecessary for improving As2O3 extraction.These observations could reasonably be accounted for the reversibility of the dissolution reaction.Kinetically,the leaching was described satisfactorily by the semi-empirical Avrami model with the apparent activation energy of 36.08 kJ/mol.The purity of the obtained product As2O3 could reach 98.7%,while the indium could be enriched in the leaching residue without loss.展开更多
This paper focused on investigating high-efficient reductants of recovering selenium and tellurium from degoldizedsolution of copper anode slimes.Firstly,the effect of various reductants on recovery rates of Se and Te...This paper focused on investigating high-efficient reductants of recovering selenium and tellurium from degoldizedsolution of copper anode slimes.Firstly,the effect of various reductants on recovery rates of Se and Te was investigated based onthermodynamic analysis of various metallic ions in degoldized solution.Secondly,the single factor experiments were made toinvestigate the effect of the process parameters on recovering Se and Te with hydrazine hydrate.Finally,the hydroxylaminehydrochloride was added to intensify the extraction efficiencies of Se and Te.The results indicated that hydrazine hydrate was themost suitable reductant,and the recovery rates of Se and Te are71.23%and76.50%,respectively;the recovery rates of Se and Tewere92.07%and97.81%,respectively,under the optimal process conditions of hydrazine hydrate dosage of0.2133mol/L,H+concentration of4.305mol/L,reaction temperature of85°C and reaction time of5h;the recovery rate of Se was97.59%,and that Tereached up to100%when hydroxylamine hydrochloride dosage was1.5116mol/L.展开更多
Nitrogen and phosphorous concentrations of effluent water must be taken into account for the design and operation of wastewater treatment plants. In addition, the requirement for effluent quality is becoming strict. T...Nitrogen and phosphorous concentrations of effluent water must be taken into account for the design and operation of wastewater treatment plants. In addition, the requirement for effluent quality is becoming strict. Therefore, intelligent control approaches are recently required in removing biological nutrient. In this study, fuzzy control has been successfully applied to improve the nitrogen removal. Experimental results showed that a close relationship between nitrate concentration and oxidation-reduction potential (ORP) at the end of anoxic zone was found for anoxic/oxic (A/O) nitrogen removal process treating synthetic wastewater. ORP can be used as online fuzzy control parameter of nitrate recirculation and external carbon addition. The established fuzzy logic controller that includes two inputs and one output can maintain ORP value at - 86 mV and - 90 mV by adjusting the nitrate recirculation flow and external carbon dosage respectively to realize the optimal control of nitrogen removal, improving the effluent quality and reducing the operating cost.展开更多
In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consi...In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted ofCu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4% （by weight）. The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ~C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea- ched as well as Ag. To separate Ag from leach solution HCI was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabilizers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.展开更多
A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly...A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly basic anion exchanger Two important factors, swelling and ion exchange, which directly affect the volume of ion exchangers were taken into account. An ion exchange mechanism has been found for the forward reaction RCl/[UO2 CO3)3]4- at pH 8.5～10.0, where the rate is controlled by liquid-film diffusion at low concentration of the tetravalent uranyl complex anion [UO2 (CO3)3]4-, and is partical diffusion governing at high concentration of the complex anion. The mechanism of RCl/U(Ⅳ) at pH 5. 5～7. 5 is a chemical reaction taking place at the moving boundary of the unreacted nucleus. For the reverse reaction RnU/NaCl, the uranyl tricarbonate complex anion in the resin phase is replaced by Cl- ions with an ion exchange mechanism always determined by particle diffusion. The other forms of uranium in the solid phase loaded on the resin at pH 5. 5～7. 5 should belong to non-exchangeable uranium. The mechanism of the reverse reaction RnU/HCl is always chemical reaction which is not restricted to the moving boundary of the unreacted core.展开更多
The silicon organic polymer containing PSOT-3 （dioxothiocarbamide groups） has been synthesized and characterized, and the adsorption of Au（III） on PSOT-3 was investigated. The results showed that PSOT-3 had good a...The silicon organic polymer containing PSOT-3 （dioxothiocarbamide groups） has been synthesized and characterized, and the adsorption of Au（III） on PSOT-3 was investigated. The results showed that PSOT-3 had good adsorption capacity for Au（III）, and the adsorption of Au（III） was found to be the most effective in 0.1-0.3 mol/dm^3 hydrochloric acid solution. The adsorption is physical and the process is endothermic, and Freundlich isotherm fits the data better than the Langmuir isotherm. The adsorption can be generally described by electrostatic interaction （Coulomb＇s force） between the adsorbent and the adsorbate. The high adsorption capacity of this sorbent has significant potential for gold recovery from aqueous solutions.展开更多
Abstract： The search for ＂new materials＂ to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics： Low-density polyethylene （LDPE）, rec...Abstract： The search for ＂new materials＂ to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics： Low-density polyethylene （LDPE）, recycled out of discarded soft drink packs： Polyethylene-terephthalate （PET）, recycled out of discarded soft drink bottles; and several plastics, from the printed films used like packages of candies （remainder of production plant by faults in the thickness of the films or in the inked process of themt. These conveniently grounded plastics were taken as ＂arids＂ to be mixed with Normal Portland cement, replacing heavy sand and gravel habitually used in these mixtures. These materials are used in constructive elements such as bricks, blocks and plates for economical houses closures or traditional construction. The developed constructive elements offer high thermal insulation, so they can be used in closures with a smaller thickness than conventional bricks and blocks. Besides, they have a lower specific weight than these traditiunal constructive elements. Recycling means lowering costs, making part of the environment contaminating waste useful and providing the unemployed and/or unqualified work force with jobs through uncomplicated technologies. Therefore, this recycling technology has an economic as well as an ecological purpose.展开更多
基金Projects(2012AA062502,2012AA06A118)supported by the National High-tech Research and Development Program of China
文摘Several physical and chemical detection methods were used to study the basic properties of sintering dust （ESP dust） collected from Baogang Steel Corporation. The result shows that the major constituents of the ESP dust are KCl, NaCl, Fe2O_3 and Fe3O_4. Water leaching experiment on the sintering dust shows that KCl in the ESP dust can be separated and recovered by water leaching and fractional crystallization. Component analysis of leaching solution indicates that the massive calcium sulfate in the leaching solution should be removed first in order to obtain the pure potassium salt. In order to provide theoretical guidance to inhibit the dissolution of calcium ions from the sintering dust, the water leaching experiment of ESP dust and the dissolution behavior of CaSO_4 in the potassium chloride, sodium chloride, potassium sulfate and their mixed salt solution were studied. It is found that, a lower liquid-solid ratio should be chosen in the leaching process to inhibit the dissolution of calcium sulfate dehydrate. Using sodium carbonate solution as a precipitating agent, the influences of the concentration of sodium carbonate solution, reaction temperature, stirring speed and equilibrium time on the preparation of the spherical calcium carbonate were studied. Spherical calcium carbonate with good dispersing performance and grain size distribution in nanometer range of less than 10 μm was obtained. Furthermore, a potassium recovery process with joint production of spherical calcium carbonate was designed. This process is technically viable and considerable in economic benefit.
基金Project(51874356)supported by the National Natural Science Foundation of China
文摘Water leaching of As2O3 from metallurgical dust containing various metals was investigated,serving the purpose of dearsenization and simultaneous metal enrichment especially for indium.Effects of leaching temperature,liquid/solid ratio(LSR)and leaching time were studied.It was found that the initial dissolution was very fast but was then so inhibited by the increasingly dissolved As2O3,which makes it difficult to saturate enough arsenic in the leaching solution or in leaching out all the soluble arsenic with excess dosage of water within acceptable time(120 min).Only about 73%of As2O3 was extracted under the optimal conditions investigated.Two-step leaching showed similar trends and was thus unnecessary for improving As2O3 extraction.These observations could reasonably be accounted for the reversibility of the dissolution reaction.Kinetically,the leaching was described satisfactorily by the semi-empirical Avrami model with the apparent activation energy of 36.08 kJ/mol.The purity of the obtained product As2O3 could reach 98.7%,while the indium could be enriched in the leaching residue without loss.
基金Project(201407300993)supported by Xinjiang Autonomous Region Science and Technology Support Project,China
文摘This paper focused on investigating high-efficient reductants of recovering selenium and tellurium from degoldizedsolution of copper anode slimes.Firstly,the effect of various reductants on recovery rates of Se and Te was investigated based onthermodynamic analysis of various metallic ions in degoldized solution.Secondly,the single factor experiments were made toinvestigate the effect of the process parameters on recovering Se and Te with hydrazine hydrate.Finally,the hydroxylaminehydrochloride was added to intensify the extraction efficiencies of Se and Te.The results indicated that hydrazine hydrate was themost suitable reductant,and the recovery rates of Se and Te are71.23%and76.50%,respectively;the recovery rates of Se and Tewere92.07%and97.81%,respectively,under the optimal process conditions of hydrazine hydrate dosage of0.2133mol/L,H+concentration of4.305mol/L,reaction temperature of85°C and reaction time of5h;the recovery rate of Se was97.59%,and that Tereached up to100%when hydroxylamine hydrochloride dosage was1.5116mol/L.
基金Supported by the Key International Cooperation Project of NSFC, Key Project of NSFC (No. 50138010)863 Hi-Technology Research and Development Program of China (2003AA601010).
文摘Nitrogen and phosphorous concentrations of effluent water must be taken into account for the design and operation of wastewater treatment plants. In addition, the requirement for effluent quality is becoming strict. Therefore, intelligent control approaches are recently required in removing biological nutrient. In this study, fuzzy control has been successfully applied to improve the nitrogen removal. Experimental results showed that a close relationship between nitrate concentration and oxidation-reduction potential (ORP) at the end of anoxic zone was found for anoxic/oxic (A/O) nitrogen removal process treating synthetic wastewater. ORP can be used as online fuzzy control parameter of nitrate recirculation and external carbon addition. The established fuzzy logic controller that includes two inputs and one output can maintain ORP value at - 86 mV and - 90 mV by adjusting the nitrate recirculation flow and external carbon dosage respectively to realize the optimal control of nitrogen removal, improving the effluent quality and reducing the operating cost.
基金the International Center for Science, High Technology & Environmental Sciences for financial support of this work (No. 1.213)
文摘In this paper, recovery of silver from anode slime of Sarcheshmeh copper complex in lran and subsequent synthesis of silver nanoparticles from leaching solution is investigated. Sarcheshmeh anode slime is mainly consisted ofCu, Ag, Pb and Se. Amount of Ag in the considered anode slime was 5.4% （by weight）. The goal was to recover as much as possible Ag from anode slime at atmospheric pressure to synthesize Ag nanoparticles. Therefore, acid leaching was used for this purpose. The anode slime was leached with sulfuric and nitric acid from room to 90 ~C at different acid concentrations and the run which yielded the most recovery of Ag was selected for Ag nanoparticles synthesis. At this condition, Cu, Pb and Se are lea- ched as well as Ag. To separate Ag from leach solution HCI was added and silver was precipitated as AgCl which were then dissolved by ammonia solution. The Ag nanoparticles are synthesized from this solution by chemical reduction method by aid of sodium borohydride in the presence of PVP and PEG as stabilizers. The synthesized Ag nanoparticles showed a peak of 394 nm in UV-vis spectrum and TEM images showed a rather uniform Ag nanoparticles of 12 nm.
文摘A moving boundary model under considering the volume change of spherical resin beads during ion exchange processes was employed to recognize the mechanisms of recovering uranium from carbonate solutions using strongly basic anion exchanger Two important factors, swelling and ion exchange, which directly affect the volume of ion exchangers were taken into account. An ion exchange mechanism has been found for the forward reaction RCl/[UO2 CO3)3]4- at pH 8.5～10.0, where the rate is controlled by liquid-film diffusion at low concentration of the tetravalent uranyl complex anion [UO2 (CO3)3]4-, and is partical diffusion governing at high concentration of the complex anion. The mechanism of RCl/U(Ⅳ) at pH 5. 5～7. 5 is a chemical reaction taking place at the moving boundary of the unreacted nucleus. For the reverse reaction RnU/NaCl, the uranyl tricarbonate complex anion in the resin phase is replaced by Cl- ions with an ion exchange mechanism always determined by particle diffusion. The other forms of uranium in the solid phase loaded on the resin at pH 5. 5～7. 5 should belong to non-exchangeable uranium. The mechanism of the reverse reaction RnU/HCl is always chemical reaction which is not restricted to the moving boundary of the unreacted core.
文摘The silicon organic polymer containing PSOT-3 （dioxothiocarbamide groups） has been synthesized and characterized, and the adsorption of Au（III） on PSOT-3 was investigated. The results showed that PSOT-3 had good adsorption capacity for Au（III）, and the adsorption of Au（III） was found to be the most effective in 0.1-0.3 mol/dm^3 hydrochloric acid solution. The adsorption is physical and the process is endothermic, and Freundlich isotherm fits the data better than the Langmuir isotherm. The adsorption can be generally described by electrostatic interaction （Coulomb＇s force） between the adsorbent and the adsorbate. The high adsorption capacity of this sorbent has significant potential for gold recovery from aqueous solutions.
文摘Abstract： The search for ＂new materials＂ to manufacture building elements for economical housing is the aim of this work. These materials are the following recycled plastics： Low-density polyethylene （LDPE）, recycled out of discarded soft drink packs： Polyethylene-terephthalate （PET）, recycled out of discarded soft drink bottles; and several plastics, from the printed films used like packages of candies （remainder of production plant by faults in the thickness of the films or in the inked process of themt. These conveniently grounded plastics were taken as ＂arids＂ to be mixed with Normal Portland cement, replacing heavy sand and gravel habitually used in these mixtures. These materials are used in constructive elements such as bricks, blocks and plates for economical houses closures or traditional construction. The developed constructive elements offer high thermal insulation, so they can be used in closures with a smaller thickness than conventional bricks and blocks. Besides, they have a lower specific weight than these traditiunal constructive elements. Recycling means lowering costs, making part of the environment contaminating waste useful and providing the unemployed and/or unqualified work force with jobs through uncomplicated technologies. Therefore, this recycling technology has an economic as well as an ecological purpose.
