Innovations of mining technologies were proposed by beneficial utilizations of unfavorable factors such as high geostress,high geotemperature and high mining depth to achieve green mining as mining depth increases ine...Innovations of mining technologies were proposed by beneficial utilizations of unfavorable factors such as high geostress,high geotemperature and high mining depth to achieve green mining as mining depth increases inevitably.Cuttability of deep hard rock was investigated by experimental and regressed analyses to find the reasonable stress adjustment method to improve non-explosive mechanized fragmentation for hard ore-rock.A non-explosive mechanized and intellectualized mining method was proposed to continuously and precisely exploit phosphate underground,which promoted the high-recovery,low-waste and high-efficiency exploitation of phosphate with recovery rate over 90%,dilution rate near 5%and cutting efficiency about 107.7 t/h.A circular economy model and the backfill system were proposed to conduct resource utilizations of solid waste,by which the utilization amount of waste increased year after year.In 2018,the utilization amounts of phosphogypsum,yellow phosphorus slag and waste rock increased to 1853.6×10^3 t/a,291.1×10^3 t/a and 1493.8×10^3 t/a,respectively.展开更多
This study aims to explore the potential of using a blended pulp from Mikania micrantha(M.micrantha)and waste paper for producing composite paper.The effects of the mass ratio of M.micrantha stem to waste paper(MRMW),...This study aims to explore the potential of using a blended pulp from Mikania micrantha(M.micrantha)and waste paper for producing composite paper.The effects of the mass ratio of M.micrantha stem to waste paper(MRMW),the beating time(BT),the water-to-pulp mass ratio(WPMR)and the times of pulp suspension screening(TPSS)on the paper’s basic structural,optical and mechanical properties are investigated.It is found that MRMW primarily affects the grammage(mass per unit area),density,bulkness and whiteness;WPMR mainly affects the thickness and density;TPSS mainly affects the thickness and grammage.When MRMW is 3:7,the composite paper shows higher values for thickness,grammage,density and whiteness;whereas when MRMW is 7:3,these values are lower.Extending BT can increase paper density.The tensile strengths of all prepared samples fall in the range of 1.5 to 4.1 kN/m,indicating their excellent strength properties that meet the demands of many paper applications.The artistic bags and lampshades crafted from this composite paper exhibit a more natural texture compared to conventional packaging paper.This research demonstrates the feasibility of papermaking by using M.micrantha,while showcasing the potential for synergistic integration of waste resources with traditional hand papermaking techniques.展开更多
The development and utilization of mineral resources are accompanied by the production of a large number of solid wastes such as tailings and smelting slag.Bayan Obo tailings and blast furnace slag were used as the ma...The development and utilization of mineral resources are accompanied by the production of a large number of solid wastes such as tailings and smelting slag.Bayan Obo tailings and blast furnace slag were used as the main raw materials.Coal gangue was used as pore-forming agent to prepare ceramsite which can efficiently treat ammonia nitrogen wastewater.The optimum preparation process parameters were obtained.The mineral evolution process of ceramsite prepared by smelting solid waste during roasting was clarified.The effects of sintering process parameters on the properties of ceramsite and its removal of ammonia nitrogen wastewater were revealed.The results show that,the optimum proportion of raw materials for preparing ceramsite was:25%Bayan Obo tailings,65%blast furnace slag and 10%coal gangue.The reasonable process for preparing ceramsite was:temperature of 400℃,preheating for 20 min,heating rate of 10℃/min,calcination at 1090℃for 15 min,and cooling with the furnace.With the increase in calcination temperature,the main crystal phase changes from dolomite,kaolinite,fluorite and calcite to melilite and Fe2O3.Finally,the ceramsite with porosity of 48.13%,specific surface area of 2.44 m^(2)/g and soluble rate of hydrochloric acid of 1.88%was prepared.The removal rate of ammonia nitrogen wastewater by the ceramsite was 54.13%.展开更多
Low grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al2O3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the...Low grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al2O3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the sample was initiated with desliming of the feed sample of -100 μm to remove the siliceous ultrafine particles and to improve the feed quality. Flotation study was carried out by column flotation technique varying the collector dosage, superficial air flow velocity and froth depth to assess their effect on silica reduction and CaO recovery. It was observed that increased collector dosage and superficial air velocity increases the recovery of CaO, and increase in the froth depth reduces the mass flow and silica content in the concentrate. The best result was found at 1.25 cm/sec superficial air velocity, 25 cm froth depth, 1.25 kgpt collector dosage and concentrate assayed 47.3% CaO, 2.8% silica with 72% CaO recovery.展开更多
The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its...The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its use to adjust the silica/alumina ratio of the high calcium fly ash geopolymer were studied. To recycle the raw Al-rich waste, the waste was dried at 110℃ and calcined at 400 to 1000℃. Mineralogical analyses were conducted using X-ray diffraction （XRD） to study the phase change. The increase in calcination temperature to 600, 800, and 1000℃ resulted in the phase transformation. The more active alumina phase of active θ-Al2O3 was obtained with the increase in calcination temperature. The calcined Al-rich waste was then used as an additive to the fly ash geopolymer by mixing with high calcium fly ash, water glass, 10 M sodium hydroxide （NaOH）, and sand. Test results indicated that the calcined Al-rich waste could be used as an aluminium source to adjust the silica/alumina ratio and the strength of geopolymeric materials. The fly ash geopolymer mortar with 2.5wt% of the Al-rich waste calcined at 1000℃ possessed the 7-d compressive strength of 34.2 MPa.展开更多
Chicken eggshell is one of the most common wastes generated from households,restaurants and other food processing outlets.Waste Chicken Eggshells(WCES)also constitutes an environmental nuisance and ends up discarded a...Chicken eggshell is one of the most common wastes generated from households,restaurants and other food processing outlets.Waste Chicken Eggshells(WCES)also constitutes an environmental nuisance and ends up discarded at dumping site with no consideration of further usage.The main constituent of WCES is calcium carbonate from which calcium or calcium oxide can be extracted for various applications.This current effort reviews recently published literature on the diverse applications of WCES.The considered utilization avenues include catalysts for biofuel production,construction industry,wastewater purification,industrial sector,food industry,medical,and agricultural applications.The specific areas of application apart from the transesterification reactions include cement additives and replacement in concrete,asphalt binder,adsorbent of metals and dyes,production of hydroxyapatite,food supplement and fortification,dentistry,therapeutics,bone formation,drug delivery,poultry feeds as well as organic fertilizer.For most of the identified applications,the WCES is subjected to pretreatment and other modification techniques before utilization.The conversion of WCES to valuable products is a cost-effective,safe,environmentally friendly,non-toxic and viable means of waste disposal and utilization.More investigations are needed to further explore the benefits derivable from this bioresource.展开更多
Zinc extraction residue,a solid waste generated from the treatment of zinc-containing dust in rotary kilns,is commonly stockpiled in steel companies for extended periods.It poses significant disposal challenges and en...Zinc extraction residue,a solid waste generated from the treatment of zinc-containing dust in rotary kilns,is commonly stockpiled in steel companies for extended periods.It poses significant disposal challenges and environmental pollution risks.So far,research on the treatment of zinc extraction residues has been slow,inadequate,and sporadic.For this gap,a novel approach was proposed to effectively treat the zinc extraction residue via the iron ore sintering process.It was feasible to add 1 wt.%of zinc extraction residues to the sintering raw materials.The more adequate mineralization reaction resulted in higher yield and tumbler indexes,despite a slight decrease in sintering speed.Although this may result in a slight decrease in sintering speed,the more complete mineralization reaction leads to improved sintering yield and tumbler index.Interestingly,the addition of zinc extraction residues reduced the CO and NO_(x) concentrations in the sintering flue gas.Thus,the iron ore sintering process provided a viable solution for resource utilization and environmentally friendly treatment of zinc extraction residues.展开更多
In recent years, China pays more attention to the protection of environment and resources in the process of social and economic development, puts forward the development concept of green, energy saving and environment...In recent years, China pays more attention to the protection of environment and resources in the process of social and economic development, puts forward the development concept of green, energy saving and environmental protection, and carries on a clear specification for the development of various industries. Under the current situation, flue gas waste heat recovery and utilization technology has attracted more and more attention, which can avoid the waste of energy and maximize the interests of enterprises. Therefore, relevant personnel should pay attention to study and analyze the application of flue gas waste heat recovery and utilization technology, in order to provide some help for the development of enterprises.展开更多
Xylitol,one of the top twelve chemical building blocks,is commercially synthesized through the xylose hy-drogenation reaction using a metal catalyst.Biochar has emerged as an eco-efficient catalyst support material.In...Xylitol,one of the top twelve chemical building blocks,is commercially synthesized through the xylose hy-drogenation reaction using a metal catalyst.Biochar has emerged as an eco-efficient catalyst support material.In this study,biochar derived from corn stover(BCS)was first used as a metal catalyst support material for xylose hydrogenation into xylitol.The catalyst was prepared by carbonizing corn stover(CS),impregnating the resulting biochar with metal,and reducing the metal-impregnated BCS.The catalyst characteristics were comprehensively explored.The Ru/BCS catalyst was employed in xylose conversion to xylitol at different process temperatures(100-160℃),retention times(3-12 h),H_(2)pressures(2-5 MPa),and Ru contents(1-5%).The highest xylitol yield(87.0 wt.%)and selectivity(91.6%)were derived at 120℃ for 6 h under 4 MPa H_(2)using 5%Ru.Interestingly,the Ru/BCS catalyst showed high stability under the promising process condition.Additionally,xylitol production from hydrolysates enriched with CS xylose was subsequently explored.On the other hand,the catalyst characterization results revealed that the superior catalytic efficiency of 5Ru/BCS was mainly due to the metal nanoparticles embedded in the biochar.Additionally,BCS proved to be an outstanding support material for a bimetallic hydrogenation catalyst(Ru-Ni/BCS).Therefore,these results indicate that BCS can be a competitive support material for metal hydrogenation catalysts,enhancing environmental friendliness and potentially being employed in industrial-scale xylitol production.展开更多
Red mud, an insoluble residue produced during alkali leaching of bauxite, is considered as a low-grade iron ore containing 30% to 50% iron. The present paper deals with the use of thermal plasma technology for produci...Red mud, an insoluble residue produced during alkali leaching of bauxite, is considered as a low-grade iron ore containing 30% to 50% iron. The present paper deals with the use of thermal plasma technology for producing pig iron from red mud waste fines. The smelting reduction of red mud was carried out in a 35 kW DC extended arc thermal plasma reactor. Red mud was properly mixed with fluxes and graphite （fixed carbon, 99%） as a reductant as per stoichiometric requirement. The effect of various process parameters like a reductant, fluxes and smelting time on iron recovery was studied and optimized. An optimum condition for the maximum recovery of iron was obtained. A new thermal plasma process applicable to direct iron making from red mud waste fines that would achieve significant utilization of red mud was proposed.展开更多
Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas,which cause serious environmental problems.In this study,a new process for the comprehensive u...Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas,which cause serious environmental problems.In this study,a new process for the comprehensive utilization of vanadium slag was proposed,wherein zeolite A and a V2O5/TiO2 system were synthesized.The structural properties of the as-synthesized zeolite A and the V2O5/TiO2system were characterized using various experimental techniques,including X-ray diffraction,X-ray fluorescence,scanning electron microscopy,and infrared spectroscopy.The results reveal that zeolite A and the V2O5/TiO2 system are successfully obtained with high purity.The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO2 over N2 and is a candidate material for CO2 capture from flue-gas streams.展开更多
The purpose of this paper was to explore the possility of using low alkalinity cementitious materials as binders,in which ground blast furnace slag and fly ash acted as a partial replacement of ordinary Portland cemen...The purpose of this paper was to explore the possility of using low alkalinity cementitious materials as binders,in which ground blast furnace slag and fly ash acted as a partial replacement of ordinary Portland cement,and CaSO_(4),Na_(2)SO_(4),and CaO were used as a sulfate activator and alkali activated additives,to solidify gold mine tail-ings for preparation of a green,inexpensive cemented paste backill(CPB).For this target,the effects of cement/tailings ratio,superplasticizer dosage,solid content,tailings fineness on the mechanical properties of the CPB were inves tigated.Additionally,the hydration mechanism of the CPB was analyzed based on X-ray diffraction and scanning electron microscopy results.The results showed that the fuidity of the CPB slurry could be improved by adding polycarboxylic acid superplasticizer.The unconfined compressive strength(UCS)of the CPB specimens was increased with the increase of cement/tailings ratio and solid content.Under the same experi-mental conditions,the 28 d UCS of the CPB specimens was 3.8-4.9 times higher than that of ordinary Portland cement.The softening coefficient of the CPB specimens was increased with the increasing cement/tailings ratio,ranging from 0.83 to 0.92.The shrinkage rate of the CPB specimens was decreased from 0.70%to 0.54%with the increase of cement/tailings ratio from 1:12 to 1:4 The UCS of the full tailings CPB was the highest,followed by the fine tailings CPB specimens,and the UCS of the coarse tailings CPB specimens was the lowest.The low alka-linity binder was proved to be a promising material to improve the engineering performances of the CPB.The optimal mixing ratio is 1:6 cement/tailings ratio,0.15 wt% superplastizer dosage,and 70 wt%solid content.Pre-pared by this mixing ratio,the UCS values of the CPB after 3,7,and 28 d curing ages reached 1.85,5.87,and 9.16 MPa,respectively,which were suitable as CPB for the Zhaoyuan gold mine in terms of strength requirements.展开更多
Synthetic plastics are often considered to be materials that cannot be broken down by natural processes.One such plastic,polyethylene terephthalate(PET),is commonly used in everyday items but when these products are d...Synthetic plastics are often considered to be materials that cannot be broken down by natural processes.One such plastic,polyethylene terephthalate(PET),is commonly used in everyday items but when these products are discarded,they can cause serious harm to the environment and human health.In this study,PET plastic waste was used to create activated carbon using a physical activation process that involved using CO2 gas.The researchers investigated the effects of different temperatures,carbonization,and activation times on the resulting activated carbon’s surface area.The activated carbon was then analyzed using scanning electron microscopy(SEM),X-ray diffraction(XRD),FTIR,and BET.The activated carbon created from PET plastic waste showed excellent absorption properties for methylene blue in aqueous solutions across a wide range of pH levels.By creating activated carbon from plastic waste,not only are environmental issues addressed,but high-value activated carbon is produced for environmental remediation purposes.展开更多
Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high...Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”展开更多
Wollastonite, a mineral of wide industrial applications was synthesised from rice husk ash silica and limestone. A number of raw batches consisting of these starting materials, in 1:1 molar ratio, were heat treated to...Wollastonite, a mineral of wide industrial applications was synthesised from rice husk ash silica and limestone. A number of raw batches consisting of these starting materials, in 1:1 molar ratio, were heat treated to produce it through solid state reaction from 900℃ to 1300℃. The conducted reaction was monitored by XRD step by step. Amount of Wollastonite formed at every temperature was also studied to some extent. Analyses of the obtained data indicated that the target mineral formation was quite effective and almost proportional to a rise in temperature up to 1200℃. The results from both, XRD and chemical analysis were found in fair agreement with one another展开更多
Combining the characteristics of the black pulping liquor that contains a lot of lignin and other biomass resources, the technology of comprehensive waste utilization is employed. The reconstructive preparation of mod...Combining the characteristics of the black pulping liquor that contains a lot of lignin and other biomass resources, the technology of comprehensive waste utilization is employed. The reconstructive preparation of modified urea-formaldehyde glue by adding black pulping liquor and the application in extruding the medium density fibre board using this modified urea-formaldehyde glue is researched. Results show that when applying the preparation technology that alkaline reaction and then weak acid reaction, the appropriate preparation process is as follows： the adding urea process is divided into three stages （proportion 2 ： 1 ： 1） ; the pH value is 8.0, and the reaction time is 40 min in the addition reaction stage; the pH value will be naturally reduced to 3.5 -5.0, and the reaction time is 45 min in the aggregation reaction stage; the pH value is 8.0 in the urea complement stage. And the optimal condition of the reconstructive preparation the modified ureaformaldehyde glue is adding the condensed black pulping liquor after hydroxymethylation in the beginning of polycondensation reaction by 5% proportion. The application in extruding medium density fibre board with this modified urea-fosmaldehyde glue is proved feasible.展开更多
Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection...Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection of waste slag yard of water diversion project and design of water and soil conservation measures are discussed.Rationality of site selection of waste slag yard and pertinence of prevention and control measures of water and soil loss in waste slag yard are analyzed,and comprehensive utilization of waste slag in large-scale production and construction projects is explored.展开更多
The electricity demand is increasing rapidly with the development of society and technology.Coal-fired thermal power plants have become one of the primary sources of electricity generation for urbanization.However,coa...The electricity demand is increasing rapidly with the development of society and technology.Coal-fired thermal power plants have become one of the primary sources of electricity generation for urbanization.However,coal-fired thermal power plants produce a great amount of by-product coal fly ash every year.Coal fly ash disposal in landfills requires a sizable space and has negative environmental impacts.Therefore,it is crucial to develop new technologies and methods to utilize this enormous volume of solid waste in order to protect the environment.In this review,the fundamental physical and chemical character-istics of coal fly ash are introduced,and afterward the disposal policies and utilization ways of coal fly ash are discussed to gain a comprehensive understanding of the various ways this waste.The leaching of valuable metals in coal fly ash and the extraction of metal elements in leachate under different conditions are also summarized.Furthermore,the possibility of coal fly ash to serve as a supplementary source for mineral resources is analyzed,providing a basis for its extensive use as a raw material in the metal industry in China and worldwide.展开更多
Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying t...Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.展开更多
Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save ...Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save energy and water in the slag flushing process of blast furnaces,an ideal comprehensive cascade utilization system scheme for annual recovery of waste heat is proposed.Based on the measured waste heat data of a steel plant,design calculations are carried out to further analyze the economic feasibility of the new scheme and provide reference for its promotion and application.展开更多
基金Projects(41630642,51904335,51904333)supported by the National Natural Science Foundation of China
文摘Innovations of mining technologies were proposed by beneficial utilizations of unfavorable factors such as high geostress,high geotemperature and high mining depth to achieve green mining as mining depth increases inevitably.Cuttability of deep hard rock was investigated by experimental and regressed analyses to find the reasonable stress adjustment method to improve non-explosive mechanized fragmentation for hard ore-rock.A non-explosive mechanized and intellectualized mining method was proposed to continuously and precisely exploit phosphate underground,which promoted the high-recovery,low-waste and high-efficiency exploitation of phosphate with recovery rate over 90%,dilution rate near 5%and cutting efficiency about 107.7 t/h.A circular economy model and the backfill system were proposed to conduct resource utilizations of solid waste,by which the utilization amount of waste increased year after year.In 2018,the utilization amounts of phosphogypsum,yellow phosphorus slag and waste rock increased to 1853.6×10^3 t/a,291.1×10^3 t/a and 1493.8×10^3 t/a,respectively.
文摘This study aims to explore the potential of using a blended pulp from Mikania micrantha(M.micrantha)and waste paper for producing composite paper.The effects of the mass ratio of M.micrantha stem to waste paper(MRMW),the beating time(BT),the water-to-pulp mass ratio(WPMR)and the times of pulp suspension screening(TPSS)on the paper’s basic structural,optical and mechanical properties are investigated.It is found that MRMW primarily affects the grammage(mass per unit area),density,bulkness and whiteness;WPMR mainly affects the thickness and density;TPSS mainly affects the thickness and grammage.When MRMW is 3:7,the composite paper shows higher values for thickness,grammage,density and whiteness;whereas when MRMW is 7:3,these values are lower.Extending BT can increase paper density.The tensile strengths of all prepared samples fall in the range of 1.5 to 4.1 kN/m,indicating their excellent strength properties that meet the demands of many paper applications.The artistic bags and lampshades crafted from this composite paper exhibit a more natural texture compared to conventional packaging paper.This research demonstrates the feasibility of papermaking by using M.micrantha,while showcasing the potential for synergistic integration of waste resources with traditional hand papermaking techniques.
基金supported by the National Key Research and Development Program of China(Nos.2020YFC1909100 and 2020YFC1909105)the Major Science and Technology Project of lnner Mongolia Autonomous Region(No.2021ZD0016)+1 种基金the Program for Young Talents of Science and Technology in Universities of lnner Mongolia Autonomous Region(No.NJYT22060)the Fundamental Research Funds for Inner Mongolia University of Science&Technology(Nos.2022QNJS011 and 2023YXXS006).
文摘The development and utilization of mineral resources are accompanied by the production of a large number of solid wastes such as tailings and smelting slag.Bayan Obo tailings and blast furnace slag were used as the main raw materials.Coal gangue was used as pore-forming agent to prepare ceramsite which can efficiently treat ammonia nitrogen wastewater.The optimum preparation process parameters were obtained.The mineral evolution process of ceramsite prepared by smelting solid waste during roasting was clarified.The effects of sintering process parameters on the properties of ceramsite and its removal of ammonia nitrogen wastewater were revealed.The results show that,the optimum proportion of raw materials for preparing ceramsite was:25%Bayan Obo tailings,65%blast furnace slag and 10%coal gangue.The reasonable process for preparing ceramsite was:temperature of 400℃,preheating for 20 min,heating rate of 10℃/min,calcination at 1090℃for 15 min,and cooling with the furnace.With the increase in calcination temperature,the main crystal phase changes from dolomite,kaolinite,fluorite and calcite to melilite and Fe2O3.Finally,the ceramsite with porosity of 48.13%,specific surface area of 2.44 m^(2)/g and soluble rate of hydrochloric acid of 1.88%was prepared.The removal rate of ammonia nitrogen wastewater by the ceramsite was 54.13%.
文摘Low grade dumped limestone sample having high silica of 8.1%, 36.8% CaO, and 3% Al2O3 has been studied with the aim to reduce the silica level to below 3% for its utilization in iron making. Beneficiation study of the sample was initiated with desliming of the feed sample of -100 μm to remove the siliceous ultrafine particles and to improve the feed quality. Flotation study was carried out by column flotation technique varying the collector dosage, superficial air flow velocity and froth depth to assess their effect on silica reduction and CaO recovery. It was observed that increased collector dosage and superficial air velocity increases the recovery of CaO, and increase in the froth depth reduces the mass flow and silica content in the concentrate. The best result was found at 1.25 cm/sec superficial air velocity, 25 cm froth depth, 1.25 kgpt collector dosage and concentrate assayed 47.3% CaO, 2.8% silica with 72% CaO recovery.
基金supported by the Higher Education Research Promotion and National Research University Project of Thailand,Office of the Higher Education Commission, through the Advanced Functional Materials Cluster of Khon Kaen Universitythe Thailand Research Fund (TRF) under TRF Senior Research Scholar contract No.RTA5480004
文摘The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its use to adjust the silica/alumina ratio of the high calcium fly ash geopolymer were studied. To recycle the raw Al-rich waste, the waste was dried at 110℃ and calcined at 400 to 1000℃. Mineralogical analyses were conducted using X-ray diffraction （XRD） to study the phase change. The increase in calcination temperature to 600, 800, and 1000℃ resulted in the phase transformation. The more active alumina phase of active θ-Al2O3 was obtained with the increase in calcination temperature. The calcined Al-rich waste was then used as an additive to the fly ash geopolymer by mixing with high calcium fly ash, water glass, 10 M sodium hydroxide （NaOH）, and sand. Test results indicated that the calcined Al-rich waste could be used as an aluminium source to adjust the silica/alumina ratio and the strength of geopolymeric materials. The fly ash geopolymer mortar with 2.5wt% of the Al-rich waste calcined at 1000℃ possessed the 7-d compressive strength of 34.2 MPa.
文摘Chicken eggshell is one of the most common wastes generated from households,restaurants and other food processing outlets.Waste Chicken Eggshells(WCES)also constitutes an environmental nuisance and ends up discarded at dumping site with no consideration of further usage.The main constituent of WCES is calcium carbonate from which calcium or calcium oxide can be extracted for various applications.This current effort reviews recently published literature on the diverse applications of WCES.The considered utilization avenues include catalysts for biofuel production,construction industry,wastewater purification,industrial sector,food industry,medical,and agricultural applications.The specific areas of application apart from the transesterification reactions include cement additives and replacement in concrete,asphalt binder,adsorbent of metals and dyes,production of hydroxyapatite,food supplement and fortification,dentistry,therapeutics,bone formation,drug delivery,poultry feeds as well as organic fertilizer.For most of the identified applications,the WCES is subjected to pretreatment and other modification techniques before utilization.The conversion of WCES to valuable products is a cost-effective,safe,environmentally friendly,non-toxic and viable means of waste disposal and utilization.More investigations are needed to further explore the benefits derivable from this bioresource.
基金supported by the National Natural Science Foundation of China (52204331)Natural Science Foundation of Anhui Province Youth Project (2208085QE145)Open Fund of Key Laboratory of Metallurgical Emission Reduction and Resource Utilization,Ministry of Education (JKF20-03).
文摘Zinc extraction residue,a solid waste generated from the treatment of zinc-containing dust in rotary kilns,is commonly stockpiled in steel companies for extended periods.It poses significant disposal challenges and environmental pollution risks.So far,research on the treatment of zinc extraction residues has been slow,inadequate,and sporadic.For this gap,a novel approach was proposed to effectively treat the zinc extraction residue via the iron ore sintering process.It was feasible to add 1 wt.%of zinc extraction residues to the sintering raw materials.The more adequate mineralization reaction resulted in higher yield and tumbler indexes,despite a slight decrease in sintering speed.Although this may result in a slight decrease in sintering speed,the more complete mineralization reaction leads to improved sintering yield and tumbler index.Interestingly,the addition of zinc extraction residues reduced the CO and NO_(x) concentrations in the sintering flue gas.Thus,the iron ore sintering process provided a viable solution for resource utilization and environmentally friendly treatment of zinc extraction residues.
文摘In recent years, China pays more attention to the protection of environment and resources in the process of social and economic development, puts forward the development concept of green, energy saving and environmental protection, and carries on a clear specification for the development of various industries. Under the current situation, flue gas waste heat recovery and utilization technology has attracted more and more attention, which can avoid the waste of energy and maximize the interests of enterprises. Therefore, relevant personnel should pay attention to study and analyze the application of flue gas waste heat recovery and utilization technology, in order to provide some help for the development of enterprises.
基金supported by Specific League Funds from Mahidol University,and partially supported by Office of the Permanent Secretary,Ministry of Higher Education,Science,Research and Inno-vation(OPS MHESI),Thailand Science Research and Innovation(TSRI)(Grant No.RGNS 63-167).
文摘Xylitol,one of the top twelve chemical building blocks,is commercially synthesized through the xylose hy-drogenation reaction using a metal catalyst.Biochar has emerged as an eco-efficient catalyst support material.In this study,biochar derived from corn stover(BCS)was first used as a metal catalyst support material for xylose hydrogenation into xylitol.The catalyst was prepared by carbonizing corn stover(CS),impregnating the resulting biochar with metal,and reducing the metal-impregnated BCS.The catalyst characteristics were comprehensively explored.The Ru/BCS catalyst was employed in xylose conversion to xylitol at different process temperatures(100-160℃),retention times(3-12 h),H_(2)pressures(2-5 MPa),and Ru contents(1-5%).The highest xylitol yield(87.0 wt.%)and selectivity(91.6%)were derived at 120℃ for 6 h under 4 MPa H_(2)using 5%Ru.Interestingly,the Ru/BCS catalyst showed high stability under the promising process condition.Additionally,xylitol production from hydrolysates enriched with CS xylose was subsequently explored.On the other hand,the catalyst characterization results revealed that the superior catalytic efficiency of 5Ru/BCS was mainly due to the metal nanoparticles embedded in the biochar.Additionally,BCS proved to be an outstanding support material for a bimetallic hydrogenation catalyst(Ru-Ni/BCS).Therefore,these results indicate that BCS can be a competitive support material for metal hydrogenation catalysts,enhancing environmental friendliness and potentially being employed in industrial-scale xylitol production.
文摘Red mud, an insoluble residue produced during alkali leaching of bauxite, is considered as a low-grade iron ore containing 30% to 50% iron. The present paper deals with the use of thermal plasma technology for producing pig iron from red mud waste fines. The smelting reduction of red mud was carried out in a 35 kW DC extended arc thermal plasma reactor. Red mud was properly mixed with fluxes and graphite （fixed carbon, 99%） as a reductant as per stoichiometric requirement. The effect of various process parameters like a reductant, fluxes and smelting time on iron recovery was studied and optimized. An optimum condition for the maximum recovery of iron was obtained. A new thermal plasma process applicable to direct iron making from red mud waste fines that would achieve significant utilization of red mud was proposed.
基金supported by the Natural Science Foundation of China (Nos. 51406029 and 51474067)the Key Laboratory Project of Liaoning Province of Education (No.LZ2015032)
文摘Traditional processes for treating vanadium slag generate a huge volume of solid residue and a large amount of harmful gas,which cause serious environmental problems.In this study,a new process for the comprehensive utilization of vanadium slag was proposed,wherein zeolite A and a V2O5/TiO2 system were synthesized.The structural properties of the as-synthesized zeolite A and the V2O5/TiO2system were characterized using various experimental techniques,including X-ray diffraction,X-ray fluorescence,scanning electron microscopy,and infrared spectroscopy.The results reveal that zeolite A and the V2O5/TiO2 system are successfully obtained with high purity.The results of gas adsorption measurements indicate that the prepared zeolite A exhibits high selectivity for CO2 over N2 and is a candidate material for CO2 capture from flue-gas streams.
基金The current work was financially supported by the Key Research and Development Program of Anhui Province(202004a07020039).
文摘The purpose of this paper was to explore the possility of using low alkalinity cementitious materials as binders,in which ground blast furnace slag and fly ash acted as a partial replacement of ordinary Portland cement,and CaSO_(4),Na_(2)SO_(4),and CaO were used as a sulfate activator and alkali activated additives,to solidify gold mine tail-ings for preparation of a green,inexpensive cemented paste backill(CPB).For this target,the effects of cement/tailings ratio,superplasticizer dosage,solid content,tailings fineness on the mechanical properties of the CPB were inves tigated.Additionally,the hydration mechanism of the CPB was analyzed based on X-ray diffraction and scanning electron microscopy results.The results showed that the fuidity of the CPB slurry could be improved by adding polycarboxylic acid superplasticizer.The unconfined compressive strength(UCS)of the CPB specimens was increased with the increase of cement/tailings ratio and solid content.Under the same experi-mental conditions,the 28 d UCS of the CPB specimens was 3.8-4.9 times higher than that of ordinary Portland cement.The softening coefficient of the CPB specimens was increased with the increasing cement/tailings ratio,ranging from 0.83 to 0.92.The shrinkage rate of the CPB specimens was decreased from 0.70%to 0.54%with the increase of cement/tailings ratio from 1:12 to 1:4 The UCS of the full tailings CPB was the highest,followed by the fine tailings CPB specimens,and the UCS of the coarse tailings CPB specimens was the lowest.The low alka-linity binder was proved to be a promising material to improve the engineering performances of the CPB.The optimal mixing ratio is 1:6 cement/tailings ratio,0.15 wt% superplastizer dosage,and 70 wt%solid content.Pre-pared by this mixing ratio,the UCS values of the CPB after 3,7,and 28 d curing ages reached 1.85,5.87,and 9.16 MPa,respectively,which were suitable as CPB for the Zhaoyuan gold mine in terms of strength requirements.
基金The Ministry of Natural Resources and Environment(No.TNMT.2022.05.04).
文摘Synthetic plastics are often considered to be materials that cannot be broken down by natural processes.One such plastic,polyethylene terephthalate(PET),is commonly used in everyday items but when these products are discarded,they can cause serious harm to the environment and human health.In this study,PET plastic waste was used to create activated carbon using a physical activation process that involved using CO2 gas.The researchers investigated the effects of different temperatures,carbonization,and activation times on the resulting activated carbon’s surface area.The activated carbon was then analyzed using scanning electron microscopy(SEM),X-ray diffraction(XRD),FTIR,and BET.The activated carbon created from PET plastic waste showed excellent absorption properties for methylene blue in aqueous solutions across a wide range of pH levels.By creating activated carbon from plastic waste,not only are environmental issues addressed,but high-value activated carbon is produced for environmental remediation purposes.
基金National Natural Science Foundation of China(No.51774331)Funds for Nationsl&Local Joint Engineering Research Center of Mineral Salt Deep Utilization(No.SF202103).
文摘Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”
文摘Wollastonite, a mineral of wide industrial applications was synthesised from rice husk ash silica and limestone. A number of raw batches consisting of these starting materials, in 1:1 molar ratio, were heat treated to produce it through solid state reaction from 900℃ to 1300℃. The conducted reaction was monitored by XRD step by step. Amount of Wollastonite formed at every temperature was also studied to some extent. Analyses of the obtained data indicated that the target mineral formation was quite effective and almost proportional to a rise in temperature up to 1200℃. The results from both, XRD and chemical analysis were found in fair agreement with one another
基金Sponsored by the Ministerial Level Advanced Research Foundation(20060013)
文摘Combining the characteristics of the black pulping liquor that contains a lot of lignin and other biomass resources, the technology of comprehensive waste utilization is employed. The reconstructive preparation of modified urea-formaldehyde glue by adding black pulping liquor and the application in extruding the medium density fibre board using this modified urea-formaldehyde glue is researched. Results show that when applying the preparation technology that alkaline reaction and then weak acid reaction, the appropriate preparation process is as follows： the adding urea process is divided into three stages （proportion 2 ： 1 ： 1） ; the pH value is 8.0, and the reaction time is 40 min in the addition reaction stage; the pH value will be naturally reduced to 3.5 -5.0, and the reaction time is 45 min in the aggregation reaction stage; the pH value is 8.0 in the urea complement stage. And the optimal condition of the reconstructive preparation the modified ureaformaldehyde glue is adding the condensed black pulping liquor after hydroxymethylation in the beginning of polycondensation reaction by 5% proportion. The application in extruding medium density fibre board with this modified urea-fosmaldehyde glue is proved feasible.
文摘Water supply project of drawing from the Songhua River in central cities of Jilin is taken as research object.On the basis of analyzing project characteristics and natural conditions of the project area,site selection of waste slag yard of water diversion project and design of water and soil conservation measures are discussed.Rationality of site selection of waste slag yard and pertinence of prevention and control measures of water and soil loss in waste slag yard are analyzed,and comprehensive utilization of waste slag in large-scale production and construction projects is explored.
基金supported by Major science and technology projects of Gansu Province(22ZD6GA008,22ZD6GA014)National Natural Science Foundation of China(52304368,52164034)+2 种基金Science and Technology Project of Gansu Province(Postdoctoral project at the station)(23JRRA781,23JRRA812)Science and Technology Project of Gansu Province(Special Project of Science and Technology Specialist)(23CXGA0068)The Tamarisk Outstanding Young Talents Program of Lanzhou University of Technology.The 74th batch of China Postdoctoral Science Foundation(Regional Special Support Program)(2023MD744218).
文摘The electricity demand is increasing rapidly with the development of society and technology.Coal-fired thermal power plants have become one of the primary sources of electricity generation for urbanization.However,coal-fired thermal power plants produce a great amount of by-product coal fly ash every year.Coal fly ash disposal in landfills requires a sizable space and has negative environmental impacts.Therefore,it is crucial to develop new technologies and methods to utilize this enormous volume of solid waste in order to protect the environment.In this review,the fundamental physical and chemical character-istics of coal fly ash are introduced,and afterward the disposal policies and utilization ways of coal fly ash are discussed to gain a comprehensive understanding of the various ways this waste.The leaching of valuable metals in coal fly ash and the extraction of metal elements in leachate under different conditions are also summarized.Furthermore,the possibility of coal fly ash to serve as a supplementary source for mineral resources is analyzed,providing a basis for its extensive use as a raw material in the metal industry in China and worldwide.
基金Project(22178392)supported by the National Natural Science Foundation of China。
文摘Preparation of high purity ruthenium nitrosyl nitrate using spent Ru-Zn/ZrO_(2)catalyst was studied,including melting and leaching to obtain potassium ruthenate solution,reduction,dissolving,concentrating and drying to obtain ruthenium trichloride,nitrosation and hydrolysis to obtain ruthenium nitrosyl hydroxide,removing of K^(+)and Cl^(-),and neutralization with nitric acid.The effects of temperature,concentration,time and pH on the yield and purity of intermediates and final product were studied,and the optimum process conditions were obtained.The yield of ruthenium nitrosyl nitrate is 92%,the content of ruthenium in high purity product is 32.16%,and the content of Cl^(-)and K^(+)are much less than 0.005%.The reaction kinetics of ruthenium nitrosyl chloride to ruthenium nitrosyl hydroxide was studied.The reaction orders of Ru(NO)Cl_(3)at 40,55 and 70℃are 0.39,0.37 and 0.39,respectively,while those of KOH are 0.16,0.15 and 0.17,respectively.The activation energy is-2.33 k J/mol.
文摘Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save energy and water in the slag flushing process of blast furnaces,an ideal comprehensive cascade utilization system scheme for annual recovery of waste heat is proposed.Based on the measured waste heat data of a steel plant,design calculations are carried out to further analyze the economic feasibility of the new scheme and provide reference for its promotion and application.
