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
Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ...Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ore and red mud. A ferronickel product of 1.98wt% nickel and 87.98wt% iron was obtained with 20wt% petroleum coke, when the roasting temperature and time was 1250°C and 60 min, respectively. The corresponding recoveries of nickel and total iron were 99.54wt% and 95.59wt%, respectively. Scanning electron microscopy-energy dis- persive spectrometry (SEM-EDS) analysis showed metallic nickel and iron mainly existed in the form of ferronickel particles which distrib- uted uniformly at a size of approximately 30 μm with high purity. This study demonstrated that petroleum coke is a promising reductant in the co-reduction of laterite ore and red mud. Compared to other alternatives, petroleum coke is advantageous with reduced production cost and high applicability in anthracite-deficient areas.展开更多
The purpose of this paper was using gold mine tailings and cemented materials with low alkalinity to fabricate baking-free bricks.The obtained baking-free brick samples were evaluated by unconfined compressive strengt...The purpose of this paper was using gold mine tailings and cemented materials with low alkalinity to fabricate baking-free bricks.The obtained baking-free brick samples were evaluated by unconfined compressive strength(UCS),water absorption percentage,freezing-thawing cycle,and drying-wetting cycle.The microstructures of the baking-free brick samples were analyzed using X-ray diffraction(XRD)and scanning electron microscope(SEM)techniques.The baking-free brick specimens cured for 28 days with the addition of 10%mixing water consumption and 1:6 cement/tailing ratio tended to obtain favorable comprehensive properties such as a high compressive strength of 15.15 MPa,a low water absorption percentage of 11.8%,excellent freezing-thawing resistance with a 8.9%UCS loss rate after 15 freezing-thawing cycles and good drying-wetting resistance with a 11%UCS loss rate after 10 drying-wetting cycles.The XRD and SEM test results verified that different kinds of hydrate products including C-S-H and C-S-A-H gels,and ettringite were produced during hydration process,which were responsible for good physical,mechanical properties,and durability of the obtained baking-free bricks.Therefore,the experimental results showed that it was practical and reasonable to utilize the homemade cementitious materials in our laboratory to stabilize the gold tailings for production of baking-free bricks,which still met the requirements of major regional construction standards in some countries.展开更多
Ultrafine steel slag powder(shield powder)was prepared by grinding ordinary steel slag with a functional compound.As a substitute for aluminum hydroxide,the shield powder was combined with rubber to prepare flame-reta...Ultrafine steel slag powder(shield powder)was prepared by grinding ordinary steel slag with a functional compound.As a substitute for aluminum hydroxide,the shield powder was combined with rubber to prepare flame-retardant composites.Vulcanization tests showed that the incorporation of shield powder enhances the crosslinkage of the composite and speeds up the curing rate.The gaseous products formed in the pyrolysis process are mainly hydrocarbons.Mechanical and combustion tests revealed that the introduction of shield powder improves flame-retardant performance without sacrificing mechanical properties.Specifically,the optimum substitution ratio of shield powder for aluminum hydroxide is 50.0%.In this case,the composite has the highest degree of graphitization and exhibits excellent flame-retardant performance.展开更多
Red mud(RM),as an alkaline waste,was recently proved to be a promising substitute for the SCR catalyst.Dealkalization could improve the acidity and reducibility of red mud,which were critical for SCR reaction.However,...Red mud(RM),as an alkaline waste,was recently proved to be a promising substitute for the SCR catalyst.Dealkalization could improve the acidity and reducibility of red mud,which were critical for SCR reaction.However,the dealkalization effect depended on the reaction between acid solution and red mud.In this study,we realized the directional control of the chemical state of active sites through tuning the acid pretreatment(dealkalization)process.The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid.When the pH values of red mud were 3 and 5(CRM-3 and CRM-5),activated catalysts showed NOx conversion above 90%at 275℃–475℃.The high initial reaction rate,Ce^(3+)/(Ce^(3+)+Ce^(4+))ratio,and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst.Meanwhile,more Fe^(3+) on the CRM-3 surface improved the NH_(3) adsorption.There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts.DFT results showed that the adsorption capacity of the Al-O_(3)-Fe for NH_(3) and NO is stronger than that of Fe-O_(3)-Fe,which enhanced the NOx conversion of the catalyst.However,the almandine was formed in CRM-4,consumed part of Fe^(3+) and Al^(3+),and the interaction between Al and Fe was weakened.Also,deposited almandine on the catalyst surface covered the active sites,thus leading to lower NH_(3)-SCR activity.展开更多
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.”
基金the National Nat-ural Science Foundation of China(No.51874017).
文摘Petroleum coke is industrial solid wastes and its disposal and storage has been a great challenge to the environment. In this study, petroleum coke was utilized as a novel co-reduction reductant of low-grade laterite ore and red mud. A ferronickel product of 1.98wt% nickel and 87.98wt% iron was obtained with 20wt% petroleum coke, when the roasting temperature and time was 1250°C and 60 min, respectively. The corresponding recoveries of nickel and total iron were 99.54wt% and 95.59wt%, respectively. Scanning electron microscopy-energy dis- persive spectrometry (SEM-EDS) analysis showed metallic nickel and iron mainly existed in the form of ferronickel particles which distrib- uted uniformly at a size of approximately 30 μm with high purity. This study demonstrated that petroleum coke is a promising reductant in the co-reduction of laterite ore and red mud. Compared to other alternatives, petroleum coke is advantageous with reduced production cost and high applicability in anthracite-deficient areas.
基金the Key Research and Development Program of Anhui Province(No.202004a07020039).
文摘The purpose of this paper was using gold mine tailings and cemented materials with low alkalinity to fabricate baking-free bricks.The obtained baking-free brick samples were evaluated by unconfined compressive strength(UCS),water absorption percentage,freezing-thawing cycle,and drying-wetting cycle.The microstructures of the baking-free brick samples were analyzed using X-ray diffraction(XRD)and scanning electron microscope(SEM)techniques.The baking-free brick specimens cured for 28 days with the addition of 10%mixing water consumption and 1:6 cement/tailing ratio tended to obtain favorable comprehensive properties such as a high compressive strength of 15.15 MPa,a low water absorption percentage of 11.8%,excellent freezing-thawing resistance with a 8.9%UCS loss rate after 15 freezing-thawing cycles and good drying-wetting resistance with a 11%UCS loss rate after 10 drying-wetting cycles.The XRD and SEM test results verified that different kinds of hydrate products including C-S-H and C-S-A-H gels,and ettringite were produced during hydration process,which were responsible for good physical,mechanical properties,and durability of the obtained baking-free bricks.Therefore,the experimental results showed that it was practical and reasonable to utilize the homemade cementitious materials in our laboratory to stabilize the gold tailings for production of baking-free bricks,which still met the requirements of major regional construction standards in some countries.
基金supported by the University Synergy Innovation Program of Anhui Province(GXXT-2020-072)Anhui Province Science Foundation for Excellent Young Scholars(2208085J19).
文摘Ultrafine steel slag powder(shield powder)was prepared by grinding ordinary steel slag with a functional compound.As a substitute for aluminum hydroxide,the shield powder was combined with rubber to prepare flame-retardant composites.Vulcanization tests showed that the incorporation of shield powder enhances the crosslinkage of the composite and speeds up the curing rate.The gaseous products formed in the pyrolysis process are mainly hydrocarbons.Mechanical and combustion tests revealed that the introduction of shield powder improves flame-retardant performance without sacrificing mechanical properties.Specifically,the optimum substitution ratio of shield powder for aluminum hydroxide is 50.0%.In this case,the composite has the highest degree of graphitization and exhibits excellent flame-retardant performance.
基金financially supported by the National Natural Science Foundation of China(Grant No.21906090)the National Key Research and Development Program of China(Nos.2017YFC0210200 and 2017YFC0212800)+1 种基金the Primary Research&Development Project of Shandong Province(China)(Nos.2018GSF117034 and 2019JZZY020305)The scientific calculations in this paper have been done on the HPC Cloud Platform of Shandong University(China).
文摘Red mud(RM),as an alkaline waste,was recently proved to be a promising substitute for the SCR catalyst.Dealkalization could improve the acidity and reducibility of red mud,which were critical for SCR reaction.However,the dealkalization effect depended on the reaction between acid solution and red mud.In this study,we realized the directional control of the chemical state of active sites through tuning the acid pretreatment(dealkalization)process.The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid.When the pH values of red mud were 3 and 5(CRM-3 and CRM-5),activated catalysts showed NOx conversion above 90%at 275℃–475℃.The high initial reaction rate,Ce^(3+)/(Ce^(3+)+Ce^(4+))ratio,and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst.Meanwhile,more Fe^(3+) on the CRM-3 surface improved the NH_(3) adsorption.There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts.DFT results showed that the adsorption capacity of the Al-O_(3)-Fe for NH_(3) and NO is stronger than that of Fe-O_(3)-Fe,which enhanced the NOx conversion of the catalyst.However,the almandine was formed in CRM-4,consumed part of Fe^(3+) and Al^(3+),and the interaction between Al and Fe was weakened.Also,deposited almandine on the catalyst surface covered the active sites,thus leading to lower NH_(3)-SCR activity.
