The preparation of sulfoaluminate cementitious materials(SCM)is a promising way to massively utilize solid wastes.Iron phases are significant in SCM system but the thermodynamic data of some key minerals,such as6 CaO&...The preparation of sulfoaluminate cementitious materials(SCM)is a promising way to massively utilize solid wastes.Iron phases are significant in SCM system but the thermodynamic data of some key minerals,such as6 CaO·Al2 O3·2 Fe2 O3(C6 AF2)and 6 CaO·2 Al2 O3·Fe2 O3(C6 A2 F),are missing,which greatly hinders the SCM optimization in a theoretical way.This work,for the first time,calculated the standard formation enthalpy,Gibbs free energy of formation,entropy and molar heat capacity for C6 AF2 and C6 A2 F and lowered the errors to the least with the reference of C4 AF data in the literature.By building the function diagram of Gibbs free energy changes with temperature for the basic iron phase formation reactions with the obtained thermodynamic data,it is proved that the formation likeliness of C6 AF2 is higher than that of C6 A2 F,as is accordant to the literatures and verifies the correctness of obtained data.This work provides a good theoretical foundation to optimize SCM mineral system and to study relevant mechanism deeply.展开更多
The behavior of soluble salts contained in the municipal solid waste incinerator(MSWI) ash significantly affects the strength development and hardening reaction when stabilized with cement.The present study focuses on...The behavior of soluble salts contained in the municipal solid waste incinerator(MSWI) ash significantly affects the strength development and hardening reaction when stabilized with cement.The present study focuses on the compaction and strength behavior of mixed specimens of cement and MSWI ash.A series of indices such as unconfined compressive strength,split tensile strength,California bearing ratio(CBR) and pH value was examined.Prior to this,the specimens were cured for 7 d,14 d,and 28 d.The test results depict that the maximum dry density(MDD) decreases and the optimum moisture content(OMC)increases with the addition of cement.The test results also reveal that the cement increases the strength of the mixed specimens.Thus,the combination of MSWI ash and cement can be used as a lightweight filling material in different structures like embankment and road construction.展开更多
Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-i...Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid waste disposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results show that (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still be used in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement, and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard (GB 16297-1996).展开更多
城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作...城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作性能、力学性能和耐久性能的影响。此外,本工作还表征了GM的微观孔结构和微观形貌。最后,本工作通过分析1 m 3GM的能耗、碳排放、生产成本,评估了MSWIFA替代水泥制备GM的经济、社会和生态效益。研究表明:(1)MSWIFA的掺入导致GM的抗折强度、抗压强度分别降低了10.54%~29.97%、18.74%~39.54%;(2)硅酸盐水泥可以固化MSWIFA,GM的重金属浸出满足国家规定限值;(3)当MSWIFA的替代率为15%时,1 m 3GM的能耗、碳排放、生产成本分别降低14.90%、14.63%、10.36%,而其工作性能、力学性能、耐久性依然能够满足建筑砂浆要求,表明采用MSWIFA制备GM能够实现该固体废弃物的资源化利用,具有巨大的经济、社会和生态效益。展开更多
基金Supported by the Program for National Key R&D Plan(2017YFC0703100).
文摘The preparation of sulfoaluminate cementitious materials(SCM)is a promising way to massively utilize solid wastes.Iron phases are significant in SCM system but the thermodynamic data of some key minerals,such as6 CaO·Al2 O3·2 Fe2 O3(C6 AF2)and 6 CaO·2 Al2 O3·Fe2 O3(C6 A2 F),are missing,which greatly hinders the SCM optimization in a theoretical way.This work,for the first time,calculated the standard formation enthalpy,Gibbs free energy of formation,entropy and molar heat capacity for C6 AF2 and C6 A2 F and lowered the errors to the least with the reference of C4 AF data in the literature.By building the function diagram of Gibbs free energy changes with temperature for the basic iron phase formation reactions with the obtained thermodynamic data,it is proved that the formation likeliness of C6 AF2 is higher than that of C6 A2 F,as is accordant to the literatures and verifies the correctness of obtained data.This work provides a good theoretical foundation to optimize SCM mineral system and to study relevant mechanism deeply.
文摘The behavior of soluble salts contained in the municipal solid waste incinerator(MSWI) ash significantly affects the strength development and hardening reaction when stabilized with cement.The present study focuses on the compaction and strength behavior of mixed specimens of cement and MSWI ash.A series of indices such as unconfined compressive strength,split tensile strength,California bearing ratio(CBR) and pH value was examined.Prior to this,the specimens were cured for 7 d,14 d,and 28 d.The test results depict that the maximum dry density(MDD) decreases and the optimum moisture content(OMC)increases with the addition of cement.The test results also reveal that the cement increases the strength of the mixed specimens.Thus,the combination of MSWI ash and cement can be used as a lightweight filling material in different structures like embankment and road construction.
文摘Destruction of industrial waste in cement rotary kilns (CRKs) is an alternative technology for the treatment of certain types of industrial waste (IW). In this paper, three typical types of industrial wastes were co-incinerated in the CRK at Beijing Cement Plant to determine the effects of waste disposal (especially solid waste disposal) on the quality of clinker and the concentration of pollutants in air emission. Experimental results show that (1) waste disposal does not affect the quality of clinker and fly ash, and fly ash after the IW disposal can still be used in the cement production, (2) heavy metals from IW are immobilized and stabilized in the clinker and cement, and (3) concentration of pollutants in air emission is far below than the permitted values in the China National Standard-Air Pollutants Emission Standard (GB 16297-1996).
文摘城市生活垃圾焚烧飞灰(MSWIFA)是城市生活垃圾焚烧产生的副产品之一,处理不当会导致严重的环境问题。采用MSWIFA部分替代水泥制备绿色水泥砂浆(GM)能够实现MSWIFA在建筑材料中的资源化利用。本工作主要研究不同替代率的MSWIFA对GM工作性能、力学性能和耐久性能的影响。此外,本工作还表征了GM的微观孔结构和微观形貌。最后,本工作通过分析1 m 3GM的能耗、碳排放、生产成本,评估了MSWIFA替代水泥制备GM的经济、社会和生态效益。研究表明:(1)MSWIFA的掺入导致GM的抗折强度、抗压强度分别降低了10.54%~29.97%、18.74%~39.54%;(2)硅酸盐水泥可以固化MSWIFA,GM的重金属浸出满足国家规定限值;(3)当MSWIFA的替代率为15%时,1 m 3GM的能耗、碳排放、生产成本分别降低14.90%、14.63%、10.36%,而其工作性能、力学性能、耐久性依然能够满足建筑砂浆要求,表明采用MSWIFA制备GM能够实现该固体废弃物的资源化利用,具有巨大的经济、社会和生态效益。
