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cementitious property of NaAlO2-activated Ge slag as cement supplement

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International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1594-1603页

作者： Hua-zhe Jiao Shu-fei Wang Ai-xiang Wu Hui-ming Shen Jian-dong Wang International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention Henan Polytechnic UniversityJiaozuo 454000China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

Germanium(Ge),a waste residue leaching from zinc(Zn)smelting process,has potential cementitious properties and could be recycled as a cement supplement activated by chemical *** this work,a test was conducted to determine the hydration properties of Ge slag-cement-based composites with Ge slag(GS)/ordinary Portland cement(PC)contents of 0wt%,5wt%,10wt%,15wt%,20wt%,and 25wt% and water-to-binder ratio(w/b)of *** activators Ca(OH)2,AlCl3,NaAlO2,and Na2CO3 were mixed under 1wt%,2wt%,3wt%,and 4wt% dosages of GS *** composition and microstructure of the hydration products were investigated by the combined approaches of X-ray diffraction(XRD),thermogravimetry-differential scanning calorimetry(TG-DSC),scanning electron microscopy(SEM),and energy-dispersive X-ray spectroscopy(EDS).First,the GS cementitious property is attributed to the high content of CaSO4·***,the activators affected the acceleration performance in the following order:NaAlO2,Na2CO3,AlCl3,and Ca(OH)*** importantly,the 28-day unconfined compressive strength(UCS)is 45.34 MPa at the optimum formula of 0.6wt% NaAlO2,15wt% GS,and 85wt% PC,which is 9.16% higher than the ***,NaAlO2 is beneficial for the ettringite(AFt)generation,resulting in the C-S-H structure ***,the Zn^2+ residue inhibited the AFt formation,representing an important challenge to the strength growth with curing ***,the GS could be recycled as a supplement to the cement under the activator NaAlO2.

关键词： Ge slag from zinc process recycling activator cement supplements strength

Carbon uptake by cement in China:Estimation and contribution to carbon neutrality goals

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Science China Earth Sciences 2024年第6期67卷 2056-2067页

作者： Mingjing MA Zi HUANG Jiaoyue WANG Le NIU Wenfeng ZHANG Xiaowei XU Fengming XI Zhu LIU Institute of Applied Ecology Chinese Academy of SciencesShenyang 110016China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Department of Earth System Science Tsinghua UniversityBeijing 100084China Department of Engineering Science University of OxfordOxfordOX13UK

cement is a widely used construction material *** manufacturing contributes to anthropogenic CO_(2)emissions ***,its alkaline compounds can absorb CO_(2)from the surrounding environment and engage in a carbonation reaction,thereby functioning as a carbon *** a major cement producer and consumer,China has an important responsibility to rigorously investigate and accurately account for cement carbon *** study presents a comprehensive analytical model of cement carbon uptake from China,revealing a substantial increase in carbon uptake from 1930 to 2021,peaking at 426.77 Mt CO_(2)(95% Confidence Interval:317.67-874.33 Mt CO_(2))in *** uptake accounts for 8.10% to 45.40% of China’s annual land sink and 2.51% to 4.54% of the global land *** cumulative carbon uptake by cement is approximately 7.06 Gt CO_(2)(95%CI:5.22–9.44 Gt CO_(2))during this period,offsetting 50.7% of the total emissions(13.91 Gt CO_(2),95%CI:12.44–17.00 Gt CO_(2))from the cement ***,cement mortar contributed to most absorption(65.64%).From a life cycle perspective,the service stage of cement materials is the period where the largest CO_(2)sink is formed,accounting for 90.03% of the ***,the potential for carbon sequestration in cement materials and their waste is ***,the model improves the accuracy of cement carbon accounting,supporting both China and global carbon neutrality ***,it is crucial for China to achieve its carbon neutrality goals sooner by prioritizing the environmental benefits of cement materials and wastes,and accelerating the development and commercialization of CO_(2)sequestration technologies for cement and its by-products.

关键词： cement Carbon uptake Life cycle assessment Carbon emission reduction Carbon neutrality

Calibration curve and support vector regression methods applied for quantification of cement raw meal using laser-induced breakdown spectroscopy

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Plasma Science and Technology 2019年第3期21卷 23-30页

作者： Junwei JIA Hongbo FU Zongyu HOU Huadong WANG Zhibo NI Fengzhong DONG Anhui Provincial Key Laboratory of Photonic Devices and Materials Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences University of Science and Technology of China State Key Lab of Power Systems Department of Thermal Engineering Tsinghua-BP Clean Energy Center Tsinghua University

Laser-induced breakdown spectroscopy(LIBS) is a qualitative and quantitative analytical technique with great potential in the cement industrial analysis. Calibration curve(CC) and support vector regression(SVR) methods coupled with LIBS technology were applied for the quantification of three types of cement raw meal samples to compare their analytical concentration range and the ability to reduce matrix effects, respectively. To reduce the effects of fluctuations of the pulse-to-pulse, the unstable ablation and improve the reproducibility, all of the analysis line intensities were normalized on a per-detector basis. The prediction results of the elements of interest in the three types of samples, Ca, Si, Fe, Al, Mg, Na, K and Ti, were compared with the results of the wet chemical analysis. The average relative error(ARE),relative standard deviation(RSD) and root mean squared error of prediction(RMSEP) were employed to investigate and evaluate the prediction accuracy and stability of the two prediction methods. The maximum average ARE of the CC and SVR methods is 34.62% instead of 6.13%,RSD is 40.89% instead of 7.60% and RMSEP is 1.34% instead of 0.43%. The results show that SVR method can accurately analyze samples within a wider concentration range and reduce the matrix effects, and LIBS coupled with it for a rapid, stable and accurate quantification of different types of cement raw meal samples is promising.

关键词： cement raw meal calibration curves SVR LIBS

Development of a Laboratory cement Quality Analysis Apparatus Based on Laser-Induced Breakdown Spectroscopy

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Plasma Science and Technology 2015年第11期17卷 897-903页

作者：樊娟娟张雷王鑫李郁芳弓瑶董磊马维光尹王保王哲李政张向杰李逸贾锁堂 State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi University State Key Lab of Power Systems Department of Thermal EngineeringTsinghua-BP Clean Energy CenterTsinghua University Taiyuan Amethyst Technology Co. Ltd. Shanxi Zhongtiaoshan New Building Materials Co. Ltd.

Determination of the chemical composition of cement and ratio values of clinker plays an important role in cement plants as part of the optimal process control and product quality evaluation. In the present paper, a laboratory laser-induced breakdown spectroscopy （LIBS） apparatus mainly comprising a sealed optical module and an analysis chamber has been designed for possible application in cement plants for on-site quality analysis of cement. Emphasis is placed on the structure and operation of the LIBS apparatus, the sealed optical path, the temperature controlled spectrometer, the sample holder, the proper calibration model established for minimizing the matrix effects, and a correction method proposed for overcoming the ＇drift＇ obstacle. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The absolute measurement errors presented here for oxides analysis are within 0.5%, while those of ratio values are in the range of 0.02 to 0.05. According to the obtained results, this laboratory LIBS apparatus is capable of performing reliable and accurate, composition and proximate analysis of cement and is suitable for application in cement plants.

关键词： laser-induced breakdown spectroscopy LIBS cement composition analysis,proximate analysis ratio values linear correction method

Mg-P/c-SWCNT Bone cement: The Effect of Filler on Setting Behavior,Compressive Strength and Biocompatibility

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Journal of Bionic Engineering 2020年第1期17卷 100-112页

作者： Mohammad Hossein Esnaashary Alireza Khavandi Hamid Reza Rezaie Jafar Javadpour School of Metallurgical and Materials Engineering Iran University of Science and TechnologyNarmakTehran 16844Iran

Improving the strength of bone cement is one of the critical goals in cement designing to maintain their integrity and stabilize connection between the cement and their surrounding tissue during the time that the cement has been replaced by matured bone *** this aim,the authors decided to evaluate setting behavior and compressive strength of Magnesium Phosphate cement(MPC)by adding carboxylated Single-Walled Carbon Nanotubes(c-SWCNTs)and assess the biocompatibility of the composite *** containing 0 wt%to 0.5 wt% of c-SWCNTs at the Powder to Liquid Ratio(PLR)of 1 g·mL^-1 to 2 g·mL^-1 were *** c-SWCNTs to MPC postponed the setting time of the cement at the beginning of the cementation process and preserved the reaction with a high rate for a longer *** addition,the compressive strength of MPC was enhanced to 28 MPa by adding 0.2 wt%c-SWCNTs because of producing cement with compact and uniform *** addition,cell behavior on MPC with/without c-SWCNTs indicated no cytotoxic effect alongside a suitable adhesion and proliferation of them.

关键词： magnesium phosphate cement carbon nanotube compressive strength MTT bone cement biocompatibility

cement industry control system based on multi agent

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Journal of Central South University of Technology 2004年第1期11卷 41-44页

作者：王海东邱冠周黄圣生 School of Resources Process and Bioengineering Central South University Changsha 410083 China

cement production is characterized by its great capacity, long-time delay, multi variables, difficult measurement and multi disturbances. According to the distributed intelligent control strategy based on the multi (agent,) the multi agent control system of cement production is built, which includes integrated optimal control and diagnosis control. The distributed and multiple level structure of multi agent system for the cement control is studied. The optimal agent is in the distributed state, which aims at the partial process of the cement production, and forms the optimal layer. The diagnosis agent located on the diagnosis layer is the diagnosis unit which aims at the whole process of the cement production, and the central management unit of the system. The system cooperation is realized by the communication among optimal agents and diagnosis agent. The architecture of the optimal agent and the diagnosis agent are designed. The detailed functions of the optimal agent and the diagnosis agent are analyzed. At last the realization methods of the agents are given, and the application of the multi agent control system is presented. The multi agent system has been successfully applied to the off-line control of one cement plant with capacity of 5 000 t/d. The results show that the average yield of the clinker increases 9.3% and the coal consumption decreases 7.5 kg/t.

关键词： agent multi agent system cement production process control

Utilization of MSWI fly ash as partial cement or sand substitute with focus on cementing efficiency and health risk assessment

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Frontiers of Environmental Science & Engineering 2020年第1期14卷 87-97页

作者： Lei Zheng Xingbao Gao Wei Wang Zifu Li Lingling Zhang Shikun Cheng School of Energy and Environmental Engineering University of Science and Technology Beijing.Beijing 100083China Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China School of Environment Tsinghua UniversityBeijing 100084China

The strength of cement substituted mortar decreases with the increase in fly ash amount,whereas the strength increases when the fly ash is blended as sand substitute.A mortar with highest strength(compressive strength=30.2 Mpa;flexural strength=7.0 Mpa)was obtained when the sand replacement ratio was 0.75%.The k value(cementing efficiency)of fly ash varied between 0.36 and 0.15 for the fly ash fraction in binder between 5%and 25%.The k values of fly ash used for sand replacement were all significantly above that used for cement *** macropores assigned to the gaps between particles decreased when the fly ash was used as sand replacement,providing an explanation for the strength *** waste-extraction procedure(toxicity-sulphuric acid and nitric acid method(HJ/T 299-2007))was used to evaluate metal leaching,indicating the reuse possibility of fly ash blended *** the mortar with the mass ratio of fly ash to binder of 0.5%,the carcinogenic risks(CR)and non-carcinogenic hazard quotient(HQ)in sensitive scenario for blended mortar utilization were 9.66 x 10 and 0.06,respectively;these results were both lower than the threshold values,showing an acceptable health *** CR(9.89 x 105)and HQ(3.89)of the nonsensitive scenario for fly ash treatment exceeded the acceptable threshold values,indicating health risks to onsite *** main contributor to the carcinogenic and non-carcinogenic risk is Cr and Cd,*** CR and HQ from inhalation was the main route of heavy metal exposure.

关键词： MSWI fly ash cementing efficiency Health risk assessment of heavy metal Sand replacement cement replacement

Recent developments in the application of oil palm fibers in cement composites

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 94-108页

作者： Emmanuel Owoichoechi MOMOH Adelaja Israel OSOFERO School of Engineering University of AberdeenAberdeenAB243UEUK

Fibers obtained from different parts of the oil palm tree(Elaeis guineensis)have been under investigation for possible use in *** have been carried out investigating the engineering properties and possible applications of these ***,the experimental methods employed and the values of mechanical and physical properties recorded by various authors are *** has therefore become necessary to organize information which would be useful in the design of oil palm fiber cement composites and help researchers and engineers make informed decisions in further research and *** review provides information about fibers from different parts of the oil palm,their properties,enhancement techniques,current and potential application in cement composites.

关键词： broom cement composite concrete oil palm fiber Natural fiber-concrete sustainability

Brominated dioxins and furans in a cement kiln co-processing municipal solid waste

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Journal of Environmental Sciences 2019年第5期31卷 339-345页

作者： Lili Yang Yuyang Zhao Miwei Shi Minghui Zheng Yang Xu Cui Li Yuanping Yang Linjun Qin Guorui Liu State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences University of Chinese Academy of Sciences Hebei Engineering Research Center for Geographic Information Application Institute of Geographical Sciences Hebei Academy of Sciences

A field study and theoretical calculations were performed to clarify the levels, profiles, and distributions of polybrominated dibenzo-p-dioxins and dibenzofurans(PBDD/Fs) in a cement kiln co-processing solid waste, with a focus on the PBDF formation *** raw materials contributed greatly to input of PBDD/Fs into the cement kiln. The PBDD/F concentrations in the raw materials were much higher than those in particle samples from different process stages in the cement kiln. The PBDD/F concentrations in the clinkers were1.40% of the concentrations in the raw materials, which indicated that the high destruction efficiencies for PBDD/Fs by cement kiln. PBDD/F distribution patterns in particle samples collected from different process stages indicated the cement kiln backend was a major site for PBDD/F formation. PBDFs with high levels of halogenation, such as heptabrominated furans(Hp BDF), were the dominant contributors to the total PBDD/F concentrations and accounted for 42%–73% of the total PBDD/F concentrations in the particle samples. Our results showed that co-processing of municipal solid waste in a cement kiln may influence the congener profile of PBDD/Fs, especially for the higher halogenated PBDD fraction. In addition, there were significant correlations between the decabromodiphenyl ether and heptabrominated furan concentrations, which is an indicator of transformation from polybrominated diphenyl ethers to PBDD/Fs. Theoretical calculations were performed and demonstrated that elimination of HBr and Br_2 from polybrominated diphenyl ethers were the dominant formation pathways for PBDD/Fs. These pathways differed from that for polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs).

关键词： Polybrominated dibenzo-p-dioxin and dibenzofuran(PBDD/F) cement kiln Municipal solid waste Dioxin Formation mechanism