scholarly journals Effects of high salinity wastewater on the properties of coal gasification residue-based cementitious material

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4161-4169
Author(s):  
Feng Wu ◽  
Hui Li
Keyword(s):  
Coal Gasification ◽  
High Salinity ◽  
Tap Water ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Raw Material ◽  
Strength Development ◽  
The Sustainable Development ◽  
Salinity Wastewater ◽  
Mixing Water

High salinity wastewater and coal gasification residue are the by-products which need to be utilized as resources for the sustainable development of coal-to-chemicals technology. Using coal gasification residue as the main raw material, supplemented with 10% Portland cement, and high salinity wastewater as the mixing water instead of tap water to prepare cementitious materials. The XRD, TG-DTG, FTIR, SEM, and MIP were used to analyze the influence mechanism of high salinity wastewater on the properties of cementitious materials. The results show that high salinity wastewater was beneficial to the strength development of the cementitious material. When 25% high salinity mastewater was used instead of tap water, the enhancing rates of compressive strength was 294%, 177%, and 186% curing at 3, 7, and 28 days. This is main due to the sulfate and chloride in the high salinity wastewater can promote the formation of C-S-H gels, Friedel?s, salts and C-A-S-H gels in the hydration process of pastes, which can promote the densification of structure. The pores distribution and structure were optimized, increasing the proportion of capillary pores and decreasing macropore to promote the micro-structure more dense. This study can provide a new idea for the comprehensive utilization of industrial waste and achieve the purpose of ?waste control by waste?.

scholarly journals Coupled Preparation of Ferronickel and Cementitious Material from Laterite Nickel Ores

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4992
Author(s):  
Ruimeng Shi ◽  
Xiaoming Li ◽  
Yaru Cui ◽  
Junxue Zhao ◽  
Chong Zou ◽  
...  
Keyword(s):  
Direct Reduction ◽  
Cementitious Materials ◽  
Tricalcium Silicate ◽  
Cementitious Material ◽  
Raw Material ◽  
Tricalcium Aluminate ◽  
Thermodynamic Conditions ◽  
Nickel Ores ◽  
Main Components ◽  
Factsage Software

Nickel slags can be produced through ferronickel preparation by the pyrometallurgical processing of laterite nickel ores; however, such techniques are underutilized at present, and serious environmental problems arise from the stockpiling of such nickel ores. In this study, a modification to the process of ferronickel preparation by the direct reduction of carbon bases in laterite nickel ores is proposed. The gangue from the ore is used as a raw material to prepare a cementitious material, with the main components of tricalcium silicate and tricalcium aluminate. By using FactSage software, thermodynamic calculations are performed to analyze the reduction of nickel and iron and the effect of reduction on the formation of tricalcium silicate and tricalcium aluminate. The feasibility of a coupled process to prepare ferronickel and cementitious materials by the direct reduction of laterite nickel ore and gangue calcination, respectively, is discussed under varying thermodynamic conditions. Different warming strategies are applied to experimentally verify the coupled reactions. The coupled preparation of ferronickel and cementitious materials with calcium silicate and calcium aluminate as the main phases in the same experimental process is realized.

The Experimental Study on Performance of the High-Content Slag Cementitious Materials

2013 ◽  
Vol 634-638 ◽  
pp. 311-316
Author(s):  
Ping Yang ◽  
Zhi Gui Qin ◽  
Wei Xia Zhao ◽  
Xi Nan Cai ◽  
Xiao Lin Yuang
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Mass Production ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Hydration Heat ◽  
Raw Material ◽  
Heat Temperature ◽  
Economic Profit ◽  
Easy Operation

The research adopts the raw material of 89% slag with the composite activators and the compressive strength, hydration heat, temperature and expansion property of the material are studied. And the new cementitious material is obtained with the properties of low-heat and small expansion, convenience-confect, easy-operation and need no mass production. This material has the remarkable economic profit and good application foreground especially in the mass grouting engineering.

scholarly journals Exploring Structural Evolution of Portland Cement Blended with Supplementary Cementitious Materials in Seawater

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1210
Author(s):  
Solmoi Park ◽  
Jun Kil Park ◽  
Namkon Lee ◽  
Min Ook Kim
Keyword(s):  
Portland Cement ◽  
Tap Water ◽  
Structural Evolution ◽  
Extended Period ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Main Reaction ◽  
Strength Development ◽  
Main Reaction Product ◽  
Reaction Degree

The present study investigated the structural evolution of Portland cement (PC) incorporating supplementary cementitious materials (SCMs) exposed to seawater. The samples were made with replacing Portland cement with 10 mass-% silica fume, metakaolin or glass powder. The reaction degree of SCMs estimated by the portlandite consumption shows that metakaolin has the highest reaction degree, thus metakaolin-blended PC exhibits the highest strength. The control exposed to seawater exhibited 14.82% and 12.14% higher compressive strengths compared to those cured in tap water at 7 and 28 days. The samples incorporating metakaolin showed the highest compressive strength of 76.60 MPa at 90 days tap water curing and this was 17% higher than that of the control. Exposure to seawater is found to retard the rate of hydration in all SCM-incorporating systems, while the strength development of the neat PC system is enhanced. The main reaction product that forms during exposure to seawater is Cl-AFm and brucite, while it is predicted by the thermodynamic modelling that a significant amount of M-S-H, calcite and hydrotalcite is to form at an extended period of exposure time.

scholarly journals Hydration and Strength Development of Cementitious Materials Prepared with Phosphorous-Bearing Clinkers

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 508
Author(s):  
Lilan Xie ◽  
Min Deng ◽  
Jinhui Tang ◽  
Kaiwei Liu
Keyword(s):  
Mechanical Properties ◽  
Raw Materials ◽  
Cementitious Materials ◽  
Raw Material ◽  
Strength Development ◽  
Hydration Reaction ◽  
Low Grade ◽  
Hydration Kinetics ◽  
Cement Pastes ◽  
The One

To rationally use low-grade phosphorous limestone as the raw materials for cement production, the influence of phosphorous introduced by fluorapatite during the clinker calcination process on the mechanical properties of cementitious materials is investigated. Hydration kinetics, phase evolutions, and microstructure of cement pastes have been studied by using calorimetry, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that the mechanical properties of cementitious materials can be slightly improved due to the mineralization effect of the small amount of phosphorous in the clinker and significantly decreased with an increase of phosphorous. High content of phosphorous will reduce the content of C3S and make the formation of α′-C2S-xC3P(x: 0–0.05), whose hydration reactivity is rather lower, such that on the one hand less-hydrated products, such as calcium silicate hydrate (C-S-H) gel, can be obtained, and on the other hand, the hydration reaction will be slowed by severely prolonging the induction period. Interestingly, small particles can be observed on the surface of hydration products, but no new phase can be detected by XRD. When the content of P2O5 is 2.0%, the cement can meet the requirements of P·II 42.5 cement in China. Hopefully, this can provide significant guidance for the use of cement prepared by fluorapatite as raw material.

Strength development monitoring and dynamic modulus assessment of cementitious materials using EMI-Miniature Prism based technique

2019 ◽  
Vol 19 (2) ◽  
pp. 373-389 ◽  
Author(s):  
Xubin Lu ◽  
Yee Yan Lim ◽  
Iman Izadgoshasb ◽  
Chee Kiong Soh
Keyword(s):  
Lead Zirconate Titanate ◽  
Dynamic Modulus ◽  
Model Updating ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Experimental Results ◽  
Strength Development ◽  
Fe Model ◽  
Curing Process ◽  
Electromechanical Impedance

Electromechanical impedance (EMI) technique provides an alternative means of characterizing strength development of early age concrete on a real-time basis. However, most existing studies employing the technique heavily rely on statistical tools for strength development characterization. This article proposes a new impedance-based approach to strength and dynamic modulus assessment of cementitious materials. In this approach, a lead zirconate titanate patch is surfaced-bonded on a customized cementitious material specimen, known as ‘Miniature Prism’, in which the conductance signatures throughout the curing process are acquired. A 3D coupled field finite element (FE) model is then developed to compute the conductance signatures and model updating is performed using the experimental results. The conductance signatures computed by the updated FE model are found to be in good agreement with experimental results. The key contribution of this approach is the use of ‘Miniature Prism’ which ensures consistency of the resonance peaks in the conductance spectrum between identical specimens. This has been very difficult, if not impossible, to achieve with the conventional EMI technique. This merit allows for modelling of the electromechanical system and hence parametrically predicting the dynamic modulus of elasticity of the cementitious material throughout the curing process. Comparative study is also conducted on various conventional and advanced techniques and results indicate that the proposed technique is effective in strength assessment of cementitious materials. In addition, the technique is suitable for autonomous online monitoring purpose, and thus exhibits promising potential to substitute the conventional non-destructive testing methods.

Development of Green Cementitious Materials by Using the Abrasive Waterjet Garnet Wastes: Preliminary Studies

2021 ◽  
Vol 1164 ◽  
pp. 87-96
Author(s):  
Cornelia Baeră ◽  
Vasilica Vasile ◽  
Claudiu Matei ◽  
Aurelian Gruin ◽  
Henriette Szilagyi ◽  
...  
Keyword(s):  
Environmental Protection ◽  
Construction Industry ◽  
High Performance ◽  
Building Materials ◽  
Cementitious Materials ◽  
Raw Material ◽  
Abrasive Waterjet ◽  
The Sustainable Development ◽  
Fine Grain ◽  
Reduced Toxicity

The constant need for recycling, waste prevention and general environmental protection represent the new directive approaches imposed by the geo-political, industrial and environmental context, at the regional, European and global level. Ensuring the environmental protection and reducing the natural resources consumption represent general purposes of the sustainable development and also considerations to implement the Circular Economy Model [1]. The present study is developed with respect to the previously mentioned principles: the waterjet cutting operations by the use of abrasive GARNETs for quality, speed and accuracy gain, are in continuous expansion, generating proportionally increasing wastes, which could be valorized by innovatively integrating them in advanced cementitious materials for the construction industry. The international research regarding the use of abrasive waterjet Garnet wastes as raw material for construction industry are at incipient stage and quite limited, but preliminary results are promising. Further studies are presently developed, considering the potential benefits and also the reduced toxicity degree of abrasive Garnet wastes. This paper offers a general overview concerning the recent studies performed in the topic of efficient use of abrasive Garnet wastes in different building materials. Supplementary, further research, both theoretical and experimental is considered, for developing green, advanced, high performance cement-based materials by using the abrasive waterjet Garnet wastes, mainly as fine grain addition or replacement in the composites.

scholarly journals Utilization of volcanic ejecta as a high-performance supplementary cementitious material by gravity classification and pulverization

2018 ◽  
Vol 3 ◽  
pp. 66-74 ◽  
Author(s):  
Atsushi Tomoyose ◽  
Takafumi Noguchi ◽  
Kenichi Sodeyama ◽  
Kazuro Higashi
Keyword(s):  
High Performance ◽  
Clay Fraction ◽  
Volcanic Glass ◽  
Cementitious Material ◽  
Raw Material ◽  
Strength Development ◽  
Supplementary Cementitious Material ◽  
Natural Pozzolans ◽  
Binder Ratio ◽  
Volcanic Ejecta

The reaction of natural pozzolans is caused by volcanic glass composed of amorphous silicate; however, volcanic ejecta also contains crystal mineral, pumice, and sometimes weathered clay fraction in their natural conditions. By focusing on the differences of physical properties between these components, high-purity volcanic glass powder (VGP) was manufactured by dry gravity classification and pulverization. This paper reports the results of investigations to utilize pyroclastic flow deposits as a supplementary cementitious material (SCM). Through this method, the glass content of VGP increased to 88% with a mean particle size of 1 μm, when that of the raw material is about 60%. Chemical analysis indicated that VGP is principally composed of silica (about 72%) and alumina (about 13%). The performance of VGP as a SCM was evaluated by conducting tests on concrete mixtures, replacing 0% to 30% by weight of portland cement by VGP with a 20% to 60% water to cement ratio. VGP concrete showed better results of 7-and 28-day compressive strength compared to control concrete in all experiments. In particular, VGP demonstrated better flowability and strength development in concrete with a low water-binder ratio in comparison to silica fume.

Relationship between availability of basic amenities and proportion of Slum population in Maharashtra

2020 ◽  
Vol 6 (11) ◽  
pp. 1343-1354
Author(s):  
Dr. Sakreen Hasan
Keyword(s):  
Drinking Water ◽  
Tap Water ◽  
Policy Implications ◽  
Class I ◽  
Urban Centers ◽  
The Sustainable Development ◽  
Closed Drainage ◽  
The People ◽  
Basic Infrastructure ◽  
Slum Population

The urban centers offering diverse employment opportunities and means of livelihood are the main centers of attraction for migration. But the availability of infrastructure is low to accommodate the invariably growing population. The access to basic amenities like electricity, drinking water, toilet facility, wastewater outlet and clean fuel are critical determinants of quality of urbanization. And if it lacks, then it would facilitates the growth of slum.  In this paper it being tried to capture the interdependent relationship between basic amenities and slum population residing in the class I towns in Maharashtra; largest slum populated state of India. As the slum is all about the situation or condition in which the people of medium and lower strata are living. A detailed analysis of proportion of slum population and availability of amenities which includes good housing condition, treated tap water as the source of drinking water, electricity as the source of lightning, households having latrine and bathing facility within the premises, waste water outlet connected to closed drainage, and households availing the banking facilities. This may be a limitation of the study that only these indicators have been taken to assess the availability of amenities and to calculate the amenity index of class I towns of the state of Maharashtra. To achieve the sustainable development goal (Sustainable cities and communities), we have to control the growth of slum population and to combat the formation of slum; we have to analyze the situation of basic infrastructure provided in urban centers. Amenities and slum population has policy implications as to reduce the slum population, provide basic amenities to the households which will improve their standard of living and ultimately lead to reduction in growth of slum and check the future slum formation.

Wastewater Treatment Using Marine Algae Biomass as Pollutants Removal

2018 ◽  
Vol 69 (5) ◽  
pp. 1089-1098
Author(s):  
Elena Suzana Biris Dorhoi ◽  
Maria Tofana ◽  
Simona Maria Chis ◽  
Carmen Elena Lupu ◽  
Ticuta Negreanu Pirjol
Keyword(s):  
Wastewater Treatment ◽  
Green Algae ◽  
Marine Algae ◽  
Tap Water ◽  
Ulva Lactuca ◽  
Raw Material ◽  
Bioactive Substances ◽  
Algae Biomass ◽  
Marine Biomass ◽  
Pollutants Removal

The valorification of the marine biomass is an important resource for many industries like pharmaceutical, supplying raw material for the extraction of bioactive substances (vitamins, sterols and collagen), cosmetics, biofertilizers and wastewater treatment. In the last years a special attention has been given to the use of macroalgae. The aim of this study was to emphasize the capacity of two representative green algae species frequent presents on the Romanian shore, Ulva lactuca (L.) and Cladophora vagabunda (L.) Hoek, to remove two usual detergents from wastewater. The green algae washed, dried at room temperature, macerated to powder were introduced into different filter paper for comparison, then immersed in waste water treated with different concentrations of detergents. Tap water was used for the experiment. The results show that Ulva lactuca (L.) species is suitable than Cladophora vagabunda (L.) Hoek species, for wastewater treatment.

scholarly journals Use of Treated Non-Ferrous Metallurgical Slags as Supplementary Cementitious Materials in Cementitious Mixtures

2021 ◽  
Vol 11 (9) ◽  
pp. 4028
Author(s):  
Asghar Gholizadeh Vayghan ◽  
Liesbeth Horckmans ◽  
Ruben Snellings ◽  
Arne Peys ◽  
Priscilla Teck ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Strength Development ◽  
Supplementary Cementitious Material ◽  
Performance Requirements ◽  
Metallurgical Slags ◽  
Leaching Behaviour ◽  
Kinetics Of

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement.

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