scholarly journals Effect of the Cooling Regime on the Mineralogy and Reactivity of Belite-Sulfoaluminate Clinkers

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 910
Author(s):  
Sabina Dolenec ◽  
Katarina Šter ◽  
Maruša Borštnar ◽  
Klara Nagode ◽  
Andrej Ipavec ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Isothermal Calorimetry ◽  
Bottom Ash ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Cooling Regime ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
Size And Morphology

This study investigated the influence of different cooling regimes on the microstructure and consequent reactivity of belite-sulfoaluminate clinkers. The cement clinkers were synthesized by incorporating secondary raw materials, such as titanogypsum and bottom ash, to the natural raw materials. Clinker phases were determined by Rietveld quantitative phase analysis, while the distribution morphology and the incorporation of substitute ions in the phases were characterized by scanning electron microscopy using energy-dispersive X-ray spectroscopy (SEM/EDS). Clinker reactivity was studied using isothermal calorimetry and was additionally investigated through compressive strength, which was determined for the cement prepared from the synthesized clinkers. X-ray diffraction analysis showed that, as well as the three main phases (belite, calcium sulfoaluminate, and ferrite), the clinkers contained additional minor phases (mayenite, gehlenite, arkanite, periclase, and perovskite), the ratios of which varied according to the cooling regime utilized. Microscopic observations indicated that the cooling regime also influenced the crystal size and morphology of the main phases, which consequently affected clinker reactivity. Furthermore, a smaller amount of substitute elements was incorporated in the main phases when cooling was slowed. Results showed that, in comparison to clinkers cooled at slower rates, air quenched clinkers reacted faster and exhibited a higher compressive strength at 7 days.

Influence of Mix Fly and Bottom Ashes from Biomass on Selected Properties of Cement Mortars

2019 ◽  
Vol 828 ◽  
pp. 14-17
Author(s):  
Malgorzata Ulewicz ◽  
Jakub Jura
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Industrial Waste ◽  
Cement Mortar ◽  
Raw Materials ◽  
Bottom Ash ◽  
Waste Materials ◽  
X Ray ◽  
Cement Mortars ◽  
Fluorescence Spectrometer

The preliminary results of utilization of fly and bottom ash from combustion of biomass for the produce of cement mortars has been presented. Currently, this waste are deposited in industrial waste landfills. The chemical composition of waste materials was determined using X-ray fluorescence (spectrometer ARL Advant 'XP). ). In the studies sand was replaced by mix of fly and bottom ash from the combustion of biomass in an amount of 10-30% by weight of cement CEM I 42.5 R (Cemex). The obtained cement mortar concrete were subjected to microscopic examination (LEO Electron Microscopy Ltd.) and their compressive strength (PN-EN-196-1), frost resistance (PN-EN 1015-11 and PN-B -04500 ) and absorbability (PN-85/B-04500) were identified. The obtained results showed, the replacement of the cement by mix ashes from combustion of biomass reduce consumption of raw materials and will have a good influence on the environment.

scholarly journals Application of Isothermal and Isoperibolic Calorimetry to Assess the Effect of Zinc on Hydration of Cement Blended with Slag

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2930 ◽  
Author(s):  
Šiler ◽  
Kolářová ◽  
Novotný ◽  
Másilko ◽  
Bednárek ◽  
...  
Keyword(s):  
Cement Hydration ◽  
Raw Materials ◽  
Isothermal Calorimetry ◽  
Real Life ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isoperibolic Calorimetry ◽  
Poorly Soluble ◽  
Furnace Slag

This work deals with the influence of zinc on cement hydration. The amount of zinc in cement has increased over recent years. This is mainly due to the utilization of solid waste and tires, which are widely used as a fuel in a rotary kiln. Zinc can also be introduced to cement through such secondary raw materials as slag, due to increased recycling of galvanized materials. The aim of this work was to determine the effect of zinc on the hydration of Portland cement, blended with ground blast furnace slag (GBFS). This effect was studied by isothermal and isoperibolic calorimetry. Both calorimetry methods are suitable for measurements during the first days of hydration. Isoperibolic calorimetry monitors the hydration process in real-life conditions, while isothermal calorimetry does so at a defined chosen temperature. Zinc was added to the cement in the form of two soluble salts, namely Zn(NO3)2, ZnCl2, and a poorly soluble compound, ZnO. The concentration of added zinc was chosen to be 0.05, 0.1, 0.5, and 1mass percent. The amount of GBFS replacement was 15% of cement dosage. The newly formed hydration products were identified by X-ray diffraction method (XRD).

Fabrication of Baking-free Bricks from Iron Ore Tailings

2020 ◽  
Vol 13 ◽  
Author(s):  
H. J. Chen ◽  
Zi Wang ◽  
Lizhai Pei ◽  
Z. Y. Xue ◽  
C. H. Yu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Iron Ore ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Safety Hazard ◽  
Xrd Pattern ◽  
X Ray ◽  
Iron Ore Tailings ◽  
Brick Powder ◽  
Micro Morphology

Aims: The aim is to prepare baking-free bricks using iron ore tailings as the main raw materials. Objective: Iron ore tailings have increased dramatically in recent decades. The storage of the iron ore tailings has potential environmental and safety hazard. Therefore, it is urgent to use the tailings to produce valuable products. Objective: The objective of the research is to treat the tailings by preparing the baking-free bricks. Method: The phases and micro-morphology of the baking-free bricks have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optimal components and preparation parameters of the baking-free bricks were determined by controlling the ratio of the raw materials and forming pressure. The physical properties of the baking-free bricks including compressive strength and density have been analyzed by controlling the forming pressure and curing time. Result: The optimal components of the baking-free bricks is 65wt.% tailings, 5wt.% titanium gypsum, 17wt.% slag, 5wt. Conclusion: Baking-free bricks have been successfully prepared from the iron ore tailings adding a small amount of cementing materials including titanium gypsum, slag, acetylene sludge and waste brick powder. Other: The XRD pattern and SEM observation show that 28 d tailing bricks are mainly composed of irregular particles and a large number of ettringite (Aft) nanorods. The analyzed results revealed that the formed irregular particles and Aft nanorods contribute to the improvement of compressive strength and compactness of the tailing bricks.

Influence of Nano-SiO2 and Nano-TiO2 on Early Hydration of Calcium Sulfoaluminate Cement

2014 ◽  
Vol 599 ◽  
pp. 39-45 ◽  
Author(s):  
Bao Guo Ma ◽  
Hai Nan Li ◽  
Yan Chao Zhu ◽  
Lei Han ◽  
Xiang Guo Li
Keyword(s):  
Isothermal Calorimetry ◽  
Sem Analysis ◽  
Cement Stone ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
Early Hydration ◽  
Cement Pastes ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
The Difference

Calcium sulfoaluminate (CSA) cements were currently receiving a lot of attention because their manufacture produced less CO2 than ordinary Portland cement (OPC). However, it was essential to understand all parameters which might affect the hydration process. This work dealt with the effect of two nanostructured materials, such as nanoSiO2 (NS) and nanoTiO2 (NT), on the properties of CSA pastes during early hydration. Isothermal calorimetry, X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were used to analyze the pastes. Results indicated that the influence of NS and NT on the early hydration of CSA showed different: when NS and NT were added by 5% (mass fraction), the early hydration of CSA cement can be significantly promoted by NS, and slightly accelerated by NT. X-ray diffraction and SEM analysis results showed that both of NS and NT can improve the microstructure of the cement pastes, which made the cement stone more uniform and dense. For the difference, during cement hydration, except for nucleation function, NS had a high pozzolanic activity. Whereas,the effect of NT on microstructure of hardened CSA-cement was mainly due to its seeding effect.

scholarly journals Unique chemical activity in porous YbB2C2 ceramics with high porosity and high compressive strength

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhihui Li ◽  
Jixin Chen ◽  
Hao Zhang ◽  
Jinxing Yang ◽  
Minmin Hu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Chemical Activity ◽  
High Porosity ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Compressive Strength ◽  
Rate Of Reaction ◽  
Unique Chemical

AbstractHigh purity layered YbB2C2 powder is synthesized by a boro/carbothermic reduction method using YbBO3, B4C and graphite powders as raw materials. Its X-ray diffraction data are presented, and the space group P4/mbm (No. 127) is confirmed. The lattice parameters are a = b = 5.3389 Å and c = 3.5683 Å, and the atom positions are Yb (0.0000, 0.0000, 0.0000), B (0.3621, 0.8621, 0.5000), and C (0.1606, 0.6606, 0.5000). Porous YbB2C2 ceramics have a high porosity in the range of 69.89–58.11% and a high compressive strength in the range of 19.49–63.44 MPa. Furthermore, the as-produced porous YbB2C2 ceramics show unique chemical activity. Porous YbB2C2 ceramic with a porosity of 69.89% emits so much heat that it can burn a piece of paper when this ceramic is wetted by water. The rate of reaction between the porous YbB2C2 ceramic and water can be simply controlled by adjusting the porosity. The solid reaction products are YbB6, C and an unknown amorphous phase.

Preparation and Composition Optimization of Low-CO2-Emission Cement Containing Belite, Calcium Sulfoaluminate and Ferrite

2017 ◽  
Vol 727 ◽  
pp. 1067-1073 ◽  
Author(s):  
Wu Yao ◽  
Qiao Ling ◽  
Meng Xue Wu
Keyword(s):  
Compressive Strength ◽  
Cement Clinker ◽  
Strength Development ◽  
Optimal Composition ◽  
X Ray Diffraction ◽  
Scattered Electron ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
Compressive Strength Development ◽  
Composition Optimization

Cement clinker with low CO2 emission was prepared in laboratory, which mainly consist of belite (C2S), calcium sulfoaluminate (C4A3S), and ferrite (C4AF). The mineral composition of clinker was optimized for better compressive strength development. The chemical and physical properties of this prepared cement were characterized through X-ray diffraction (XRD), back scattered electron-scanning electron microscopy (BSE-SEM) and differential thermal analysis (DTA). The results reveal that C4A3S governs most of the compressive strength at early ages, while C2S contributes to the later strength development. C4AF is in liquid when fired to 1300°C, beneficial to the mass transfer but causing high crystallinity of C2S when excessive. Finally the results of experiments suggest that the optimal composition of clinker is 50wt. % C2S, 40wt. % C4A3S and 10wt. % C4AF.

Effect of Phosphogypsum on the Clinkerization Temperature of Portland Cement Clincker

2012 ◽  
Vol 730-732 ◽  
pp. 94-99 ◽  
Author(s):  
Maria Margarida Rolim Augusto Lima ◽  
L.F.C. Braz ◽  
Regina da Conceição Corredeira Monteiro ◽  
J.P. Veiga
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Raw Materials ◽  
Cement Clinker ◽  
X Ray Diffraction ◽  
X Ray ◽  
Portland Cement Clinker ◽  
Alternative Material ◽  
Heating Up ◽  
Mineralogical Compositions

Phosphogypsum (PG) is a pollutant residue resulting from the production of phosphoric acid in the phosphated fertilizers industry. About 180 millions of tons of PG are generated worldwide per year, which originates storage problems because of the environmental restrictions and the high costs of storage spaces. Taking into account the mineralizer properties of PG it has been studied a way to valorize this residue as an alternative material in the production of Portland cement clinker. The PG and the raw-materials (limestone, marl, sand and iron oxide) were chemical, mineralogical and thermally characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and differential thermal analysis and termogravimetric analysis (DTA/TGA). After milling, the phosphogypsum was mixed with the raw-materials in different amounts up to 10% weight. The raw mixtures were submitted to two types of firing schedules, heating up to 1500°C without any holding time or heating up to 1350°C and holding for 20 minutes. After firing, the clinkers were analyzed by optical microscopy, milled and characterized in terms of chemical and mineralogical compositions. The clinkers were used to produce cement mortar according to NP EN 196-1 standard. The resultant test specimens were mechanically tested at 2 and 28 days according to the same standard. The obtained results show a reduction of about 140°C in the clinkerization temperature, when a raw mixture with 5% phosphogypsum was used. Standard clinkers, without phosphogypsum addition, which were fired at 1500°C, originated test specimens with a compressive strength of 48.1MPa at 28 days. Test specimens produced with clinker containing 5% phosphogypsum present higher compressive strength values at 28 days, being 55.1MPa for clinkers produced at 1500°C, and 49.4 MPa for clinkers produced at 1350°C.

scholarly journals Effect of Naphthalene-Based Superplasticizer and Polycarboxylic Acid Superplasticizer on the Properties of Sulfoaluminate Cement

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 662
Author(s):  
Yonghua Wu ◽  
Qiqi Li ◽  
Guoxin Li ◽  
Shiying Tang ◽  
Mengdie Niu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Hydration Products ◽  
Polycarboxylic Acid ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
X Ray ◽  
Initial Setting Time ◽  
Calcium Sulfoaluminate ◽  
Initial Setting

In order to study what the effect of superplasticizers on the setting time, fluidity and compressive strength of calcium sulfoaluminate cement (CSA) a naphthalene-based superplasticizer (BNS) and a polycarboxylic acid superplasticizer (PC) were selected to interact with CSA pastes and ye’elimite, respectively. X-ray diffraction (XRD), thermogravimetric (TG) analysis and scanning electron microscopy (SEM) analytical methods were used to investigate the class, amount and microstructure of the CSA pastes and ye’elimite pastes hydration products under the effect of the superplasticizers. The results showed that the addition of BNS can promote ettringite generation and thus improve the early compressive strength. As the addition of BNS increased from 0.8 wt% to 2.0 wt%, the initial setting time was prolonged 10 min, the final setting time was prolonged 7 min, the 5 min fluidity was improved from no fluidity to 220 mm. However, as the addition of PC increased from 0.08 wt% to 0.20 wt%, the setting time of the PC just changed within 3 min; the 5 min fluidity increased from 110 mm to 195 mm and no 15 min fluidity at all was observed. AS seen by SEM, it can be stated that generated ettringite under the addition of PC was layered and lacking bonding, and its morphology changed from rod-like to flake-like, leading to a decrease in early compressive strength.

scholarly journals The Use of Dredged Sediment from the Watsongpeenong Canal with Paper Mill Residue to Produce Facing Bricks

2018 ◽  
pp. 13-22
Author(s):  
Jiraporn Namchan ◽  
Nuta Supakata
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Raw Materials ◽  
Paper Mill ◽  
Microstructural Properties ◽  
Dredged Sediment ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
The Right

The potential to use dredged sediment from the Watsongpeenong Canal and paper mill residue as the primary raw materials for producing facing bricks was studied in the laboratory. Dredged sediment and paper mill residue were chemically, mineralogically, and thermally characterized using X-ray fluorescence (XRF) and X-ray diffraction (XRD). To evaluate the effects of the contents of the paper mill residue on pore-forming, large amounts of paper mill residue, ranging from 5 to 7 % by mass, were blended with dredged sediments and fired at 700oC. The physical-mechanical properties, including dimensions and tolerances, wryness, deviation of the right angle, water absorption, compressive strength, stain, hole, rails, and cracks, as well as the microstructural properties of the facing bricks, were investigated. In addition, the heavy metals (Mn, Pb, Cd, and Cr) in the facing bricks were identified. The results indicated that the dimensions and tolerance, wryness, deviation from the right angle, water absorption, compressive strength, holes, and rails of the facing bricks with 5 % and 7 % by weight of paper mill residue were compliant with the requirements of the TIS 168-2546 standard. For stains and cracks, no batches of the facing bricks complied with the standard. Facing bricks made from 93 % dredged sediment and 7 % paper mill residue (93D+7P) obtained the highest compressive strength, with a value of 23.66 MPa. Therefore, dredged sediment and paper mill residue can be considered as suitable for use as primary raw materials in the production of facing bricks.

Effects of the Addition Amount of Silica Aerogels on Mechanical Properties and Microstructure of Insulating Materials

2011 ◽  
Vol 374-377 ◽  
pp. 803-806
Author(s):  
Lin Ma ◽  
Jia Bin Wang ◽  
Gui Yan Xin ◽  
Qi Yao She
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Glass ◽  
Raw Materials ◽  
Silica Aerogels ◽  
X Ray Diffraction ◽  
Insulating Materials ◽  
X Ray ◽  
Addition Amount ◽  
Scanning Electron

Insulating materials were prepared by microsilica, silica aerogels and quartz fibers as raw materials, water glass as binder, and molded by the semi-dry method. In this paper, the effects of the addtion amount of silica aerogels on mechanical properties and microstructure of insulating materials were studied. X-ray diffraction (XRD) was used to characterize the phase composition and scanning electron microscope (SEM) was used to characterize the microstructure of the materials. The results show that when the silica aerogels content was at 40%, the material had the best properties in present study of true porosity of 45.9%, flexural strength of 5.0MPa and compressive strength of 37.9MPa, respectively.

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