scholarly journals Stabilization of a Clay Soil Using Cementing Material from Spent Refractories and Ground-Granulated Blast Furnace Slag

2021 ◽  
Vol 13 (6) ◽  
pp. 3015
Author(s):  
Andres Seco ◽  
Jesus María del Castillo ◽  
Sandra Espuelas ◽  
Sara Marcelino-Sadaba ◽  
Benat Garcia

Nowadays, huge amounts of refractory materials are generated around the world. The majority of them lack valorization methods. This study analyzes the ability of a doloma and two magnesia spent refractory wastes as soil stabilizers on their own, as well as when combined with Ground-Granulated Blast Furnace Slags (GGBS). These materials showed a limited ability for the soil’s plasticity modification from a plasticity index of 15.6 to a minimum of 12.7. The high pH of the additives increased the soil’s pH from 7.88 to values in the range of 10.94–11.25 before the 28 days, allowing the development of the pozzolanic reactions. Unconfined compressive strength (UCS) increased along the curing time, reaching a maximum value of 5.68 MPa after 90 days. Based on the UCS, the optimum refractory GGBS ratios oscillate between 30:70 and 50:50. The UCS values after soaking samples reduced the unsoaked results between 68.70% to 94.41%. The binders considered showed a low effect against the soil swelling and the lack of delayed expansive effects because of the MgO hydration. Finally, X Ray Diffraction (XRD) tests showed that the stabilization only slightly modified the combinations of mineralogy and the formation of Magnesium Silicate Hydrate (MSH) gels.

2014 ◽  
Vol 633 ◽  
pp. 240-244 ◽  
Author(s):  
Su Ping Cui ◽  
Ling Ling Liu ◽  
Jing Chen ◽  
Ya Li Wang ◽  
Jian Feng Wang ◽  
...  

Granulated blast furnace slag (GBFS) is a by-product of manufacturing iron. Samples of GBFS with different ratio of SiO2/Al2O3 were prepared by simulating the actual process of GBFS in laboratory. This study investigated the influence of SiO2/Al2O3 content on structure and hydration activity of GBFS which were characterized by X-ray fluorescence (XRF), powder X-ray diffraction (XRD), infrared radiation (IR) and mechanical testing. It is found that the vitreous content of each sample is above 97% and the hydration activity indexes of 7d and 28d of samples significantly decrease with the increase of SiO2/Al2O3 ratio. The IR characteristic absorption spectrum shows that the silicates mainly exist in [SiO4]-tetrahedra and the aluminum atoms are in different coordination states and the bonding strengths rise with the increase of SiO2/Al2O3 ratio.


1994 ◽  
Vol 9 (1) ◽  
pp. 188-197 ◽  
Author(s):  
Paul J. Schilling ◽  
Amitava Roy ◽  
H.C. Eaton ◽  
Philip G. Malone ◽  
Newell W. Brabston

Ground granulated blast-furnace slag was reacted in 5 M (pH 14.7) and 1.5 M (pH 14.2) NaOH solutions at a water/slag ratio of ∼0.4, and characterized by unconfined compressive strength testing, scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The reacted material consisted of a dense layered matrix interspersed with unreacted glass particles and regions of reaction products with higher porosity. CSH(I) and (C, M)4AH13 were identified by x-ray diffraction. The C-S-H (calcium silicate hydrate) phase is proposed to consist mainly of structurally imperfect layers of tobermorite, interleaved with layers of (C, M)4AH13. Other cations, most significantly Na+, are incorporated into the structure. Use of the highly concentrated solution (5 M) produced a higher degree of reaction and, consequently, higher compressive strength (38 MPa after 28 days for 5 M solution vs 21 MPa for 1.5 M).


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2131 ◽  
Author(s):  
G.U. Ryu ◽  
G.M. Kim ◽  
Hammad R. Khalid ◽  
H.K. Lee

Blast furnace slag, an industrial by-product, is emerging as a potential raw material to synthesize hydroxyapatite and zeolite. In this study, the effects of temperature on the hydrothermal synthesis of hydroxyapatite-zeolite from blast furnace slag were investigated. Specimens were synthesized at different temperatures (room temperature, 50, 90, 120, or 150 °C). The synthesized specimens were analyzed qualitatively and quantitatively via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), BET/BJH, and scanning electron microscopy/energy dispersive using X-ray analysis (SEM/EDX). It was found that the hydroxyapatite phase was synthesized at all the reaction temperatures, while faujasite type zeolite appeared in the specimens synthesized at 90 and 120 °C. Moreover, faujasite was replaced by hydroxysodalite in the specimens synthesized at 150 °C. Additionally, the crystals of the hydroxyapatite tended to become larger and total crystallinity increased as the reaction temperature increased.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3511 ◽  
Author(s):  
Joonho Seo ◽  
Solmoi Park ◽  
Hyun No Yoon ◽  
Jeong Gook Jang ◽  
Seon Hyeok Kim ◽  
...  

The solidification and stabilization of calcium carbide residue (CCR) using granulated blast furnace slag was investigated in this study. CCR binding in hydrated slag was explored by X-ray diffraction, 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and thermodynamic calculations. Mercury intrusion porosimetry and and compressive strength tests assessed the microstructure and mechanical properties of the mixtures of slag and CCR. C-A-S-H gel, ettringite, hemicarbonate, and hydrotalcite were identified as the main phases in the mixture of slag and CCR. The maximum CCR uptake by slag and the highest volume of precipitated solid phases were reached when CCR loading in slag is 7.5% by mass of slag, according to the thermodynamic prediction. This feature is also experimentally observed in the microstructure, which showed an increase in the pore volume at higher CCR loading.


2011 ◽  
Vol 250-253 ◽  
pp. 870-874
Author(s):  
Hong Mei Ai ◽  
Jing Wei ◽  
Jun Ying Bai ◽  
Pu Guang Lu

Eco-cement produced from waste concrete was proved to be feasible in early research. The seed crystal of ground granulated blast furnace slag (GGBS) was utilized in this research to lower the sintering temperature of eco-cement clinker. The mineral compositions of clinker with GGBS seed crystal was analyzed by X-ray diffraction (XRD), and the mechanical properties of eco-cement with GGBS seed crystal was also tested. Four main cement minerals were all observed in eco-cement clinker and the compressive strength of the eco-cement pastes can approach to about 66 MPa at 28 curing days. The results showed that GGBS seed crystal was favourable for the formation of cement minerals at a lower temperature. It can help reduce by about 50~100°C for the sintering process of cement clinker. Content of GGBS seed crystal should better be in the rage of 5%~8%, and the suitable sintering temperature should be 1350°C.


2014 ◽  
Vol 976 ◽  
pp. 246-250
Author(s):  
Reyna Sánchez-Ramírez ◽  
Manuela Diaz-Cruz ◽  
Sebastían Díaz de La Torre ◽  
Enrique Rocha-Rangel

In this work, they were produced and characterized cementing composites made with blast furnace slag replacement, for their use in the construction of oil wells. To this, slurries were prepared with a replacement of 20 and 30% slag, as well as a slurry with 100 % slag and a slurry with 100% H-cement were prepared. Starting materials were characterized by chemical analysis, X-ray diffraction and Fourier Transformed Infra Red. Slurries also were activated with sodium silicate in order to study theirs hydration kinetics, driving by isothermal calorimetry. These studies were complemented by the preparation of specimens of 4 X 4 X 16 cm to which they determine its compressive and bending strength during 2 and 28 days of curing. From the results it can be concluded that it was obtained a product that can be effectively used in the construction of oil wells.


2013 ◽  
Vol 641-642 ◽  
pp. 363-366 ◽  
Author(s):  
Wu Zhang ◽  
Li Zhang ◽  
Nai Xiang Feng

Abstract. Effect of oxidation on phase transformation in Ti-bearing blast furnace slag is studied. The slag is analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), EDX and metallographic microscope. The experiment results indelicate that the phase composition of the oxidized slag is simpler which are only rutile and glass phase. The titanaugite, Ti-rich diopside and perovskite phase are vanished and most of the Ti components were enriched in the rutile phase.


2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Katalin Orosz ◽  
Abeer Humad ◽  
Hans Hedlund ◽  
Andrzej Cwirzen

Deformations of alkali-activated slag concrete (AASC) with high MgO and Al2O3 content, subjected to variable curing temperature were studied. Sodium silicate and sodium carbonate were used as alkali activators. The obtained results showed development of deformations consisting of both shrinkage and expansion. Shrinkage appeared not to be affected by the activator type, while the expansion developed after the cooling down phase in stabilized isothermal conditions and did not stop within the duration of the tests. X-ray diffraction analysis performed shortly after the cooling down phase indicated the formation of crystalline hydrotalcite, which was associated with the observed expansion. A mixture with a higher amount of sodium silicate showed less expansion, likely due to the accelerated hydration and geopolymerization leading to the increased stiffness of the binder matrix.


2012 ◽  
Vol 220-223 ◽  
pp. 117-122
Author(s):  
Guo Ping Luo ◽  
Yan Ban ◽  
Yi Ci Wang ◽  
Wen Wu Yu ◽  
Qi Jiang

The mineral composition of the solidified blast furnace slag and the occurrence of special components CaF2, K2O, Na2O, RexOy and ThO2 were researched by optical microscope analysis, X-ray diffraction analysis and scanning electron microscopy and energy spectrum analysis. The results showed that the major minerals in solidified furnace slag are akermanite and gehlenite; the special component CaF2 is not hosted in the cuspidine (3CaO•2SiO2•CaF2), but in the magnesium and aluminum silicate mineral; the special components K2O,Na2O is hosted in akermanite, magnesium and aluminum silicate mineral and perovskite; the element thorium cannot form an independent mineral, but coexist with the rare earth element Ce in the perovskite. The results will lay a foundation for further study on the influence of these special components on the crystallization behavior of glass-ceramics.


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