Alkali activation of blast furnace slag using a carbonate-calcium carbide residue alkaline mixture to prepare cemented paste backfill

2022 ◽  
Vol 320 ◽  
pp. 126234
Author(s):  
Xiaogang Sun ◽  
Jie Liu ◽  
Jingping Qiu ◽  
Pinqi Wu ◽  
Yunqi Zhao
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Calcium Carbide ◽  
Alkali Activation ◽  
Cemented Paste Backfill ◽  
Calcium Carbide Residue ◽  
Paste Backfill ◽  
Furnace Slag

scholarly journals Utilization of Calcium Carbide Residue Using Granulated Blast Furnace Slag

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3511 ◽  
Author(s):  
Joonho Seo ◽  
Solmoi Park ◽  
Hyun No Yoon ◽  
Jeong Gook Jang ◽  
Seon Hyeok Kim ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Calcium Carbide ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Granulated Blast Furnace Slag ◽  
Calcium Carbide Residue ◽  
Angle Spinning ◽  
Furnace Slag

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.

scholarly journals Substitution of Cement with Granulated Blast Furnace Slag in Cemented Paste Backfill: Evaluation of Technical and Chemical Properties

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1068
Author(s):  
Soili Solismaa ◽  
Akseli Torppa ◽  
Jukka Kuva ◽  
Pasi Heikkilä ◽  
Simo Hyvönen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Mine Tailings ◽  
Blast Furnace Slag ◽  
Partial Substitution ◽  
Cemented Paste Backfill ◽  
X Ray ◽  
Granulated Blast Furnace Slag ◽  
Paste Backfill ◽  
Furnace Slag

Cemented paste backfill (CPB) offers an environmentally sustainable way to utilize mine tailings, one of the largest waste streams in the world. CPB is a support and filler material used in underground mine cavities, which consists of mine tailings, water, and binder material that usually is cement. Replacing cement with secondary raw materials like granulated blast-furnace slag reduces the total CO2 emissions and strengthens the internal microstructure of the CPB. This study characterizes the total- and soluble contents of CPB starting materials and five CPB specimens containing different levels of slag substitution. In addition, phase composition (mineral liberation analysis, MLA) and internal structure (X-ray tomography) of five CPB specimens is documented, and measurements of compressive strength are used to evaluate their suitability as backfill material. Mine tailings and CPB specimens used in this study are rich in sulphates and arsenic, but low in sulphides. Stronger As leaching of ground CPB specimens compared with ground mine tailings is related to the elevating pore water pH during the cement hydration. The hydration product ettringite is found in all CPB specimens and its content is the lowest in the slag containing specimens. X-ray tomography revealed vertically differentiated density structures in the CPB specimens. The lower parts of all specimens are denser in comparison with the upper parts, which is probably due to the compaction of the solid particles at the base. The compressive strength test results indicate that partial substitution of cement with slag improves the strength of the CPB. The total replacement of cement with slag reduces the early strength but gives excellent strength and lower porosity over longer time intervals. The results of the study can be utilized in developing more durable and environmentally responsible CPB recipes for gold mines of similar mineral composition and gold extraction method.

Comparison of Selected Properties of Portland Cement Based Materials and Alkali Activated Materials Based on Granulated Blast Furnace Slag

2016 ◽  
Vol 865 ◽  
pp. 107-113 ◽  
Author(s):  
Pavel Mec ◽  
Jana Boháčová ◽  
Josef Koňařík
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Water Glass ◽  
Sodium Metasilicate ◽  
Alkali Activation ◽  
Granulated Blast Furnace Slag ◽  
Cement Based Materials ◽  
One Year ◽  
Furnace Slag ◽  
Alkali Activated

Alkali activated systems are materials formed by alkali-activation of latent hydraulic or pozzolanic materials. The outcome is a polymeric structure with properties comparable to materials based on cement.The principle of the experiment is to compare selected properties of alkali-activated materials based on blast furnace slag and using various types of activator (sodium water glass, potassium water glass, DESIL AL and sodium metasilicate) to binders based on white and Portland cements of the highest quality. The samples were left for one year in environments simulating the conditions in the interior and exterior. Selected physical-mechanical properties were evaluated and compared.

Effect of Sodium Silicate Properties in Alkali-Activation of Mexican Blast Furnace Slag

2016 ◽  
Vol 1813 ◽  
Author(s):  
O. F. Cortés-Salmerón ◽  
M. L. García-Chávez ◽  
T. A. García-Mejía
Keyword(s):  
Blast Furnace ◽  
Sodium Silicate ◽  
Blast Furnace Slag ◽  
Alkali Activation ◽  
X Ray Diffraction ◽  
Weight Percentage ◽  
Average Value ◽  
Accelerated Curing ◽  
Compressive Strength Test ◽  
Furnace Slag

ABSTRACTThe present work is a study on alkali activation of Mexican blast furnace slag, using sodium silicate. The aim is to produce an optimal specimen, homogeneous without carbonation, and with small fraction of crystalline phases, similar to CSH, which provide mechanical properties suitable to use in the construction industry. The samples were prepared using sodium silicate activator solutions with modulus (SiO2/Na2O) of 1.25, 1.5, and 1.75. The weight percentage of Na2O in the activator solutions was added at 4, 6 and 8% relative to the slag weight. The prepared samples were stored in sealed molds, at room temperature (20°C), during 7 days. The X-ray diffraction has revealed the presence of an amorphous phase, semi crystalline clinotobermorite phase and signals of calcium carbonate for the samples of 4 and 6 % of Na2O; in contrast with the 8% Na2O, where the latter signals almost disappeared. The specimen selected as optimal was prepared with an activator concentration of 8% of Na2O /Slag, and SiO2/Na2O of 1.25. A specimen under these optimal conditions was prepared with accelerated curing (40°C, humidity, 48 hours), and a compressive strength test was attained, with an average value of 52 MPa at 3 days.

Synthesis and characterization of new inorganic polymeric composites based on kaolin or white clay and on ground-granulated blast furnace slag

2003 ◽  
Vol 18 (11) ◽  
pp. 2571-2579 ◽  
Author(s):  
I. Lecomte ◽  
M. Liégeois ◽  
A. Rulmont ◽  
R. Cloots ◽  
F. Maseri
Keyword(s):  
Blast Furnace ◽  
Vickers Hardness ◽  
Blast Furnace Slag ◽  
Polymeric Materials ◽  
Magic Angle Spinning ◽  
Alkali Activation ◽  
Magic Angle ◽  
Scanning Calorimetry ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Alkali activation of dehydroxylated kaolin or clay yielded high-strength polymeric materials, so-called geopolymers. They were synthesized by mixing the aluminosilicate with solutions of sodium metasilicate and KOH followed by adding 45 wt.% of ground-granulated blast furnace slag. The influence of the aluminosilicate source, its activation temperature, and the order of mixing raw materials were studied on the workability of the blending paste, the microstructure, and the Vickers hardness of the geopolymer samples. The polymeric material is completely amorphous according to x-ray diffraction. Solid-state 27Al and 29Si magic-angle-spinning nuclear magnetic resonance showed that the geopolymer consists of AlO4 and SiO4 tetrahedra linked together through a polymeric network constituted by branched entities SiQ4(4Al) and SiQ4(3Al), but also by less-polymerized silicates SiQ1 and SiQ2. Scanning electron microscopy showed a homogeneous polymeric gel matrix containing unreacted slag (and quartz) grains; thermogravimetric analysis and differential scanning calorimetry exhibited a high content of water and an elevated melting point (1260°C). Vickers hardness values are in the range of 200 MPa.

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