Preliminary Evaluation of Fly Ash and Lime for Use as Supplementary Cementing Materials in Cold-Agglomerated Blast Furnace Briquetting

Mäkelä, Mikko; Paananen, Timo; Kokkonen, Tommi; Makkonen, Hannu V.; Heino, Jyrki; Dahl, Olli

doi:10.2355/isijinternational.51.776

Cited by 11 publications

(7 citation statements)

References 12 publications

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“…2 and 3. When comparing the particle size to our previous investigation, 22) in which the fly ash samples were from the equivalent industrial facilities, the results are surprising as the particle size of F1 sample was previously notably smaller than that of the F2 sample. In the present investigation, the F1 sample with a volume weighted mean diameter of 42.7 μm had a significantly larger particle size than the other samples.…”

Section: Sample Composition Particle Size and Scanningcontrasting

confidence: 54%

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Influence of Fly Ash and Ground Granulated Blast Furnace Slag on the Mechanical Properties and Reduction Behavior of Cold-Agglomerated Blast Furnace Briquettes

Mäkelä

Paananen²,

Heino

et al. 2012

ISIJ Int.

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The utilization of fly ash and ground granulated blast furnace slag (GGBFS) as supplementary cementing materials in cold-agglomerated blast furnace briquetting was investigated. Sample analysis included chemical and mineralogical composition, particle size, and scanning electron microscopy and the produced briquettes were evaluated for mechanical durability (2, 7, and 28 day tumble strength), mineralogy, thermal decomposition (DSC-TG-MS), and disintegration under reducing conditions at 800°C (LTD). Based on the data, only the use of GGBFS with or without fly ash led to satisfactory 28 day mechanical durability compared to the 28 day reference mean value. The most promising series, where 20% of Portland cement was replaced by a threefold amount of GGBFS, attested to a 30% strength increase at 28 day compared to the respective reference mean value. However, the 48 hour durability values proved inferior to respective references due to the comparatively larger particle size (one fly ash sample) and slower strength development provided by the supplements. The LTD (800°C) values determined by isothermal reduction at 800°C were strongly correlated (R 2 = 0.694) with briquette mechanical durability governed by the dehydration of the C-S-H phase at approximately 320-360°C established by DSC-TG-MS. Subsequent to the dehydration of C-S-H, briquette durability was possibly maintained by the formation of an intermediate carbonated phase prior to final breakdown under the conditions of the LTD (800°C) test. Briquette moisture optimization was encouraged by the variation in detected levels, prospectively emphasized by the ability of industrial-scale briquetting plants to operate on comparatively lower moisture levels.

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Section: Sample Composition Particle Size and Scanningcontrasting

confidence: 54%

“…An attempt is made to provide a continuum for the preliminary evaluation of fly ash and lime for use in blast furnace briquetting, which was reported in our previous publication. 22)…”

Section: Introductionmentioning

confidence: 99%

Influence of Fly Ash and Ground Granulated Blast Furnace Slag on the Mechanical Properties and Reduction Behavior of Cold-Agglomerated Blast Furnace Briquettes

Mäkelä

Paananen²,

Heino

et al. 2012

ISIJ Int.

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“…Higher weight losses in this region were observed for samples with BFA and mixes with an N5-C10 activator. This can be a result of the higher water absorption of a calcium compound or differences in levels of unburned carbon since carbon particles adsorb water and effectively eliminate it from the pore system by decreasing weight loss connected with free water [73,74].…”

Section: Tgamentioning

confidence: 99%

Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars

et al. 2020

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The aim of this work was to study the influence of the type of activator on the formulation of modified fly ash based geopolymer mortars. Geopolymer and alkali-activated materials (AAM) were made from fly ashes derived from coal and biomass combustion in thermal power plants. Basic activators (NaOH, CaO, and Na2SiO3) were mixed with fly ashes in order to develop binding properties other than those resulting from the use of Portland cement. The results showed that the mortars with 5 mol/dm3 of NaOH and 100 g of Na2SiO3 (N5-S22) gave a greater compressive strength than other mixes. The compressive strengths of analyzed fly ash mortars with activators N5-S22 and N5-C10 (5 mol/dm3 NaOH and 10% CaO) varied from 14.3 MPa to 5.9 MPa. The better properties of alkali-activated mortars with regular fly ash were influenced by a larger amount of amorphous silica and alumina phases. Scanning electron microscopy and calorimetry analysis provided a better understanding of the observed mechanisms.

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“…The mass losses observed at higher temperatures are mainly attributed to the evaporation of alkali-containing components. Therefore, the reduction in mass noted in the temperature segment 850–1000 °C characterized by the endothermic DSC peak (especially in SSA) is likely to be assigned to KCl evaporation, K 2 CO 3 decomposition [ 44 ] or formation of SO 2 [ 49 ]—reduction of sulfates or melting.…”

Section: Test Results and Discussionmentioning

confidence: 99%

Reactivity and Pozzolanic Properties of Biomass Ashes Generated by Wheat and Soybean Straw Combustion

Šupić¹,

Malešev²,

Радоњанин³

et al. 2021

Materials

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A sustainable use of locally available wastes from agriculture as supplementary cementitious materials (SCMs) is an alternative solution for the prevention of excessive raw material usage, reduction of CO2 emission and cost-effective concrete production. This paper studies the reactivity of non-traditional waste SCMs: Wheat straw ash (WSA), mixture of wheat and soybean straw ash (WSSA) and soybean straw ash (SSA), which are abundant as agricultural by-products in Serbia. The chemical evaluation using XRF technique, thermal analysis (TGA/DSC), XRD and FTIR methods were performed along with physical properties tests to investigate the feasibility of utilizing biomass ashes as cement substitutes. The obtained results demonstrate a high pozzolanic activity of WSA, which is attributed to a high reactive silica content of the ash and its satisfactory level of fineness. A wider hump in XRD pattern of WSA compared to WSSA and SSA confirmed that it abounds in amorphous (reactive) phase. The insufficient activity index of soybean-based biomass ashes, characterized with a low silica content, was improved by additional grinding and/or blending with amorphous silica-rich material. This points out the mechanical activation, i.e., grinding procedure, and chemical activation, i.e., modification of the chemical composition, as techniques efficient at producing pozzolanic materials from biomass wastes. Tested biomass ashes are characterized with negligible leaching values of heavy metals, thereby satisfying eco-friendly principles of SCM utilization. The application of biomass ashes as SCMs leads to substantial cost savings, as well as benefits to the environment, such as lower consumption of cement, reduction of CO2 emissions during the production of cement and sustainable waste management.

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Preliminary Evaluation of Fly Ash and Lime for Use as Supplementary Cementing Materials in Cold-Agglomerated Blast Furnace Briquetting

Cited by 11 publications

References 12 publications

Influence of Fly Ash and Ground Granulated Blast Furnace Slag on the Mechanical Properties and Reduction Behavior of Cold-Agglomerated Blast Furnace Briquettes

Influence of Fly Ash and Ground Granulated Blast Furnace Slag on the Mechanical Properties and Reduction Behavior of Cold-Agglomerated Blast Furnace Briquettes

Influence of Activators on Mechanical Properties of Modified Fly Ash Based Geopolymer Mortars

Reactivity and Pozzolanic Properties of Biomass Ashes Generated by Wheat and Soybean Straw Combustion

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