Alkali-Activated Zeolite 4A Granules—Characterization and Suitability Assessment for the Application of Adsorption

A major problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this study, the physical and mechanical properties of a novel binder based on metakaolin and its composite with zeolite 4A in the granular form were studied. Metakaolin was used as a precursor for alkali-activated binder, which was synthesized using an 8M NaOH activation solution. Raw materials were characterized using granulometry, X-ray diffraction (XRD), and differential thermal analysis (DTA); and final products were characterized using density measurements, a compressive strength test, XRD, Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM). Alkali-activated metakaolin was found to be efficient as a binding material when data for morphological properties were analyzed. A relationship was observed—by increasing the liquid-to-solid ratio (L/S), compressive strength decreased. Zeolite granule attrition was higher than expected: 2.42% and 4.55% for ZG-0.8, 3.64% and 5.76% for ZG-1.0, and 2.73% and 4.85% for ZG-1.2, measured at 4 and 5 atmospheres, respectively.

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Alkali-Activated Metakaolin as a Zeolite-Like Binder for the Production of Adsorbents

Inorganics ◽

10.3390/inorganics7120141 ◽

2019 ◽

Vol 7 (12) ◽

pp. 141 ◽

Cited By ~ 2

Author(s):

Kristine Vegere ◽

Laura Vitola ◽

Pauls P. Argalis ◽

Diana Bajare ◽

Andrey E. Krauklis

Keyword(s):

Compressive Strength ◽

Co2 Adsorption ◽

Physical And Mechanical Properties ◽

Curing Conditions ◽

Bet Analysis ◽

Naoh Solution ◽

Binder Material ◽

Alkali Activated Binders ◽

Adsorptive Properties ◽

Alkali Activated

This work reports and describes a novel alkali-activated metakaolin as a potential binder material for the granulation of zeolites, which are widely used as CO2 adsorbents. The alkali-activated binders are zeolite-like materials, resulting in good material compatibility with zeolite-based adsorbents. A major problem during the granulation of zeolites is that their adsorption capacities decrease by about 15–20%, because typical binder materials (for example bentonite or kaolin clay) are inactive towards CO2 adsorption. A possible pathway to solve this problem is to introduce a novel binder that is also able to sorb CO2. In such a case, a binder plays a dual role, acting both as a binding material and as a sorbent. However, it is important that, alongside the adsorptive properties, a novel binder material must fulfil mechanical and morphological requirements. Thus, in this work, physical and mechanical properties of this novel binder for zeolite granulation for CO2 adsorption are studied. Alkali-activated metakaolin was found to be efficient and competitive as a binder material, when mechanical and physical properties were concerned. The compressive strengths of most of the obtained binders reported in this work are above the compressive strength threshold of 10 MPa. The future work on this novel binder will be conducted, which includes granulation-related details and the CO2 adsorptive properties of the novel binder material. Metakaolin was used as a precursor for alkali-activated binders. Binders were synthesized using varying molarity of a NaOH solution and at varying curing conditions. The final products were characterized using density measurements, compressive strength tests, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM).

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Enhancing Density-Based Mining Waste Alkali-Activated Foamed Materials Incorporating Expanded Cork

CivilEng ◽

10.3390/civileng2020029 ◽

2021 ◽

Vol 2 (2) ◽

pp. 523-540

Author(s):

Imed Beghoura ◽

Joao Castro-Gomes

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Pore Size ◽

Physical And Mechanical Properties ◽

Critical Parameters ◽

Porous Structures ◽

Foaming Agent ◽

Al Powder ◽

Highly Porous ◽

Alkali Activated

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components.

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Research on Simulation Test of Coal Similar Material

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.850-851.847 ◽

2013 ◽

Vol 850-851 ◽

pp. 847-850 ◽

Cited By ~ 2

Author(s):

Lin Chao Dai

Keyword(s):

Compressive Strength ◽

Raw Materials ◽

Similarity Theory ◽

Design Method ◽

Uniform Design ◽

Physical And Mechanical Properties ◽

Raw Material ◽

Similar Material ◽

Cement Ratio ◽

Water Cement Ratio

In order to study the coal and gas outburst similar simulation experiment, coal similar material was made up based on the similarity theory. Based on the previous similar material study, the cement, sand, water, activated carbon and coal powder was selected as the raw material of similar material. Meanwhile similar material matching program with 5 factors and 6 levels was designed by using Uniform Design Method. And the physical and mechanical properties of the similar material compressive strength was measured under different proportions circumstances. The relationship between similar material and the raw materials was analyzed. The results show that choosing different materials can compound different similar materials with different requirements. And the water-cement ratio plays a decisive influence on the compressive strength of similar material. The compressive strength of similar material decreases linearly when the water-cement ratio increases.

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One-Part Alkali-Activated Pastes and Mortars Prepared with Metakaolin and Biomass Ash

Applied Sciences ◽

10.3390/app10165610 ◽

2020 ◽

Vol 10 (16) ◽

pp. 5610

Author(s):

Alessandra Mobili ◽

Francesca Tittarelli ◽

Hubert Rahier

Keyword(s):

Compressive Strength ◽

Reaction Kinetics ◽

Isothermal Calorimetry ◽

Molar Ratio ◽

Alkaline Solutions ◽

Strength Increase ◽

Biomass Ash ◽

Solid Ratio ◽

User Friendly ◽

Alkali Activated

Common alkali-activated materials (AAMs) are usually manufactured with highly alkaline solutions. However, alkaline solutions are dangerous for workers who must wear gloves, masks, and glasses when handling them. This issue makes common (or two-part) AAMs not user-friendly and problematic for bulk production if no safety procedures are followed. In this paper, the possibility of manufacturing alkali-activated pastes and mortars without alkaline solution is investigated. These innovative one-part AAMs have been prepared with metakaolin as the aluminosilicate precursor, potassium-rich biomass ash as the alkaline activator, and water. AAMs have been prepared by varying the K/Al molar ratio: pastes have been studied in terms of reaction kinetics, through isothermal calorimetry, and mortars have been tested in terms of mechanical compressive strength. Results show that the K/Al molar ratio governs both the reaction kinetics and the mechanical strength of these innovative materials. The highest compressive strength is obtained when the K/Al ratio is equal to 2.5 and the water/solid ratio is equal to 0.49. If biomass ash is heated at 700 °C to decompose the calcium carbonate, its reactivity and the final compressive strength increase.

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Expansion volume of alkali activated foamed cork composites from tungsten mining mud waste with aluminium

MATEC Web of Conferences ◽

10.1051/matecconf/201927403002 ◽

2019 ◽

Vol 274 ◽

pp. 03002

Author(s):

Imed Beghoura ◽

Joao Castro-Gomes ◽

Haroon Ihsan ◽

John Pickstone ◽

Nuno Estrada

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Physical And Mechanical Properties ◽

Mechanical And Thermal Properties ◽

Porous Structures ◽

Expansion Process ◽

Foaming Agent ◽

Al Powder ◽

Highly Porous ◽

Alkali Activated

Several mixes of alkali activated foams from tungsten mud waste (MW), grounded glass (GG) and metakaolin (MK) were developed incorporating expanded granulated cork (EGC). This study presents preliminary results of the expansion process obtained with the addition of aluminium (AL) powder as a foaming agent. 0.3 wt.%, 0.4 wt.% to 0.5wt.% of AL powder were added to the alkali activated matrix. The physical and mechanical properties of the obtained foams, the effects of the type and amount of the foaming agent added are presented and discussed. Highly porous structures were obtained, with overall expansion up to 68.2% when the AL powder was added. The size and distribution of pores are shown. The compressive strength of foams in the case of highly porous structures achieved of 1.2 MPa for the samples containing 0.5 wt.% of AL powder. Mechanical and thermal properties of the cured structure are good and can therefore be used for applications in acoustic panels and lightweight prefabricated components for thermal insulation purposes.

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EFFECT OF MIXING PROPORTION ON COMPRESSIVE STRENGTH OF FLY-ASH BASED GEOPOLYMER PASTE AND MORTAR USING TAGUCHI’S METHOD

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2015.72 ◽

2015 ◽

Vol 2 (1) ◽

Author(s):

Sajid Khan Afridi ◽

Vanissorn Vimonsatit

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Elevated Temperatures ◽

Three Dimensional ◽

Silica Content ◽

Polymeric Chain ◽

Low Carbon ◽

Solid Ratio ◽

Mix Proportion ◽

Alkali Activated

Alkali activated pozzolan are known low carbon cementitious binders which can be used to replace cement. The material is also known as geopolymer because of its three dimensional polymeric chain and ring like structure consisting silica and alumina. A common type of pozzolan used is fly ash because of its rich silica content; therefore the term alkali activated fly-ash based binders is adopted. Despite much research and development of this material, there is no specific standard for design mix proportion. This research used the Taguchi’s design of experiment method to determine the optimum mix proportion of alkali activated fly ash based cement paste and mortar. Four factors were considered in the tests, silica fume, sand to cementitious ratio, liquid to solid ratio, and percentage of superplasticiser. Tests were conducted on the 9 batches of alkali activated fly-ash based paste and mortar samples to determine the compressive strength under ambient condition. Tests were also conducted to determine the residual strength of the samples after exposed to elevated temperatures. ANOVA analysis of the test results revealed the main factors contribution on the tested properties and led to the determination of the optimum design proportion of the factors considered in these tests.

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MECHANICAL PROPERTIES OF FLY ASH-BASED ALKALI-ACTIVATED CEMENT USING A STATISTICAL ANALYSIS TECHNIQUE

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2014.38 ◽

2014 ◽

Vol 1 (1) ◽

Author(s):

Hyuk Lee ◽

Vanissorn Vimonsatit

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Statistical Analysis ◽

Fly Ash ◽

Silica Fume ◽

Dry Density ◽

Analysis Method ◽

Solid Ratio ◽

Alkali Activated ◽

Alkali Activated Cement

This paper presents the mechanical properties of fly ash-based alkali-activated cement (AAC). A statistical analysis method was used to determine the effect of mix proportion parameters on the dry density and compressive strength of fly ash-based AAC pastes and mortars. For that purpose, sample mixtures were designed according to Taguchi’s experimental design method, i.e., in a L9 orthogonal array. Four factors were selected: “silica fume content” (SF), “sand to solid ratio” (s/c), “liquid to solid ratio” (l/s), and “superplasticiser content” (SP). The experimental results were analysed by using signal to noise for quality control of each mixture, and analysis of variance (ANOVA) was used to determine the significant effect on the compressive strength of fly ash-based AAC. Furthermore, a regression-analysis method was used to predict the compressive strength according to the variation of the four factors. Results indicated that silica fume is the most influencing parameter on compressive strength, which could be decreased by superplasticiser and l/s ratio. There is no significant effect of sand-to-cementitious ratio on compressive strength of fly ash-based AAC. The dry density decreases as the sand-to-cementitious ratio is decreased. The increasing l/s ratio and superplasticiser dosage could further decrease the dry density of fly ash-based AAC.

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Effect of mixing method on the mini-slump spread of Portland cement pastes

Revista IBRACON de Estruturas e Materiais ◽

10.1590/s1983-41952018000200010 ◽

2018 ◽

Vol 11 (2) ◽

pp. 410-431

Author(s):

J. S. RAUCCI ◽

R. T. CECEL ◽

R. C. O. ROMANO ◽

R. G. PILEGGI ◽

V. M. JOHN

Keyword(s):

Compressive Strength ◽

Water Demand ◽

Rotation Speed ◽

Raw Materials ◽

Fixed Time ◽

Mixing Conditions ◽

Cement Pastes ◽

Compressive Strength Test ◽

Mixing Method ◽

European Standards

Abstract The current compressive strength test for cement classification is performed under a fixed water to cement ratio according to the Brazilian and European standards, regardless the consistency obtained. However, under practical conditions the amount of water required is related to the rheological need to obtain and maintain a desired workability. Intrinsic cement characteristics influence the water demand such as the cement particle’s granulometry, specific surface area, density, the presence or not of water reducing admixtures, chemical and mineralogical nature of raw materials, etc., influence particles agglomeration state. Because water demand influences the mechanical properties of cement based products, the compressive strength class under a fixed water to solids ratio specified by the standards may not be representative for the user. The present work investigates the influence of mixing conditions on mini-slump spread results, a test that has been used for many years but never standardized. Cement paste samples were produced with varied mixing conditions (time and rotation speed) using a conventional stirrer and subjected to mini-slump spread test immediately after mixing and at fixed hydration times. Results show that mixing and hydration time do influence on mini-slump spread. At lower rotation speeds, results variability increases. Under fixed time after first contact with water, increasing rotation speed leads in a reduction of results variability and increase the test’s repeatability on cement pastes.

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The Solidification of Lead-Zinc Smelting Slag through Bentonite Supported Alkali-Activated Slag Cementitious Material

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16071121 ◽

2019 ◽

Vol 16 (7) ◽

pp. 1121 ◽

Cited By ~ 3

Author(s):

Yanhong Mao ◽

Faheem Muhammad ◽

Lin Yu ◽

Ming Xia ◽

Xiao Huang ◽

...

Keyword(s):

Compressive Strength ◽

Water Glass ◽

Cementitious Material ◽

Curing Temperature ◽

Solid Ratio ◽

Zinc Smelting ◽

Lead Zinc ◽

Smelting Slag ◽

Alkali Activated ◽

Zinc Smelting Slag

The proper disposal of Lead-Zinc Smelting Slag (LZSS) having toxic metals is a great challenge for a sustainable environment. In the present study, this challenge was overcome by its solidification/stabilization through alkali-activated cementitious material i.e., Blast Furnace Slag (BFS). The different parameters (water glass modulus, liquid-solid ratio and curing temperature) regarding strength development were optimized through single factor and orthogonal experiments. The LZSS was solidified in samples that had the highest compressive strength (after factor optimization) synthesized with (AASB) and without (AAS) bentonite as an adsorbent material. The results indicated that the highest compressive strength (AAS = 92.89MPa and AASB = 94.57MPa) was observed in samples which were prepared by using a water glass modulus of 1.4, liquid-solid ratio of 0.26 and a curing temperature of 25 °C. The leaching concentrations of Pb and Zn in both methods (sulfuric and nitric acid, and TCLP) had not exceeded the toxicity limits up to 70% addition of LZSS due to a higher compressive strength (>60 MPa) of AAS and AASB samples. While, leaching concentrations in AASB samples were lower than AAS. Conclusively, it was found that the solidification effect depends upon the composition of binder material, type of leaching extractant, nature and concentration of heavy metals in waste. The XRD, FTIR and SEM analyses confirmed that the solidification mechanism was carried out by both physical encapsulation and chemical fixation (dissolved into a crystal structure). Additionally, bentonite as an auxiliary additive significantly improved the solidification/stabilization of LZSS in AASB by enhancing the chemical adsorption capacity of heavy metals.

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Alkali Activated Binders Based on Metakaolin

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2015vol1.204 ◽

2015 ◽

Vol 1 ◽

pp. 200

Author(s):

Laura Sele ◽

Diana Bajare ◽

Girts Bumanis ◽

Laura Dembovska

Keyword(s):

Compressive Strength ◽

Portland Cement ◽

Water Absorption ◽

Raw Materials ◽

Sodium Silicate Solution ◽

Total Porosity ◽

Lead Silicate ◽

Cement Production ◽

Alkali Activated Binders ◽

Alkali Activated

According to research conducted in last 25 years, alkali activated binders have been considered as one of the most progressive alternative binders, which can effectively replace Portland cement. Production of alkali activated binders differs from the Portland cement production and is associated with lower CO2 emissions. The use of recycled industrial by-products and wastes is also possible, what corresponds to the future guidelines and principles of sustainable binder production in the world. The aim of this study was to create innovative alkali activated binders by using secondary raw materials, which will be different from the ones described in the scientific literature – alkali activated binders with porous structure. Raw materials used for the binders were metakaolin containing waste, waste from aluminium scrap recycling factory and recycled lead-silicate glass; solid contents were activated with modified sodium silicate solution with an addition of sodium hydroxide. The physical properties of alkali activated binders, such as density, water absorption, open and total porosity, were determined and flexural and compressive strength of hardened alkali-activated binders were tested at the age of 28 days. Durability was examined by sulphate resistance test, which was performed according to SIA 262/1, appendix D: applicability and relevance for use in practice. 40x40x160 mm prismatic specimens were used for expansion measurement and determination of compressive strength. The open porosity of obtained materials was up to 45%, density from 380 to 1720 kg/m3, compressive strength up to 29,8 MPa, water absorption 6 – 114 wt.%. After analysing the results from the sulphate test it was concluded that glass additive reduced the alkali activated binder resistance to sulphate attack.

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