Mechanism of Mn(II) Absorption and Desorption with CFBC Fly Ash Modified by Alkaline Wet Ball Milling

2018 ◽  
Vol 914 ◽  
pp. 151-159
Author(s):  
Ya Hong Xu ◽  
Zhong Hui Xu ◽  
Zao Jiang ◽  
Na Li ◽  
Ping Li ◽  
...  
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Circulating Fluidized Bed ◽  
Low Cost ◽  
Fluidized Bed Combustion ◽  
Freundlich Isotherms ◽  
Elovich Equation ◽  
Pseudo Second Order ◽  
Cfbc Fly Ash ◽  
Physical And Chemical

In this study, the adsorption properties of modified circulating fluidized-bed combustion (CFBC) fly ash by alkali wet millingwere investigated for Mn (II) cations. The effects ofNaOH content,milling speed and milling timeon the modification processof CFBC fly ashwerestudied. Preliminary statistical analysis has indicated thatmetal concentration, time, pH, fly ash dosage and temperaturewere the most importantvariables that affect the adsorption capacity. Results lead towards the conclusion that alkali wet millingtreatment cansignificantly increasethe adsorption capacity of the CFBC fly ash. The adsorption mechanism of the modified CFBCfly ash was determined using Langmuir, Freundlich isotherms and the Lagergren pseudo-first-order, pseudo-second-order, Elovich equation and the intraparticle diffusion equation, which indicated it was not thesole rate determiningstep, and the adsorption process was controlled by physical and chemical adsorption.The results showed that theCFBC fly ash can be utilized as a low-cost adsorbent for the removal of Mn (II) ionsfrom solution.

scholarly journals Comparative studies on the adsorption of Pb(II) ions by fly ash and slag obtained from CFBC technology

2019 ◽  
Vol 21 (4) ◽  
pp. 72-81 ◽  
Author(s):  
Tomasz Kalak ◽  
Ryszard Cierpiszewski
Keyword(s):  
Fly Ash ◽  
Circulating Fluidized Bed ◽  
Chemical Properties ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Maximum Adsorption Capacity ◽  
Fluidized Bed Combustion ◽  
Freundlich Model ◽  
Pseudo Second Order ◽  
Physical And Chemical

Abstract Fly ash and slag were examined for the removal processes of Pb(II) ions from water in batch experiments under different conditions of adsorbent dosage, initial concentration, pH and contact time. The materials are industrial waste generated from the high temperature treatment of sewage sludge by the circulating fluidized bed combustion (CFBC) technology. Physical and chemical properties, as well as adsorption efficiency and calculated maximum adsorption capacity of Pb(II) ions were determined using a variety of methods. The kinetic analysis revealed that the adsorption process is better described by the pseudo-second order equation and it is well fitted to the Freundlich model.

Utilization of Circulating Fluidized Bed Combustion (CFBC) Fly Ash and Coal-Fired Fly Ash in Portland Cement

2014 ◽  
Vol 629-630 ◽  
pp. 306-313 ◽  
Author(s):  
Mao Chieh Chi ◽  
Ran Huang ◽  
Te Hsien Wu ◽  
Toun Chun Fou
Keyword(s):  
Fly Ash ◽  
Portland Cement ◽  
Fluidized Bed ◽  
Building Materials ◽  
Circulating Fluidized Bed ◽  
Setting Time ◽  
Fluidized Bed Combustion ◽  
Initial Setting Time ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) fly ash is a promising admixture for construction and building materials due to its pozzolanic activity and self-cementitious property. In this study, CFBC fly ash and coal-fired fly ash were used in Portland cement to investigate the pozzolanic and cementitious characteristics of CFBC fly ash and the properties of cement-based composites. Tests show that CFBC fly ash has the potential instead of cementing materials and as an alternative of pozzolan. In fresh specimens, the initial setting time of mortars increases with the increasing amount of cement replacement by CFBC fly ash and coal-fire fly ash. In harden specimens, adding CFBC fly ash to replace OPC reduces the compressive strength. Meanwhile, CFBC fly ash would results in a higher length change when adding over 30%. Based on the results, the amount of CFBC fly ash replacement cement was recommended to be limited below 20%.

Chemical Properties and Reactivity of CFBC Fly Ash

2016 ◽  
Vol 722 ◽  
pp. 132-139 ◽  
Author(s):  
Tomáš Váchal ◽  
Rostislav Šulc ◽  
Tereza Janků ◽  
Pavel Svoboda
Keyword(s):  
Thermal Properties ◽  
Fly Ash ◽  
Circulating Fluidized Bed ◽  
Chemical Properties ◽  
Total Content ◽  
Calorimetric Measurement ◽  
Fluidized Bed Combustion ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion ◽  
Methods Of Measurement

This paper describes chemical properties of fly ash from Circulating fluidized Bed Combustion (CFBC). There are shown thermal properties of fly ash using calorimetric measurement and the total content of calcium oxide CaO was determined. This paper describes the methods of measurement for determining these properties including granulometric measurement and chemical analysis. Also there were described and evaluated properties of fly ash and the reactivity of the fly ash was compared.

Influence of Milling on some Chemical Properties and Reactivity of CFBC Fly Ash

2018 ◽  
Vol 760 ◽  
pp. 73-80 ◽  
Author(s):  
Tomáš Váchal ◽  
Rostislav Šulc ◽  
Tereza Janků ◽  
Pavel Svoboda
Keyword(s):  
Fly Ash ◽  
Chemical Analysis ◽  
Circulating Fluidized Bed ◽  
Chemical Properties ◽  
Total Content ◽  
Calorimetric Measurement ◽  
Fluidized Bed Combustion ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion ◽  
Methods Of Measurement

This paper describes influence of milling on chemical properties of fly ash from Circulating fluidized Bed Combustion (CFBC). Specific properties of fly ash was determined using calorimetric measurement. It was determined heat properties and total content of calcium oxide CaO. The following methods of measurement were also performed: granulometric measurement and chemical analysis. The ash properties of non-milled and milled ashes were also described and evaluated and the ash reactivity was compared.

Grindability of CFBC Fly Ash and High Temperature Fly Ash

2016 ◽  
Vol 722 ◽  
pp. 100-107
Author(s):  
Rostislav Šulc ◽  
Martin Vašák ◽  
Jaromír Poláček
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Power Plant ◽  
Circulating Fluidized Bed ◽  
Physical And Mechanical Properties ◽  
Physical Parameters ◽  
Fluidized Bed Combustion ◽  
Particle Size Analyzer ◽  
Cfbc Fly Ash ◽  
Circulating Fluidized Bed Combustion

This article presents the results of fly ash from Circulating fluidized Bed Combustion (CFBC) and high temperature fly ash (defined in EN 450-1) with modified physical parameters by grinding. For this treatment was used the mechanical mill. In this case were used two fly ashes. The first sample was from Tisová power plant (CFBC fly ash) and the second one from Počerady power plant (high temperature fly ash). The modified samples were tested for the effect of grinding time on its grindability and granulometry. For testing of samples was used laser diffraction with particle size analyzer and the grindability was determined. The reason for this step was found more stable and better material which achieves better physical and mechanical properties. The first step is mechanical treatment of fly ash’s granule.

scholarly journals Utilization of CFBC Fly Ash as a Binder to Produce In-Furnace Desulfurization Sorbent

2018 ◽  
Vol 10 (12) ◽  
pp. 4854 ◽  
Author(s):  
Chulseoung Baek ◽  
Junhyung Seo ◽  
Moonkwan Choi ◽  
Jinsang Cho ◽  
Jiwhan Ahn ◽  
...  
Keyword(s):  
Fly Ash ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Coal Ash ◽  
Limestone Powder ◽  
Fluidized Bed Combustion ◽  
High Concentration ◽  
Cfbc Fly Ash ◽  
Desulfurization Efficiency ◽  
Free Cao

Circulating fluidized bed combustion (CFBC) power generation technology is known to efficiently reduce the emission of air pollutants, such as SO2 and NO2, from coal combustion. however, CFBC coal ash contains high contents of free CaO, making it difficult to recycle. This research has been conducted to find ways to use the self-hardening property of CFBC coal ash, one of its inherent characteristics. As part of these efforts, the present study intended to investigate the properties and desulfurization efficiency of Ca-based desulfurization sorbents using CFBC fly-ash as a binder. Limestone powder was mixed with CFBC fly-ash and Ca(OH)2 to fabricate desulfurization sorbents, and it generated hydrate of cement, including portlandite, ettringite, and calcium silicate, etc. The compressive strength of the desulfurization absorbent prepared by CFBC fly ash and Ca(OH)2 was 72–92% that of the desulfurized absorbent prepared by using general cement as a binder. These absorbents were then compared in terms of desulfurization efficiency using a high-temperature fluidized bed reactor. It was confirmed that the desulfurization absorbents fabricated using CFBC fly-ash as a binder achieved the best performance in terms of absorption time, which reflects the time taken for them to remove over 90% of high-concentration SO2 gas, and the conversion ratio, which refers to the ratio of CaO turning into CaSO4.

scholarly journals Utilization of low sulfur fly ash from circulating fluidized bed combustion burner as geopolymer binder

2020 ◽  
Vol 22 (2) ◽  
pp. 94-100
Author(s):  
Antoni Antoni ◽  
Stacia Dwi Shenjaya ◽  
Maria Lupita ◽  
Samuel Santosa ◽  
David Wiyono ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Water Demand ◽  
Circulating Fluidized Bed ◽  
Fluidized Bed Combustion ◽  
Naoh Solution ◽  
Cfbc Fly Ash ◽  
Low Sulfur ◽  
Circulating Fluidized Bed Combustion

Circulating fluidized bed combustion (CFBC) is a newer type of burner that employ a circulating process to burn fuel effectively. CFBC burning process is gaining more popularity due to its compact size, high efficiency and lower burning temperature compared to the pulverized coal combustion (PCC) burner. The CFBC burner produces fly ash with different physical properties compared to the PCC burner, i.e. the fly ash is not rounded, and required higher water content for comparable workability. The CFBC fly ash also has a high sulfur content that is detrimental for hardened concrete. Due to its drawbacks, the CFBC hardly used as cementitious material and geopolymer precursor. This study focuses on comparing variations in the concentration of NaOH solution and variations in the ratio of alkaline activators to the setting time and compressive strength of geopolymer mortars on a new class of CFBC fly ash, which have low sulfur content. The concentrations of NaOH solution were 6M, 8M, 10M, and 12M, while the alkaline activator ratios used were 3.0, 2.5, 2.0, 1.0, and 0.5. It was concluded that the low sulfur CFBC fly ash has a potential to be utilized as geopolymer precursor, however, with a shortcoming in its high water demand. The CFBC fly ash used in this study resulted in a geopolymer matrix with good compressive strength and stability. The water demand varies with the fly ash sampling time shows the challenges in the utilization of the fly ash. The highest mortar’s compressive strength, 33.4 MPa at 90 days was achieved at NaOH concentration of 8M and ratio of sodium silicate solution to sodium hydroxide solution of 2.5 with excellent stability.

Optimization of the Composition of the Binder Based on CFBC Fly Ash

2018 ◽  
Vol 760 ◽  
pp. 184-192 ◽  
Author(s):  
Petr Formáček ◽  
Rostislav Šulc
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Computer Programs ◽  
Fluidized Bed Combustion ◽  
Slaked Lime ◽  
Cfbc Fly Ash ◽  
Main Components ◽  
Circulating Fluidized Bed Combustion

This paper is bound to previous research of materials based on fly ash. The main objective was to design an optimal ternary (three-component) binder based on fly ash from Circulating fluidized Bed Combustion (CFBC). The design of the binder is based on the optimization of individual components. Main components of the binder are CFBC fly ash, high-temperature fly ash and slaked lime. The binder was progressively designed and optimized. The strength characteristics of the various binders were measured, evaluated and the results were inserted into computer programs Surfer 8 and Grapher 8 from which ternary diagrams with strength maps were created. The best binder mixture were selected from the optimization process.

scholarly journals Effect of Elevated Temperature on Engineering Properties of Ternary Blended No-cement Mortar

2018 ◽  
Vol 206 ◽  
pp. 02008
Author(s):  
Harry Hermawan ◽  
Ta-Peng Chang ◽  
Herry Suryadi Djayaprabha ◽  
Hoang-Anh Nguyen
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Elevated Temperatures ◽  
Circulating Fluidized Bed ◽  
Cement Mortar ◽  
Strength Loss ◽  
Pulse Velocity ◽  
Engineering Properties ◽  
Fluidized Bed Combustion ◽  
Cfbc Fly Ash

This paper aims to examine the engineering properties of ternary blended no-cement mortar which subjected to the various elevated temperatures exposure. The mortars were produced by mixing ground granulated blast furnace slag (S), Type-F fly ash (F) and circulating fluidized bed combustion (CFBC) fly ash (C). The water-to-binder ratio was fixed at 0.40 and the CFBC fly ash content was fixed at 15 wt.% of the mixture that acts as the main activator. The specimens were exposed to the elevated temperatures ranging from 200°C to 800°C. The mass loss, compressive strength, and ultrasonic pulse velocity were determined before and after exposure to the elevated temperatures. The obtained results showed after exposed to high temperature, the mortar weight reduction was discovered in the range of 6.0–8.7% when temperature rose from 200°C to 600°C, and decreased significantly up to 12.4% as temperature reached 800°C. The major strength loss occurred after 600°C with the residual compressive strength approximately at 44.2%. At 200°C, increased strength was found on SFC mixture and when temperature rose to 400°C, the specimens still can resist the load reliably with the strength loss less than 8.0%. Consequently, SFC mortar generates good durability and heat resistance below 400°C.

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