scholarly journals The Mineral Carbonation Process of High Calcium Fly Ash under Elevated Carbon Dioxide Pressure and Temperature

2020 ◽  
Vol 3 (6) ◽  
pp. 71-77
Author(s):  
Jakub Sobala ◽  
Natalia Czuma ◽  
Jakub Bator ◽  
Paweł Baran ◽  
Piotr Zabierowski ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Fly Ash ◽  
Elevated Carbon Dioxide ◽  
Mineral Carbonation ◽  
Carbonation Process ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Carbon Dioxide Pressure

scholarly journals Influencing Factors of the Mineral Carbonation Process of Iron Ore Mining Waste in Sequestering Atmospheric Carbon Dioxide

2021 ◽  
Vol 13 (4) ◽  
pp. 1866
Author(s):  
Noor Allesya Alis Ramli ◽  
Faradiella Mohd Kusin ◽  
Verma Loretta M. Molahid
Keyword(s):  
Carbon Dioxide ◽  
Particle Size ◽  
Chemical Composition ◽  
Iron Ore ◽  
Divalent Cations ◽  
Mining Industry ◽  
Mining Waste ◽  
Aluminum Silicate ◽  
Mineral Carbonation ◽  
Carbonation Process

Mining waste may contain potential minerals that can act as essential feedstock for long-term carbon sequestration through a mineral carbonation process. This study attempts to identify the mineralogical and chemical composition of iron ore mining waste alongside the effects of particle size, temperature, and pH on carbonation efficiency. The samples were found to be alkaline in nature (pH of 6.9–7.5) and contained small-sized particles of clay and silt, thus indicating their suitability for mineral carbonation reactions. Samples were composed of important silicate minerals needed for the formation of carbonates such as wollastonite, anorthite, diopside, perovskite, johannsenite, and magnesium aluminum silicate, and the Fe-bearing mineral magnetite. The presence of Fe2O3 (39.6–62.9%) and CaO (7.2–15.2%) indicated the potential of the waste to sequester carbon dioxide because these oxides are important divalent cations for mineral carbonation. The use of small-sized mine-waste particles enables the enhancement of carbonation efficiency, i.e., particles of <38 µm showed a greater extent of Fe and Ca carbonation efficiency (between 1.6–6.7%) compared to particles of <63 µm (0.9–5.7%) and 75 µm (0.7–6.0%). Increasing the reaction temperature from 80 °C to 150–200 °C resulted in a higher Fe and Ca carbonation efficiency of some samples between 0.9–5.8% and 0.8–4.0%, respectively. The effect of increasing the pH from 8–12 was notably observed in Fe carbonation efficiency of between 0.7–5.9% (pH 12) compared to 0.6–3.3% (pH 8). Ca carbonation efficiency was moderately observed (0.7–5.5%) as with the increasing pH between 8–10. Therefore, it has been evidenced that mineralogical and chemical composition were of great importance for the mineral carbonation process, and that the effects of particle size, pH, and temperature of iron mining waste were influential in determining carbonation efficiency. Findings would be beneficial for sustaining the mining industry while taking into account the issue of waste production in tackling the global carbon emission concerns.

scholarly journals Mineral carbonation process of carbon dioxide using animal bone

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110196
Author(s):  
Brendon Mpofu ◽  
Hembe E Mukaya ◽  
Diakanua B Nkazi
Keyword(s):  
Carbon Dioxide ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Economic Feasibility ◽  
Mineral Carbonation ◽  
Agitation Rate ◽  
Carbonation Reaction ◽  
Carbonation Process ◽  
The Cost ◽  
Cow Bone

Carbon dioxide has been identified as one of the greenhouse gases responsible for global warming. Several carbon capture and storage technologies have been developed to mitigate the large quantities of carbon dioxide released into the atmosphere, but these are quite expensive and not easy to implement. Thus, this research analyses the technical and economic feasibility of using calcium leached from cow bone to capture and store carbon dioxide through the mineral carbonation process. The capturing process of carbon dioxide was successful using the proposed technique of leaching calcium from cow shinbone (the tibia) in the presence of HCl by reacting the calcium solution with gaseous carbon dioxide. AAS and XRF analysis were used to determine the concentration of calcium in leached solutions and the composition of calcium in cow bone respectively. The best leaching conditions were found to be 4 mole/L HCl and leaching time of 6 h. Under these conditions, a leaching efficiency of 91% and a calcium conversion of 83% in the carbonation reaction were obtained. Other factors such as carbonation time, agitation rate, and carbonation reaction temperature had little effect on the yield. A preliminary cost analysis showed that the cost to capture 1 ton of CO2 with the proposed technique is about US$ 268.32, which is in the acceptable range of the capturing process. However, the cost of material used and electricity should be reviewed to reduce the preliminary production cost.

Natural fiber reinforced high calcium fly ash geopolymer mortar

2020 ◽  
Vol 241 ◽  
pp. 118143 ◽  
Author(s):  
Ampol Wongsa ◽  
Ronnakrit Kunthawatwong ◽  
Sakchai Naenudon ◽  
Vanchai Sata ◽  
Prinya Chindaprasirt
Keyword(s):  
Fly Ash ◽  
Natural Fiber ◽  
Fiber Reinforced ◽  
High Calcium ◽  
High Calcium Fly Ash

scholarly journals Novel Analytical Method for Mix Design and Performance Prediction of High Calcium Fly Ash Geopolymer Concrete

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 900
Author(s):  
Chamila Gunasekara ◽  
Peter Atzarakis ◽  
Weena Lokuge ◽  
David W. Law ◽  
Sujeeva Setunge
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Gradient Algorithm ◽  
Geopolymer Concrete ◽  
Statistical Regression ◽  
Solid Ratio ◽  
Marquardt Algorithm ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Matlab Programming

Despite extensive in-depth research into high calcium fly ash geopolymer concretes and a number of proposed methods to calculate the mix proportions, no universally applicable method to determine the mix proportions has been developed. This paper uses an artificial neural network (ANN) machine learning toolbox in a MATLAB programming environment together with a Bayesian regularization algorithm, the Levenberg-Marquardt algorithm and a scaled conjugate gradient algorithm to attain a specified target compressive strength at 28 days. The relationship between the four key parameters, namely water/solid ratio, alkaline activator/binder ratio, Na2SiO3/NaOH ratio and NaOH molarity, and the compressive strength of geopolymer concrete is determined. The geopolymer concrete mix proportions based on the ANN algorithm model and contour plots developed were experimentally validated. Thus, the proposed method can be used to determine mix designs for high calcium fly ash geopolymer concrete in the range 25–45 MPa at 28 days. In addition, the design equations developed using the statistical regression model provide an insight to predict tensile strength and elastic modulus for a given compressive strength.

scholarly journals Influence of Particle Size Distribution of High Calcium Fly Ash on HVFA Mortar Properties

2018 ◽  
Vol 20 (2) ◽  
pp. 51
Author(s):  
Antoni . ◽  
Hendra Surya Wibawa ◽  
Djwantoro Hardjito
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Setting Time ◽  
High Volume ◽  
High Volume Fly Ash ◽  
High Calcium ◽  
High Calcium Fly Ash

This study evaluates the effect of particle size distribution (PSD) of high calcium fly ash on high volume fly ash (HVFA) mortar characteristics. Four PSD variations of high calcium fly ash used were: unclassified fly ash and fly ash passing sieve No. 200, No. 325 and No. 400, respectively. The fly ash replacement ratio of the cementitious material ranged between 50-70%. The results show that with smaller fly ash particles size and higher levels of fly ash replacement, the workability of the mixture was increased with longer setting time. There was an increase in mortar compressive strength with finer fly ash particle size, compared to those with unclassified ones, with the highest strength was found at those with fly ash passing mesh No. 325. The increase was found due to better compactability of the mixture. Higher fly ash replacement reduced the mortar’s compressive strength, however, the rate was reduced when finer fly ash particles was used.

scholarly journals Durability of blended cement against sodium sulphate attack and alkali-silica reaction

2021 ◽  
Author(s):  
Giri Raj Adhikari
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Alkali Silica Reaction ◽  
Sulphate Attack ◽  
Ternary Blends ◽  
Replacement Level ◽  
Fly Ashes ◽  
Study Results ◽  
High Calcium ◽  
High Calcium Fly Ash

Blended cements were studied for their efficacy against sulphate attack and alkali-silica reaction using six different types of fly ashes, a slag, a silica fume and four types of General Use Portland cement of different alkalinity. The study results showed that low calcium fly ash, silica fume and ground granulated blast furnace slag enhanced the sulphate resistance of cement with increased efficacy with the increase in the replacement level. However, slag and silica fume, especially at low replacement levels, exhibited increased rate of expansion beyond the age of 78 weeks. On the contrary, high calcium fly ashes showed reduced resistance to sulphate attack with no clear trend between the replacement level and expansion. Ternary blends consisting of silica fume, particulary in the amount of 5%, high calcium fly ashes and General Use (GU) cement provided high sulphate resistance, which was attributable to reduced permeability. In the same way, some of ternary blends consisting of slag, high calcium fly ash and GU cement improved sulphate resistance. Pre-blending optimum amount of gypsum with high calcium fly ash enhanced the latter's resistance to sulphate attack by producing more ettringite at the early stage of hydration. In the context of alkali-silica reaction permeability was found to be a contributing factor to the results of the accelerated mortar bar test. High-alkali, high-calcium fly ash was found to worsen the alkali silica reaction when used in concrete containing some reactive aggregates. Ternary blend of slag with high calcium fly ash was found to produce promising results in terms of counteracting alkali-silica reaction.

scholarly journals Resistance to Sulfuric Acid Corrosion of Geopolymer Concrete Based on Different Binding Materials and Alkali Concentrations

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7109
Author(s):  
Wei Yang ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang ◽  
Wei Ge ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Fly Ash ◽  
Acid Corrosion ◽  
Geopolymer Concrete ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Naoh Solution ◽  
Sulfuric Acid Corrosion

Geopolymer binder is expected to be an optimum alternative to Portland cement due to its excellent engineering properties of high strength, acid corrosion resistance, low permeability, good chemical resistance, and excellent fire resistance. To study the sulfuric acid corrosion resistance of geopolymer concrete (GPC) with different binding materials and concentrations of sodium hydroxide solution (NaOH), metakaolin, high-calcium fly ash, and low-calcium fly ash were chosen as binding materials of GPC for the geopolymerization process. A mixture of sodium silicate solution (Na2SiO3) and NaOH solution with different concentrations (8 M and 12 M) was selected as the alkaline activator with a ratio (Na2SiO3/NaOH) of 1.5. GPC specimens were immersed in the sulfuric acid solution with the pH value of 1 for 6 days and then naturally dried for 1 day until 98 days. The macroscopic properties of GPC were characterized by visual appearance, compressive strength, mass loss, and neutralization depth. The materials were characterized by SEM, XRD, and FTIR. The results indicated that at the immersion time of 28 d, the compressive strength of two types of fly ash-based GPC increased to some extent due to the presence of gypsum, but this phenomenon was not observed in metakaolin-based GPC. After 98 d of immersion, the residual strength of fly ash based GPC was still higher, which reached more than 25 MPa, while the metakaolin-based GPC failed. Furthermore, due to the rigid 3D networks of aluminosilicate in fly ash-based GPC, the mass of all GPC decreased slightly during the immersion period, and then tended to be stable in the later period. On the contrary, in metakaolin-based GPC, the incomplete geopolymerization led to the compressive strength being too low to meet the application of practical engineering. In addition, the compressive strength of GPC activated by 12 M NaOH was higher than the GPC activated by 8 M NaOH, which is owing to the formation of gel depended on the concentration of alkali OH ion, low NaOH concentration weakened chemical reaction, and reduced compressive strength. Additionally, according to the testing results of neutralization depth, the neutralization depth of high-calcium fly ash-based GPC activated by 12 M NaOH suffered acid attack for 98 d was only 6.9 mm, which is the minimum value. Therefore, the best performance was observed in GPC prepared with high-calcium fly ash and 12 M NaOH solution, which is attributed to gypsum crystals that block the pores of the specimen and improve the microstructure of GPC, inhibiting further corrosion of sulfuric acid.

Sign in / Sign up

Export Citation Format

Share Document