Sugar Cane Wastes as Pozzolanic Materials: Application of Mathematical Model (original) (raw)
Related papers
Cement and Concrete Research, 2005
The reaction kinetics of a mixture of sugar cane straw with 20% and 30% of clay burned at 800 and 1000-C and lime (calcium hydroxide) is studied. A direct method (accelerated chemical method) based on the measurement of the amount of lime reacted as the reaction proceeds is applied. A kinetic-diffusive model published in a previous paper by some authors of this research is used. The fitting of the model by computerized methods allows determining the kinetic coefficients that characterize the process: in particular, the reaction rate constant. The index of pozzolanic activity evaluated according to the obtained values of the reaction rate constant permits to characterize the pozzolanic activity of these materials in a rigorous way. The results are compared with the results obtained applying an indirect method (conductometric method). The kinetic results obtained in the current paper allow affirming that the kinetic-diffuse model used in order to evaluate the pozzolanic reaction is valid, independently of the method used for the evaluation of the pozzolanic activity.
This paper reports on the influence of calcining temperature (800 and 1000°C) on the pozzolanic activation of sugar cane straw (SCS). The reaction kinetics of SCS ash-lime mixtures were inferred from physicochemical characteristics (X-ray diffraction patterns and thermogravimetry analysis. The fitting of a kinetic-diffusive model to the experimental data (fixed lime versus time) allowed the computing of the kinetic parameters (reaction rate constant) of the pozzolanic reaction. Results obtained confirm that the sugar cane straw ash (SCSA) calcined at 800 and 1000°C have properties indicative of very high pozzolanic activity. No influence of calcining temperature on the pozzolanic activity was observed. Also, no crystalline compounds during the pozzolanic reaction were identified up to 90 days of reaction. Environmental durability and strength of the consequential mortars remain to be assessed.
2001
In this paper the kinetics of the pozzolanic reaction between lime (calcium hydroxide) and sugar cane straw ash with 20 and 30% of clay burned at 800 and 1000 0 C is studied. A simple experimental technique where the conductivity is the experimental variable was used. A calibration curve was established for correlating the conductivity with the concentration of calcium hydroxide (CH). We elaborated a mathematical model that allows us to describe the process in kinetic -diffusive or kinetic regimen. The fitting of the model by computerized methods lets us determine the parameters that characterize the process: i.e. the diffusion coefficient and reaction rate constant. The pozzolanic activity is evaluated according to the obtained values of the reaction rate constant. The results show that sugar cane straw ash (SCSA) has a good pozzolanic activity comparable to that of the rice husk ask (RHA).
ACS Sustainable Chemistry & Engineering, 2016
Biomass has gained in importance as an energy source in recent years. One of the crops that presents interesting opportunities with regard to biomass is sugar cane. In Brazil, sugar cane production is increasing for alcohol and sugar manufacture. Some by-products, such as sugar cane straw, also are obtained during harvesting. Due the calorific value of the sugar cane straw, its use as biomass is increasing. After the straw is burned to produce energy, an ash is obtained: sugar cane straw ash (SCSA). This waste needs an appropriate destination and, since the recent publication of successful studies using biomass derived-ashes as pozzolanic material, the present study aimed to assess the pozzolanic reactivity of sugar cane straw ash. The pozzolanic activity was assessed using a new and simple recently proposed method: evaluation of the electrical conductivity of calcium hydroxide (CH) and pozzolan suspensions, in which solid CH is initially present. These results were compared to those of two other well-established techniques: Fourier transformed infrared spectroscopy and thermogravimetric analysis. The evaluation by all three techniques is similar and shows that sugar cane straw ash is a good pozzolanic material: high lime fixation values for CH:SCSA mixes were determined by thermogravimetric analysis and unsaturation respect to CH in 3.5:6.5 CH:SCSA suspension was achieved at 60ºC. According to this behaviour, a bright future for SCSA as a replacement for Portland cement is expected.
In this paper the kinetics of the pozzolanic reaction between lime (calcium hydroxide) and sugar cane straw ash with 20 and 30% of clay burned at 800 and 1000 0 C is studied. A simple experimental technique where the conductivity is the experimental variable was used. A calibration curve was established for correlating the conductivity with the concentration of calcium hydroxide (CH). We elaborated a mathematical model that allows us to describe the process in kinetic -diffusive or kinetic regimen. The fitting of the model by computerized methods lets us determine the parameters that characterize the process: i.e. the diffusion coefficient and reaction rate constant. The pozzolanic activity is evaluated according to the obtained values of the reaction rate constant. The results show that sugar cane straw ash (SCSA) has a good pozzolanic activity comparable to that of the rice husk ask (RHA).
Crimson Publishers LLC, 2020
In this research work a synthetic review of the quantitative characterization of various materials (sugar cane waste ashes, bamboo leaf ash, calcined paper sludge, loessic soils, zeolite, fly ash and silica fume) based on the computing of the kinetic parameters of the pozzolanic reaction in pozzolan/calcium hydroxide(CH) systems is offered. The paper presents of more relevant results in the quantitative characterization (computing of the kinetic parameters) of the pozzolanic reaction of different materials originated from agriculture, mining or industry activities carried out by the authors.Two pozzolanic activity tests (conductometric method and accelerated chemical method) are employed. A kinetic-diffusive model (published by the authors in previous works) is used to describe the pozzolanic reaction. The kinetic parameters that characterize the process (in particular, the reaction rate constant and free energy of activation) are determined with relative accuracy in the fitting process of the model. The pozzolanic activity is quantitatively evaluated according to the results obtained for the kinetic parameters. This allows the comparison in a direct way of the pozzolanic reactivity of the materials, which is very useful for the employment of these materials for envisaged applications. The values of the reaction rate constant jointly with the free energy of activation give a precise index of the reactivity or pozzolanic activity of the materials. Complementary experimental techniques, such as X-ray diffraction (XRD) and scanning electron microscope (SEM), were also employed, but not shown in the paper for space reason since that would necessitate a much larger paper.
Influence of calcining temperature on the activation of sugar-cane bagasse: kinetic parameters
Advances in Cement Research, 2007
The present paper describes a study of the influence of calcining temperature (800 and 10008C) on the activation of sugar-cane bagasse. The reaction kinetics in a bagasse ash-lime system were investigated by means of X-ray diffraction patterns and thermogravimetric curves. The kinetic parameters were calculated by applying a kineticdiffusive model. The results obtained in this study show, on one hand, that the bagasse ash calcined at 800 and 10008C has a similar pozzolanic activity after 28-90 days of reaction. There were, however, important differences with regard to its activation rate. On the other hand, no crystalline compounds from a pozzolanic reaction were detected. The values of the kinetic parameters confirmed the different activation of bagasse ash as a function of the calcining temperature applied.
Cement & Concrete Composites, 2009
In this paper a study of calcining conditions on the microstructural features of sugar cane waste ash (SCWA) is carried out. For this purpose, some microparticles (<90 lm) of sugar cane straw ash and sugar cane bagasse ash of samples calcined at 800°C and 1000 are studied by combining the bright field and the dark field images with the electron diffraction patterns in the transmission electron microscopy (TEM). It is appreciated that the morphology and texture of these microparticles change when silicon or calcium are present. Furthermore, it is observed that iron oxide (magnetite Fe 3 O 4 ) is located in the calcium-rich particles.
Pozzolanic behaviour of a bagasse ash from the boiler of a Cuban sugar factory
Advances in Cement Research, 2013
The paper presents a study of the pozzolanic reaction kinetics between calcium hydroxide and sugar cane bagasse ash (SCBAB) from the boiler of a sugar factory. A pozzolanic activity method (conductometric method) based on measurement of the electrical conductivity of the SCBAB/calcium hydroxide solution as the reaction proceeds is applied and the kinetic parameters are then quantified by applying a kinetic–diffusive model to the process. The kinetic parameters that characterise the process (in particular, the reaction rate constant and the free energy of activation) were determined with relative accuracy in the fitting process of the model. The pozzolanic activity is quantitatively evaluated according to the obtained values of the kinetic parameters. Other experimental techniques, such as X-ray diffraction and scanning electron microscopy, are also employed. Comparison with another bagasse ash calcined under controlled conditions in the laboratory is carried out. The results show th...
Characterization of the Pozzolanic Activity of Various Agroindustrial Wastes : Kinetic Parameters
2015
In this research work a quantitative characterization of various materials (sugar cane waste ashes, bamboo leaf ash, calcined paper sludge, loessic soils, zeolite and fly ash) as pozzolanic materials based on the computing of the kinetic parameters of the pozzolanic reaction in pozzolan/calcium hydroxide systems is offered. The paper presents a synthetic overview of the more relevant results in the quantitative characterization of the pozzolanic reaction (computing of the kinetic parameters) of different materials carried out by the authors. Other experimental techniques, such as X-ray diffraction (XRD) and scanning electron microscope (SEM), were also employed. Two pozzolanic activity tests (conductometric method and accelerated chemical method) are employed. A kinetic-diffusive model (published by the authors in previous works) is used to describe the pozzolanic reaction. The kinetic parameters that characterize the process (in particular, the reaction rate constant and free energ...