Kinetic Calculations for the Calcination Reaction of Limestone Modified by Alkaline Industrial Wastes

2011 ◽  
Vol 356-360 ◽  
pp. 1175-1179 ◽  
Author(s):  
Hong Tao Liu ◽  
Kui Hua Han ◽  
Sheng Li Niu ◽  
Chun Mei Lu
Keyword(s):  
Calcium Content ◽  
Isoconversional Method ◽  
Differential Method ◽  
Point Of View ◽  
Industrial Wastes ◽  
Heating Rates ◽  
Metal Impurities ◽  
Carbide Slag ◽  
High Calcium ◽  
Kinetic Calculations

The enhancement of alkaline industrial wastes on the desulfurization performance and utilization of limestone has already been found. In order to explore the reason of this phenomenon from the kinetic point of view, two typical alkaline wastes, carbide slag with a high calcium content and Bayer process red mud with more metal impurities, were adopted to research. Kinetic behavior of calcination reaction was calculated using the isoconversional method of Kissinger-Akahira-Sunose method (a differential method) and Flynn-Wall-Ozawa method (an integral method) at four different heating rates: 10, 20, 40 and 80 K•min-1. Values calculated by these two methods are very close, and the calculated result shows that calcination rate constant of modified limestone is obviously greater than that of original limestone, under the same calcination temperature, which means that alkaline wastes are advantageous to the thermal decomposition of limestone.

Metallic Calcium as a Precursor for Sol-Gel Synthesis of CaCO3-SiO2 and CaO-SiO2 Systems

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 278-290
Author(s):  
Piotr Marciniak ◽  
Bogna Sztorch ◽  
Agnieszka Martyła ◽  
Agnieszka Czapik ◽  
Mikołaj Stodolny ◽  
...  
Keyword(s):  
Sol Gel ◽  
Phase Segregation ◽  
Calcium Content ◽  
Nitrogen Adsorption ◽  
Point Of View ◽  
Oxide Systems ◽  
Molar Ratios ◽  
High Calcium ◽  
Sol Gel Synthesis ◽  
Metallic Calcium

A series of binary oxide systems with Ca/Si molar ratios of 0.05, 0.1, 0.25, 0.5 and 1.0 have been synthesized by the sol-gel technique from tetraethyl orthosilicate (TEOS) and metallic calcium powder. Upon calcination, a side effect of wollastonite formation as a result of the reaction between the components of the material has been observed in the two calcium-richest systems. The increase in calcium content produces an effect of porosity promotion. At high calcium contents, the homogeneity of the systems is limited by the ability of silica to disperse the calcium component. The properties of these systems are determined by the silica surface coverage with a large amount of the scattered CaCO3 fine microcrystallites (calcite), resulting from the phase segregation. The gels were characterized by X-ray powder diffraction, low temperature nitrogen adsorption, transmission and scanning electron microscopy (TEM, SEM and SEM/EDS), thermogravimetric analysis (TGA), and FT-IR spectra, to describe the parameters important from the point of view of their application as a support for metal-based catalysts.

Variasi Penambahan Tepung Daun Kelor (Moringa Oleifera Lam.) pada Pembuatan Flakes Ditinjau dari Sifat Fisik, Sifat Organoleptik dan Kadar Kalsium

2017 ◽  
Vol 19 (1) ◽  
pp. 31-35
Author(s):  
Frieda Rosita Majid ◽  
Nur Hidayat ◽  
Waluyo Waluyo
Keyword(s):  
Physical Characteristic ◽  
Nutritional Value ◽  
Calcium Content ◽  
Organoleptic Characteristics ◽  
High Calcium ◽  
Randomized Experimental Design ◽  
Leaf Powder ◽  
The Difference ◽  
The Tropics ◽  
Moringa Oleifera Lam

Background:Moringa (Moringaoleifera Lam.) Is a plant of high nutritional value, grows scattered in the tropics and sub-tropics, but utilization is still low. Each section has its benefits Moringa one part is the Moringa leaves contain a high calcium. In 100 grams of material, fresh Moringa leaves contain as much as 440 mg of calcium in the form of flour whereas if it contains as much as 2,003 mg of calcium. One of its use in the manufacture of flakes added. Objective: Know the difference physical harateristi, organoleptic characteristic and calcium levels in flakes variations addition of Moringa leaf powder. Methods: The study is a randomized experimental design with simple, includes four kinds of treatments, two replications with two experimental units. Observations of physical characteristic were analyzed by descriptive, the organoleptic characteristic of data analysis using statistical test Kruskal-Wallis continued Mann-Whitney and methods of test calcium content using permanganometri then the data were analyzed descriptive. Results: The physical characteristics of flakes greenish-yellow, slightly fragrant aroma typical of flakes, rather unpleasant taste typical of Moringa leaves and a slightly crunchy texture. Organoleptic characteristics the color of flakes with moringa leaf powder 5%, the aroma of the flakes without addition moringa leaf powder, the flavour of flakes with additions moringa leaf powder 5% and the texture of flakes with additions moringa leaf powder 7,5% most prefered panelist and high levels calcium of flakes with additions 10% moringa leaf powder. Conclusion: There is a difference variations addition of moringa leaf powder on physical, organoleptic characteristic (color) and the level of calcium flakes.Flakes with the addition of 5% moringa leaf powder is the most prefered panelist.   Keywords:Moringa Leaf Flour, Flakes, Physical characteristic, organoleptic, Calcium

scholarly journals Location of Biorefineries Based on Olive-Derived Biomass in Andalusia, Spain

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3052
Author(s):  
Diego Cardoza ◽  
Inmaculada Romero ◽  
Teresa Martínez ◽  
Encarnación Ruiz ◽  
Francisco J. Gallego ◽  
...  
Keyword(s):  
Rural Areas ◽  
Raw Materials ◽  
Value Added ◽  
Olive Tree ◽  
Point Of View ◽  
Industrial Wastes ◽  
Olive Pomace ◽  
Crop Fields ◽  
Lignocellulosic Feedstock ◽  
Olive Stones

A biorefinery integrated process based on lignocellulosic feedstock is especially interesting in rural areas with a high density of agricultural and agro-industrial wastes, which is the case for olive crop areas and their associated industries. In the region of Andalusia, in the south of Spain, the provinces of Jaén, Córdoba and Seville accumulate more than 70% of the olive wastes generated in Spain. Therefore, the valorisation of these wastes is a matter of interest from both an environmental and a social point of view. The olive biorefinery involves a multi-product process from different raw materials: olive leaves, exhausted olive pomace, olive stones and olive tree pruning residues. Biorefinery processes associated with these wastes would allow their valorisation to produce bioenergy and high value-added renewable products. In this work, using geographic information system tools, the biomass from olive crop fields, mills and olive pomace-extracting industries, where these wastes are generated, was determined and quantified in the study area. In addition, the vulnerability of the territory was evaluated through an environmental and territorial analysis that allowed for the determination of the reception capacity of the study area. Then, information layers corresponding to the availability of the four biomass wastes, and layers corresponding to the environmental fragility of the study area were overlapped and they resulted in an overall map. This made it possible to identify the best areas for the implementation of the biorefineries based on olive-derived biomass. Finally, as an example, three zones were selected for this purpose. These locations corresponded to low fragility areas with a high availability of biomass (more than 300,000 tons/year) in a 30 km radius, which would ensure the biomass supply.

scholarly journals Kinetic Parameters of Nut Shells Pyrolysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 682
Author(s):  
Tomasz Noszczyk ◽  
Arkadiusz Dyjakon ◽  
Jacek A. Koziel
Keyword(s):  
Kinetic Parameters ◽  
Waste Treatment ◽  
Model Fitting ◽  
Thermal Conversion ◽  
Point Of View ◽  
The European Union ◽  
Heating Rates ◽  
Isothermal Model ◽  
Biomass Residues ◽  
Conversion Point

The European Union created a European Green Deal Program (EGDP). This program aims at a sustainable economy through the transformation of the challenges related to climate and the environment. The main goal of EGDP is climate neutrality by 2050. The increase of alternative biomass residues utilization from various food processing industries and cooperation in the energy and waste management sector is required to meet these expectations. Nut shells are one of the lesser-known, yet promising, materials that can be used as an alternative fuel or a pre-treated product to further applications. However, from a thermal conversion point of view, it is important to know the energy properties and kinetic parameters of the considered biowaste. In this study, the energy and kinetic parameters of walnut, hazelnut, peanut, and pistachio shells were investigated. The results showed that raw nut shells are characterized by useful properties such as higher heating value (HHV) at 17.8–19.7 MJ∙kg−1 and moisture content of 4.32–9.56%. After the thermal treatment of nut shells (torrefaction, pyrolysis), the HHV significantly increased up to ca. 30 MJ∙kg−1. The thermogravimetric analysis (TGA) applying three different heating rates (β; 5, 10, and 20 °C∙min−1) was performed. The kinetic parameters were determined using the isothermal model-fitting method developed by Coats–Redfern. The activation energy (Ea) estimated for β = 5 °C∙min−1, was, e.g., 60.3 kJ∙mol−1∙K−1 for walnut, 59.3 kJ∙mol−1∙K−1 for hazelnut, 53.4 kJ∙mol−1∙K−1 for peanut, and 103.8 kJ∙mol−1∙K−1 for pistachio, respectively. Moreover, the increase in the Ea of nut shells was observed with increasing the β. In addition, significant differences in the kinetic parameters of the biomass residues from the same waste group were observed. Thus, characterization of specific nut shell residues is recommended for improved modeling of thermal processes and designing of bioreactors for thermal waste treatment.

Variants of the Circle of Willis as seen on magnetic resonance angiography and carotid siphon calcifications in community-dwelling older adults

2021 ◽  
pp. 197140092110428
Author(s):  
Oscar H Del Brutto ◽  
Bettsy Y. Recalde ◽  
Robertino M Mera
Keyword(s):  
Older Adults ◽  
Magnetic Resonance ◽  
Calcium Content ◽  
Circle Of Willis ◽  
Community Dwelling ◽  
Anatomical Variants ◽  
Study Results ◽  
High Calcium ◽  
Independent Association ◽  
Community Dwelling Older Adults

Background and purpose Information on the association between anatomical variants of the Circle of Willis (CoW) and intracranial atherosclerotic disease (ICAD) is limited and results are controversial. In this population-based study, we aimed to assess whether an incomplete CoW is associated with high calcium content in carotid siphons (a reliable biomarker of ICAD) in community-dwelling older adults of Amerindian ancestry. Methods Individuals aged ≥60 years enrolled in the Three Villages Study received a head computed tomography (CT) and magnetic resonance angiogram (MRA) of intracranial vessels. The CoW was classified in complete or incomplete according to the presence or absence of one A1 segment of the anterior cerebral artery or one or both P1 segments of posterior cerebral arteries. Calcium content in carotid siphons was rated as low or high. A multivariate logistic model was fitted to assess the independent association between incompleteness of the CoW and high calcium content in carotid siphons, after adjusting for demographics and cardiovascular risk factors. Results A total of 581 individuals were enrolled (mean age: 71 ± 8.4 years; 57% women). MRA revealed an incomplete CoW in 227 (39%) individuals, and high-resolution CT disclosed high calcium content in carotid siphons in 185 (32%). A risk factor logistic regression model showed no independent association between incompleteness of the CoW and high calcium content in carotid siphons (odds ratio: 0.91; 95% confidence interval: 0.62–1.34; p = 0.631). Conclusion Study results disclosed no association between anatomical variants of the CoW and the presence of high calcium content in carotid siphons.

scholarly journals Industrial Wastes in Soil Improvement

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
G. V. Rama Subbarao ◽  
D. Siddartha ◽  
T. Muralikrishna ◽  
K. S. Sailaja ◽  
T. Sowmya
Keyword(s):  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cost Effective ◽  
Dry Weight ◽  
Soil Improvement ◽  
Geotechnical Properties ◽  
Point Of View ◽  
Industrial Wastes ◽  
Engineering Structures

Soil existing at a particular site may not be appropriate for construction of engineering structures. The present study made an attempt to enhance the geotechnical properties of a soil replaced with industrial wastes having pozzolanic value like rice husk ash (RHA) and fly ash (FA). Soil is replaced with RHA in 2%, 4%, and 6% to dry weight of soil. It is observed that soil replaced with 4% RHA is the optimum for the soil used in this study from geotechnical point of view. To know the influence of fly ash, soil is further replaced with 4% FA along with 4% RHA. It is found that results of soil replacement by both RHA and FA proved to be soil modification and not the improvement. Hence, a cost-effective accelerator like lime is used for further replacing the above soil-4%, RHA-4% FA mix. The optimum lime content is found to be 4%.

Extraction and Atomic Absorption Analysis of Lead in Plant and Animal Products

1969 ◽  
Vol 52 (4) ◽  
pp. 708-714 ◽  
Author(s):  
William L Hoover ◽  
John C Reagor ◽  
Julianne C Garner
Keyword(s):  
Atomic Absorption ◽  
Ammonium Carbonate ◽  
Calcium Content ◽  
Atomic Absorption Spectrophotometry ◽  
Animal Tissue ◽  
Good Recovery ◽  
Animal Products ◽  
Absorption Spectrophotometry ◽  
Strontium Sulfate ◽  
High Calcium

Abstract Samples of plant or animal tissue are digested in a mixture of HNO3, H2SO4, and HClO4. Lead released in the digestion is entrained with strontium sulfate. The sulfate precipitate is separated from the digest and then converted to the carbonate by agitation with ammonium carbonate solution. The carbonate precipitate is dissolved in 1N HNO3, and lead is determined by atomic absorption spectrophotometry. Good recovery of lead (100 ± 3%) was observed except in samples with high calcium content (> 1%). For the latter samples, good recoveries were obtained after separation of the calcium from the digested samples. Moderate quantities of the following elements do not interfere: Al, Fe, P, Sn, Ca, Bi, and Tl. Most elements are soluble as sulfates and, hence, do not interfere. The procedure is rugged. Dry samples containing from 0.5 ppm to 1% lead can be routinely analyzed.

Nonisothermal reaction kinetics and preparation of ferroelectric strontium bismuth niobate with a layered perovskite structure

2004 ◽  
Vol 19 (10) ◽  
pp. 2956-2963 ◽  
Author(s):  
Chung-Hsin Lu ◽  
Wei-Tse Hsu ◽  
Jiun-Ting Lee
Keyword(s):  
Reaction Kinetics ◽  
Formation Mechanism ◽  
Integral Method ◽  
Correlation Coefficients ◽  
Differential Method ◽  
Layered Perovskite ◽  
Heating Rates ◽  
Integral Methods ◽  
Diffusion Controlled ◽  
Layered Perovskite Structure

Ferroelectric layered perovskite SrBi2Nb2O9 has been successfully prepared through a new process using BiNbO4 as a precursor. The SrBi2Nb2O9 formation mechanism was investigated using a nonisothermal analysis method at constant heating rates. The weight loss recorded in thermal analysis under different heating rates was analogized to the reaction conversion. A combination of the differential and integral methods was introduced to solve the reaction mechanisms. Analysis using the differential method revealed that two kinds of diffusion-controlled models have higher linear correlation coefficients than other models. Based on the integral method principle, a new integral equation combining the Arrhenius equation and the Lobatto approximation was derived in this study. The established equation significantly simplified the conventional calculation process and improved the accuracy for predicting the reaction models. Analysis using the integral method corroborated that the SrBi2Nb2O9 formation mechanism is governed by Jander's diffusion controlled model, and the activation energy was calculated to be 192.1 kJ/mol. The proposed methods and the derived equations can be further applied to other solid-state-reaction systems to elucidate their reaction kinetics and estimate the related kinetic parameters.

scholarly journals ANÁLISE DE CÁLCIO EM DIFERENTES TIPOS DE BEBIDAS

2002 ◽  
Vol 3 (2) ◽  
Author(s):  
L. BATTESTIN ◽  
R. M. B. TACLA ◽  
E. B. TIBONI ◽  
R. J. S. FREITAS ◽  
S. C STERTZ
Keyword(s):  
Soy Protein ◽  
Calcium Content ◽  
Black Tea ◽  
Hot Water ◽  
Soy Milk ◽  
Freeze Dried ◽  
High Calcium ◽  
Two Samples ◽  
Powder Milk ◽  
Isolated Soy Protein

Foram analisadas infusos de duas amostras de chá preto, uma amostra de orange pekoe tipo Assam, duas amostras de chá mate tostado, quatro amostras de erva-mate e uma amostra de café liofilizado, dissoluções à quente de uma amostra de leite em pó desnatado, uma amostra de leite em pó integral e uma amostra de alimento com proteína isolada de soja instantâneo. Estas amostras foram adquiridas em supermercados da Região Metropolitana de Curitiba; com a finalidade de verificar e comparar os teores de cálcio desses diferentes tipos de bebidas. Nas determinações foi utilizada metodologia oficial e todas as análises em triplicata. Os teores de cálcio obtidos foram analisados estatisticamente: as amostras de chá preto apresentaram o menor teor de cálcio que variou de 16,94 mg/100 mL até 24,84 mg/100 mL. As amostras de chámate tostado mostraram valores mais elevados, sendo que uma delas acusou 78,39 mg/100 mL, equivalendo aomesmo teor de cálcio de umleite empó. Quanto às amostras de erva-mate, amaioria comparase à quantidade de cálcio dos leites empó e do alimento comproteína isolada de soja instantâneo, onde uma destacou-se significativamente das demais com valor de 171,55 mg/100 mL, seguida apenas da amostra de café liofilizado que apresentou 141,68 mg/100 mL. CALCIUM ANALYSIS IN DIFFERENT DRINKS Abstract Two samples of black tea, a sample of orange pekoe variety Assam, two samples of toasted tea, four varieties of erva-mate, a freeze dried coffee sample were prepared by hot infusion, samples of skimmed powder milk and powder wholemilk and one instant isolated soy protein sample were prepared in hot water. These samples were purchased in markets in Curitiba to identify and analyze calcium content in comparison with Official methodologies were used and for all determinations three analyses were done. Black tea samples resulted minor calcium content (16.94 to 24.84 mg/ 100 mL). Toasted tea resulted major calcium amount with 78.39 mg/100 mL, similar to calcium amount of powder and soy milk. Erva-mate samples are comparable to calcium content in powder milk. Freeze dried coffee presented high calcium amount (141.68 mg/100 mL).

scholarly journals Adaptation of plants to high-calcium content kart regions: possible involvement of symbiotic microorganisms and underlying mechanisms

2020 ◽  
Vol 80 (1) ◽  
pp. 209-214
Author(s):  
F. Li ◽  
X. He ◽  
M. Tang ◽  
X. Tang ◽  
J. Liu ◽  
...  
Keyword(s):  
Host Plants ◽  
Molecular Mechanisms ◽  
Calcium Content ◽  
Ecological Functions ◽  
Rhizosphere Microorganisms ◽  
High Calcium ◽  
Volatile Organic ◽  
Underlying Mechanisms ◽  
Host Genes ◽  
Adverse Environments

Abstract Rhizosphere microorganisms and endophytes can help their hosts absorb nutrients and regulate the levels of plant hormones. Moreover, they can modulate the expressions of host genes, assist hosts in eliminating reactive oxygen species (ROS) and secreting volatile organic compounds. Therefore, rhizosphere microorganisms and endophytes are considered as determinant factors driving processes involved in the growth of host plants. However, the physiological and ecological functions, as well as the molecular mechanism underlying the behavior of rhizosphere microorganisms and endophytes in their role in the adaptive capacity of host plants in the karstic high-calcium environment have not been systematically studied. This review summarizes the physiological and molecular mechanisms of rhizosphere microorganisms and endophytes which help host plants to adapt to various kinds of adverse environments. The adaptive capacities of plants growing in adverse environments, partly, or totally, depends on microorganisms co-existing with the host plants.

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