scholarly journals Mathematical Modelling to Control the Chemical Composition of Blast Furnace Slag Using Artificial Neural Networks and Empirical Correlation

2021 ◽  
Vol 1203 (3) ◽  
pp. 032096
Author(s):  
Wandercleiton Cardoso ◽  
Danielle Barros ◽  
Raphael Baptista ◽  
Renzo di Felice
Keyword(s):  
Blast Furnace ◽  
Chemical Composition ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Raw Material ◽  
Operational Parameters ◽  
Materials Research ◽  
Artificial Neural ◽  
Furnace Slag ◽  
Alkali Activated

Abstract Portland cement additions have been used for many years with the main objective of reducing the amount of clinker. Among the additions, blast furnace slag, resulting from the production of pig iron, that is, reusing this by-product, reduces the emission of carbon dioxide as well as decreases the exploitation of natural limestone and clay reserves, which are raw materials for Portland clinker. In order to reduce these emissions and increase the availability of raw materials, research has been directed to study clinker-free binders, as is the case with activated alkali cements and supersulfated cements. In this way, alkali-activated cements can only involve the reuse of industry by-products and do not require the calcination of the raw material, thus reducing the emission of polluting gases into the atmosphere. Supersulfated cement are composed of up to 90% blast furnace slag, in addition to 10 to 20% calcium sulfate. One of the most important characteristics of blast furnace slag is the ratio of the content of CaO and SiO2, also known as the simplified basicity index (B2). This paper proposes the mathematical modeling of an artificial neural network to predict the final chemical composition of the blast furnace slag to be produced based on the operational parameters of the blast furnace aiming its use in the production of special cements such as alkali-activated cements and supersulfated cements. The high values of (R) associated with low values (RMSE) show the good statistical performance of ANN demonstrating that the mathematical model is efficient to carry out the forecast of the production of blast furnace slag.

scholarly journals Influence of the increased content of Calumite blast-furnace slag on the melting of sodium–calcium–silicate glass

2019 ◽  
Vol 138 (6) ◽  
pp. 4571-4583
Author(s):  
Anna A. Kuśnierz ◽  
Magdalena Szumera ◽  
Magda Kosmal ◽  
Paweł Pichniarczyk
Keyword(s):  
Thermal Analysis ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Melting Process ◽  
Raw Material ◽  
Glass Mass ◽  
Sodium Calcium ◽  
The Cost ◽  
Furnace Slag

Abstract A glass set with a high content of blast-furnace slag and a reduced amount of traditional raw materials requires optimization of the raw material composition and adjustment of its specificity to the temperature regime of melting, homogenizing and clarifying the glass mass. The introduction of an increased amount of blast-furnace slag allows to reduce the cost of raw materials: soda, limestone and high-class sand, reduce energy costs, whose consumption significantly decreases and reduces CO2 emissions in line with EU requirements. The tests of thermal analysis of a glass set with different contents of Calumite are aimed at learning the mechanism of its operation by determining the changes caused by its different presence in the course of subsequent reactions between the components of the glass set. Analysis of the influence of the addition of different Calumite slag contents treated as a substitute for the raw material on the melting process of glassware sets was analyzed. The tests were carried out using differential thermal analysis (DTA) and thermogravimetry (TG) based on the model glass [mass%]: 73.0% SiO2, 1.0% Al2O3, 10.0% CaO, 2.0% MgO and 14.0% Na2O. The effect of combining Calumite with sulphate and multi-component fining agent—mixtures of As2O3, Sb2O3, NaNO3 in proportions of 1:1:1 for chemical reaction and phase transformation, was investigated.

scholarly journals Effects of Fineness and Chemical Composition of Blast Furnace Slag on Properties of Alkali‐Activated Binder

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3447 ◽  
Author(s):  
Humad ◽  
Habermehl-Cwirzen ◽  
Cwirzen
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Chemical Composition ◽  
Thermogravimetric Analysis ◽  
Blast Furnace Slag ◽  
Drying Shrinkage ◽  
Liquid Sodium ◽  
Carbonation Resistance ◽  
Furnace Slag ◽  
Alkali Activated

The effects of fines and chemical composition of three types of ground granulated blast furnace slag (GGBFS) on various concrete properties were studied. Those studied were alkali activated by liquid sodium silicate (SS) and sodium carbonate (SC). Flowability, setting times, compressive strength, efflorescence, and carbonation resistance and shrinkage were tested. The chemical composition and microstructure of the solidified matrixes were studied by X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) coupled with EDX analyser. The results showed that the particle size distribution of the slags and the activator type had significantly stronger effects on all measured properties than their chemical composition. The highest compressive strength values were obtained for the finest slag, which having also the lowest MgO content. SC‐activated mortar produced nearly the same compressive strength values independently of the used slag. The most intensive efflorescence and the lowest carbonation resistance developed on mortars based on slag containing 12% of MgO and the lowest fineness. The slag with the highest specific surface area and the lowest MgO content developed a homogenous microstructure, highest reaction temperature and lowest drying shrinkage. Thermogravimetric analysis indicated the presence of C‐(A)-S-H, hydrotalcite HT, and carbonate like‐phases in all studied mortars.

scholarly journals Interactions of Various types between Rock and Alkali-Activated Blast Furnace Slag

2017 ◽  
Vol 63 (1) ◽  
pp. 22-26
Author(s):  
Pavel Mec ◽  
Lucie Gembalová
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Matrix Composition ◽  
Cement Binder ◽  
Alkali Activated Binders ◽  
Furnace Slag ◽  
Alkali Activated

Abstract Alkali-activated binders (AAB) are very intensively studied materials nowadays. Because of possible usage as secondary raw materials, they can be environmentally efficient. Intensive research is focused especially on binder matrix, composition and its structure. For industrial usage, it is necessary to work with some aggregate for the preparation of mortars and concretes. Due to different structures of alkali-activated binders, the interaction with the aggregate will be different in comparison to an ordinary Portland cement binder. This paper deals with the study of interactions between several types of rocks used as aggregate and alkali-activated blast furnace slag. The research was focused especially on mechanical properties of prepared mortars.

scholarly journals Influence of Pb Dosage on Immobilization Characteristics of Different Types of Alkali-Activated Mixtures and Mortars

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Jan Koplík ◽  
Jaromír Pořízka ◽  
Lukáš Kalina ◽  
Jiří Másilko ◽  
Matěj Březina
Keyword(s):  
Mechanical Properties ◽  
Heavy Metals ◽  
Heavy Metal ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Inductively Coupled Plasma ◽  
Raw Materials ◽  
Leaching Tests ◽  
Furnace Slag ◽  
Alkali Activated

Alkali-activated matrices are suitable materials for the immobilization of hazardous materials such as heavy metals. This paper is focused on the comparison of immobilization characteristics of various inorganic composite materials based on blast furnace slag and on the influence of various dosages of the heavy metal Pb on the mechanical properties and fixation ability of prepared matrices. Blast furnace slag (BFS), fly ash, and standard sand were used as raw materials, and sodium water glass was used as an alkaline activator. Pb(NO3)2served as a source of heavy metal and was added in various dosages in solid state or as aqueous solution. The immobilization characteristics were determined by leaching tests, and the content of Pb in the eluate was measured by inductively coupled plasma optical emission spectroscopy (ICP-OES). The microstructure of matrices and distribution of Pb within the matrix were determined by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Increasing the dosage of the heavy metal had negative impacts on the mechanical properties of prepared matrices. The leaching tests confirmed the ability of alkali-activated materials to immobilize heavy metals. With increasing addition of Pb, its content in eluates increased.

Degradation of Materials Based on Alkali-Activated Blast-Furnace Slag after Exposure to Aggressive Environments

2021 ◽  
Vol 325 ◽  
pp. 131-136
Author(s):  
Iveta Plšková ◽  
Petr Hrubý ◽  
Libor Topolář ◽  
Michal Matysík
Keyword(s):  
Blast Furnace ◽  
Ammonium Nitrate ◽  
Sodium Sulfate ◽  
Blast Furnace Slag ◽  
Nitrate Solution ◽  
Ammonium Nitrate Solution ◽  
Degradation Of Materials ◽  
Non Destructive ◽  
Furnace Slag ◽  
Alkali Activated

The paper summarizes partial results of a study of degradation of materials based on alkali-activated blast-furnace slag (AAS) and comparative on cement CEM III/A 32.5 R after exposure to aggressive environments. It further specifies the possibilities for utilising destructive and non-destructive techniques to determine the progress of degradation and characterizes the degree of their correlation. After 28 days of ageing in a water environment, the produced test specimens (40×40×160 mm beams) were placed in aggressive media (ammonium nitrate solutions; sodium sulfate, rotating water) and after subsequent 28, 56 and 84 days of degradation were subjected to testing. Testing comprised both a destructive form (determination of compressive strength and flexural strength) and a selected non-destructive technique (Impact-echo method). The partial outputs were supplemented by the results acquired from monitoring weight changes. In addition, the development of Ultrasonic Pulse Velocity in relation to the progress of the degradation processes was also monitored. While the exposure of both test specimens to water and sodium sulfate did not result in any significant changes, the exposure to the ammonium nitrate solution exhibited rapid signs of degradation associated with a significant reduction in functional characteristics.

Modeling of Alteration Behavior on Blended Cementitious Materials

2011 ◽  
Author(s):  
Hitoshi Owada ◽  
Tomoko Ishii ◽  
Mayumi Takazawa ◽  
Hiroyasu Kato ◽  
Hiroyuki Sakamoto ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Chemical Composition ◽  
Mineral Composition ◽  
Blast Furnace Slag ◽  
Fine Powder ◽  
Cementitious Materials ◽  
Leaching Tests ◽  
Measured Concentration ◽  
Furnace Slag

A “realistic alteration model” is needed for various cementitious materials. Hypothetical settings of mineral composition calculated based on the chemical composition of cement, such as Atkins’s model, have been used to estimate the alteration of cementitious material. However, model estimates for the concentration of certain elements such as Al and S in leachate have been different from experimental values. In a previous study, we created settings for a mineralogical alteration model by taking the initial chemical composition of cementitious materials from analysis results in experiments and applying their ratios to certain hydrated cement minerals, then added settings for secondary generated minerals in order to account for Ca leaching. This study of alteration estimates for ordinary portland cement (OPC) in groundwater showed that the change in Al and S concentrations in simulated leachate approached values for actual leachate[1]. In the present study, we develop an appropriate mineral alteration model for blended cementitious materials and conduct batch-type leaching experiments that use crushed samples of blast furnace slag cement (BFSC), silica cement (SC), and fly ash cement (FAC). The cement blends in these experiments used OPC blended with blast furnace slag of 70 wt.%, silica cement consisting of an amorphous silica fine powder of 20 wt.%, and fly ash of 30 wt.%. De-ionized water was used as the leaching solution. The solid-liquid ratios in the leaching tests were varied in order to simulate the alteration process of cement hydrates. The compositions of leachate and minerals obtained from leaching tests were compared with those obtained from models using hypothetical settings of mineral composition. We also consider an alteration model that corresponds to the diversity of these materials. As a result of applying the conventional OPC model to blended cementitious materials, the estimated Al concentration in the aqueous solution was significantly different from the measured concentration. We therefore propose an improved model that takes better account of Al behavior by using a more reliable initial mineral model for Al concentration in the solution.

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