Study on Extraction of Mesophase from Steel Slag by Potassium Hydroxide-Sucrose (KOSH) Solution Method

2014 ◽  
Vol 1015 ◽  
pp. 492-496
Author(s):  
Zhao Feng Li ◽  
Shu Cai Li ◽  
Zong Hui Zhou ◽  
Ren Tai Liu
Keyword(s):  
Activation Energy ◽  
Potassium Hydroxide ◽  
Solution Method ◽  
Steel Slag ◽  
Organic Ligands ◽  
Extraction Temperature ◽  
Slag Surface ◽  
Alkaline Environment ◽  
Slag Temperature ◽  
Partical Size

The mesophase (iron aluminate, etc.) in steel slag was extracted by potassium hydroxide-sucrose (KOSH) solution method. The effects of partical size of steel slag, temperature and time of extraction on dissolution of mesophase phase were studied. The composition and morphology of the residue were analyzed by XRD and SEM. The results show the mesophase in steel slag powders (the weight was and the fineness was) could be fully dissolved when 4.00 g sample with a fineness about 600m2/kg is used and extraction temperature is kept at 90oC, however, other minerals in the steel slag could be hardly dissolved. The reason might be for that, in alkaline environment which provided by potassium hydroxide, the replacement of ions were took place between the mesophase in steel slag and the organic ligands formed by sugar and potassium hydroxide, and through the adsorption and polarization between ligand and steel slag surface, it will result in the decrease of activation energy of iron aluminate.

scholarly journals Synergistic Excitation Mechanism of CaO-SiO2-Al2O3-SO3 Quaternary Active Cementitious System

2021 ◽  
Vol 8 ◽  
Author(s):  
Fusheng Niu ◽  
Yukun An ◽  
Jinxia Zhang ◽  
Wen Chen ◽  
Shengtao He
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Test Block ◽  
Hydration Reaction ◽  
Alkaline Environment ◽  
Granulated Blast Furnace Slag ◽  
Cementitious System ◽  
Furnace Slag

In this study, the influence of steel slag (SS) content on the strength of the cementitious materials was investigated. The quaternary active cementitious material (CaO-SiO2-Al2O3-SO3) was prepared using various proportions of steel slag (SS), granulated blast furnace slag (BFS), and desulfurized gypsum (DG). The mechanism of synergistic excitation hydration of the cementitious materials was examined using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The strength of the mortar test block was initially increased and decreased later with the increase of the SS content. Mortar test block with 20% steel slag, 65% granulated blast furnace slag, and 15% desulfurized gypsum with 0.35 water-binder ratio showed the highest compressive strength of 57.3 MPa on 28 days. The free calcium oxide (f-CaO) in the SS reacted with water and produced calcium hydroxide (Ca(OH)2) which created an alkaline environment. Under the alkaline environment, the alkali-activated reaction occurred with BFS. In the early stage of hydration reaction, calcium silicate hydrate (C-S-H) gel and fibrous hydration product ettringite (AFt) crystals were formed, which provided early strength to the cementitious materials. As the hydration reaction progressed, the interlocked growth of C-S-H gel and AFt crystals continued and promoted the increase of the strength of the cementitious system.

scholarly journals KINETICS OF PALM OIL TRANSESTERIFICATION IN METHANOL WITH POTASSIUM HYDROXIDE AS A CATALYST

2010 ◽  
Vol 8 (2) ◽  
pp. 219-225
Author(s):  
Yoeswono Yoeswono ◽  
Triyono Triyono ◽  
Iqmal Tahir
Keyword(s):  
Activation Energy ◽  
Palm Oil ◽  
Rate Constants ◽  
Potassium Hydroxide ◽  
Catalyst Concentration ◽  
Time Interval ◽  
Pseudo First Order Reaction ◽  
Exponential Factor ◽  
Potassium Methoxide ◽  
First Order

A study on palm oil transesterification to evaluate the effect of some parameters in the reaction on the reaction kinetics has been carried out. Transesterification was started by preparing potassium methoxide from potassium hydroxide and methanol and then mixed it with the palm oil. An aliquot was taken at certain time interval during transesterification and poured into test tube filled with distilled water to stop the reaction immediately. The oil phase that separated from the glycerol phase by centrifugation was analyzed by 1H-NMR spectrometer to determine the percentage of methyl ester conversion. Temperature and catalyst concentration were varied in order to determine the reaction rate constants, activation energies, pre-exponential factors, and effective collisions. The results showed that palm oil transesterification in methanol with 0.5 and 1 % w/w KOH/palm oil catalyst concentration appeared to follow pseudo-first order reaction. The rate constants increase with temperature. After 13 min of reaction, More methyl esters were formed using KOH 1 % than using 0.5 % w/w KOH/palm oil catalyst concentration. The activation energy (Ea) and pre-exponential factor (A) for reaction using 1 % w/w KOH was lower than those using 0.5 % w/w KOH.   Keywords: palm oil, transesterification, catalyst, first order kinetics, activation energy, pre-exponential factor

Thermally Induced Activation Energy of Crystalline Silicon in Alkaline Solution

1970 ◽  
Vol 11 ◽  
pp. 215-222
Author(s):  
SK Lamichhane
Keyword(s):  
Activation Energy ◽  
Potassium Hydroxide ◽  
Etch Rate ◽  
Crystalline Silicon ◽  
Lattice Parameter ◽  
Device Fabrication ◽  
Strong Anisotropy ◽  
Temperature Dependent ◽  
Thermal Agitation ◽  
Thermally Induced

Etching of crystalline silicon by potassium hydroxide (KOH) etchant with temperature variation has been studied. Results presented here are temperature dependent ER (etch rate) along the crystallographic orientations. Etching and activation energy are found to be consistently favorable with the thermal agitation for a given crystal plane. Study demonstrates that the contribution of microscopic activation energy effectively controls the etching process. Such a strong anisotropy in ER on KOH allows us a precious control of lateral dimensions of the silicon microstructure as well as surface growth of the crystal during micro device fabrication. Key words: anisotropy; activation energy; etch rate; lattice parameter; micromachining DOI: 10.3126/njst.v11i0.4148Nepal Journal of Science and Technology 11 (2010) 215-222

scholarly journals Experimental investigation on anisotropic surface properties of crystalline silicon

BIBECHANA ◽  
2012 ◽  
Vol 8 ◽  
pp. 59-66
Author(s):  
Shobha Kanta Lamichhane
Keyword(s):  
Activation Energy ◽  
Potassium Hydroxide ◽  
Etch Rate ◽  
Crystalline Silicon ◽  
Etching Rate ◽  
Energy Concentration ◽  
Temperature Dependent ◽  
Thermal Agitation ◽  
Anisotropic Surface ◽  
Experimental Values

Anisotropic etching of silicon has been studied by wet potassium hydroxide (KOH) etchant with its variation of temperature and concentration. Results presented here are temperature dependent etch rate along the crystallographic orientations. The etching rate of the (111) surface family is of prime importance for microfabrication. However, the experimental values of the corresponding etch rate are often scattered and the etching mechanism of (111) remains unclear. Etching and activation energy are found to be consistently favorable with the thermal agitation for a given crystal plane. Study demonstrate that the contribution of microscopic activation energy that effectively controls the etching process. Such a strong anisotropy in KOH allows us a precious control of lateral dimensions of the silicon microstructure.Keywords: microfabrication; activation energy; concentration; anisotropy; crystal planeDOI: http://dx.doi.org/10.3126/bibechana.v8i0.4828  BIBECHANA 8 (2012) 59-66  

Sulfur-zinc modified kaolin/steel slag: A particle electrode that efficiently degrades norfloxacin in a neutral/alkaline environment

Chemosphere ◽  
2021 ◽  
pp. 131328
Author(s):  
Bo Song ◽  
Zhaoyang Wang ◽  
Junfeng Li ◽  
Mengqiao Luo ◽  
Pengwei Cao ◽  
...  
Keyword(s):  
Steel Slag ◽  
Alkaline Environment

scholarly journals Thermodynamic Properties, Viscosity, and Structure of CaO–SiO2–MgO–Al2O3–TiO2–Based Slag

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 124
Author(s):  
Jinle Fang ◽  
Zhuogang Pang ◽  
Xiangdong Xing ◽  
Runsheng Xu
Keyword(s):  
Activation Energy ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Heat Supply ◽  
Enthalpy Change ◽  
Tio2 Content ◽  
Constant Heat ◽  
Slag Structure ◽  
Tio2 Addition ◽  
Slag Temperature

The effect of TiO2 and the MgO/Al2O3 ratio on the viscosity, heat capacity, and enthalpy change of CaO–SiO2–Al2O3–MgO–TiO2 slag at constant heat input was studied. The variation of slag structure was analyzed by the calculation of activation energy and FTIR spectrum measurements. The results showed that the heat capacity and enthalpy change of the slag decreased with the increase of TiO2 content. Under constant heat supply, the fluctuations in slag temperature were relatively apparent, and the temperature of slag increased as the TiO2 content increased. The viscosity of slag decreased due to the increase in slag temperature. Increasing the MgO/Al2O3 ratio could decrease the temperature and viscosity of slag. The effect of increasing the MgO/Al2O3 ratio on the viscosity was more pronounced than the decreasing temperature caused by increasing the MgO/Al2O3 ratio. The apparent activation energy decreased with increasing TiO2 content and MgO/Al2O3 ratio. The Ti–O bonds formed with TiO2 addition, and the Ti–O bonds were weaker than Si–O bonds, which resulted in the decrease in heat capacity and viscosity of slag.

scholarly journals Effect of Basicity and Al2O3 on Viscosity of Blast Furnace Slag and Thermodynamic Analysis

2021 ◽  
Author(s):  
Jian Zhang ◽  
Zhengjian Liu ◽  
Jianliang Zhang ◽  
Cui Wang ◽  
Hengbao Ma ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Blast Furnace ◽  
Constant Temperature ◽  
Slag Basicity ◽  
Al2o3 Content ◽  
Wave Number ◽  
Slag Viscosity ◽  
Slag Structure ◽  
Slag Temperature

With the increased use of laterite nickel ore, the impact of high Al2O3 slag on blast furnace smelting has gradually increased. In this paper, the effects of slag basicity and Al2O3 content on slag viscosity and enthalpy change under constant temperature conditions was investigated. The changes in slag structure were analyzed by activation energy and Fourier Transform Infrared (FT-IR) spectroscopy. The relationship between slag components and slag temperature and viscosity when slag heat is reduced was investigated. The results showed that the viscosity first slightly decreased and then significantly increased with increasing basicity at constant temperature. With the addition of Al2O3 content, the viscosity of the slag increases. The activation energy increases with increasing slag basicity and Al2O3. With increasing basicity, the [SiO4]4- tetrahedral unit trough depth becomes shallow, the [AlO4]5- asymmetric stretching band migrates to lower wave numbers, and the slag structure depolymerizes. With the increase of Al2O3 content, the trough of [SiO4]4- tetrahedra deepens and the center of the symmetric stretching band moves to a higher wave number. The [AlO4]5- asymmetric stretching band becomes obvious, indicating the complexity of the slag structure. When the heat decreases, the slag temperature increases as the basicity increases, and the slag thermal stability is better at the basicity of 0.95-1.05. As the Al2O3 content increases, the thermal stability of the slag becomes worse.

Existence Forms of Magnesium Oxide in Steel Slag by Chemical Phase Separation

2010 ◽  
Vol 177 ◽  
pp. 481-484 ◽  
Author(s):  
Zhao Feng Li ◽  
Zong Hui Zhou ◽  
Li Fu Shan
Keyword(s):  
Salicylic Acid ◽  
Phase Separation ◽  
Magnesium Oxide ◽  
Potassium Hydroxide ◽  
Sucrose Solution ◽  
Steel Slag ◽  
Methanol Solution ◽  
Silicate Phase ◽  
Chemical Phase ◽  
Complex Forms

Magnesium oxide solid dissolved in silicate phase, mesophase and RO-phase which are the major constituents of steel slag. The MgO exists in the steel slag with complex forms, which results in the bad soundness of the steel slag. In this paper, the silicate phase and mesophase were separated by salicylic acid methanol solution and potassium hydroxide-sucrose solution respectively and were studied combining with the XRD and SEM. The results show that the silicate phase and mesophase can be fully dissolved, however, the RO phase is not influenced by the two solutions in this process. The content of magnesium oxide existed in different minerals can be detected by chemical analysis. It can be found that the magnesium oxide mainly exists as RO-phase in steel slag, and some of them exist as free state, while only a small quantity of solid dissolve in the silicate phase and mesophase.

scholarly journals KINETIC RESEARCH ON THE OBTAINING OF POTASSIUM HUMATE FROM BROWN COAL OF THE LENGER DEPOSIT

2021 ◽  
Vol 74 (2) ◽  
pp. 71-77
Author(s):  
B. М. SMAILOV ◽  
◽  
O. K. Beysenbayev ◽  
A.S. Tleuov ◽  
B.S. Zakirov ◽  
...  
Keyword(s):  
Activation Energy ◽  
Brown Coal ◽  
Kinetic Data ◽  
Potassium Hydroxide ◽  
Mineralogical Composition ◽  
Chemical Characteristics ◽  
Potassium Humate ◽  
Biochemical Processes ◽  
Environmentally Safe ◽  
Physical And Chemical

This article provides information about the method of obtaining potassium humate obtained from brown coal of the Lenger deposit, and also describes the elemental and mineralogical composition of potassium humate determined with SEM (JSM-6490l V, Jeol). Kinetic data on the decomposition of brown coal with solutions of potassium hydroxide are presented. The area of chemical reactions and the activation energy are determined. The benefits of the obtained potassium humate are that they are environmentally safe and have high bioactivity. They are also characterized by a high content of humic substances that are involved in the structure formation of the soil, accelerate biochemical processes, and increase the physical and chemical characteristics in the soil. Under the influence of humate-containing substances, the function of microflora elements in the soil is activated, and the number of beneficial microorganisms increases.

scholarly journals KINETICS AND THERMODYNAMICS OF PEPPERMINT OIL EXTRACTION FROM PEPPERMINT LEAVES

2019 ◽  
Vol 20 (4) ◽  
pp. 1-6
Author(s):  
Khalid M. Abed ◽  
Bedoor M. Kurji ◽  
Sarmad A. Rashid ◽  
Basma A. Abdulmajeed
Keyword(s):  
Activation Energy ◽  
Extraction Process ◽  
Oil Extraction ◽  
Extraction Temperature ◽  
Peppermint Oil ◽  
Distillation Method ◽  
Kinetics And Thermodynamics ◽  
A Value ◽  
Rate Capacity ◽  
Initial Extraction

This study aimed to extraction of essential oil from peppermint leaves by using hydro distillation methods. In the peppermint oil extraction with hydro distillation method is studied the effect of the extraction temperature to the yield of peppermint oil. Besides it also studied the kinetics during the extraction process. Then, 2nd -order mechanism was adopted in the model of hydro distillation for estimation many parameters such as the initial extraction rate, capacity of extraction and the constant rat of extraction with various temperature. The same model was also used to estimate the activation energy. The results showed a spontaneous process, since the  Gibbs free energy had a value negative sign.

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