scholarly journals Isothermal Kinetic Mechanism of Coke Dissolving in Hot Metal

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 470
Author(s):  
Wei Zhang ◽  
Fubo Hua ◽  
Jing Dai ◽  
Zhengliang Xue ◽  
Guojun Ma ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Kinetic Mechanism ◽  
Rate Coefficients ◽  
Dissolution Time ◽  
Hot Metal ◽  
Pure Graphite ◽  
Carbon Iron ◽  
Protective Gas ◽  
Isothermal Kinetic ◽  
Iron Bath

The carburization of molten iron is close to saturation in the blast furnace process, while that in the flash ironmaking process is uncertain because there is no pressure from solid charge and no carburization reactions occurring between the deadman and hot metal. Some experiments were conducted to reveal the kinetic mechanism of coke dissolving in carbon-iron melts. Reduced iron powder, electrolytic iron as well as chemical pure graphite were used as experiment materials. With high-purity argon injected as the protective gas, the specimens were heated up to 1873 K in a tubular resistance furnace to study the isothermal mechanism. The results show that the composition of the ferrous sample affects the dissolution rate. When the FeO content of the iron-bearing material rises from 0% to 4.76%, the apparent dissolution rate constant, kt, falls from 7.98 × 10−6 m/s to 5.48 × 10−6 m/s. There are some differences amongst the dissolution rate coefficients of different cokes despite interacting with similar carbon-iron melts, with coke 1 of 7.98 × 10−6 m/s, coke 2 of 5.17 × 10−6 m/s, and coke 3 of 3.77 × 10−6 m/s. Besides, this index decreases with the increase of the dissolution time and solely depends on the procedure of the mass transfer. A negative correlation is demonstrated between kt and the sulfur content in the iron bath as well. The content of silicon dioxide in the coke has a significant influence on kt. Additionally, the dissolution rate coefficient increases with the increase of the graphitization degree of coke.

Dissolution rate coefficients for surface slicks on rivers

1999 ◽  
Vol 33 (8) ◽  
pp. 1811-1816 ◽  
Author(s):  
David E. Hibbs ◽  
John S. Gulliver
Keyword(s):  
Dissolution Rate ◽  
Rate Coefficients

scholarly journals The Dissolution Rate of Solid Lime into Molten Slag Used for Hot-metal Dephosphorization

2004 ◽  
Vol 44 (2) ◽  
pp. 263-267 ◽  
Author(s):  
Tasuku Hamano ◽  
Masashi Horibe ◽  
Kimihisa Ito
Keyword(s):  
Dissolution Rate ◽  
Molten Slag ◽  
Hot Metal

scholarly journals Effect of Lime Dissolution Rate in Slag on Hot Metal Dephosphorization

2020 ◽  
Vol 60 (5) ◽  
pp. 922-929
Author(s):  
Naoki Kikuchi ◽  
Akitoshi Matsui ◽  
Yu-ichi Uchida
Keyword(s):  
Dissolution Rate ◽  
Hot Metal

Cr and Ni Recovery and Oxidational Dephosphorization of Stainless Steel Dust during the Iron-Bath Smelting Reduction Process

2014 ◽  
Vol 933 ◽  
pp. 32-37
Author(s):  
Shuai Niu ◽  
Yong Ren ◽  
Hua Zhang ◽  
Hui Long Fu ◽  
Xin Hong
Keyword(s):  
Stainless Steel ◽  
Phosphorus Content ◽  
Reduction Process ◽  
Hot Metal ◽  
Smelting Reduction ◽  
Yield Rate ◽  
Steel Dust ◽  
Iron Bath ◽  
The Cost ◽  
Dephosphorization Rate

According to the comprehensive utilization of 300 series and 400 series stainless steel dust (SSD), and the dephosphorization of the reclaimed Cr-Ni contained hot metal, an experimental method of smelting reduction in iron-bath and oxidational dephosphorization was studied. The result shows: The yield rate of Cr in 300SSDand 400SSDis 98.13% and 98.39% respectively, the yield rate of Ni is almost 100%; During the dephosphorization, through the BaO and CaO-BaO based dephosphorizer has a higher Dephosphorization rate, it can bring pollution problems and the cost is too high, however, under some circumstance when the requirement of phosphorus content is not critical, the CaO based dephosphorizer can also achieved the dephosphorization goal.

Measurement of Glass Corrosion in Boom Clay Disposal Conditions

2001 ◽  
Author(s):  
Karel Lemmens ◽  
Marc Aertsens ◽  
Véra Pirlet ◽  
Hélène Serra ◽  
Elie Valcke ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Kinetic Modeling ◽  
Dissolution Time ◽  
Dissolution Test ◽  
Dissolution Rates ◽  
Boom Clay ◽  
Glass Dissolution ◽  
Dissolution Tests ◽  
Environmental Materials

Abstract To estimate the life-time of vitrified high level waste (HLW-glass) in geological disposal conditions in Boom Clay, the dissolution behaviour of waste glass has been studied in experiments in surface laboratories and in the HADES underground research facility of SCK•CEN since the 1980’s. The programme consists mainly of dissolution tests. The purpose of these tests is to understand the basic glass dissolution mechanisms, and to demonstrate realistic long-term dissolution rates. The main experimental variables are glass composition, environmental materials, temperature, and test duration. The studied glasses are the COGEMA glass R7T7, and the PAMELA glasses with SM539, SM527 and SM513 glass frit. The environmental materials comprise Boom Clay, metallic corrosion products and engineered barrier materials. Dissolution tests have been performed at temperatures from 40 to 190°C, for test durations from days to several years. The tests are performed with inactive glasses, which can be doped with radionuclides of interest. Because of the importance of silica sorption by the environmental materials, the dissolution test programme was extended with silica diffusion- and sorption tests in Boom Clay and FoCa clay. The interpretation of the experimental results is supported by geochemical and kinetic modeling. In the area of kinetic modeling, both analytical and Monte Carlo codes are applied. The dissolution tests have demonstrated that, although the presence of Boom Clay initially increases the glass dissolution rate, the long-term dissolution rate decreases for diluted clay / clay water slurries. This decrease has not yet been demonstrated for the R7T7 glass in compact Boom Clay, but is expected to occur here also on the long term. The dissolution rate decreases faster after sufficient addition of glass powder to the medium. This was tested in experiments with the R7T7 glass at relatively high clay concentration (2000 g of humid Boom Clay per liter clay water, this is about half the solid/liquid ratio of compact Boom Clay), at 40 and 90°C. Linear interpolation of the long-term mass losses resulted in dissolution rates of ∼ 0.01 g.m−2.day−1. The statistical uncertainties on the dissolution test results did not allow to demonstrate smaller rates. The minimum statistically significant dissolution rate depends on the test conditions. Therefore, the present SCK•CEN programme includes dissolution tests at long-term near-field conditions (this is at 30°C, with compact Boom Clay and FoCa clay), which are considered more representee for the long-term situation. In view of the uncertainties on the experimental long-term dissolution rates and on the long-term dissolution mechanisms, rates smaller than 0.01 g.m−2.day1 (about 1 μ/year) should not be used as best estimate in the present performance assessment studies for disposal in Boom Clay. A constant dissolution rate of 0.01 g.m−2.day−1 would correspond to a dissolution time for a R7T7 glass package of approximately 150 000 years. The minimum dissolution time is of the order of 104 years.

Desulfurization of Hot Metal Through In Situ Generation of Magnesium in 30-kg Molten Iron Bath-Influence of Inert Gas Flow Rate

2013 ◽  
Vol 85 (5) ◽  
pp. 927-934 ◽  
Author(s):  
Anil Kumar ◽  
Zachariah Elanjickal Chacko ◽  
Madurai Malathi ◽  
Kesri Mino Godiwalla ◽  
Satish Kumar Ajmani ◽  
...  
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Molten Iron ◽  
Inert Gas ◽  
Gas Flow Rate ◽  
Hot Metal ◽  
In Situ Generation ◽  
Iron Bath

Ultrasonic-Assisted Dissolution of Polystyrene in Decahydronaphthalene for the Preparation of Poly(Cyclohexylethylene)

2014 ◽  
Vol 651-653 ◽  
pp. 157-160
Author(s):  
Jia Jia Wang ◽  
Hui Huang ◽  
Ting Li ◽  
Shi Ying Tao
Keyword(s):  
Kinetic Model ◽  
Dissolution Rate ◽  
Rate Constant ◽  
Dissolution Kinetic ◽  
Dissolution Process ◽  
Dissolution Time ◽  
Mechanical Agitation ◽  
Ultrasonic Assisted ◽  
Dissolution Rate Constant ◽  
Dissolution Ratio

Dissolution process of polystyrene in decahydronaphthalene solution was conducted and compared under different conditions. The effects of dissolution time and temperature on the dissolution ratio of polystyrene were performed with the assistance of ultrasonic and mechanical agitation, respectively. The dissolution ratio of polystyrene increased with the increment of dissolution time and dissolution temperature, polystyrene dissolved faster under ultrasonic-assisted process. The polystyrene dissolution kinetic model was developed and used to calculate the dissolution rate constant. The kinetic model showed good agreement with the experimental data, and the dissolution rate constant indicated that ultrasonic can obviously enhance the dissolution process of polystyrene in decahydronaphthalene solution.

scholarly journals Effect of Lime Dissolution Rate in Slag on Hot Metal Dephosphorization

2019 ◽  
Vol 105 (6) ◽  
pp. 610-618 ◽  
Author(s):  
Naoki Kikuchi ◽  
Akitoshi Matsui ◽  
Yu-ichi Uchida
Keyword(s):  
Dissolution Rate ◽  
Hot Metal

scholarly journals Impact of Tablet Shape on Drug Dissolution Rate Through Immediate Released Tablets

2020 ◽  
Vol 10 (4) ◽  
pp. 656-661
Author(s):  
Fatima Molavi ◽  
Hamed Hamishehkar ◽  
Ali Nokhodchi
Keyword(s):  
Dissolution Rate ◽  
Release Kinetics ◽  
Immediate Release ◽  
Drug Dissolution ◽  
Dissolution Time ◽  
Sufficient Information ◽  
Onset Of Action ◽  
Disintegration Time ◽  
Dissolution Efficiency

Purpose : The aim of this study was to evaluate the influence of the geometric shape on the dissolution rate of the domperidone, a drug model for immediate release dosage form. In this regard, a lack of sufficient information about the effective dissolution rate of the drugs regarding their shapes has made this issue an interesting subject for researchers. Methods: For this purpose, three tablet shapes, namely flat and biconvex both in a round and oblong shapes, with different four sizes were modelled for the preparation of domperidone tablet. In vitro dissolution test was accomplished using a USP dissolution apparatus II. The drug dissolution rate was assessed by calculating various dissolution parameters; e.g., dissolution efficiency (DE), mean dissolution rate (MDR), mean dissolution time (MDT), and difference and similarity factors (f1 and f2 ). Results: Regarding the disintegration time, the larger tablets showed a faster disintegration time. When the size of the tablets was smaller, the amount of released drug was significantly decreased. In addition, #9 tablets with a flat or biconvex geometry had obvious effects on the DE values. Generally, biconvex tablets had higher DE percentage than the flat tablets. Conclusion: Noticeable differences in dissolution parameters by considering the different geometric shapes play an important role in the drug release kinetics which makes a significant effect on quick onset of action in oral administration.

scholarly journals Stimuli-Responsive Dual Cross-Linked N-Carboxyethylchitosan Hydrogels with Tunable Dissolution Rate

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 188
Author(s):  
Svetlana Bratskaya ◽  
Anna Skatova ◽  
Yuliya Privar ◽  
Andrey Boroda ◽  
Ekaterina Kantemirova ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Hydrophobic Interactions ◽  
Dermal Fibroblasts ◽  
Molar Ratio ◽  
Dissolution Time ◽  
Cross Linking ◽  
Stimuli Responsive ◽  
Human Colon Carcinoma Cell ◽  
Weakly Alkaline ◽  
Physiological Conditions

Here, we discuss the applicability of (methylenebis(salicylaldehyde)—MbSA) for the fabrication of the stimuli-responsive N-carboxyethylchitosan (CEC) hydrogels with a tunable dissolution rate under physiological conditions. In comparison with non-covalent salicylimine hydrogels, MbSA cross-linking via covalent bis(‘imine clip’) and non-covalent hydrophobic interactions allowed the fabrication of hydrogels with storage moduli > 1 kPa at ten-fold lower aldehyde/CEC molar ratio with the preservation of pH- and amino-acid responsive behavior. Although MbSA-cross-linked CEC hydrogels were stable at neutral and weakly alkaline pH, their disassembly in cell growth medium (Dulbecco’s modified Eagle’s medium, DMEM) under physiological conditions was feasible due to transimination reaction with amino acids contained in DMEM. Depending on the cross-linking density, the complete dissolution time of the fabricated hydrogels varied from 28 h to 11 days. The cytotoxicity of MbSA cross-linked CEC hydrogels toward a human colon carcinoma cell line (HCT 116) and primary human dermal fibroblasts (HDF) was remarkably lower in comparison with CEC-salicylimine hydrogels. Fast gelation, relatively low cytotoxicity, and tunable stimuli-induced disassembly under physiological conditions make MbSA cross-linked CEC hydrogels promising for drug encapsulation and release, 3D printing, cell culturing, and other biomedical applications.

Sign in / Sign up

Export Citation Format

Share Document