scholarly journals Effect of 2CaO·SiO2 particles addition on dephosphorization behavior

2020 ◽  
Vol 39 (1) ◽  
pp. 219-227
Author(s):  
Aijun Deng ◽  
Yunjin Xia ◽  
Jie Li ◽  
Dingdong Fan
Keyword(s):  
Liquid Slag ◽  
Solid Phase ◽  
Solid Particles ◽  
Hot Metal ◽  
Liquid Silicate ◽  
Phase Complex ◽  
Dephosphorization Slag ◽  
Stage 1 ◽  
Two Stages ◽  
Complex Liquid

AbstractThe effect of the addition of 2CaO·SiO2 solid particles on dephosphorization behavior in carbon-saturated hot metal was investigated. The research results showed that the addition of 2CaO·SiO2 particles have little influence on desilication and demanganization, and the removal of [Si] and [Mn] occurred in the first 5 min with different conditions where the contents of 2CaO·SiO2 particles addition for the conditions 1, 2, 3, 4, and 5 are 0, 2.2, 6.4, 8.6, and 13.0 g, respectively. The final dephosphorization ratios for the conditions 1, 2, 3, 4, and 5 are 61.2%, 66.9%, 79.6%, 63.0%, and 78.1%, respectively. The dephosphorization ratio decreases with the increase of 2CaO·SiO2 particles in the first 3 min. The reason for this is that the dephosphorization process between hot metal and slag containing C2S phase consisted of two stages: Stage 1, [P] transfers from hot metal to liquid slag and Stage 2, the dephosphorization production (3CaO·P2O5) in liquid slag reacts with 2CaO·SiO2 to form C2S–C3P solid solution. The increase of 2CaO·SiO2 particles increases the viscosity of slag and weakens the dephosphorization ability of the stage 1. The SEM and XRD analyses show that the phase of dephosphorization slag with the addition of different 2CaO·SiO2 particles is composed of white RO phase, complex liquid silicate phase, and black solid phase (C2S or C2S–C3P). Because the contents of C2S–C3P and 2CaO·SiO2 in slag and the dephosphorization ability of the two stages are different, the dephosphorization ability with different conditions is different.

Formation of Nanocrystalline Silicon in Tin-Doped Amorphous Silicon Films

2020 ◽  
Vol 65 (3) ◽  
pp. 236
Author(s):  
R. M. Rudenko ◽  
O. O. Voitsihovska ◽  
V. V. Voitovych ◽  
M. M. Kras’ko ◽  
A. G. Kolosyuk ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Nanocrystalline Silicon ◽  
Recrystallization Temperature ◽  
Nanocrystalline Phase ◽  
Silicon Phase ◽  
Silicon Nanocrystallites ◽  
Lower Temperature ◽  
Two Stages

The process of crystalline silicon phase formation in tin-doped amorphous silicon (a-SiSn) films has been studied. The inclusions of metallic tin are shown to play a key role in the crystallization of researched a-SiSn specimens with Sn contents of 1–10 at% at temperatures of 300–500 ∘C. The crystallization process can conditionally be divided into two stages. At the first stage, the formation of metallic tin inclusions occurs in the bulk of as-precipitated films owing to the diffusion of tin atoms in the amorphous silicon matrix. At the second stage, the formation of the nanocrystalline phase of silicon occurs as a result of the motion of silicon atoms from the amorphous phase to the crystalline one through the formed metallic tin inclusions. The presence of the latter ensures the formation of silicon crystallites at a much lower temperature than the solid-phase recrystallization temperature (about 750 ∘C). A possibility for a relation to exist between the sizes of growing silicon nanocrystallites and metallic tin inclusions favoring the formation of nanocrystallites has been analyzed.

Comparative Study on Compositions of Oil-Water Transition Layer before and after ClO2-Treatment Process

2013 ◽  
Vol 652-654 ◽  
pp. 749-752
Author(s):  
Dan Dan Yuan ◽  
Hong Jun Wu ◽  
Hai Xia Sheng ◽  
Xin Sui ◽  
Bao Hui Wang
Keyword(s):  
Chemical Composition ◽  
Transition Layer ◽  
Solid Phase ◽  
Settling Tank ◽  
Physical Structure ◽  
Solid Particles ◽  
Viscosity Reduction ◽  
Insoluble Residue ◽  
Before And After ◽  
Oil Water

In order to meet the need of separating oil from water in the settling tank of the oilfield, ClO2 treatment for oil-water transition layer in settling tank is introduced. The field test displayed that the technique was achieved by a good performance. For understanding the oxidation and mechanism, compositions of oil-water transition layer were comparatively studied for before/after ClO2-treatment in this paper.The experimental results show that the compositions before and after ClO2-treatment, including physical structure and chemical composition, were varied in the great extension. The physical structure, consisting of water, oil and solid phase, was reduced to less than 5% of water and 0.5% of solid particle and increased to 95% of oil in layer compared with before-treatment, easily leading to clearly separating water from oil. The chemical composition of iron sulfide and acid insoluble substance in solid phase was decreased to more than 90% while the carbonate was reduced more than 70% . After the treatment, the viscosity reduction of the water phase in the layer was reached to 50% after oxidation demulsification with ClO2. The chemistry was discussed based on the principles and experiments. Due to ClO2 destroying (oxidizing) the rigid interface membrane structure which is supported by natural surfactant, polymer and solid particles with interface-active materials, the action accelerates the separating of water and oil and sedimentation of insoluble residue of acid in the layer. By demonstrating the experimental data and discussion, we can effectively control the oxidation performance of chlorine dioxide, which is very meaningful for oilfield on the aspect of stable production of petroleum.

scholarly journals Influence of Solid CaO and Liquid Slag on Hot Metal Desulfurization

2012 ◽  
Vol 52 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Koichi Takahashi ◽  
Keita Utagawa ◽  
Hiroyuki Shibata ◽  
Shin-ya Kitamura ◽  
Naoki Kikuchi ◽  
...  
Keyword(s):  
Liquid Slag ◽  
Hot Metal ◽  
Hot Metal Desulfurization

scholarly journals Archaeological studies In theIlmeny state reserve, South Urals

2020 ◽  
pp. 112-122
Author(s):  
V.S. Mosin
Keyword(s):  
Bronze Age ◽  
Iron Age ◽  
Early Iron Age ◽  
South Urals ◽  
Stone Age ◽  
Stage 1 ◽  
Two Stages

The paper describes two stages of archeological studies at the territory of the Ilmeny State Reserve. Stage 1 is related to expedition of L.Ya. Krizhevskaya in 1961–1970, which resulted in fn-ding of more than 40 settlements and sites of the Stone Age, Bronze Age and Early Iron Age. Seven settlements were excavated. Stage 2 studies began in 2010 and are continued at present. These works allowed us to fnd about 40 sites and settlements of the Stone Age and to excavate of the Stone Age sites and Bronze Ages burials.

scholarly journals KRISTALISASI AMMONIUM PERKLORAT (AP) DENGAN SISTEM PENDINGINAN TERKONTROL UNTUK MENGHASILKAN KRISTAL BERBENTUK BULAT

2012 ◽  
Vol 9 (2) ◽  
Author(s):  
Anita Pinalia
Keyword(s):  
Ethylene Glycol ◽  
Ammonium Perchlorate ◽  
Crystal Size ◽  
Crystallization Process ◽  
Cooling System ◽  
Solid Particles ◽  
Crystal Shape ◽  
Controlled Cooling ◽  
Slow Cooling ◽  
Two Stages

AP is the solid particles with the largest composition in compossite propellant, with fractions 60-80%. Rounded particles of AP indirectly gives better performance of propellant. Therefore we need experiment the crystallization process to produce rounded AP crystal. In this experiment, crystallization was conducted by using a controlled cooling system. Cooling is done through two stages and using a different coolant. The first stage of slow cooling using water (30°C), and continued rapid cooling with ethylene glycol (-27°C). These experiment generate 45.45 kg AP with a purity 99.67%, 40 mesh crystal size, crystal shape close to round, yield 39.71%. Keywords: Ammonium perchlorate, Crystallization, Rounded crystal

Thermodynamics Analysis of Hot Metal Dephosphorization Flux Reaction Process

2011 ◽  
Vol 402 ◽  
pp. 354-357
Author(s):  
Hui Ding ◽  
Yan Jin ◽  
Zhi Bing Tian ◽  
Dan Jiang Wu
Keyword(s):  
Calcium Phosphate ◽  
Solid Phase ◽  
Equilibrium Temperature ◽  
Quality Data ◽  
Hot Metal ◽  
Phosphate Capacity ◽  
Different Temperatures ◽  
Factsage Software ◽  
The Right ◽  
Calculation Software

In this paper, CaO-Fe2O3-CaCl2and CaO-Fe3O4-CaCl2system dephosphorizer depho- -sphorization of the thermodynamics of the use of FactSage thermodynamic calculation software Equilib module of hot metal dephosphorization flux and the balance between the response calculated, to find the right dephosphorizer dephosphorization ratio and the conditions for optimal phosphorus removal. First of all, by the beginning of slag and the final calculated optical basicity slag and phosphate capacity, calculated on the balance FactSage software phosphorus content mapping, and comparative analysis. Followed by software at different temperatures to calculate the iron liquid, liquid slag, slag liquid solid phase of calcium phosphate and calcium phosphate and quality data on the thermodynamic equilibrium temperature mapping analysis..

Comparative Assessment of Turbulence Models for Prediction of Flow-Induced Corrosion Damages

2011 ◽  
Author(s):  
Kaushik Das ◽  
Debashis Basu ◽  
Todd Mintz
Keyword(s):  
Corrosion Rate ◽  
Cross Sections ◽  
Volume Fraction ◽  
Solid Phase ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Comparative Assessment ◽  
Solid Particles ◽  
Protective Film

The present study makes a comparative assessment of different turbulence models in simulating the flow-assisted corrosion (FAC) process for pipes with noncircular cross sections and bends, features regularly encountered in heat exchangers and other pipeline networks. The case study investigates material damage due to corrosion caused by dissolved oxygen (O2) in a stainless steel pipe carrying an aqueous solution. A discrete solid phase is also present in the solution, but the transport of the solid particles is not explicitly modeled. It is assumed that the volume fraction of the solid phase is low, so it does not affect the continuous phase. Traditional two-equation models are compared, such as isotropic eddy viscosity, standard k-ε and k-ω models, shear stress transport (SST) k-ω models, and the anisotropic Reynolds Stress Model (RSM). Computed axial and radial velocities, and turbulent kinetic energy profiles predicted by the turbulence models are compared with available experimental data. Results show that all the turbulence models provide comparable results, though the RSM model provided better predictions in certain locations. The convective and diffusive motion of dissolved O2 is calculated by solving the species transport equations. The study assumes that solid particle impingement on the pipe wall will completely remove the protective film formed by corrosion products. It is also assumed that the rate of corrosion is controlled by diffusion of O2 through the mass transfer boundary layer. Based on these assumptions, corrosion rate is calculated at the internal pipe walls. Results indicate that the predicted O2 corrosion rate along the walls varies for different turbulence models but show the same general trend and pattern.

A numerical study of the nucleation, growth and settling of crystals from a turbulent convecting fluid

2021 ◽  
Author(s):  
Vojtech Patocka ◽  
Nicola Tosi ◽  
Enrico Calzavarini
Keyword(s):  
Magma Chamber ◽  
Solid Fraction ◽  
Large Scale ◽  
Solid Phase ◽  
Numerical Study ◽  
Equilibrium Concentration ◽  
Solid Particles ◽  
Settling Rate ◽  
Carrier Fluid ◽  
Nucleation Growth

<p>We evaluate the equilibrium concentration of a thermally convecting suspension that is cooled from above and in which<br>solid crystals are self-consistently generated in the thermal boundary layer near the top. In a previous study (Patočka et<br>al., 2020), we investigated the settling rate of solid particles suspended in a highly vigorous (Ra = 10<sup>8</sup> , 10<sup>10</sup>, and 10<sup>12</sup> ),<br>finite Prandtl number (Pr = 10, 50) convection. In this follow-up study we additionally employ the model of crystal<br>generation and growth of Jarvis and Woods (1994), instead of using particles with a predefined size and density that are<br>uniformly injected into the carrier fluid.</p><p>We perform a series of numerical experiments of particle-laden thermal convection in 2D and 3D Cartesian geometry<br>using the freely available code CH4 (Calzavarini, 2019). Starting from a purely liquid phase, the solid fraction gradually<br>grows until an equilibrium is reached in which the generation of the solid phase balances the loss of crystals due to<br>sedimentation at the bottom of the fluid. For a range of predefined density contrasts of the solid phase with respect to<br>the density of the fluid (ρ<sub>p</sub> /ρ<sub>f</sub> = [0, 2]), we measure the time it takes to reach such equilibrium. Both this time and<br>the equilibrium concentration depend on the average settling rate of the particles and are thus non-trival to compute for<br>particle types that interact with the large-scale circulation of the fluid (see Patočka et al., 2020).</p><p>We apply our results to the cooling of a large volume of magma, spanning from a large magma chamber up to a<br>global magma ocean. Preliminary results indicate that, as long as particle re-entrainment is not a dominant process, the<br>separation of crystals from the fluid is an efficient process. Fractional crystallization is thus expected and the suspended<br>solid fraction is typically small, prohibiting phenomena in which the feedback of crystals on the fluid begins to govern the<br>physics of the system (e.g. Sparks et al, 1993).</p><p>References<br>Patočka V., Calzavarini E., and Tosi N.(2020). Settling of inertial particles in turbulent Rayleigh-Bénard convection.<br>Physical Review Fluids, 26(4) 883-889.</p><p>Jarvis, R. A. and Woods, A. W.(1994). The nucleation, growth and settling of crystals from a turbulently convecting<br>fluid. J. Fluid. Mech, 273 83-107.</p><p>Sparks, R., Huppert, H., Koyaguchi, T. et al (1993). Origin of modal and rhythmic igneous layering by sedimentation in<br>a convecting magma chamber. Nature, 361, 246-249.</p><p>Calzavarini, E (2019). Eulerian–Lagrangian fluid dynamics platform: The ch4-project. Software Impacts, 1, 100002.</p>

scholarly journals Apical Debris Extrusion by Adaptive Root Canal Instrumentation in Oval Canals: Full-Sequence SAF System vs. the XP-Endo Shaper Plus Sequence

2020 ◽  
Vol 10 (16) ◽  
pp. 5684 ◽  
Author(s):  
Ajinkya M. Pawar ◽  
Bhaggyashri A. Pawar ◽  
Anuj Bhardwaj ◽  
Alexander Maniangat Luke ◽  
Zvi Metzger ◽  
...  
Keyword(s):  
Root Canal ◽  
Significance Level ◽  
Full Sequence ◽  
Apical Extrusion ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Stage 1 ◽  
Two Stages ◽  
Root Canal Instrumentation

Apical extrusion of debris (AED) by the full sequence of the self-adjusting file (SAF) system was compared with that of the XP-endo shaper plus sequence. Sixty permanent mandibular incisors were randomly assigned to two groups (n = 30) for root canal instrumentation: Group A: Stage 1—pre-SAF OS, pre-SAF 1 and pre-SAF 2 files, followed by Stage 2—1.5 mm SAF; and Group B: Stage 1— hand K-file 15/0.02, followed by Stage 2—XP-endo shaper and Stage 3—XP-endo finisher. The AED produced during instrumentation at each stage was collected in pre-weighed Eppendorf tubes. The weights of AED by the two methods were compared using t tests with significance level set at 5%. Group A produced significantly less total AED than Group B (p < 0.001), with no significant difference in debris extrusion between the two stages (p = 0.3014). Conversely, in Group B, a significant difference was noted between Stage 1 and Stages 2 and 3 (p < 0.01), with no significant difference between Stages 2 and 3 (p = 0.488). Both sequences resulted in measurable amounts of AED. Each phase, in either procedure, made its own contribution to the extrusion of debris.

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