Effects of B2O3 and CaF2 on Melting Properties of CaO-Based Slags

2012 ◽  
Vol 217-219 ◽  
pp. 511-514
Author(s):  
Hong Ming Wang ◽  
De Fu ◽  
Gui Rong Li ◽  
Xiang Zhu ◽  
Zhao Zhao ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Steelmaking Process ◽  
Melting Temperatures ◽  
Steelmaking Slags ◽  
Melting Properties ◽  
Fluxing Agent

B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3 steelmaking slags to substitute for CaF2. The influences of B2O3 and CaF2 on the melting properties of this system slags were investigated and compared. The results indicate that the fluxing effect of B2O3 is more remarkable than that of CaF2. Therefore, B2O3 promotes the dissolution of CaO, SiO2 and 2CaO•SiO2, etc, then the slagging speed can be improved greatly. The melting temperatures of slags increase with the increasing of basicity, especially, when CaF2 is used as fluxing agent as well as the basicity is up to 5.0, the melting temperature is increased higher than 1420°C. These characteristics of boron-containing slgas are more suitable for steelmaking process than those of fluoride-containing slags.

Analysis of structures and melting properties of the 19-atom Ni–Co clusters

2014 ◽  
Vol 28 (25) ◽  
pp. 1450171 ◽  
Author(s):  
Shi-Wei Ren ◽  
Jing-Wei Sun ◽  
Yan-Zhong Hao
Keyword(s):  
Melting Temperature ◽  
Nickel Atom ◽  
Melting Temperatures ◽  
Pure Cobalt ◽  
Melting Phenomenon ◽  
Nickel Clusters ◽  
Melting Properties ◽  
Mixed Clusters ◽  
Dynamics Method ◽  
Cobalt And Nickel

In this paper, by using the classical molecular dynamics method and the GEAM potential, the geometric structure and the melting properties of the 19-atom Ni – Co clusters with different compositions are studied. It is found that all the clusters have the double icosahedron structures although some of the structures are slightly deformed. With the increase of the temperature, a pre-melting phenomenon is observed. The pre-melting temperatures of the pure cobalt and nickel clusters are very close. But on the whole, the pre-melting temperature decreases with the increase of the number of the nickel atom for the mixed clusters. The effects of the substitution atoms on the melting temperature of the clusters are similar to that on the pre-melting temperature although there are some oscillations in the decrease process. The mechanism of these findings are also investigated and analyzed.

The Melting Temperature of CaO-(2CaO•SiO2)-B2O3-SiO2-(Al2O3) Slag System

2012 ◽  
Vol 217-219 ◽  
pp. 35-38 ◽  
Author(s):  
Hong Ming Wang ◽  
Pei Si Li ◽  
Gui Rong Li ◽  
Mian Zhang ◽  
Zhao Zhao ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Slag System ◽  
Refining Process ◽  
Alumina Content ◽  
Melting Temperatures ◽  
High Basicity ◽  
Secondary Refining ◽  
Mass Ratios ◽  
Fluxing Agent

The melting temperatures of CaO-(2CaO•SiO2)-B2O3-SiO2-(Al2O3) slag system were investigated. The results indicate that B2O3 has significant fluxing effect on this slag system. When the content of B2O3 is about 10% in these slag system, the mass ratios of w(CaO)/w(SiO2) and (CaO)/w(Al2O3) can be controlled in the scope of 1.5-8.0, the melting temperature of slag is still lower than 1340°C, which is suitable for steelmaking and secondary refining process. As a conclusion, when 10% B2O3 is employed as fluxing agent, a kind of CaO-based slag system with ultra-high basicity, ultra-low alumina content as well as low melting temperature can be obtained.

Melting Properties of Preparing Compound Desulphurizer by Aluminothermy Reducing Caustic Calcined Dolomite

2013 ◽  
Vol 634-638 ◽  
pp. 3138-3142
Author(s):  
Shi Jun Wang ◽  
Xue Sen Zhang ◽  
Chang Cheng Zhou ◽  
Jie Li ◽  
Jun Pan
Keyword(s):  
Melting Temperature ◽  
Influence Factors ◽  
Mean Value ◽  
Melting Properties ◽  
The Mean ◽  
Fluxing Agent ◽  
Addition Amount ◽  
Main Influence

Taken caustic calcined dolomite based compound desulfurizer as the research object, influence of fluxing agent CaF2, Al2O3, SiO2 and heating agent on the melting temperature of the compound desulfurizer was mainly investigated during its directly reducing process. Fluxing agent SiO2 and heating agent are the main influence factors, which influence melting temperature of the compound desulfurizer, the next are CaF2 and Al2O3. The mean value of compound desulfurizer melting temperature is respectively 1190.3°C and 1199Subscript text.1°C when the addition amount of SiO2 and heating agent is respectively 8.33% and 33.55%. With the increase of CaF2, the mean value of compound desulfurizer melting temperature decreases gradually, however, which increases first and then decreases with the increase of Al2O3.The conditions of the lowest melting temperature about the compound desulfurizer is A4, B1, C1, D2, namely 9% CaF2 + 0% Al2O3 + 8.33% SiO2 + 33.55% heating agent.

Effect of Boron Mud on Melting Temperature of CaO-Based Steelmaking Slag

2012 ◽  
Vol 535-537 ◽  
pp. 647-650
Author(s):  
Hong Ming Wang ◽  
Gui Rong Li ◽  
Ting Wang Zhang ◽  
Li Li Yang ◽  
Xiang Zhu ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Steelmaking Slag ◽  
Remarkable Effect ◽  
Melting Properties ◽  
Boron Mud ◽  
Fluxing Agent

For the elimination of the fluorine pollution of steelmaking slag, boron mud is employed as fluxing agent for CaO-based fluorine-free slag. The effect of boron mud on the melting properties of slag is investigated. Hemisphere method is used to determine the melting temperature of samples. The results indicate that when the content of boron mud is lower than 7%, the melting temperature can be decreased by boron mud. With the content of boron mud increasing higher than 7%, the melting temperature is increased with increase of boron mud content. The basicity and the content of F2O3 have remarkable effect on the melting temperature of boron mud containing slag. When the basicity is in scope of 2.0-5.0, the melting temperature is in the range of 1350-1450°C correspondingly. The melting temperature of boron mud containing slag can be decreased significantly with increase of F2O3 content.

Compare the Fluxing Effect of Boron Sludge and CaF2 on CaO-Based Steelmaking Slag

2013 ◽  
Vol 575-576 ◽  
pp. 382-385
Author(s):  
Hong Ming Wang ◽  
Xiang Zhu ◽  
Gui Rong Li ◽  
Li Li Yang ◽  
Cong Xiang Peng ◽  
...  
Keyword(s):  
Melting Temperature ◽  
Slag System ◽  
Steelmaking Slag ◽  
Melting Temperatures ◽  
Fluxing Agent

To reduce the pollution caused by employing CaF2 as fluxing agent in metallurgical flux, boron sludge is used as fluxing agent to substitute for CaF2. The melting temperatures of CaO-SiO2-Fe2O3-boron sludge system were investigated. The melting temperature of CaO-SiO2-Fe2O3-boron sludge slag system is increased with the increase of ω (CaO)/ω (SiO2) at first, and then fluctuates at about 1430°C. Moreover, the melting temperature of CaO-SiO2-Fe2O3-boron sludge system is decreased with the increase of boron sludge content at first and then increased, 7% content of boron sludge has the best fluxing effect and the melting temperature is1445°C. As a conclusion, the fluxing effect of boron sludge is close to CaF2, boron sludge may be considered to substitute for CaF2.

Studies on the Melting of DNA

1974 ◽  
Vol 29 (3-4) ◽  
pp. 130-132
Author(s):  
Gokul Chandra Das
Keyword(s):  
Ionic Strength ◽  
Melting Temperature ◽  
Thermal Denaturation ◽  
Spectrophotometric Methods ◽  
Melting Temperatures

Abstract The thermal denaturation of the native DNA in solvents of varying salt concentrations was studied by viscometric and spectrophotometric methods. It was observed that within the molarity range of 0.02 ᴍ to 0.3 ᴍ, the melting temperatures obtained by the two independent methods agreed well, but that at lower ionic strength the agreement was not satisfactory. Both the visco­metric and the spectrophotometric measurements showed an increase of the melting temperature with increasing counterion concentration and a levelling off effect in the neighbourhood of 0.3 ᴍ.

Crystallization in Stretched Polymer Networks. I. trans-Polychloroprene

1967 ◽  
Vol 40 (4) ◽  
pp. 1071-1083 ◽  
Author(s):  
A. N. Gent
Keyword(s):  
Melting Temperature ◽  
Polymer Networks ◽  
Crystal Form ◽  
Simple Extension ◽  
Theoretical Treatment ◽  
Nucleation Kinetics ◽  
Segmental Mobility ◽  
Melting Temperatures ◽  
Direct Measurements ◽  
Stress Changes

Abstract Changes in tensile stress afford a simple means of studying the rates of crystallization and the melting temperatures in crosslinked polymers subjected to simple extension. The form and magnitude of the stress changes in networks of trans-polychloroprene are closely similar to those observed for cis-1:4-polyisoprene and cis-l:4-polybutadiene networks. They are in accord with the formation of oriented crystallites and incompatible with folded chain crystallization at extensions as low as 15 per cent. It seems likely that the present networks do not crystallize by chain folding even in the unstretched state. The large increases in rate of crystallization with extension are approximately accounted for by corresponding increases in the equilibrium melting temperature. Direct measurements of the melting temperature show similar rises with extension. The rise in melting temperature is in good agreement with Flory's theoretical treatment of oriented crystallization at extension ratios of three and higher (when the crystallite orientation is complete) for three networks having different degrees of crosslinking. When referred to a constant segmental mobility, namely, that obtaining at Tg+50° C, the rates of crystallization at various extensions obey a common dependence upon the degree of supercooling. This relation is in fair accord with theories of nucleation kinetics, except at the lowest temperatures where there is some indication of the appearance of a new crystal form.

Thermodynamics of Crystallization in High Polymers. Natural Rubber

1955 ◽  
Vol 28 (3) ◽  
pp. 718-727 ◽  
Author(s):  
Donald E. Roberts ◽  
Leo Mandelkern
Keyword(s):  
Natural Rubber ◽  
Melting Temperature ◽  
Low Temperatures ◽  
Rapid Heating ◽  
Heat Of Fusion ◽  
Low Molecular Weight ◽  
Heating Rates ◽  
Equilibrium Melting Temperature ◽  
Clapeyron Equation ◽  
Melting Temperatures

Abstract The existence of an equilibrium melting temperature, T0m, at 28 ± 1°, for unstretched natural rubber has been established, using dilatometric methods. The lower melting temperatures previously observed are a consequence of the low temperatures of crystallization and the rapid heating rates employed. From melting point studies of mixtures of the polymer with low molecular-weight diluents, the heat of fusion per repeating unit, ΔHu has been evaluated as 15.3 ± 0.5 cal./g. The values of ΔHu and T0m have then been combined with data of other workers to obtain the following information concerning natural rubber: (1) The variation of melting temperature with applied hydrostatic pressure has been calculated from the Clapeyron equation to be 0.0465° C/atm. (2) The degree of erystallinity resulting from maintaining a sample at 0° until the rate of crystallization is negligible has been calculated, by three independent methods, to be in the range 26 to 31 per cent. (3) Analysis of the stress-strain-temperature relationship has indicated that crystallization is the cause of the large internal energy changes that are observed at relatively high elongations.

Comparison of Effects of B2O3 and CaF2 on Metallurgical Properties of High Basicity CaO-Based Flux

2011 ◽  
Vol 311-313 ◽  
pp. 966-969
Author(s):  
Hong Ming Wang ◽  
Li Li Yang ◽  
Hua Zhu ◽  
Yong Qi Yan
Keyword(s):  
Melting Temperature ◽  
Inflection Point ◽  
Equal Mass ◽  
Temperature Curve ◽  
Point Temperature ◽  
Metallurgical Properties ◽  
High Basicity ◽  
Mass Ratios ◽  
Fluxing Agent ◽  
Better Than

B2O3 is employed as fluxing agent of high basicity CaO-based flux to substitute for CaF2. The effects of B2O3 and CaF2 on the metallurgy properties of CaO-based flux were investigated. The results indicate that the fluxing action of B2O3 is better than that of CaF2. For the high basicity CaO-based flux, when CaF2 is substituted with B2O3, the melting temperature can be decreased remarkably. Especially, when the mass ratios of CaO/SiO2 are in range of 5.25~8.0, the flux melting temperature is lower than 1300 °C. The inflection point temperature of flux viscosity-temperature curve is lowered remarkably when B2O3 is employed to substitute for CaF2. Meanwhile, the desulfurization capacity of flux can be improved markedly when CaF2 is substituted with equal mass of B2O3.

Effect of Al2O3 and CaF2 on Melting Temperature of High Calcium Ladle Desulfurization Slag

2015 ◽  
Vol 1094 ◽  
pp. 325-328
Author(s):  
Wei Fan ◽  
Jin Zhu Zhang ◽  
Wan Zhong Ao ◽  
Jun Huang
Keyword(s):  
Melting Temperature ◽  
Orthogonal Design ◽  
Molten Iron ◽  
Iron And Steel ◽  
Melting Temperatures ◽  
High Calcium ◽  
Analytical Reagent ◽  
The Impact

The external desulphurization of molten iron has become an important step in the production of steel and iron. The melting temperatures of high calcium desulfurization slag, which were taken from Shougang Shuicheng Iron and Steel (Group) Co. Limited, were investigated on basis of the method of hemisphaerium temperature. The contents of CaO, Al2O3 and CaF2 in the slag were adjusted in 47%-53%, 14%-20% and 2%-10% respectively by adding analytical reagent Ca (OH)2, Al2O3 and CaF2 using orthogonal design. The results show that the melting temperature of desulfurization slag decreases obviously with the increase of the content of Al2O3 between 14% and 20%, and decreased markedly with the increase of the content of CaF2 lower than 8%. The impact to the melting temperature of the high calcium slag is as follows: Al2O3 > CaF2 > CaO.

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