Technology of producing high-grade electroengineering periclase by melting in an induction furnace with a cold crucible

Shurygina, I. V.; Polonskii, Yu. A.; Masover, I. F.; Aleksandrov, B. P.; Dobrovol'skaya, V. I.; Byndin, V. M.

doi:10.1007/bf01398177

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…This is accompanied by a volume increase by a factor 1.97 -2.17, and the hydration rate increases with temperature [9]. To reduce these effects, special bonding agents are used that have a hydrophobic effect, and the powders are treated with surfactants [10 -12] or additional heat treatment is applied to the plagioclase with the addition of talc [13]. However, one cannot completely eliminate the effect of hydration, so a very complicated process is involved in making periclase and periclase-bearing refractories, particularly by vibrocasting.…”

Section: Introductionmentioning

confidence: 99%

Effects of dispersant form and amount on the properties of vibrocast periclase-spinel material for making crucibles

Primachenko¹,

Ustichenko²,

Chaplyanko³

et al. 2008

Refract Ind Ceram

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The effects have been examined from the form and amount of dispersant on the flow of suspensions based on microgranular periclase, and also the fluidity in the vibration of granular periclase-spinel materials. The best form and amount have been established for dispersants that provide the required flow at various environmental temperatures in the vibration of the granular periclase-spinel materials of water content 5.0 -6.5% and working time not less than 3 h.

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Section: Introductionmentioning

confidence: 99%

Effects of dispersant form and amount on the properties of vibrocast periclase-spinel material for making crucibles

Primachenko¹,

Ustichenko²,

Chaplyanko³

et al. 2008

Refract Ind Ceram

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“…pure materials were chemically pure magnesium oxide and magnesium oxide obtained from bishofire. The oxides were melted in an induction furnace (a Crystal-402) which has been described in [9].…”

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confidence: 99%

Microhardness of fused periclase

et al. 1984

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Fused periclase is widely used in the manufacture of several types of refractory articles and also as an electrical-insulation material in tubular electric heaters (TEH). During the manufacture of the electric heaters, the metal tubes filled with fused periclase are compressed on roller machinery. As a result, there is a significant compaction of the powdered periclase, for example, from an apparent density of 2.30-2.35 to 2.90 g/cm 3. Therefore, it seemed important to study the microhardness of periclase and the possibility of lowering this parameter with the aim of improving the compression process and the pressing of the refractory articles.The mierohardness of minerals is associated with the strength of the crystal. As Lomonosov stated; "the harder the solid, the more strongly associated are its particles" [i]. In the classical crystallochemical works by GolVdshmidt [2] and Fersman [3], the hardness is associated with the strength of the crystal lattice of the mineral which depends on the cation and anion charges and the interatomic distances.A further development of crystallochemical theorywas made by A. S. Povarennykh [4,5] who suggested that as well as the valence (charge) of the ions and the interatomic distances, the coordination number, the packing density of the atoms, the strength of the ionic and covalent bonds, and the structure of the electron shell must also be taken into account.However, the dependences obtained on the basis of crysta!lochemical hypotheses only give approximate values for the hardness, for example, for periclase by comparison with other minerals.In fact, the hardness is a strength characteristic and can change significantly even for the same crystal depending on the plane chosen for the measurement, the presence of dislocations, and other factors [6]. One of the important factors affecting the strength of crystals and, consequently, their hardness is the interaction between dislocations [7]. The interaction between dislocations leads to an increase in the resistance to movement in the plane where the dislocations lie in proportion to the accumulation of defects and to the strengthening (increase in hardness) of the crystal.An important effect on the hardness of crystals is provided by defects and impurities. Their action is twofold: on the one hand, the defects in the structure help to lower the hardness and, on the other, they strengthen the crystal by preventing the free movements of the dislocations.The strengthening of the structure can be explained by the fact that when the dislocation passes a hindrance (structural defects, inclusion, impurity of atom of a different size) it is forced to bend round the hindrance (to form a loop) and then straighten out again (Fig. i). Such a process is accompanied by the elongation of the dislocation and the local distortion of the structure for which an additional expenditure of energy is required. As a result, the defective part of the crystal is characterized by a high resistance to deformation, i.e., by an increase in hardness.As in ot...

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“…Crucible cooling is also a reason for a solidified layer formation that does not allow any contact of the remaining material with the crucible wall. Moreover, the melted metal partly levitates due to Lorentz forces [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

The Influence A Crucible Arrangement On The Electrical Efficiency Of The Cold Crucible Induction Furnace

Smalcerz

Oleksiak

Siwiec

2015

Archives of Metallurgy and Materials

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A big interest in application of cold crucible furnace (CCF) for industrial, particularly metallurgical, processes has been observed in recent years. They are mainly utilised for melting of metal, glass and other materials. Analyses of processes that occur in such devices are performed; however, computer modelling is rarely applied. As a precise determination of the electromagnetic field distribution is essential for a proper analysis of processes in furnaces with cold crucibles, a complex 3D model development is necessary. In the paper, effects of a crucible design and current frequency on the efficiency of the induction furnace with cold crucible are presented. Numerical calculations were performed with the use of the Flux 3D professional software.

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Technology of producing high-grade electroengineering periclase by melting in an induction furnace with a cold crucible

Cited by 3 publications

References 2 publications

Effects of dispersant form and amount on the properties of vibrocast periclase-spinel material for making crucibles

Effects of dispersant form and amount on the properties of vibrocast periclase-spinel material for making crucibles

Microhardness of fused periclase

The Influence A Crucible Arrangement On The Electrical Efficiency Of The Cold Crucible Induction Furnace

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