Basic-Composition Mixture for the Consumable Lining of Intermediate Ladles

Thermomechanical and chemical-ceramic properties of the PTMS basic-composition mixture for the consumable refractory lining of intermediate ladles in service at the Kombinat Magnezit Joint-Stock Co. are considered and some details of the fabrication technique are discussed. Results for the mixture tested for performance at various metallurgical plants are given. Advantages of the mixture for practical application, its microstructural characteristics in pre- and post-service conditions, and the wear behavior are discussed.     

New Carbon-Containing Refractories for the Lining of Steel-Teeming Ladles from the Kombinat Magnezit Joint-Stock Co.

Test results for new carbon-containing refractories for the lining of steel-teeming ladles — PUSK, PShUK, PShUP, PUPK, and ShPUP-grade, available from the Kombinat Magnezit JSC, are presented. The properties of refractory components (including heat resistance) in the as-received and subjected to coking condition are reported. The enhanced resistance of the new materials to thermal spalling under varying temperature conditions is noted. Results of the tests (carried out at the Magnitigorsk Iron-and-Steel Works and Oskol'skii Electrical ISW) provide the basis for an analysis of the economic feasibility of large-scale production of these materials.     

Influence of mechanical activation of basic refractories and mixtures on sintering

Conclusions Mechanical activation leads to partial breakdown of the crystalline structures of refractory materials, conferring a higher reaction state on them. This is manifest as a reduction in the temperature range in which the magnesite and dolomite undergo conversions during heating, and also in the greater degree of exposure of the periclase and chrome concentrate.The porosity of the clinker obtained from activated sintered periclase with (CaO + SiO₂) >3.5%, fused periclase obtained from magnesite calcined in a shaft furnace, raw magnesite and periclase-skin, is reduced by more than an order compared with the original. It is considerably less for periclase-chromite skin, is reduced by more than an order compared with the original. It is considerably less for periclase-chromite skin, sintered periclase with (CaO + SiO₂) <3.5%, fused periclase-chromite, and periclase obtained from Kul'dursk brucite.To determine the possibility of applying these results in production conditions, research is now being conducted to select effective production activators, e.g., equipment with an elastic deformable working component.The authors would like to thank N. B. Kusin'sh, G. I. Vikulina, G. N. Bondarenko, and A. P. Kima for assistance in completing this work.Translated from Ogneupory, No. 3, pp. 14–17, March, 1993.     

Specific features of thermal decomposition of ammonium perchlorate subjected to γ radiation

Results of studying thermal decomposition of ammonium perchlorate (AP) samples in the original form and after irradiation by γ-quanta of ⁶⁰Co by methods of differential scanning calorimetry and dynamic thermogravimetry with heating rates b = 0.1–0.3 K/sec are described. Irradiation is performed in air at a temperature of 298 ± 2 K and a dose rate of ≈0.2 Gy/sec in the range of absorbed doses D = 0–150 kGy. Preliminary irradiation is demonstrated to lead to substantial transformations of the pattern of thermal decomposition of ammonium perchlorate in the dynamic regime of heating: the single-stage process of decomposition of non-irradiated samples proceeding at b = 0.107 K/sec in the temperature range of 625 to 743 K is replaced by a multistage process. At D = 150 kGy, exothermal transformations accompanied by noticeable losses of sample mass are observed starting from 473 K. Within experimental errors, the total thermal effect of AP decomposition is found to be independent of the absorbed dose and amounts to −1150 kJ/kg on the average. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 6, pp. 69–74, November–December, 2007.     

Present Status and Future Prospects of the Work on the Moscow Meson Factory

The current status and prospects of work on the Moscow meson factory are described. The maximum energy obtained at the present time is limited by the existing powerful klystrons and is 247 MeV. The maximum beam intensity is 150 A. The accelerator beam is used for fundamental research and for solving applied problems. The average duration of the sessions is 2000 h per year. Three of the five branches of the proton channel which are provided in the design are in operation in the experimental complex. This includes the branch on the multifunctional neutron complex, which is to be used for, among other things, research on nuclear transmutation of long-lived fission products, Np, Am, Cm, and the electronuclear method of generating electricity. The first phase of the proton therapy complex is under construction.     

Melting of magnesia refractory materials in an OKB-955N ore melting furnace

Conclusions The experinece in service of the IKB-955N furnace at Magnesite Plant in melting of different magnesia materials was summarized. The influence of a number of factors, including magnesium oxide content in the charge, on the indices of the melting process, was established.The optimum diameter of decomposition of the electrodes, diameter of reaction zone, and specific surface power in the molten material were determined for the different materials.On the basis of approximation equations of the experimental data a method of approximate evaluation of the basic production parameters of the melting process was proposed.Means of increasing the productivity of ore melting furnaces by selection of the optimum diameter of decomposition of the electrodes, adjustment of the automatic system, reduction of melting time, and increasing the average input power were shown.Translated from Ogneupory, No. 1, pp. 34–38, January, 1990.     

A Study of the Kinetics of Decarbonization of Magnesite Concentrated by Flotation

The kinetics of decarbonization of magnesite concentrated by the method of flotation is studied in a laboratory under various conditions (stationary unblown layer, fluidized layer, layer mixed in a rotary furnace). Typical features of the process of decarbonization of magnesite are determined (constancy of the temperature of the material up to a decarbonization of 80 – 90%, self-fluidizing of the roasted material due to intense emission of CO₂ gas, etc.).