Slag resistance of refractories in the lining of an arc steel melting furnace

The interaction of refractories of various grades with liquid slags whose samples were taken in different stages of melting from an electric furnace are investigated by wetting for temperatures ranging from 20 to 1550°C. The compositions of the slags differed in the CaO/SiO₂ proportion and the content of chromium oxide. It has been established that the olivinite refractory has advantages under the conditions of electric melting, which seems to be explainable by its chemical composition and specific pore structure. The results of the investigation were used to develop compositions of gunite powders for torch guniting of linings of the slag belt of an arc steel melting furnace. Translated from Ogneupory, No. 9, pp. 18 – 20, September, 1995.     

浅谈矿热炉炉盖内衬结构的施工对比

通过对矿热炉炉盖内衬结构的3种施工模式进行对比,提出了炉盖内衬采用轻质浇注料与重质浇注料分层浇注模式的优点,力求达到改善和延长炉盖使用寿命,提高矿热炉冶炼水平,降低热损失,提高经济效益。     

Mechanism of wear of electric arc steel melting furnace wall linings and means of increasing their life

Conclusions The walls of electric arc steel melting furnaces and especially the region of the slag belt operate under very severe conditions. Together with physicochemical factors the life of the lining is also determined by the design of the refractory shell of the working space of the furnace and the ratio of its primary dimensions.A method of increasing the wall refractory lining life as the result of rational construction in the design of new and reconstruction of existing furnaces was proposed.In the form of a discussion.Translated from Ogneupory, No. 2, pp. 51–53, February, 1988.     

Fusing baddeleyite in an electric arc furnace

Refractories and Industrial Ceramics -     

Cementitious and pozzolanic behavior of electric arc furnace steel slags

The cementitious and pozzolanic behavior of electric arc furnace steel slag, both as received and treated has been studied in detail. The as received slag was completely crystalline and multi-phasic with Fe-substituted monticellite as the predominant phase. Treatment of this slag, remelting and water quenching, results in reduction of Fe-oxide content coupled with an increase in basicity index which makes it more hydraulic compared to the as received slag. The remelted slag has several phases with merwinite as the dominant phase. Thermal analysis of the hydrated slag shows that treating the as received slag increases the water absorption capacity, a property essential for cementitious behavior. Compression strength of the slag blended cements was studied and it was found that substitution of 20% ground granulated blast furnace slag with electric arc furnace steel slag does not decrease the strength beyond 28 days. The control cement has a strength of 58.6 MPa compared to 58 MPa for the cement comprising of 20% untreated slag. The substitution of this untreated slag with treated slag exhibits the highest strength, 61 MPa and a potential for further strength increase after 28 days. In the case of cement mix with no blast furnace slag, substitution of 15% clinker with steel slag does not decrease the strength significantly, 64.4 MPa compared to 66.5 MPa for the control cement. Substituting 30% clinker in the cement mix with electric arc furnace slag however results in significant decrease in strength, 53.4 MPa. The pozzolanic strength of the slag was found to increase significantly due to remelting from 2.0 MPa for the as received slag to 8.0 MPa for the treated slag.     

Glass melting in an electric direct-heated skull furnace

A fundamentally new process is proposed to make S88-5 glass. It involves the use of an electric direct-heated skull furnace. The furnace has a capacity of 200–250 kg/day. Translated from Steklo i Keramika, No. 5, pp. 6–7, May, 1997.     

Service of the magnesia-spinellide lining of a melting furnace roof

Conclusions On the basis of a study of the magnesia-spinellide roof of a melting furnace it was established that the refractory consists of four zones, the least changed, the working, the zone of contact with the lining slag, and in the lining slag. A nonuniform distribution of the components in specimens of lining slag taken from different portions of the roof was observed.The lining slag and the zone of contact with the lining slag consist of crystals of picrochromite, ferrite, and magnesioferrite, between which there is located a silicate binder including forsterite, hedenbergite, and the impurity phases bunsenite, hematite, and magnetite. The working zone consists of chromite, picrochromite, monticellite, and the introduced melting products copper, chalcosite, and cuprite.On the basis of analysis of the data on failure of refractories as the result of chemical interaction with the melting products, penetration of the low-melting components, and thermomechanical cracking at the boundaries of the zones it was established that one of the methods of protection of the roof is cooling.Translated from Ogneupory, No. 2, pp. 51–55, February, 1989.     

Increasing the lining life of arc furnaces for melting of cobalt

Conclusions Experimental refractory parts and a ramming mixture produced from baddeleyite concentrate have been successfully tested under conditions of the pyrometallurgical processes for production of cobalt.The chemical composition and microstructure of magnesite and baddeleyite refractories after service in production furnaces for melting of cobalt were investigated.It is desirable to line these furnaces differentially. The point of maximum wear, the charging hole, is lined with castable refractories, the side walls in the zone of entry of the electrodes with granular baddeleyite mixture-base sintered refractories, and the zone of the journals with monolithic shaped inserts produced from baddeleyite ramming mixture. The remaining portion of the lining must be made of increased density magnesite brick. Such a lining method makes it possible to substantially lengthen the furnace campaign and reduce repair costs, which in general leads to an increase in their productivity.Translated from Ogneupory, No. 2, pp. 48–51, February, 1989.     

Technological parameters for production of fused lime in an electric arc furnace

Conclusions The authors describe the construction of a pilot-scale three-phase electric arc furnace with a power of 140 kWA and the technology of obtaining fused quartz with it.They suggest a method of technicoeconomic analysis of pilot production, which gives a scientific basis for planning decisions in choosing equipment for industrial plants for producingfused lime and in determining the cost of its production.Translated from Ogneupory, No. 1, pp. 35–37, January, 1981.