The service of refractories in the lining of the VP-130 and ~SPTs vacuum degassers of Orsk-Khalilovo Metallurgical Combine is characterized by severe conditions of the aggressive action of slag containing 2-4% YeO, 3-5% TiO2, 4-7% A1203, 16-22% MgO, 1-3% Cr203, 27-36% CaO, and 18-28% SiO 2. The metal is superheated in the electric furance to 1750~ as the result of its subsequent teeming in a continuous casting machine [I]. The slag basicity of 1.6-1.9 favors the formation in it of dicalcium silicate which, as is known, penetrates into the pores of the refractory and destroys it as the result of expansion of the volume in the polymorphic transformation during cooling [2][3][4].In accordance with the normally used method for reducing the corrosive action of slag on the lining it is neutralized during treatment in the vacuum degasser by supplying a slag neutralizer to the vacuum chamber.A corundum slag neutralizer to Technical Specification 14-8-489-85 and also a ramming compound to Technical Specification 14-8-359-80 are used as the slag neutralizer in Orsk-Khalilovo Metallurgical Combine.However, these materials do not influence the polymorphic transformation of dicalcium silicate.At the same time a number of elements (boron, phosphorus, etc.) stabilizing the high-temperature phase of dicalcium silicate at low temperatures are known [2].Orsk-Khalilovo Metallurgical Combine and the All-Union Institute for Refractories have developed a corundum slag neutralizer containing oxides of boron and phosphorous which neutralizes the slag and stabilizes the high-temperature phase of dicalcium silicate in it. Aluminoborophosphate concentrate, which contains these elements, is simultaneously the binder for the mixture.Commercial-grade alumina to GOST 6972-74, Kumak clay to Technical Specification 14-8-338-80, and aluminoborophosphate concentrate to Technical Specification 113-08-10-17-84 were used for the production of this slag neutralizer.The alumina is supplied to Orsk-Khalilovo Metallurgical Combine in the form of a fine powder (with a residue on a No. 0088 sieve of not more than 30%) and it is not additionally treated.Clay from the existing production line in the form of powder with passage through a No. 054 sieve of not less than 65% was used.The aluminoborophosphate concentrate was used in the form of an aqueous solution with a density of 1.5-1.6 g/cm 3.First laboratory tests were made of four compositions of slag neutralizer on cylindrical specimens with a diameter of 36 m~n and a height of 50 mm formed on a hyraulic press. A mixture with a moisture content of 22-24% was prepared in a laboratory mill.The clay was added in the form of a slip. The compositions differed in the content of clay and aluminoborophosphate concentrate.The specimens of each form were dried in a drying chamber at 100~ and heat treated at 120, 700, and 1350~In determination of the physicomechanical properties the best results were obtained after heat treatment of the specimens of composition 4 at 1350~ (Table i). This composition was recommended f...

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The new interest in the use of monolithic linings in steel-casting ladles has been stimulated by the possibility of fully mechanizing the lining operation, replacing expensive refractory-ladle brickwork with natural material or special preparation of masses, and also significantly reducing the labor costs associated with repairing the ladles [1][2][3].The present paper deals with the problem of manufacturing cast linings for 250-ton steeJ ~ casting ladles at the Orsk-Khalilov Metallurgical Combine.* The cast linings were manufactured on a specially designed mechanized assembly consisting of equipment for preparing the self-hardening liquid mixtures and a manipulator for supplying the prepared mixture to the gap between the reinforcing lining of the ladle and the template. The layout of the assembly and the design of the manipulator were developed at our combine.The layout of the mechanized assembly is shown in Fig. I. One feature of the assembly is that during casting the ladle remains immobile, while the even cyclic supply of prepared mixture to the ladle is done by the receiving and dispensing worm of the manipulator mounted on a self-moving car. Before casting, the manipulator is moved over the ladle mounted in the repair pit and is centered; at the completion of casting, it is returned to its initial position, releasing the inlet to the ladle~ This particular arrangement of components has several advantages: The whole assembly occupies only a small area (the construction of the equipment, of course~ is carried out in the actual shop conditions, where space is limited); the supply of the prepared mass using the receiving and dispensing worms provides additional mixing; and the electrical drive of the manipulator worms is significantly smaller and simpler than that of an electrically driven platform under the ladle and it is also more reliable and is accessible for repairs.The equipment for the preparation of the mixture consists of a I0 m s bunker for quartzite, two bunkers of 0.9-m s capacity for the ferrochrome slag and additives, dosing equipment , a mixer, and a system for dosing the liquid components.The design of the mechanized assembly involves an elevated arrangement of the parts where all the raw materials in the mixture are transported from above downwards, passing through all the operations in succession.We used a siliceous filler which binds the material, and a hardener for the manufacture of the cast lining of the steel-casting ladles. As the filler we used Pervouralsk crystalline quartzite, grade ZKM-97 according to Technical Specification 14-8-92--74; as the binder we used water glass to State Standard 13078-81 with a modulus of 2.75-2.80. The hardener for the mass was ferrochrome slag to Technical Specification 14-11-95--74. This new technology for the manufacture of the casting lining included the following operations: the supply and charging of the starting materials, laying down the working layer of the ladle bottom, installing the template, casting the working layer of the lining of the ...

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