A method of calculation of a guniting flame

Conclusions A physicomathematical model and a method of calculation of the guniting flame making it possible to calculate the basic characteristics of flame guniting — combustion of the fuel and heating of the refractory — have been developed.An example is given of calculation of the guniting flame with parameters characteristic of industrial equipment. Based on its results the processes occurring in the guniting flame are described qualitatively.Translated from Ogneupory, No. 6, pp. 46–49, June, 1986.     

Taking into consideration the polydispersion of guniting powder in calculation of a guniting flame

Conclusions The principle of division of polydispersed fuel into monodispersed fractions taking into consideration the determining property of the fuel particles is presented.By calculation of three- and four-fraction guniting flames it was established that the polydispersed guniting powder must be divided into not less than four fractions.Translated from Ogneupory, No. 7, pp. 41–44, July, 1986.     

Optimization of the operating conditions of pneumatic transport systems for loose materials

Conclusions The new device for control of delivery of loose materials developed and installed provides uniform and stable flow of guniting mixture during guniting. In addition pulsations of the metal hoses through which the guniting compound is supplied are not observed.A constant flow of the solid constituent of the guniting compound to the outlet from the nozzle (nozzles) provides a stoichiometric composition of combustion with a constant specified flow of oxygen, and complete combustion of the carbon-containing constituent and fusion of the refractory constituents are obtained.Guniting with installation of the new device for controlling delivery of the guniting compound has made it possible to reduce its consumption by 0.74 kg/ton of steel under otherwise similar conditions.Translated from Ogneupory, No. 7, pp. 27–28, July, 1991.     

Guniting of the nozzles of a circulation vacuum degasser

Conclusions Ecologically clean guniting compounds which are of at least as good quality as foreign ones have been developed for guniting of the inner (base) and outer (corundum) linings of a circumation vacuum degasser leg and Technical Specifications and Technical Instructions have been approved for production and use of them. The optimum method of application of protective coatings with use of which production guniting of the Belorussian Metallurgical Plant vacuum degasser legs has been introduced, has been developed.Translated from Ogneupory, No. 8, pp. 33–35, August, 1991.     

Mechanized guniting of the lining of steelcasting ladles

Conclusions A method has been developed and equipment constructed for guniting steelcasting ladles without any manual labor. Experiments and tests were carried out with compositions based on quartzite, Chasov-Yar semiloamy sand, and fine-ground chamotte. The industrial-scale guniting tests showed that the durability of the lining of 130-ton steelcasting ladles increases by 30% (4.7 melts) on average with one guniting per ladle campaign.Translated from Ogneupory, No. 5, pp. 32–36, May, 1977.     

Improving the efficiency of guniting steel-pouring ladles

Conclusions Hot guniting of steel-pouring ladles without cooling the lining enables us to reduce the time taken to prepare them for pouring, and creates conditions for repeated hot guniting within a ladle campaign. This will make it possible to increase the stability of the lining and to reduce the energy expended on drying the gunite layer.The efficiency of mechanized guniting can also be improved by differential use of gunites with rational compositions.Translated from Ogneupory, No. 7, pp. 38–41, July, 1981.     

Guniting the necks of hot-metal transfer ladles

The components of a guniting mixture (clay and chamotte) and their optimum proportion have been determined in working out the process of guniting necks of hot-metal transfer ladles. The use of guniting increases the service life of the linings of the ladles, decreases the specific consumption of refractories, and reduces the frequency of maintenance of the top layers. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 7, pp. 35–36, July, 1997.     

Determination of the technological parameters of guniting

Conclusions The optimum guniting parameters with which it is possible to obtain strong and dense coatings with the minimum losses of compound with the springback were determined by multiple correlation analysis. The use of a regression equation makes it possible to calculate the guniting parameters for the production of coatings with previously specified properties.Translated from Ogneupory, No. 4, pp. 37–40, April, 1984.     

Guniting the lining of steel-casting ladles

Conclusions In a joint investigation by the Serp i Molot Metallurgical Plant in Moscow and the All-Union Institute of Refractories the advantages were demonstrated of guniting the lining of steel-casting ladles. The first industrial-scale trials showed that guniting results in a significant increase in the durability of the lining and in a decrease in the consumption of ladle brick. In order to extend the practice of guniting steel-casting ladles it will be necessary to organize the production of gunite at specializing establishments of the refractories industry.Translated from Ogneupory, No. 8, pp. 37–39, August, 1975.     

Guniting the lining of heating furnaces of rolling mills

Conclusions Guniting mass compositions and a procedure for guniting worn brickwork of continuous heating furnaces of rolling mills have been developed. At a number of metallurgical factories the worn brickwork of eight continuous heating furnaces of rolling mills have been repaired by guniting. The use of guniting enables the period between furnace lining repairs to be doubled (from 1 to 2 years), the volume of brickwork repair and the length of the repair work to be reduced, and a saving of 5000 rubles per annum per furnace to be obtained (merely by reducing the amount of repair work).Using IR spectroscopy the authors have investigated hydration and dehydration in alumina and high-alumina cements and aluminosilicate guniting masses with additives of these cements. They have shown that during guniting by the semidry method, hydration of the cements included in the composition of the gunite coatings does not go to completion and ends in the stage of formation of CaO·Al₂O₃·10H₂O; dehydration of the gunite coatings is completed below 300°C.Translated from Ogneupory, No. 5, pp. 30–35, May, 1980.     

Guniting of the lining of furnaces for heating of steel billets

Conclusions A method of guniting of the rolling mill heating furnaces during shutdown for cold repairs and with a lining surface temperature of 900–1200°C was developed with the use of guniting powders produced by industry of aluminosilicate and basic compositions with hydraulic and silicate binders. The introduction of composite guniting of the lining in the cold and hot conditions makes it possible to reduce the volume of lining repair work by 10–15 m³ per furnace and the consumption of brick refractories by 0.1 kg per ton of steel rolled and to increase the life of the lining by 1.5–2.0 times.Translated from Ogneupory, No. 4, pp. 48–51, April, 1988.     

Guniting the lining of 300-ton steelcasting ladles

Conclusions The practice of guniting the lining of steelcasting ladles has been introduced for the 300-ton ladles of the open-hearth division of the Cherepovetsk Metallurgical Plant. The guniting parameters are as follows: the temperature of the lining of the ladle wall should be 60–120°C; the amount of wetting agent (sodium silicate solution) for the optimal adhesion of the G unite layer to the brick masonry should give the G unite mix a moisture content of 8–15%, and the density of the aqueous sodium silicate solution should be 1.15–1.30 g/cm³.The guniting operation is carried out with a remote-controlled centrifugal-action machine which permits the operation to be carried out at a temperature in the ladle of 200°C. The durability of the ladle lining increases significantly when the lining is gunited regularly up to five times per campaign. The estimated economic benefit from the practice of guniting the 300-ton steelcasting ladles is 85,000 rubles/yr.Deceased.Translated from Ogneupory, No. 2, pp. 29–32, February, 1978.     

Guniting linings of oxygen converters in the course of melting without stopping the blow

Problems arising in guniting converter linings in the course of melting without stopping the oxygen blow are considered. Deposition of a mixture based on magnesite is conducted in an oxygen jet. As the powder particles move in the vessel, they are heated due to the heat of the converter and afterburning of carbon monoxide, which ensures their strong cohesion with the surface of the lining. The velocity and diameter of the gas-powder jet are calculated as a function of the concentration of the periclase powder, the distance from the tuyere nozzle, and the temperature of the magnesite particles heated in the vessel. An experimental installation is developed and experiments on guniting in the course of melting without interrupting the blow are conducted. It is established that the gunited coating is deposited on the lining only at the end of melting. The endurance of the coating is 1–4 heats. In guniting, the temperature of the metal increases by 20–70°C. The experiments showed the possibility in principle of guniting a converter lining in the course of melting without interrupting the blow. Translated from Ogneupory, No. 3, pp. 27–31, March, 1996.     

Guniting of the monolithic lining of steel-teeming ladles

Conclusions The authors have developed the principles of guniting the monolithic lining of steel-teeming ladles with semidry masses. Determination of the wetting of a vitrified siliceous monolithic lining with aqueous solutions of additives and suspensions of these solutions, plasticizing additives, and refractory filler has shown that a coating can be deposited onto the surface of a monolithic lining. Formation of a ceramic bond between the coating and the vitrified surface of a monolithic lining takes place at high temperatures (900°C or above). Masses of siliceous, aluminosilicate, and periclase-chromite compositions have been developed for guniting the monolithic lining of steel-teeming ladles.A procedure for guniting the monolithic lining of 180- and 350-ton steel-teeming ladles has been developed and tested. The best results have been obtained with use of gunite masses of periclase-chromite composition.Translated from Ogneupory, No. 6, pp. 25–30, June, 1981.     

Guniting the roof of open-hearth furnaces at the Zaporozhstal' plant

Conclusions Laboratory analyses and industrial-scale tests resulted in the development of the technological parameters for guniting the lining of the main roof of 500-ton open-hearth furnaces operated at an accelerated melting cycle.The microstructure of chromite and chrome — magnesite coatings containing low-melting additives was analyzed and the chemical composition and structure of coatings which had served in the roof of an open-hearth furnace were determined.The work carried out at the Zaporozhstal' Steel Plant confirmed the effectiveness and advantages of guniting the roof of large-tonnage open-hearth furnaces.Translated from Ogneupory, No. 5, pp. 28–35, May, 1976.     

Torch guniting of open-hearth roof local burns

Conclusions The All-Union Institute for Refractories and Azov Steel Zhdanov Metallurgical Plant have developed a method of flame guniting of open-hearth roofs. Tests of this process conducted in 450-ton open hearths showed the possibility, in principle, of repairing local burns of periclase-spinellide roof refractories at the end of open-hearth campaigns.Torch guniting in open hearths provided a periclase coating with a porosity of 20–30% and a thickness of up to 50 mm, strongly bonded to the periclase-spinellide roof parts. The life of the coating on the roof is up to 10 heats.Translated from Ogneupory, No. 5, pp. 57–61, May, 1983.     

Experience in the service of and measures for improving the service life of coke ovens of refractory concretes

Conclusions Experience in the operation of coke ovens of Batteries Nos. 1 and 4 of Stakhanov Coke and Chemical Plant made of large dinas-quartzite blocks has made it impossible to confirm their technical advantages over ovens of normal small-piece refractories.Several years of observations of the surface condition of the concrete lining of coke ovens has shown that in general its resistance is at least as good as the resistance of the chamotte lining. The processes of graphitization of the coke battery concrete lining occur satisfactorily during service.To prolong the service life of refractory concrete batteries it is desirable to eliminate lining defects occurring in the initial period of service of batteries of blocks without delay.The recommended compositions of guniting compounds are quite effective for repair of the serface of dinas-quartzite concretes and possess good adhesion and life in the coking medium.Questions related to broadening of the introduction of concretes into the construction and repair of large-scale coke batteries are very pressing and require the continuation of investigations.Translated from Ogneupory, No. 3, pp. 47–50, March, 1987.     

Apparatus for determining the strength of the adhesion of the Gunite coating to the refractory masonry in breakaway tests

Conclusions Apparatus was designed and constructed for determining the strength of the adhesion of Gunite compositions to refractory masonry. It was shown that the strength of adhesion of the Gunite compositions developed for guniting the roof of open-hearth furnaces during the smelting cycle is adequate.Translated from Ogneupory, No. 1, pp. 58–60, January, 1977.     

The production of refractory concrete and aluminosilicate Gunite compositions in Poland

Conclusions In view of the relatively short period of time elapsed since refractory concretes based on alumina cement were introduced in ferrous metallurgy and other industries, and in view, moreover, of the limited area of application of the concretes, the experiments with various types of concrete and the investigation of the technologies of their application should be continued.Phosphate-bonded refractory blocks and reinforced concretes should be subjected to tests in soaking pits operating under demanding conditions (at 1400–1450°C with liquid slag removal).The top part of the lining of soaking pits should be made of cast concrete reinforced with ceramic brick, or of a chemically bonded ramming compound which improves the stability of the concrete lining.In view of the considerable economic benefit than can be achieved by reconditioning the lining of heat-using equipment by guniting, this method should be introduced on a broad scale in ferrous metallurgy and other industries.The technique of guniting the hot lining of furnaces with chemically bonded compositions requires refining and calls for the use of special equipment (water-cooled nozzles of various cross sections).The users of Gunite compositions should be supplied guniting equipment, the shortage of which at present impedes the further spread of the practice of guniting heat-using equipment.Translated from Ogneupory, No. 2, pp. 50–61, February, 1977.     

Gas-flame guniting of the lining of intermediate continuous steel-casting ladles

Conclusions As a result of laboratory investigations and rig testing of the flame guniting of intermediate ladles for continuous steel-casting plant we recommend the following bodies: 90% corundum, 10% sodium tripolyphosphate; 80–90% corundum, 20–10% chamotte; 80–90% high-alumina chamotte, 20–10% chamotte. The particle size of the corundum body is <0.088 mm, high-alumina <0.25 mm.The optimum guniting cycle is: consumption of natural gas 60 m³/h, oxygen 100 m³/h, gunite body 150–200 kg/h, guniting distance 450–550 mm, rate of moving the burner 1.0 m/min.In the case of chamotte, the coefficient of gunite body utilization equals 0.75, for high-alumina 0.70, and for corundum 0.40, with an open porosity in the gunite coating of 10–15, 8–10,and 4–6%, respectively.Using the experimental equipment the body made from 90% corundum and 10% sodium tripolyphosphate was used to gunite the side surface of the lining of an intermediate ladle. The wear of the gunite section of the lining was 1.3–2.5 mm per heat.Translated from Ogneupory, No. 4, pp. 37–42, April, 1973.