Study of possibility of obtaining alternative binders from production wastes for filling man-caused voids

Basic scientific and practical results of the study of possibility of obtaining alternative binders from production wastes to fill man-made voids at underground ore mining are presented. The objective of the study was to determine the technological possibility and economic feasibility of using available low-active substances as substitutes for expensive and scarce cement. It was shown that it is possible to obtain a binder from dolomite wastes, equivalent in properties to cement, which makes it possible to meet the demands of environmentally correct ore mining technologies. It has been established that hardening mixtures based on dolomites and enrichment tailings are only 8-22% inferior in strength to mixtures with standard cement and are suitable without restrictions for the construction of nature protection massifs in mine workings. Recommended activation of wastes increases the strength of the hardening filling mixture by 15-20% in comparison with the basic technology. With additional preparation in activators, a fundamental change in the quality of dolomite products is possible. The use of wastes in the production of a hardening mixture will free up the land occupied by storage facilities and organize the production of competitive products. Alternative binders and inert materials are recommended for use.

Recognition of surface defects of rolled steel in sheets by application micro-X-ray spectral analysis

Surface defects of sheet rolled products have a significant impact on its quality, performance and further processing of products, for example, on application of a protective anticorrosive coating. Therefore, the elimination of such defects and their accurate identification is an important aspect of sheet rolling production. Reducing the rejection of metal for surface defects enables to get a significant technical and economic effect. Investigation of the causes of defectiveness of the surface of sheet rolled products will make it possible to determine the source of the appearance of the defects and methods to prevent them. Determination of the nature and morphology of surface defects, the sources of which being metallic and non-metallic inclusions, as well as remnants of slag surface layer, scales from metallurgical and rolling stages, rolled into the surface of a hot-rolled sheet, is often difficult, since the appearance of the defects is very similar. It was shown that application of a scanning electron microscope (SEM) with micro-X-ray spectral analysis (MXSA), thermodynamic analysis makes it possible to determine the chemical composition of micro-areas and associate it with the end-to-end technology of sheet production. The article presents the results of identifying surface defects of cold-rolled sheet steel.

Forecasting of industrial coke quality at JSC EVRAZ NTMK based on data of passive industrial experiment. Report 1. Forecasting of CSR and CRI of industrial coke

A forecast of coke quality takes a special place in the coke production, since it enables to increase efficiency of management of batching process of various by composition and properties coals and production of coke of stably high and required quality with minimal costs. Description of a methodological approach to processing of passive industrial experiment data of blends coking at Coke production department of JSC EVRAZ NTMK presented by application selective (general) matrix. The matrix accounts various multilevel values of influence factor CSR and CRI of coke - a complex index of coking ability of blends K.п.к.Vo. It was shown that the proposed approach provides wide variations of response function (CSR/CRI) at symmetrical enough matrix, excluding predominance of any particular area of values of indices K.п.к.Vo and CSR/CRI. By applying the passive industrial experiment, based on processing of actual report data of industrial blends coking at the coke batteries No. 5-6 (wet quenching) and No. 9-10 (dry quenching) by selective matrix, mathematical models of forecast of quality of industrial coke by wet and dry quenching (CSR/CRI) were elaborated depending on coal charges properties (K.п.к.Vo) at the existing modes of their preparation and coking at the coke batteries No. 5-6 and 9-10. Verification of accuracy of the mathematical models of coke quality forecast at wet and dry quenching (CSR/CRI) processing a large actual material of industrial coking (62 coking operations in the coke batteries No. 5-6 and 58 coking operations in the coke batteries No. 9-10 showed accuracy good enough for practical application of forecasting indices CSR and CRI of industrial coke of wet and dry quenching.

Phases and workup order of pre-investment stage of projects in metallurgy by the example of OJSC “BMZ - managing company of holding “BMK”

Preparation, organization and managing by investment projects are efficient mechanism of increasing efficiency of investment activity of an enterprise. OJSC “BMZ - managing company of holding “BMK” accumulated practical experience on preinvestment workup in the sphere of implementation of investment projects in the industry. It was noted that before the industrial production of a new for an enterprise products, it is necessary to pass a unique way from the project idea to the implementation of equipment, division, shop or creation of a new plant at all, using definite knowledge, methodology and instruments of managing by the projects. Theoretical fundamentals were presented to accomplish a pre-investment workup on a project, as well as requirements of legislation of Republic of Belarus' to the content and order of work on pre-investment stage of a project, phases and order of development of the pre-project (pre-investment) documentation for projects in the industry by the example of OJSC “BMZ - managing company of holding “BMK”.

Influence of particles size distribution on the carbon content throughout sinter bed height

By the previous studies it was established that the character of solid fuel distribution throughout the bed height considerably effects the sintering machines productivity and the sinter quality. The purpose of the study was assessment of solid fuel distribution in the agglomerated burden throughout the height of bed at sintering machine. Sinter mix samples were taken from three sections of the bed: 150 mm - top part, 150 mm - middle part and 170 mm - bottom part at the sintering machines of NLMK. After screening the samples, particle size distribution was determined, as well as carbon content throughout the bed height and in the particles of different sizes. It was found that all solid fuel, irrespective of the size, gets balled into sinter mix granules, fine fuel (fraction -0.63 mm) was almost evenly distributed over the granules of different sizes, while coarse fuel (+3 mm) is mainly picked up by large granules. Solid fuel of -3 mm +0.63 mm fraction is mostly balled into 3-5 mm granules. Such nature of solid fuel distribution in the granules of the pelletized mix results in suboptimal distribution of fuel throughout the bed height at sintering machines No. 1, 2, despite satisfactory size segregation of the mix: it changes from low content in the top part to a higher content at the bottom of the bed. At sintering machines No. 3, 4 where there was no size segregation of the mix, fuel distribution throughout the bed height changes from optimal to non-optimal (low content in the top part). To optimize solid fuel distribution throughout the bed height with both good and poor segregation of the mix, it is necessary to reduce the content of 0-0.5 mm particles fraction in coke breeze.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 3. The picture of bath blowing at application two-level oxygen lances

Further increase of resources- and energy-saving efficiency of BOF processes is unthinkable without development of new methods of blowing and designs of blowing devices. It requires information on the real physicochemical phenomena in the converter cavity accompanying the blowing of the converter bath using new designs of oxygen lances in order to assess the possible risks in the mastering of the proposed developments in industrial conditions. The paper presents the results of video filming of the top blowing of a 80-kg converter bath by groups of multi-pulse supersonic and sonic oxygen jets formed, respectively, by Laval and cylindrical two-level nozzles of two designs equipped with double-row tips with a circular arrangement of Laval nozzles and cylindrical ones and upper block with cylindrical nozzles. Previously unknown information was obtained on the picture of the bath blowing with the formation of a reaction zone of interaction of supersonic and sonic oxygen jets with a metal melt with a flow of carbon monoxide going out the bath and afterburning of CO to CO2 under conditions of a counter-directed double curtain of sonic oxygen jets at different levels of location of the foamed slag-metal emulsions. It was established that in the initial period of blowing during slag formation most of the thermal energy of CO to CO2 combustion flares is transferred to the surface of the bath with lumps of added lime, and the rest is transferred by forced convection to the converter walls and gases escaping from the bath to the neck. In the case of the location of the foamed slag level at the upper tier of the cylindrical nozzles of the lance, heat transfer from high-temperature flares of localized afterburning of CO to CO2 within a limited in size near-lance flow of exhaust gases from the reaction zone is carried out according to the laws of submerged combustion and is completed completely in foamed slag-metal emulsion with the prevention of aggressive action of afterburning flares and volumes of overheated slag on the converter lining. Revealed and recorded by video recording modes of blowing the converter bath, contributing to the development of such undesirable phenomena during smelting as the appearance of intense emissions of slag-metal suspension from the facility, coagulation of the slag with the cessation of dephosphorization of the metal melt, the development of intense dust formation and the removal of small metal particles and slag with the formation of crust on the lance barrel. A variant of the final stage of blowing with a transition to supplying nitrogen instead of oxygen through cylindrical nozzles of two-level lances was experimentally tested, which provides an effective reduction in the level of foamed slag-metal emulsion before the converter turning down. The data obtained were used in the development of an industrial design of a two-level lance with a double-row tip, blowing and slag modes of blowing a converter bath with its use.

A methodology of roll pass design calculation for rails rolling using regression equations

In process of shaped profiles experimental rolling, it is often necessary to make adjustments to new roll pass design to ensure their physical filling, control between gaps in the values of real broadenings and reductions. In order to reduce number of possible adjustments in roll pass design process and mastering new profiles, the task of developing a model for calculating roll passes becomes actual. A model for calculating roll pass design for rolling railway rails presented. This model based on roll pass design for rolling R65 rails. The regression equations of deformation logarithmic degree were derived using example of two pre-finishing and finishing roll passes, which were used to calculate UIC60E1 rail roll pass design. A high degree of convergence of the geometry of the calculated and operating roll pass has been established. The maximum deviations from geometry of existing roll pass and calculated ones according to proposed method did not exceed 1-2 mm on each of them. It was shown that the developed model calculates exact roll pass geometry, which can be loaded into the program of a processing machine. The proposed calculation methodology can be used at roll pass design of shaped profiles of the same type of different profile sizes of the same mill, resulting in significant reduction of roll pass designed development time and number of adjustments.

Choice of a method of carbon wire drawing

At present for wire production various methods of drawing are used. To choose an effective drawing method or their combination, a methodology is needed to estimate existing and new methods of drawing. A methodology of simultaneous estimation of strain-stress state of carbon wire in the area of deformation and force conditions of drawing presented. Based on it an analysis of drawing in monolith dies, roller dies of radial-shear broach, classic two- and multi-roller dies was carried out. A module-combined method of drawing was also considered. Recommended modes of reduction for drawing in monolith dies presented. It was shown that to obtain a wire of 4.0 mm diameter max, the drawing in monolith dies is most effective. For production of wire of larger diameters, roller dies are more advisable. Application of the technology of radial-shear deformation enables to obtain a fine-grained structure in the surface layers of wire. It was shown that application of a module comprising a roller die and a monolith die is most effective. An example of drawing of a round wire from 8.0 mm diameter to 3.0 mm diameter by a route developed with their application considered. Recommendations on application of various methods of drawing for wires of diameter from 0.007 mm to 15.0 mm presented.

Investigation of technology schemes for the production of cast composite functional materials

Obtaining and using ligatures, modifiers and deoxidizers to obtain structural alloys of a given composition and properties in metallurgy and foundry is an important production task. One of the existing developments in the field of technologies for the preparation of functional composites on a matrix basis for non-ferrous and ferrous alloys is the combination of solid filler with a melt of an active metal binder. At that, from the filler material, which is selected from the group comprising iron, nickel, titanium, silicon, boron, manganese, first a porous workpiece of a given geometric shape with a technological total pore volume is formed, then it is heated to a temperature corresponding to the liquidus temperature of the active binder, the heating being carried out in a gas inert medium, after which the heated workpiece is impregnated with the melt of this binder by forced infiltration of the melt into the pores of the workpiece under pressure, mainly by the method of liquid stamping. The task of the study was to expand the scope of use of composites, to create a single flexible universal, and at the same time, simplified technology that will provide an opportunity to obtain a wide range of diverse in composition and service characteristics of deoxidizers, modifiers and ligatures for non-ferrous and ferrous alloys. The developed technology, based on vacuum impregnation (suction) of the matrix alloy through porous filler, makes it possible to obtain new functional metal-matrix composite materials of a given composition for use as inexpensive ligatures, modifiers and deoxidizers in metallurgical processes, as well as to simplify and make their use safe. The proposed method for obtaining ligatures, modifiers and deoxidizers provides a possibility of their industrial serial production and is easy to perform, and also reduces the cost of the metallurgy product obtained with their application by increasing the effective content of active components and their more complete assimilation, which reduces the consumption of scarce and expensive materials.

Prospects of transition of ferrous metallurgy enterprises of Russia to the use of carbon-free technologies

The intention to preserve a comfort habitat for the mankind finds expression in the attempts to decrease the anthropogenic impact on the environment. A concept “carbon footprint” appeared, which reflects input of some kind of activity to the environment pollution. The desire to influence producers’ behavior and make them decrease their carbon footprint under existing conditions results in elaboration new kinds of taxes and duties, stimulating modernization of technological process and decrease of harmful substances emissions. It is expected that in case of the taxes being implemented by big metal products consumers, such as Western Europe, will result in considerable change of the metal products market. An analysis of various ways of metal producers’ adaptation to operation in conditions of the expected changes presented. It was shown that such organization measures as lobbying of interests and artificial differentiation of business on provisionally “clean” and “dirty” will result in a rather restricted result. Thereupon actuality of a radical modernization of production capacities to decarbonize the technologies of steel production grows. Replacement of the carbon by hydrogen for reducing of iron oxides is the most advanced technological solution. At the same time, the hydrogen metallurgy is not yet implemented anywhere on industrial scale, and the hydrogen application in the production cycle results in a lot of questions, having not yet definite answers. A SWOT-analysis presented, demonstrating advantages and disadvantages of hydrogen technology mastering by metals producers.