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The article considers the main activities over the past decade on the modernization of the metallurgical production at the PJSC Novokramatorsk Machine-Building Plant (PJSC NKMZ), including steelmaking, press-forging and thermal equipment, based on the lean production concept. [ABSTRACT FROM AUTHOR]

The work is devoted to developing a cost-efficient method for the processing of metallurgical wastes such as oiled mill scale formed upon the mechanical cleaning of a hot-rolled steel strip in scalebreakers. The most significant parameters of a chemical-metallurgical process for producing expensive and highly marketed products, such as α-Fe2O3 and γ-Fe2O3 nanopowders, are experimentally determined. The properties of initial materials and nanodispersed products have been studied by X-ray diffractometry, energy dispersive spectroscopy, scanning and transmission electron microscopy, and Mössbauer spectrometry. The temperature and field dependences for the powder magnetization have been plotted according to the measurements performed with the use of a vibration magnetometer. The mill scale under investigation consists of three main phases: wustite, magnetite and hematite at a weight ratio of 6 : 8 : 7, respectively. The initial scale was activated in a magnetic mill in a hydrogen flow and dissolved in a mixture of hydrochloric and nitric acids. The resulting solutions have been used to obtain α-Fe2O3 nanocrystalline hematite by a chemical-metallurgical method, the main stages of which consist in hydroxide precipitation with the use of alkali at constant pH, washing, drying, and dehydration. Maghemite γ-Fe2O3 has been obtained from hematite in two stages. At the first stage, hydrogen reduction has been performed, whereas at the second stage, the obtained magnetite has been oxidized in air. The particles of synthesized nanodispersed oxide powders are in the aggregated condition. The particles of α-Fe2O3 are spherical, whereas the particles of γ-Fe2O3 are rod-shaped. According to Mössbauer spectroscopy, the lattices of both oxides contain magnesium, aluminum, silicon, chromium, and manganese that originate from the initial scale. These elements determine magnetic properties of α-Fe2O3 and γ-Fe2O3 nanopowders. The set of properties inherent in nanodispersed hematite and maghemite powders obtained from metallurgical wastes (mill scale) is recommended for the application in catalytic processes, in the systems of industrial wastewater purification from heavy metal ions, as well as in the manufacturing of blood analysis markers. [ABSTRACT FROM AUTHOR]

One measure of the effectiveness of environmental management at AO EVRAZ ZSMK is how much the waste sent to storage is decreased as a result of recycling. Environmental measures may be assessed in terms of the decrease in environmental impact and decrease in the consumption of natural materials in production. The best approach is to use waste in the production of sinter and hot metal. The blast furnace is well suited to the utilization or incineration of various wastes because it contains a high-temperature oxidative zone and a large volume with reducing properties. A waste-recycling technology has been proposed for use at Russian steel works. It requires no capital expenditure and produces sinter and hot metal at low cost. This method meets global environmental standards. [ABSTRACT FROM AUTHOR]

Abstract: In a microplot field trial, the use of crushed slag to break down the capillary borders in recultivation of toxic tailings (at enrichment facilities and solid waste dumps) with minimum application of fertile soil was studied. In this approach, metallurgical wastes may be used in low-cost energy-saving technologies. Four basic types of slag produced at AO EVRAZ ZSMK in steel smelting were studied: white nonferrous slag; blast-furnace (open-hearth) slag; electrosmelting slag; and converter slag. Such slag forms an inert layer under a minimal layer of fertile soil on trial plots, where perennials (a legume-grass mixture) were planted. For each slag, we used a control plot (without fertilizer); a plot with a potassium-humate preparation; a plot with complete mineral fertilizer; and a plot with a mixture of these approaches. At the end of the growing season, the above-ground phytomass is 17-128 g/m2. The best results were obtained with converter slag and blast-furnace slag, characterized by the lowest phytoxicity. Addition of mineral fertilizer alone or in combination with potassium humate increases the phytomass by a factor of 2-4. Added alone, potassium humate had no influence on plant production but, in combination with mineral fertilizer, it increased the phytomass by a factor of 1.6-1.8. To stimulate germination and phytomass production, the addition of both mineral fertilizers and humic preparations is recommended. The converter and blast-furnace slag may be used as an inert material in reclamation, with minimum application of fertile soil. White slag and electrosmelting slag are not recommended, on account of their high phytotoxicity; in those trials, the perennials employed did not thrive. [ABSTRACT FROM AUTHOR]

The proposed socially oriented information technology is based on the integration of diversification and technological processes for the creation of additional products and infrastructure, by stepwise structural synthesis of waste processing and land reclamation. The technology relies on empirical assumptions, theoretical principles, models of the decrease in environmental impact, assessments of the requirements, practical results, and verification criteria. The main approaches to decreasing the environmental impact include prevention of environmental damage; the introduction of a complete resource-utilization cycle; reconciliation of the interests of state agencies, investors, property owners, and other stake holders; and the stepwise integration of waste processing, recultivation of degraded land, and the creation of social infrastructure. The conceptual model for decreasing the environmental impact makes coordinated use of the primary and secondary products of waste processing and land restoration, with subsequent infrastructure creation. The outcomes of socially oriented information technology are specific, interpretable, verifiable, reliable, complete, and consistent. On the basis of the proposed tool set, scenarios are developed for improving the environmental conditions in the city of Novokuznetsk, which is located in the vicinity of metallurgical enterprises. In these scenarios, industrial wastes are used in the production of raw materials for the steel industry, building materials (bricks, concrete additives), and agricultural fertilizer. Predictions are made up to 2037, in terms of economic impact, area of recovered land, environmental pollution by productive activities, population of the region, relevant standards, and the pollution prevented per capita. Construction of the new system is planned for 2019 and 2020, with operation in 2021. Stepwise construction of the social infrastructure will begin in 2033. Simulation indicates the annual growth in predicted indices under the various scenarios, on account of synthesis of waste processing and land restoration, as well as decrease in the pollution thanks to low-waste and zero-waste production. [ABSTRACT FROM AUTHOR]

For existing coal-fired power plants, current methods of utilizing ash and slag waste may be considered in addressing new environmental and economic risks. However, for new power sources, environmental considerations are much more important in selecting the coal-combustion technology. Technology based on a circulating fluidized bed is sometimes cited as the most promising approach to environmentally sound coal combustion. It permits significant decrease in emissions of sulfur and nitrogen oxides beyond the boiler, but is of no help in processing ash and slag waste. For waste disposal, a different approach is recommended for new plants or the upgrading of coal-fired plants: instead of coal combustion in a gas flux or a fluidized bed, combustion in bubbling slag melt. Such methods are described. The basic characteristics of pulverized-coal combustion and combustion in slag melt are compared. Two basic approaches to the development of coal-based power generation are proposed: coal combustion with supercritical steam parameters; and gas generation with a hybrid (steam + gas) power-generating cycle based on gasification of solid fuels. The electrical efficiency of steam-based plants may be increased from 30-36 to 44-45% with supercritical steam parameters; and to 50-55% when using a hybrid steam-gas cycle. The proposed industrial system for coal gasification in slag melt increases the overall electrical efficiency. The environmental and economic efficiency of carbon gasification is demonstrated. It is simple to produce components from slag by casting. The cast slag-coal components are of considerably higher quality than analogous cement-sand components with added fly ash. The ease of switching from one type of casting to another permits rapid response to market demand. [ABSTRACT FROM AUTHOR]

In accordance with the national energy strategy, the development of coal-fired power stations in Russia, especially in Siberia and the Far East, calls for utilization of their ash and slag wastes. The total quantity of ash and slag in Russian tailings exceeds 1.5 billion t. These wastes cover an area of more than 220 km2. The utilization of these wastes is no more than 10%. The most promising approaches are utilization of the wastes in construction materials or road building, or a hybrid approach in which valuable metals are extracted during the production of construction materials. Some fly ash can be used in agriculture. The physicochemical properties of ash and slag waste and correspondingly their applicability and the choice of technology will be determined by the mineral component of the coal and the methods by which the coal is burned. In order to use fly ash in construction, dry processing methods for ash and slag waste must be introduced. On the one hand, that involves greater capital expenditures on equipment and structures for storage, classification, crushing, and grinding of the ash and slag waste, as well as means of modifying their properties. On the other, increased transportation and organizational barriers must be expected. Examples of proposed processing technologies based on metal extraction and the production of construction materials are presented. To obtain iron-bearing concentrates, single-stage magnetic separation is mainly employed. However, the resulting quality of the concentrate is unsatisfactory. A better approach to the extraction of metals from ash and slag waste is flotation. At the same time, the available data indicate that the application of flotation may be limited by economic and organizational factors and associated environmental hazards. The conclusion is that the use of such technologies at thermal power stations that are already in operation is possible, with state support. [ABSTRACT FROM AUTHOR]

Existing processing technologies for iron-ore wastes are analyzed. For the Kemorovo region, it makes sense to employ a processing technology with products corresponding to local requirements. Effective technologies may be combined to meet the full set of requirements. The formulation of waste-processing options is considered. Various proposals are developed for stepwise processing of iron-ore wastes, with the extraction of useful components by chemical methods, restoration of the damaged landscape, and the creation of recreation areas on the reclaimed land. Recommendations are developed for year-round processing of iron-ore wastes by chemical methods, even in winter. Maps are presented for the processing of ore tailings, with stepwise restoration of the reclaimed land. The number of stages selected will depend on the investment required and the annual throughput of the waste-processing system, with the possibility of simultaneous restoration of several sections. After complete removal of the iron-ore wastes from the tailings stores, preparations begin for the development of recreation areas: offers are solicited for the design of the recreation zones, the dismantling and sale of equipment, buildings, and other structures, the restoration of the ground cover, laying of turf, and planting of trees and shrubs. Restoration of the territory may run in parallel with processing of the waste. The recreation areas go into operation after the elimination of the waste. Scilab software is used for mathematical simulation of the waste-processing proposals for the Kemerovo region, with evaluation of its effectiveness in the following terms: economic benefit; restoration of damaged land; pollutant burden; population of the affected regions with standard socioeconomic indices; and prevention of public-health impairments. By graphical means, the Pareto-optimal solutions are selected from among the various proposals. The best Pareto-optimal solutions are selected on the basis of ranking in terms of public health and environmental safety (low, moderate, and high) in the Kemerovo region. [ABSTRACT FROM AUTHOR]