The contemporary problem of recycling technogenic mineral formations (TMFs) of ferroalloy production under the conditions of increasingly stringent social and ecological constraints is analyzed. ...During the first decades of the 21st century, management outcome requirements in the metallurgical industry have been significantly toughened. In accordance with international practice, financial and economic indicators connected with maintaining the competitiveness of the industry are typically provided by metallurgical companies. However, in order for the metallurgical industry to remain competitive under these new conditions, it must ensure not only sectoral, but also national-economic effectiveness connected, first of all, in terms of achieving social and ecological goals. In the field of ferroalloy production, the already stressed ecological situation is significantly complicated by the need to apply low-quality (i.e., having an increased content of harmful impurities) mineral raw materials, resulting in a reduction of the technical and economic indices of ferroalloy production. The low utilization degree of valuable alloy components is connected with losses during mining and ore concentration processes, as well as at the stages of ferroalloy production and steel smelting. As a consequence, the total recovery proportion of manganese and chromium into finished products does not exceed 30–40% of that obtained in mining. In order to evaluate the expediency of involving technogenic formations in production process and substantiate the effectiveness of design solutions in this field, the authors propose an interdisciplinary functional approach, an algorithm for which was constructed using the
Tekhnogen-Invest
software program.
Under contemporary conditions of social development, it is necessary to rethink the role of waste produced due to economic activity and, in particular, industrial formations of the ferroalloy ...industry. In order to evaluate the expediency of involving industrial formations in the production process and substantiate the efficiency of design solutions in the field, a functional approach was proposed and its algorithm created in the Tekhnogen-Invest software. This article continues a study aimed at assessing the efficiency of processing industrial formations of the ferroalloy industry. In this part, the developed software was tested using data from the production of high-carbon ferrochrome. The relevance of the applied methodology for assessing the ecological and economic efficiency associated with processing industrial formations of ferroalloy production is confirmed, taking into account the strategic flexibility of projects. The conducted testing the developed Tekhnogen-Invest software produced positive results. The algorithm used in the software allows the cost of implementing an investment project for processing industrial formations of high-carbon ferrochrome production under current conditions of the Urals to be evaluated and the feasibility of its implementation under changing market conditions to be substantiated. The obtained results demonstrate a high potential for producing marketable products from ferroalloy industry waste, confirming the economic efficiency and feasibility of processing industrial formations.
Data on the volumes of imported and exported materials of the metallurgical industry in Russia are presented. The domestic industry, despite the rich mineral resource base, depends on imported ...supplies for a whole list of ore concentrates, oxides and other compounds, metals, and ferroalloys, as well as for certain grades of steel and metal products, which leads to high risks in the field of the country’s security and sustainable development. The authors analyze the situation associated with the dependence on supplies of ore materials, metals, and alloys from abroad and give examples of promising technological options for the development of domestic production using Russia’s own mineral resource base.
Advantages and disadvantages of deoxidizing steel with silicon carbide and calcium carbide are considered. The advantage is demonstrated of joint diffusion deoxidization technology for steel with ...silicon carbide and calcium carbide. Use of classical technology of metal deoxidation with aluminum leads in a number of cases to the appearance of individual alumina inclusions of the reject type with general high purity of steel with respect to non-metallic inclusions. Inclusions are exogenous in nature, and their origin is presumably entry of alumina growths from the CBCM submerged nozzle. The technology of diffusion deoxidation of metal during ladle treatment with combined use of silicon carbide and calcium carbide makes it possible to exclude entry into steel of large alumina inclusions. Types, composition, sizes and distribution of nonmetallic inclusions in cast metal produced by this technology are investigated. Use of diffusion deoxidation with silicon carbide and calcium carbide makes it possible to form fine globular non-metallic inclusions, predominantly small calcium aluminosilicate, and manganese and calcium sulfides.
—To describe the processes of fuming copper smelting slags by the products of methane conversion by oxygen at oxygen consumption coefficients (α) varying from 0.25 to 0.75 in the temperature range ...1473–1773 K, we have developed a thermodynamic modeling technique for open systems with fractional introduction of an initial reducing gas and periodic removal of a metallic phase and waste gases from a working medium. Relations between the contents of iron and zinc oxides in an oxide melt and the degrees of their reduction and the temperature and the amount of the introduced reducing agent are revealed. The thermodynamic equilibrium of a system is calculated on the assumption that solutions are ideal; that is, the activity coefficient of zinc oxide is 1. Under the real conditions of the slag melt of copper smelting,
a
ZnO
is close to 3. Therefore, the quantitative indicators of industrial smelting differ from the calculated ones. However, the change in the smelting parameters relative to each other would be the same. The main result of this work is a comparative analysis of the processes depending on the reducing gas temperature and composition. The amount of conversion products and, accordingly, natural gas required for their production, which is necessary for metal reduction to a given degree of zinc recovery, significantly depends on the gas temperature and composition. The data obtained are useful for predicting the thermal extraction processes that occur during the extraction of useful components from nonferrous metallurgy slags.
—The fuming of copper smelting slag in a Vanyukov furnace by the products of methane conversion by oxygen, water vapor, and carbon dioxide in the temperature range 1473–1773 K is thermodynamically ...modeled. For this purpose, a technique is developed to describe the changes in the phase compositions in the systems under study during their bubbling as functions of the amount of an introduced reducing gas; this technique is characterized by cyclic calculations and the removal of the formed gases and metal phase from the working medium composition. The calculation results demonstrate that the interaction of the gas with melt oxides proceeds in two stages regardless of the melt composition. At the first stage, Fe
3
O
4
is reduced to FeO and ZnO, to Zn. Therefore, the content of Fe
3
O
4
and ZnO in the melt decreases and that of FeO increases. At the second stage, metallic iron appears and the content of iron and zinc oxides decreases. A significant influence of temperature on fuming is shown. When the temperature increases from 1473 to 1773 K, the fuming process is significantly intensified, which is accompanied by a fourfold decrease in the amount of the reducing gas required to achieve close degrees of zinc recovery. The gas composition weakly affects the process. The most effective reducing agent is shown to be the gas formed by the steam conversion of methane, which is due to the minimal costs of its production. The results obtained make it possible to predict the indicators of the process of fuming by methane conversion products and will be useful for creating new technologies.
—
Low-temperature phase formation processes (below 1270–1450°C) underlying aluminothermic reduction of titanium from different TiO
2
polymorphs—stable rutile and metastable anatase—have been studied ...during continuous heating and isothermal heat treatment. Interaction between the components has been investigated at TiO
2
/Al molar ratios of 0.23 and 0.43 using thermal analysis and X-ray diffraction. The results demonstrate that, in the case of continuous heating of anatase + aluminum powders with TiO
2
/Al = 0.43, the reduction process begins at a temperature of 943°C and does not reach completion up to 1270°C, resulting in the formation of the intermetallic phase Al
3
Ti, Al
2
O
3
, and intermediate titanium oxides (Ti
0.78
O
0.937
and (Ti
0.99
Al
0.01
)
2
O
3
). Increasing the fraction of aluminum in the mixture (TiO
2
/Al = 0.23) increases the degree of reduction of titanium, which shows up as an increase in the amount of intermetallic phases (Al
3
Ti, Al
2
Ti, Al
1.1
Ti
0.9
, and AlTi
3
) in the reduction products and a decrease in the amount of intermediate titanium oxides. Rutile has been shown to have low reactivity: heating of rutile + aluminum mixtures to 1450°C leads to the formation of many intermediate titanium oxides along with a small amount of Al
3
Ti and AlTi
3
. The results have been confirmed by isothermal heat treatment (1400°C, 60 min) of mixtures of anatase and rutile with aluminum. The anatase-to-rutile polymorphic transformation during heating in flowing argon has been shown to occur in the range 622–913°C. During the reduction process, molten aluminum inhibits the phase transition of anatase, but its reactivity remains higher than that of rutile.
To describe the joint reduction of iron and copper from the oxide melt (1273–1773 K) of the B
2
O
3
–CaO–FeO–CuO system with carbon monoxide and hydrogen, we used thermodynamic modeling in the ...approximation to open systems, with fractional introduction of CO (H
2
) and periodic removal of metal phases and gases from the composition of the working fluid. The calculations are carried out taking into account the disproportionation of FeO into Fe and Fe
3
O
4
. For the considered compositions of the melt having a FeO/CuO ratio of 10, the disproportionation of the lower iron oxide and its interaction with CuO makes it possible to transform copper into the metallic state by 20–80% at low temperatures. The dependences of the contents of iron and copper oxides in the oxide melt, the degrees of their reduction, and the composition of the resulting alloy on the temperature and the amount of the introduced reducing agent are revealed. The required amount of hydrogen for the reduction of the metals to a fixed degree of copper metallization is shown to be significantly lower than that of carbon monoxide. The information obtained is useful for predicting thermoextraction processes occurring during the extraction of valuable components from nonferrous metallurgy slags.
The behavior of the initial ore and the concentrate of magnetoroasting beneficiation during metallization under the conditions that are close to those for reducing roasting of iron ores in a rotary ...furnace is studied in terms of works on extending the field of application of Bakal siderites. A difference in the mechanisms of the metallization of crude ore and the roasted concentrate is observed. The metallization of roasted concentrate lumps is more efficient than that of crude siderite ore. In this case, the process ends earlier and can be carried out at higher temperatures (1250–1300°C) without danger of skull formation.
Experimental and industrial data are obtained about the heating rate and degree of Cr reduction for a vertical section of the workspace of an ore reduction electric furnace during treatment of a ...mixture of lean and rich chromium ores in relation to melting period. A scheme of proposed for the temperature fields and degree of chromium reduction in reaction zones of an ore reduction furnace using data about physicochemical characteristics of the ore raw material, determined under laboratory conditions. It is shown that the degree of Cr reduction in the lower levels of the furnace bath before tapping reaches 95%, and at the end of tapping it reaches up to 85%.
