— 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.

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.

В условиях непрерывного, а также изотермического нагрева изучены процессы низкотемпературного (до 1270–1450°С) фазообразования при алюминотермическом восстановлении титана из TiO 2 различных модификаций: стабильного рутила и метастабильного анатаза. Методами термического и рентгенографического анализов изучены взаимодействия реагентов при мольных соотношениях TiO 2 /Al, равных 0.23 и 0.43. Показано, что при непрерывном нагреве порошков анатаза с алюминием (TiO 2 /Al = 0.43) процесс восстановления начинается при температуре 943 и до 1270°С протекает неполно с образованием интерметаллида Al 3 Ti и Al 2 O 3 , а также промежуточных оксидов титана (Ti 0.78 O 0.937 , (Ti 0.99 Al 0.01 ) 2 O 3 ). Увеличение расхода алюминия в смеси (TiO 2 /Al = 0.23) повышает степень восстановления титана, что проявляется в увеличении в продуктах восстановления количества интерметаллидов (Al 3 Ti, Al 2 Ti, Al 1.1 Ti 0.9 , AlTi 3 ) и в снижении промежуточных оксидов титана. Установлена слабая реакционная активность рутила, при нагреве которого до 1450°С в смеси с алюминием образуется, наряду с небольшим количеством Al 3 Ti и AlTi 3 , множество промежуточных оксидов титана. Полученные результаты подтверждены нагревом смесей анатаза и рутила с алюминием в изотермических условиях (1400°С, 60 мин). Выявлена область (622–913°С) полиморфного превращения анатаза в рутил при нагреве в потоке аргона. Установлено, что в процессе восстановления расплавленный алюминий ингибирует фазовый переход анатаза, сохраняя его повышенную, в сравнении с рутилом, реакционную способность.

Abstract—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, Fe3O4 is reduced to FeO and ZnO, to Zn. Therefore, the content of Fe3O4 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.

The Bakal deposit located in the Southern Urals near the city of Bakal, Chelyabinsk region, is one of the largest deposits of carbonate iron ores (siderites). The total deposit of siderites is about 1 billion tons. They are not in demand among metallurgists because of their low iron content and high magnesium content. At the same time, the Urals metallurgical enterprises are suffering from shortage of iron ore raw materials including steelmaking ore raw materials. The high purity of siderites in terms of phosphorus and non-ferrous metals makes it possible to use methods of coke-free metallurgy for their processing. Pyrometallurgical processing of siderites including their reduction roasting in a rotary furnace followed by grinding and magnetic separation allows obtaining a concentrate to be used as a steelmaking raw material having metallization degree above 90 % and a waste rock content under 3 – 7 %. Calculations showed that the costs of electricity used for melting scrap metal and metallized siderite concentrate containing 30 % of waste rock and loaded into the furnace at temperatures above 1000 °C are close. We propose a siderite processing method including reduction of the initial ore in a rotary furnace, and melting of resulting metallized concentrate hot loaded (at temperatures above 1000 °C) into a furnace. The empty rock of metallized siderite concentrate contains a large percentage of magnesium oxide that makes it refractory. To obtain liquid slag, it is proposed to add boric anhydride in the form of colemanite. To assess the B2O3 effect on melting of the metallized siderite oxide phase in the process of electric melting, studies on the viscosity correlation of the magnesian steelmaking slag containing B2O3 with temperature and its composition were carried out. It was found that at the discharge temperature (1600 °C) the resulting magnesia slag with the ratio of MgO/SiO2 in the initial siderite equaling to 0.75 – 1.25 has a low viscosity (less than 3.65 P).

Metallurgical companies in the Urals account for 50 – 60 % of local raw materials. Its deficit is compensated by the use of materials imported from Central Russia, the Kola Peninsula and Kazakhstan. Replacing them with the local raw materials would increase the competitiveness of metal produced in the Urals, so the question of assessing the possibility of replacing imported raw materials with local ones is very relevant. Such raw materials could be siderite ores from the Bakal deposit. They are not in demand by metallurgists because of their low iron content and high magnesium content. With growth of siderites in a charge the magnesium oxide content in slag increases that influences its viscosity and makes it difficult or impossible to smelt using more than 20 % of siderites. The use of boron oxide has been suggested to liquefy the slag. The synthetic slag containing 26.8 % CaO, 38.1 % SiO2 , 11.8 % Al2O3 , 23.6 % MgO, simulating composition of slag from MMK blast-furnace smelting with the addition of 30 % of burnt siderites is short and unstable. The temperature corresponding to the slag viscosity at the blast furnace outlet (0.5 Pa·s) is 1390 °C and the temperature corresponding to the melting point (viscosity 2.5 Pa·s) is 1367 °C. If boric anhydride is added to such a slag, it becomes long and stable. In the melts, when the proportion of B2O3 is increased from 0 to 12 %, the temperature at which the slag viscosity is 0.5 Pa·s and 2.5 Pa·s decreases to 1260 °C, and 1100 °C, respectively. This makes it possible to significantly increase the siderite content in blast furnace charge.

Выполнена экспериментальная (метод максимального давления в газовом пузыре) оценка плотности и поверхностного натяжения гомогенных расплавленных шлаков совместной плавки силикатной никелевой и медной колчеданной руд. Измерения проведены на модельных образцах: железистого, масс. % (8,9 CaO; 11,8 MgO; 12,5 Al2O3; 47,4 SiO2; 13,3 FeO и 5,0 Fe2O3) и образованного при удалении из него оксидов железа безжелезистого, масс. % (12,5 CaO; 16,0 MgO; 9,4 Al2O3 и 58,3 SiO2) шлаков, отражающих состав и структуру реальных прототипов, в интервалах температур 1550–1300 °C и 1550–1400 °C соответственно. Снижение температуры ведет к повышению плотности и поверхностного натяжения указанных шлаков в диапазонах 1,85–2,21 и 2,23–2,29 г·см–3 и 144–250 и 340–345 мН·м–1 соответственно. Структурные изменения при переходе от первого состава ко второму вызваны сокращением основности с 0,7 до 0,6 и заменой Fe2+ на Ca2+ и Mg2+. Второй фактор вносит основной вклад в рост как самих характеристик, так и их температурных коэффициентов (от –0,0015 до –0,0004 г·см–3·°C–1 и от –0,4 до –0,1 мН·м–1·°C–1 соответственно). Методом регрессионного анализа экспериментальных данных получены эмпирические модели, позволяющие достоверно прогнозировать величину плотности и поверхностного натяжения реальных шлаков рудной плавки медного и никелевого сырья в рассмотренном диапазоне температур. Результаты работы могут быть использованы при разработке и совершенствовании металлургических технологий, а также процессов стекольной и керамической промышленности. An experimental (method of maximum pressure in a gas bubble) assessment of the density and surface tension of homogeneous molten slags from the joint smelting of nickeliferous saprolitic and copper pyrite ores has been carried out. The measurements were made on model samples of iron-containing (8.9 wt. % CaO; 11.8 wt. % MgO; 12.5 wt. % Al2O3; 47.4 wt. % SiO2; 13.3 wt. % FeO and 5.0 wt. % Fe2O3) and formed upon removal of iron oxides from it iron-free (12.5 wt. % CaO; 16.0 wt. % MgO; 9.4 wt. % Al2O3 and 58.3 wt. % SiO2) slag, reflecting the composition and structure of real prototypes, in the temperature ranges of 1550–1300 °C and 1550–1400 °C, respectively. A decrease in temperature leads to an increase in the density and surface tension of these slags in the ranges of 1.85–2.21 and 2.23–2.29 g·cm–3 and 144–250 and 340–345 mN·m–1, respectively. Structural changes during the transition from the first composition to the second are caused by a reduction in basicity from 0.7 to 0.6 and the replacement of Fe2+ by Ca2+ and Mg2+. The second factor makes the main contribution to the growth of both the characteristics themselves and their temperature coefficients (from –0.0015 to –0.0004 g·cm–3·°C–1 and from –0.4 to –0.1 mN·m–1·°C–1, respectively). Using the method of regression analysis of experimental data, empirical models have been obtained that make it possible to accurately predict the density and surface tension of real slags from the smelting of copper and nickel raw materials in the considered temperature range. The results of the work can be used in the development and improvement of metallurgical technologies, as well as in the glass and ceramic industries.

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.

Metallurgical plants in the Urals are experiencing a shortage of iron ore raw materials, which is compensated by the use of materials imported from Central Russia, the Kola Peninsula and Kazakhstan. Replacing them with the local raw materials would increase the competitiveness of metal produced in the Urals, so the question of assessing the possibility of replacing imported raw materials with local ones is very relevant. Such raw materials could be siderite ores from the Bakal deposit. They are not in demand among metallurgists because of their low iron content and high magnesium content. Calculations of blast furnace smelting made by means of balance logical-statistical model showed that additions of annealed and metallized concentrates improve performance. However, with increasing siderites in the charge, content of magnesium oxide in the slag increases, which affects its viscosity and makes it difficult or impossible to smelt using more than 20 % of siderites. It was proposed to use boron oxide to liquefy the slag. Thermodynamic modeling was used to assess the effect of adding 1 – 3 % B2O3 to the charge on chemical composition of the slag and distribution of boron between the metal and oxide phases. It was shown that in the melting process, boron is recovered from the slag phase and partially transferred to the metal. This leads to a decrease in B2O3 content in the final slag. Comparative analysis of the calculated and experimental data shows a close content of boron in the metal, determined theoretically and experimentally. It should be taken into account when calculating the charge. According to the calculations, the main reducing agent of boron is silicon, and the experimental data shows that it is carbon.

This paper provides information regarding the application of niobium in industry and the scale of its production in the world and the Russian Federation. Most of the niobium deposits in Russia consist of pyrochlore, apatitepyrochlore and columbitepyrochlore types of ores. They contain a significant amount of phosphorus. Therefore, all enrichment schemes for these ores contain a dephosphorization stage which increases the price of the product and reduces the degree of niobium extraction. The paper explores the possibility of improving the end-to-end production scheme: niobium ore – beneficiation – niobium ferroalloy. The bulk of ferroniobium is intended for steel microalloying and can be replaced by complex ferroalloys with a reduced niobium content. The paper considers the issues of obtaining complex niobium ferroalloys from a rough concentrate with a weak content of niobium. It has been established that the addition of 25 – 40 % of silicon or 12 – 30 % of aliminum to the twocomponent metal system Fe – Nb causes the transfer of niobium ferroalloys (15 – 20 % Nb) from the refractory category to lowmelting materials. The crystallization temperatures are less than 1400 °C. The substantiation of using a complex niobium ferroalloy instead of ferroniobium is given. This alloy has reduced niobium content and increased silicon or aluminum content. Higher service characteristics of the complex ferroalloy are noted in comparison with ferroniobium (temperature of the initiation of crystallization and density). They indicate an increased assimilation of niobium when using a complex ferroalloy for steel microalloying. The paper presents data on the possibility of dephosphorization of niobium concentrates in the process of pyrometallurgical production of a complex ferroalloy. An improved scheme for the production of niobiumcontaining ferroalloys is proposed. This consists of the use of niobium concentrate for melting the intermediate ferroalloy containing a reduced concentration of niobium oxides and an increased concentration of silicon (aluminum). This ferroalloy can be used effectively for steel microalloying with niobium.

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

To predict the conditions for metals reduction from an oxide melt by gas in bubbling processes, a thermodynamic modeling technique has been developed that provides an approximation to real systems. The main difference between the accepted method and the well-known one is in conducting successive calculation cycles with withdrawal of the generated gases and the metal phase from the working medium. This paper presents the results of thermodynamic modeling of nickel and iron reduction processes from B2O3 – CaO– Fe2O3 – NiO melts by mixtures of CO– CO2 and H2 – H2O containing 0 – 60 % CO2 (H2O) in the temperature range of 1273 – 1673 K. The calculations evaluated the content of nickel and iron oxides in the melt and the degree of their reduction. It is shown that, regardless of the gas composition, this process proceeds in several stages. At the first stage, Fe2O3 is reduced to Fe3O4 and FeO. СFe2O3 values decrease to almost zero, while СFe3O4 and CFeO increase simultaneously. By the end of the phase, СFeO reaches its maximum value. At the second stage, the Fe3O4 → FeO transition occurs, when СFe3O4 values reach maximum, nickel and iron begin to reduce to metal. At reduction by CO– CO2 mixture, an increase in temperature reduces the metallization of both nickel and iron. Similarly, an increase in the CO2 content of the introduced gas affects. During interaction of the oxide melt with a gas containing 60 % CO2 , the third stage is absent. At reduction by H2 – H2O mixture, an increase in temperature reduces the metallization of nickel, but increases metallization of iron. With increasing water vapor content in the introduced gas, the degree of metallization of both nickel and iron decreases. The obtained data are useful for creating technologies for selective reduction of metals and formation of ferronickel of the required composition.

To describe the joint reduction of iron and copper from the oxide melt (1273–1773 K) of the B2O3–CaO–FeO–CuO system with carbon monoxide and hydrogen, we used thermodynamic modeling in the approximation to open systems, with fractional introduction of CO (H2) 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 Fe3O4. 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.