Ferrous metallurgical industry is the main consumer of m nese. The production volume of manganese ferroalloys in the world is approximately 1 % of steel production. After the collapse of the Soviet Union, Russian Federation found itself without any manganese ore base. At present, only high-carbon ferromanganese and ferrosilicomanganese are smelted from imported ore in Russia in a limited quantity. The mineral and raw base of manganese ores in Russia is quite large: the balance reserves of manganese ores are about 230 million tons (approximately 2 % of the world), forecast resources – more than 1 billion tons. Quality of the manganese ores is lower than the manganese ores of most major producing countries. Average manganese content in Russian ores is 9 – 23 %. Basis of mineral and raw base of these manganese ores are carbonate ores, share of which is more than 77 %. Manganese ore mining in Russia is sporadic and does not exceed 66 thousand tons per year. Demand of Russian ferroalloy plants, producing manganese ferroalloys, in manganese ores and concentrates is covered by imports. The problem of accelerating the creation of domestic manganese ore base from the position of economic security seems to be very important. It is necessary to solve a number of issues related to the enrichment of poor manganese ores, development of effective technologies for manganese ferroalloys smelting from concentrates obtained after the enrichment of these ores, as well as creation of more advanced methods of manganese concentrates dephosphorization. In the production of manganese ferroalloys from ore to finished alloys, about 50 % of manganese mined from the subsoil is lost; a large number of by-products are formed (sludges of enrichment, slags, screenings of small fractions of ore raw materials and finished products, sludges of smelting process and dust). The use and processing of them allow not only to reduce the consumption of initial mineral raw materials, but also to increase the efficiency of main production and to reduce environmental pollution. Additional extraction of manganese from industrial wastes and improvement of the technological processes for manganese ferroalloys smelting are the ways to increase the through extraction of manganese.

The influence of silicon (0.1–0.8%), aluminum (0.005%), and carbon (0.1%) in steel on the reduction of boron from slag (basicity 5) at 1400–1700°C is studied by thermodynamic analysis on the basis of HSC 6.1 Chemistry software (Outokumpu). Experiments on the boron distribution between CaO–SiO₂–MgO–Al₂O₃–B₂O₃ slag and steel are conducted in a high-temperature Tamman resistance furnace. Low-carbon steel with different silicon content is employed. According to the thermodynamic modeling and the experiments, direct microalloying of steel with boron is possible on the basis of its reduction by the silicon present in the steel. The reduction of boron from slag by silicon is theoretically analyzed and experimentally confirmed. The results of thermodynamic modeling indicate that boron may be reduced from CaO–SiO₂–MgO–Al₂O₃–B₂O₃ slag by silicon despite its low content in the steel (0.1–0.8%). With increase in the initial Si content in the steel, the boron concentration in the steel also increases. The influence of the Si content and the steel temperature on the final boron content is studied. When steel is held under slag containing 4.3% B₂O₃, the boron is reduced, mainly by silicon, whose content in the steel is 15–22% lower after the experiment. More boron is present in the steel sample with an elevated Si content. The degree of assimilation of boron is 5.8–6.9%; this is consistent with the thermodynamic modeling. The boron content in the metal may be regulated by adjusting the temperature and the silicon content of the steel. On the basis of the results, a technology for the direct microalloying of steel with boron may be developed.

Thermodynamic simulation of chromium reduction from the oxide system of the composition (wt %) was conducted as follows: 25.0–37.5 CaO, 25.0R

Information on the wastes of ferroalloy production in the Russian Federation, their quantity, and composition is provided. For the melting volume of all types of ferroalloys of about 1.7 mlt t, ~1.1 mln t slag and ~125.5 ths t dust and slime are shown to form at Russian plants. 44% of manganese, 30% of chromium and 18% of silicon alloys of their total amount are produced in the world, and 25, 23 and 44%, respectively, are produced in the Russian Federation. The chemical compositions of the main groups of ferroalloys are given. The sectors of the national economy in which the slags and dusts of ferroalloy production can be used are indicated. The main directions of work needed to decrease the amount of wastes and to use them more efficiently are determined.

ФИЗИКО-ХИМИЧЕСКИЕ ХАРАКТЕРИСТИКИ, ПОЛУЧЕНИЕ И ПРИМЕНЕНИЕ КОМПЛЕКСНЫХ БОРСОДЕРЖАЩИХ ФЕРРОСПЛАВОВ