V. I. Zhuchkov

Calculation of the value of manganese ore raw materials

The variety of the types of manganese ore raw materials used in ferroalloy production causes the development and improvement of approaches to their metallurgical evaluation. The calculation methods are based on the chemical composition of the raw materials. The most widely used method of determining the quality of manganese ores and concentrates from their chemical compositions [1] also takes into account the manganese, iron, and phosphorus contents and the amount and composition of gangue. As a result, it can estimate the possible degree of manganese reduction from statistical formulas derived for the manufacture of high-carbon ferromanganese and silicomanganese. For metallurgical evaluation, we chose promising manganese ore materials located in various deposits in Russia, Ukraine, and the Republic of South Africa (Table 1). The metallurgical evaluation performed according to the statistical procedure in [1] demonstrates that these materials can be used for the manufacture of both high-carbon ferromanganese and silicomanganese. The main quality indices ( KS is the phosphorus content availability of the ore, RO is the amount and composition of gangue, MF is the specific iron content in the ore) for the manufacture of carbon-containing ferromanganese are given in Table 1. The higher coefficient KS , the higher the availability of the raw materials in terms of a phosphorus content and the higher the amount of phosphorus manganese ore raw materials to be added to these materials. The sign minus before the index indicates that an alloy cannot be made with a given phosphorus content without adding high-quality raw materials with a low phosphorus content.

Status and Prospects of Ferroalloys Production in the Russian Federation

Data are presented on the production and consumption of ferroalloys in the Russian Federation from 1994 to 2014. The quantities of the main ferroalloys that were made during this period are compared to the volume of steel production, and a comparison is also made between the structure of ferroalloys production in Russia and abroad. Data on the import, export, and apparent consumption of ferroalloys ate also reported. It is noted that Russia needs to expand its raw-materials base in order to make the main ferroalloys: manganese-, chromium-, and silicon-based ferroalloys. Such expansion is necessary to ensure that Russian companies can compete in the international market and that Russia is not threatened economically. These goals can be accomplished only with the support of the government.

Distribution of boron between oxide slag and steel

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.

Production technology for low-carbon, low-sulfur boron steel

A technology for slag formation in the ladle–furnace unit is considered; the slag is based on the CaO–SiO2–MgO–Al2O3–B2O3 system. This technology permits both microalloying of the steel with boron (reduced from the oxide phase) and desulfurization of the steel. The resulting boron content in the steel is 0.001–0.008%; the sulfur content in low-alloy steel and pipe steel is low (0.004–0.010%); and the consumption of manganese ferroalloys is reduced to 0.5 kg/t for 08кп steel and 1.4 kg/t for 09Г2C steel. In addition, the proposed technology increases the strength of the rolled steel, without loss in its plasticity; and reduces the environmental impact thanks to the replacement of fluorspar by colemanite.

Development of Technology for Microalloying Steel with Boron Using Ferro-Silicon-Boron

Deoxidation technology and economic steel microalloying with complex boron-containing ferroalloy, i.e., ferro-silicon-boron, instead of expensive cored wire with FB17 filler, has been developed and introduced for the first time at the Severskii Pipe Plant.

Construction of viscosity diagrams for CaO–SiO 2 –Al 2 O 3 –8% MgO–4% B 2 O 3 slags by the simplex lattice method

The simplex lattice method of planning experiments is used to study the viscosities of CaO–SiO2–Al2O3–8% MgO–4% B2O3 slags in a wide chemical composition range. For each viscosity, we developed an adequate mathematical model in the form of a reduced third-order polynomial. The results of mathematical simulation are presented in composition–viscosity diagrams. Composition regions with a high fluidity of slags, the viscosities of which are 0.8–1.2 Pa s in the temperature range 1500–1600°C, are indicated in the diagrams.

Effect of the structure of ferrosilicon on its desintegration

The structure of commercial high-percentage ferrosilicon is analyzed. Chemical, X-ray diffraction, and electron-probe analyses are used to compare the self-desintegrated and intact ferrosilicon FS65 alloys manufactured at JSC Serov Ferroalloy Plant. The experimental results demonstrate a significant microheterogeneity caused by silicon segregation, which induces cracking in the alloy structure, and by the existence of magnesium, aluminum, titanium, and silicon phosphides, which can form phosphines during interaction with air moisture. To decrease the spontaneous desintegration of ferrosilicon, it is necessary to suppress segregation before casting, to optimize the silicon content range, and to decrease the concentrations of impurities (mainly phosphorus and aluminum, which are introduced into an alloy with charge materials).

Density of chromium-containing ferroalloys

The results of studying the densities of the alloys corresponding to low-carbon ferrochrome, silicochrome, and complex Fe-Cr-Mn-Si alloys are presented. The dependence of the chromium-containing ferroalloy density on the silicon, manganese, or the carbon content is established.

Application of boron-containing materials in metallurgy

The main physicochemical characteristics of complex boron-containing ferroalloys are studied. The methods of their production are briefly described, and the advantages of their application to boron microalloying of steel are demonstrated.

Russian Chromium Ore in Smelting High-Carbon Ferrochrome at OAO SZF

315 Most Russian chromite ores have a relatively low chromium content. Rich chromium ores are found in small volumes and in poorly studied deposits. Accordingly, the most urgent problem for all Russian producers of chromium ferroalloys is to secure high-grade chromium ore. Large deposits of rich chromite ore are mostly remote from Russian ferroalloy plants. The use of high-quality imported chromium ore is associated with shipping over large distances by sea or by rail and also with import tariffs; this significantly increases rawmaterial costs. In the past decade, OAO Serovskii Zavod Ferrosplavov (SZF) has used chromite ore from Kazakhstan, Albania, Turkey, and India. The high cost and instability of imported ore supplies entails the use of leaner Russian ore. As we know, most industrially useful chromite deposits in Russia are concentrated in the ultrabasic Ural ranges. Originally, these ores were used exclusively in the chemical industry and in refractory production. Given the limited supplies of highquality chromium ore and the consequent revision of the requirements on chromium ore for ferroalloy production, OAO SZF has been using Russian chromite ore for ferrochrome production since 1992. In recent years, industrial tests have been undertaken at the plant with a view to using a mixture of Saranovsk, Verbluzh’egorsk, and Alapaevsk ore with fine ore from Donskoi enrichment facility (Khromtau, Aktyubinsk oblast, Kazakhstan) for the production of high-carbon