Promising Directions of the Application for Poor Raw Materials of the Ferroalloy Production

The mineral base state for Russian manganese and chromium ores does not allow our country in the foreseeable future to achieve complete self-sufficiency and to abandon imported raw materials. But the problem can be significantly mitigated due to the partial involvement in the operation of the proven ore reserves with relatively low quality. Based on the performed research, four main directions are formulated that would make it possible to put into operation a number of previously known but out-of-use (or poorly used) deposits of poor mineral raw materials for the ferroalloy production: (1) selective reduction of ore components divided into metal semi-products with a low main component content suitable for the smelting of the alloyed steel grades and an oxide product with a high content of Mn or Cr oxides suitable for the smelting of the high-grade ferroalloy grades; (2) rational additional charging of poor domestic ores to beneficiate imported ones to obtain standard grades of ferroalloys; (3) smelting of new alloys, including marketable high-carbon ferromanganese and ferrochrome with reduced main component content, high silicon content, and complex ferroalloys containing, in addition to the main, other elements necessary for the composition of a number of steel grades (silicon, manganese, titanium, etc.); and (4) production of limited grades of ferro-, silico-manganese, and chromium and their application in smelting of the ferroalloys refined grades. Keywords: metallurgy, ferroalloys, mineral resource base, poor ore

Manufacturing and Application of Complex Ferroalloys

The tightening of requirements for the quality of steel, a change in the composition of raw materials requires the release of more efficient ferroalloys of the new generation, suitable for progressive steel production processes. Such products include complex ferroalloys containing, in addition to iron, two or more functional elements. Complex ferroalloys should be created in the most favorable combination of components, contributing to the necessary effective impact on the quality of the metal being processed, with a high degree of assimilation of useful elements in it. Changes in the characteristics of complex ferroalloy, affecting the assimilation of target (basic) elements, should be carried out by regulating the composition and ratio of elements that can be included in almost any ferroalloy, since they are part of all steels and cast irons or they’re required by the conditions of their smelting. Firstly, these elements should include silicon and manganese. Silicon can reduce the melting temperature, density, and melting time of ferroalloy in the liquid metal. For example, the addition of 1% silicon to low-carbon ferrochrome can reduce the melting point of the alloy by 8–9 degrees. Compositions of new complex ferroalloys of systems Fe-Si-Ca-Ba, Fe-Si-B, Fe-Si-Al-Nb, Fe-Si-Mn-V have been successfully tested and introduced into production. Keywords: metallurgy, ferroalloy, melting, density, physical and chemical properties, stee

The Thermodynamic Evaluation of the Interphase Distribution of Elements in the Chromium and Nickel-containing System

The results of thermodynamic modeling of the process of element reducing from a chrome-containing ore-lime melt by silicon ferronickel depending on temperature are presented in this article. The consumption of reducing agent is equal to 105% of the required stoichiometric amount of reducing agent for complete reduction of iron and chromium in the temperature range of 1300–2200∘С. The chemical composition of the ore-lime melt is, wt. %: 24 Cr2O3; 13 FeO; 42 CaO; 3 SiO2; 9 MgO; 9 Al2O3 and of silicon ferronickel is, wt. %: 65 Si; 28 Fe; 7 Ni. The HSC Chemistry 6.12 software package developed by Outokumpu Research Oy (Finland) is used. The composition of oxide Cr2O3-FeO-CaO-SiO2-MgO-Al2O3 and metallic Fe-Si-Ni-Cr systems are calculated using the module «Equilibrium Compositions». A gas phase pressure is 1 atm. The gas phase of the system contains 2,24 m3 N2. It is established that the increase in the process temperature from 1300 to 2200∘С contributes to reducing of the degree of chromium reduction from 98,9 to 69,8%. The degree of reduction of aluminum and magnesium increases from 0,2 to 8,7% and from 0,007 to 2,5% respectively, and the degree of reduction of iron doesn’t change over the entire temperature range and is equal to 100%. The chromium content in the metallic phase decreases with increasing temperature from 51,7 to 41% and the residual CrO content in the slag increases. The chemical composition of the alloy is, wt. %: 50,41 Cr; 44,06 Fe; 1,97 Si; 3,3 Ni; 0,035 Mg; 0,21 Al; 0,005 P at the temperature of 1700∘С. The results of thermodynamic modeling can be used for laboratory experiments and technological calculations for obtaining chromium and nickel-containing complex ferroalloys suitable for smelting stainless steel grades. Keywords: thermodynamics, system, interphase distribution, reducing agent consumption, degree of recovery, temperature, chromium, nicke

Simulation of the Melting Process for Complex Nickel-containing Ferroalloys in Steel

In this study, the melting process simulation for the complex nickel-, silicon-containing ferroalloys in a steel melt was performed. For the study, complex ferroalloys samples (∼ 10% Ni, 5–56% Si) were selected, by composition corresponding to the alloys, which can be smelted from poor Russian oxidized nickel ores. It is shown that all the alloys under consideration belong to the group of low-melting ferroalloys, in which the liquidus temperature (

Promising Measures to Reduce the Harmful Effects of Man-made Waste from Ferroalloy Production

This article formulates a list of promising measures to reduce the harmful impact of man-made waste from ferroalloy enterprises on the environment: (1) technical measures: replacement of the main and auxiliary obsolete equipment with new environmentally safe, allowing to significantly reduce or completely eliminate hazardous emissions and the formation of unclaimed production waste; (2) introduction of energy-saving technologies: the use of physical and chemical energy of top gas from ore-reduction furnaces in turbine generators and in the contrivance for preheating and partial reduction of charge materials elements, etc.; (3) prevention and localization of emissions due to the modernization of existing equipment: sealing and shelter of the main melting equipment, places of loading and unloading of bulk materials, prevention of dusting for the ore materials warehouses, tailing ponds, sludge collectors, etc.; (4) cleaning of harmful emissions, the formation of which cannot be prevented; (5) introduction of innovative waste-free and low-waste technologies with the integrated use of raw materials: utilization of accumulated and current waste (slags, sludge, etc.) that form during the production of ferroalloys, reducing or completely eliminating the waste dumps and sludge collectors; (5) deeper ore preparation with the exception of the use of toxic reagents; and (6) more complete and economical use of water, the creation of closed water systems, the use of modern highly efficient treatment facilities, etc. Keywords: metallurgy, ferroalloys, man–made wastes, slag, sludg

Stabilization of Self-slaking Slags from Ferroalloy Production

In this study, the process of stabilization for highly basic self-slaking slags of ferroalloy production by various boron-containing materials were studied: tincalconite, colemanite, and ulexite (produced in Turkey). The viscosities and temperatures of crystallization for the initial boron-containing materials are determined. Under laboratory conditions, high-base slag melts were treated with boron-containing materials to obtain slags containing 0.25 and 0.5% B2О3. It was shown that the addition of boric anhydride to the studied slag melts extends the homogeneous-liquid state interval and reduces their viscosity by 1.2–1.6 times, therefore B2О3can be used as a tool for controlling slag mobility in industrial conditions. The industrial tests were conducted to stabilize the slag of low-carbon ferrochrome using powdered calcined, briquetted, and fused colemanite. After treatment, slags contained 43–47% CaO, 0.18–0.45% B2О3. The results of pilot-industrial experiments show that all applied boron-containing materials ensure slag stabilization and differ only in the degree of boron recovery. Fused colemanite showed the highest results in the recovery of B2О3(up to 98%), a commercial product was obtained which fully complies according to the technical characteristics with the requirements of Specification TU 0798-69-00186499-2014 “Crushed stone and sand from ferroalloy slags. Technical conditions.” Keywords: ferroalloy, slag, self-slaking slag, stabilization, boron, two-calcium silicat

Situation and Development of Ferroalloy Metallurgy in Russia

Ferroalloy production is an important branch of metallurgy having a great impact on its development since the treatment of liquid metals by ferroalloys remains one of the main methods to regulate the quality of steel, cast iron,and nonferrous alloys. Manganese is the most essential element to treat ferrous and non-ferrous metals. A need for manganese alloys in Russia averages to 600–650 metric tons per year, but only a half of the quantity is satisfied by the domestic production. In contrast to manganese alloys, Russia provides itself with chromium ferroalloys obtained with the use of foreign raw materials. Domestic ores are used in limited quantities. Taking into account the strategic importance of ferroalloy industry and the necessity to create and include manganese and chromium ore bases, as well as the other basic problems, the achievement of the goals has to be implemented by enterprises with the help of the State. The output of ferrosilicon and crystal silicon in the Russian Federation exceeds its consumption in the country due to raw material reserves (quartzite, quartz), high productive capacity, and consumer demands. Ferroalloy enterprises in Russia produce ferrovanadium, ferromolybdenum, ferroniobium, ferrotungsten, ferrotitanium, and ferronickel. A traditional challenge for ferroalloy enterprises in Russia is improving the competitiveness at the expense of reducing production costs, improving the production quality, and solving the issue of import substitution for certain types of ferroalloys. Keywords: ferroalloys, manganese, ferrochromium, productio