Yu. S. Yusfin

The role of alkalis and conserving resources in blast-furnace smelting

In ferrous metallurgy, the potential for conserving resources is often determined by the behavior of the impurity elements in metals production. This behavior may be highly complex, and its features may be interpreted differently by different experts. For example, the presence of zinc and alkali metals in the blast-furnace charge is known to result in excessive coke consumption, a reduction in the productivity of the furnace, an increase in the yield of top dust, shortening of the campaign, and in some cases to complete destabilization of the smelting operation. In choosing a technology for blast-furnace smelting, accounting for the entry of alkali metals and zinc into the furnace is one of the most important factors that determines the expediency of controlling the heat “from the top” or “from the bottom” features of the slag formation process, the gasdynamics of the smelting operation, and other characteristics.

Production of generator gas from solid fuels

Analysis of literature data indicates that the production of generator gas from solid fuels is very promising. With appropriate preparation, renewable energy sources such as peat, sapropel, and solid domestic waste may be used for this purpose. The deficiencies of the current production technologies for generator gas are outlined. Experience in the production and use of generator gases is described. Criteria that must be satisfied by new technologies for solid-fuel processing are developed. The most promising approach is found to be gasification in a bubbling slag bath. A system for the preparation and gasification of solid fuel in slag melt is presented. Calculations show that the production of generator gases in a bubbling mixed-fuel system is economically efficient. The production costs of thermal and/or electrical energy by the combustion of generator gas derived from regular lignite are 35–40% less than for the combustion of natural gas.

Manganese-ferroalloy production from Russian manganese ore

Optimal technology for the production of manganese ferroalloys from Usinsk magnesium ore is developed. To that end, the chemical composition and the concentrates and the characteristics of ferroalloy smelting are analyzed. The proposed technology permits the production of standard manganese ferroalloys, without the need for imported manganese ores that are rich in manganese and low in phosphorus. The proposed technology is of strategic value in terms of national economic security and import substitution. Finally, attention turns to the possibility of increasing Russian production of high-carbon ferromanganese and ferrosilicomanganese on the basis of Russian manganese ore and developing production technologies for refined manganese ferroalloys (moderate- and low-carbon ferromanganese and metallic manganese) without reliance on imported ores.

Possibility of cyanide formation in blast furnaces

5There is great concern currently about the presence of cyanides (salts of hydrocyanic acid) and other compounds containing the CN radical in metallurgical emissions. Cyanides are highly toxic and have a very deleterious impact on human health and on the environment. Cyanide formation is highly likely in ferrous metallurgy. In particular, cyanides may be formed from the components involved in blast-furnace processes: carbon, nitrogen, hydrogen, and alkali metals. The temperature in the working space of the blast furnace varies widely: from 100‐200 ° C (at the charge hole) to 2000‐ 2300 ° C (in the tuyeres). Various compounds containing the CN group are stable within this region. Analysis of the chemical composition of metallurgical emissions confirms the presence of cyanides. Thus, in the water of the slurry tank at Kosogorsk metallurgical plant, an elevated concentration of CN radicals is observed. This tank contains the byproducts obtained in purifying blast-furnace gas: charge-hole dust and slurry. In the present work, we analyze the thermodynamic conditions of cyanide stability in various temperature zones of the blast furnace, for different compositions of the batch and atmosphere, using IVTANTERMO thermodynamic-simulation software. This software permits the calculation of complex chemical equilibria in multicomponent, multiphase systems. The equilibrium composition of the reagents in the system may be calculated for specified temperature, pressure, and concentrations of the elements. The computational algorithm is based on minimizing the Gibbs energy of the system. The distinguishing feature of the IVTANTERMO software used in the present work is that the thermodynamic parameters employed are obtained by the analysis of primary data in the literature [1, 2]. A special calculation procedure has been developed for thermodynamic simulation of the blast-furnace process. The chemical elements in the system are selected on the basis of information regarding their presence in the blast furnace for specified conditions. Thus, the initial system includes nine elements: C, O 2 , H 2 , N 2 , Fe, K, Na, Cl, and F. Preliminary calculations show that the other elements in the blast furnace, such as Si, Ca, Al, Mg, Mn, etc., have little influence on the formation and decomposition of materials containing cyanides. Research shows that most of the cyanides formed in the blast furnace are the compounds CN, CN 2 , HCN, KCN, and NaCN. The salts NaCN and KCN and hydrocyanic acid HCN are most stable, i.e., correspond to the broadest interval of existence with variation in the external conditions, such as temperature, pressure, chemical composition, and redox potential. Thermodynamic analysis indicates that the quantity of each material formed in the blast furnace is determined by the following parameters:

Improving manganese utilization in the production of manganese ferroalloys

To extract manganese from the tailings slag produced in the furnace smelting of manganese with silicon, a possible approach is to reduce the slag by means of melts of iron, high-carbon ferromanganese, or ferrosilicomanganese. Thermodynamic analysis of this process is undertaken. The reaction of these melts with the slag is also studied experimentally. It is found that the reduction of manganese from such slag by carbon from hot metal is promising for practical purposes. Hence, the overall extraction of manganese may be increased if the tailings slag from furnace smelting of manganese is used to alloy hot metal with manganese.

Predicting the Risk of Generalized Air Pollution by Metallurgical Enterprises

The main factors responsible for the transportation of gaseous emissions from industrial enterprises over large distances are identified. A general approach to predicting the spatial distribution of gaseous emissions at large distances from metallurgical enterprises is proposed. This approach is based on the principle of maximum risk.

Effect of the Removal of Arsenic from Metal on the Environment

demand for ultrapure metals and alloys has increased in recent years, which is making it necessary to elevate product quality in order to reliably maintain market share. On the other hand, requirements are also being tightened in regard to toxic emissions. This trend is embodied in the promulgation of the new standards ISO-14000. Together, these two factors , along with the increasing use of new sources of raw materials – new deposits, industrial by-products, and household wastes – are making it necessary to carefully analyze the distribution of impurity elements between the main products and by-products of metallurgical processes. Special attention should be given to the elements that are harmful both to metallur-gical products and to the environment. One of the elements most deserving of such attention is arsenic, since it is fairly widespread in the traditional raw materials – ores, coal, and secondary resources. This situation presents additional problems related to the need to remove arsenic from raw materials during the preparatory stages and in metal production processes. Arsenic is an impurity which adversely affects the quality of the products of ferrous metallurgical plants. Arsenic tends to undergo dendritic segregation during the crystallization of steel ingots, which then leads to the formation of striated structures and makes the mechanical properties of the rolled product more anisotropic. A high arsenic concentration in steel lowers its ductility properties, reduces its strength characteristics, adversely affects weldability, and somewhat increases its tendency to undergo strain-hardening. The presence of arsenic in structural carbon and alloy steels reduces their hardenabil-ity and makes them more susceptible to reversible and irreversible temper brittleness. In the course of its removal from raw materials and metals, arsenic enters slag (in blast-furnace smelting) or changes to the gaseous state (mainly in pellet and sinter production and the blast-furnace process). Thus, arsenic enters the hydro-sphere and atmosphere of industrial regions through metallurgical waste products (solid slag, sludge, gaseous emissions, etc.). As a result, one important problem which arises in the production of metal from arsenic-bearing raw materials is study of the consequences of the removal of arsenic from those materials and the behavior of arsenic in the environment. Unfortunately, these matters have thus far received little attention. We will examine the environmental aspects of metallurgical production involving arsenic – one of the elements that poses a significant danger to the environment. It has a toxic effect not only on individual organisms …

Production of manganese ferroalloys from Usinsk manganese ore

The Usinsk deposit is one of the largest deposits of manganese ore in Russia (known reserves 98.5 million t; predicted reserves 150.4 million t). Usinsk manganese ore is characterized by relatively low manganese content (18–22%) and elevated phosphorus content (0.2–0.3% or more). A system for enriching Usinsk ore has been developed, on the basis of X-ray fluorescent (X-ray radiometric) separation of large pieces, with fine residues. Analysis of the smelting of manganese ferroalloys and the chemical composition of the concentrates obtained in enriching Usinsk manganese ore permits the development of an optimal production technology for the whole range of manganese ferroalloys.

Wind Distribution of Pollutants from Metallurgical Enterprises

The composition and properties of the sample are determined by X-ray fluorescent analysis, Mossbauer spectroscopy, pH measurement, and measurement of the magnetic susceptibility. The Mossbauer data are obtained by means of an MS-1104Es spectrometer with a Co 57 source in a chromium matrix. Powder samples (particle size 0.05‐0.07 mm) are employed. The spectra are analyzed by means of Univem MS software. The magnetic susceptibility is determined on a Kappabridge KLY-2 instrument (field strength 300 A/m) and the pH on a PH-340 instrument. To elucidate the spread in the sample composition prior to averaging, each component square for one of the points (at a distance of 400 m) is analyzed separately by Mossbauer spectroscopy and magnetometric measurement. The similarity of the characteristics justifies combination of the components. X-ray fluorescent analysis 1 of soil samples taken in the direction of intense wind dispersal at a distance of 100 m shows that the content of some elements (As, Pb, Cu, Zn) significantly exceeds the maximum permitted concentration. Their concentration is plotted as a function of the distance from the plant in Fig. 1, where the horizontal line corresponds to the maximum permitted concentration. Analysis indicates that the As concentration in the samples at a distance of 100 m exceeds the maximum permitted concentration by an order of magnitude; for copper and zinc, this factor is even greater. The Pb concentration is four times the maximum permitted concentration. At 400 m, by contrast, the concentration of these elements is less by a factor of 3‐5. The curves obtained are of the same shape: the concentration declines with distance. This indicates that the pollution source is the plant, and dispersion is by the wind. The proximity of the Orlov highway may also be response for some elevation of the Pb content. By extending the curves until they intersect the maximum permitted concentration, we may estimate the boundary of the corresponding pollution zone. Analysis shows

Potential methane yields from blast furnaces

At the same time, we lack information regarding CH4 emissions from blast furnaces, which are the pri mary source of greenhouse gases in steelmaking, accounting for more than 60% of the CO2 or more than 1.5 t CO2/t of hot metal [1, 2]. For lack of infor mation, the CH4 emissions are not included in the enterprise’s environmental recordkeeping, as a rule, and not estimated in compiling the National Green house Gas Inventory [1].