INFLUENCE OF BLOWING PARAMETERS AND SLAG REGIME ON  SILICON AND SULFUR CONTENT IN BLAST-FURNACE CAST IRON

At two blast furnaces (BF) with a volume of 1386 and 1500 m³, the influence of the parameters of blast and slag modes on the content of silicon and sulfur in cast iron was investigated. The blast mode was evaluated by the consumption of pulverized coal fuel (PCF) and oxygen, the slag mode was evaluated by its basicity CaO / SiO₂. It was found that the injection of pulverized coal into the hearth of 1500 m³ BF in the range of flow rates from 108 to 120 g/m³·s, and in the hearth of 1386 m³ BF in the range from 90 to 110 g/m³·s was accompanied by a decrease in the silicon content in cast iron. The deterioration of the transition of silicon into cast iron with an increase in the consumption of pulverized coal is explained by the complex effect of factors that retard the reduction of its oxides. Extreme relationships were also established between the intensity of melting in terms of oxygen consumption and the silicon content in the cast iron of the furnaces under study. The extreme dependences of the studied variables are due to the dual effect of the melting intensity on the reduction of silicon oxides: a reduction in the time of contact of the metal with furnace gases reduces the possibility of transition of silicon into metal, and an increase in the volume of the silicon reduction zone improves these possibilities. When operating a 1386 m³ furnace on calcium slag in the range of CaO / SiO₂ basicity change from 0.9 to 1.3 without removing the blast furnace operation periods associated with a change in operating conditions, the absence of dependence of the silicon content in cast iron on the CaO/SiO₂ modulus was found/ In its turn this indicated the complexity of factors influencing the reduction of silicon oxides. In the same range of changes in basicity and different operating modes of the furnace, a noticeable effect of basicity on the sulfur content in cast iron was observed, which indicates the decisive role of basicity in the process of blast-furnace desulfurization.

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Analysis of possible ways to reduce sulfur content in pig iron

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2020-11-12-878-882 ◽

2021 ◽

Vol 63 (11-12) ◽

pp. 878-882

Author(s):

S. V. Myasoedov ◽

S. V. Filatov ◽

V. V. Panteleev ◽

V. S. Listopadov ◽

S. A. Zagainov

Keyword(s):

Blast Furnace ◽

Cast Iron ◽

Sulfur Content ◽

Sulfur Removal ◽

Slag Basicity ◽

Slag Viscosity ◽

Pig Iron ◽

Blast Furnace Smelting ◽

Coal Fuel ◽

Slag Yield

One of the ways to increase the energy efficiency and intensity of blast furnace smelting, especially when using pulverized coal fuel, is to increase the hot strength of coke. In the conditions of OJSC NLMK, an oil additive was introduced into the coal charge to improve the coke quality. At the same time, sulfur content in the coke increases, and, consequently, sulfur content in the cast iron increases as well. In this regard, the task of finding ways to improve the desulfurization of cast iron in blast furnace becomes urgent. The main factors determining the desulfurization of cast iron are slag basicity, content of MgO oxide in it, temperature of the smelting products, and the slag viscosity. The purpose of this work was to compare the efficiency of sulfur removal by increasing the slag basicity and MgO content. On the basis of wellknown equations, an algorithm was developed that allows the problem to be solved. It was established that an increase in MgO content in the slag promotes desulfurization of cast iron to a greater extent than a basicity increase. In addition, an increase in MgO content by 1 % is accompanied by an increase in slag yield by 3.0 – 3.5 kg/t of cast iron. At the same time, an increase in basicity by 0.01 leads to an increase in the slag yield by 4 – 5 kg/t of pig iron. Consequently, reducing the sulfur content in pig iron by increasing the slag basicity requires less heat. In terms of the specific consumption of coke, difference in heat demand is 0.4 – 0.5 kg/t of pig iron. It is shown that with an increase in MgO content in the slag, the slag viscosity at a temperature of 1450 °C increases to a lesser extent than with an increase in basicity.

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Investigation of the effect of silicon content in iron and its temperature on exergy indicators of the blast furnace-converter system

Fundamental and applied problems of ferrous metallurgy ◽

10.52150/2522-9117-2018-32-93-106 ◽

2018 ◽

pp. 93-106

Author(s):

A.L. Chaika ◽

A.G. Cherniatevych ◽

A.A. Sokhatsky ◽

A.A. Moskalina ◽

T.S. Golub ◽

...

Keyword(s):

Blast Furnace ◽

Cast Iron ◽

Silicon Content ◽

Oxygen Converter ◽

Converter Shop ◽

Exergy Efficiency ◽

Environmental Indicators ◽

Pulverized Coal ◽

Minor Effect ◽

Oxygen Converter Shop

The aim of the work is to study the energy intensity of metal products in the "blast furnace - oxygen converter" system during the development of pulverized coal (PCF) in the blast furnace production. One of the parameters characterizing the thermodynamic indicators of blast-furnace smelting is the silicon content in liquid iron. A study was made of the effect of silicon content in iron and its temperature on the performance and thermodynamic indicators of steel production in the blast furnace – oxygen converter shop chain during the development of pulverized coal in the blast furnace. The calculated minimum and maximum values of changes in productivity and consumption of coke, and exergy indicators with a change in the silicon content in the iron. It is established that a decrease in the silicon content and the temperature of iron in a blast furnace can reduce the loss of exergy, increase the exergy efficiency, maintain a constant level or improve environmental performance. However, reducing the temperature of the iron can lead to significant disturbances in the operation of the blast furnace. It is shown that silicon content in cast iron has the greatest impact in the blast furnace-oxygen shop technological system, a decrease of which contributes to an increase in exergy efficiency, a decrease in exergy losses and an improvement in environmental indicators. The temperature of the cast iron on the exergy and environmental indicators in the "blast furnace - oxygen converter shop" system has a minor effect, however, a decrease in the temperature of the iron can lead to significant disturbances in the operation of the "blast furnace - oxygen converter" complex.

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Exergy analysis of silicon content in hot metal and its temperature influence on energy efficiency of “BF shop – BOF shop” complex operation

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2019-2-189-197 ◽

2019 ◽

Vol 75 (2) ◽

pp. 189-197 ◽

Cited By ~ 1

Author(s):

A. L. Chaika ◽

A. G. Chernyatevich ◽

A. A. Sokhatskii ◽

A. A. Moskalina ◽

T. S. Golub ◽

...

Keyword(s):

Energy Efficiency ◽

Blast Furnace ◽

Silicon Content ◽

Exergy Analysis ◽

Pulverized Coal ◽

Hot Metal ◽

Complex Operation ◽

Coal Fuel ◽

Pulverized Coal Fuel ◽

Exergy Losses

Application of pulverized-coal fuel in BF production results in changes of blast furnace heat operation, in particular, in hot metal temperature and silicon content in it changes, that effects the energy efficiency of “BF shop – BOF shop” complex operation. Isolated consideration of energy utilization by facilities (blast furnace, basic oxygen furnace) without taking into account their energy-technological ties does not provide steel smelting rational solutions obtaining. An exergy analysis of silicon content in hot metal and its temperature influence on energy efficiency of “BF shop – BOF shop” complex operation accomplished by application of the elaborated method of calculation of complete energy balance of “BF shop – BOF shop” system under existing conditions of pulverized-coal fuel application in Ukraine. It was shown, that silicon content decreasing down to level, which does not allow malfunctions of BF heat operation is strategically important for improving of energy efficiency of “BF shop – BOF shop” complex operation under conditions of pulverized-coal fuel application in BF production. It was determined, that under conditions of pulverized-coal fuel application in “BF shop – BOF shop” system, silicon content in hot metal decrease by 0.1% results in decreasing of exergy losses by 18–180 MJ/ton of steel, which is equivalent to standard fuel consumption decrease by 0.5–6.0 kg/ton of steel, increase of hot metal production by ~0.3–1.2 %. Hot metal temperature in blast furnace increase by 50 °С results in exergy losses decrease by 26–29 MJ/ton of steel, which is equivalent to standard fuel decrease by 0.9–1.0 kg/ton of steel.

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