DonNTU   Masters' portal

Abstract

Content

Introduction

With all the rising prices of energy and materials is becoming urgent the problem of saving and rational use of alloying materials and auxiliary materials in the production of steel. The study of processes occurring during the smelting and processing of steel allows you to find ways to conserve materials.

1. State of the art

In the process of finding the oxidized metal and slag in contact (eg in contact with the ladle furnace slag in the production of metal from the furnace) is the recovery of manganese and phosphorus. This process is explained superequilibrium silicon content in a given period of time Thus, while the silicon content is not reduced to the equilibrium values ??in the reduction of manganese and phosphorus from the slag. After the burning process of transition of silicon manganese, and phosphorus is drawn - is their reduction to equilibrium values. For example at LLC "Electrostal" Kurakhovo some batches were obtained coefficients of absorption of manganese excess of 100%: 100.6%, 123.6%, 110.3%.

2. Investigation of the effect of phase mixing in steelmaking units in the distribution of elements between metal and slag

To study the behavior of manganese during the finding of metal and slag in contact on the issue of a furnace held simulation of steelmaking 10G2S through a system of "oracle". To begin with, and obtained a semi-slag chemical compositions are given in Table 1 and Table 2 respectively.

Table 1 - Chemical composition of semiproduct, %
O C Mn Si S P Cr Ni Cu
0.15 0.37 0.23 0.0003 0.23 0.0055 0.16 0.23 0.24
Table 1 - Chemical composition of slag, %
SiO2 FeO Al2O3 CaO MgO MnO P2O5
22.2 25 8 28 6 11.067 0.5

Upon receipt of the metal and slag with a certain chemical composition in the "kinetics" draw graphical study of the processes occurring after the release of the metal in the bucket for two cases: with a hit in the ladle furnace slag in the production of slag and the cut-off. The processing time will take 40 minutes to become, a lot of the reaction zone of the metal will take 0.5 and 0.08 to the slag thus simulating the metal has a higher rate than the mixing of the slag. The first case - to become 10G2S, in the process of production furnace slag, a large number of falls into the ladle with the metal. Table 3 lists the materials that are used to achieve a given chemical composition of steel.

Table 3 - materials used in steel production, t
Time Material Weight, t
0 Metal (распл) 100
1 Al (11) 0,2
1 Coke 0,1
2 СМн17 1,150
3 ФС65 1,2
5 Slag (распл) 6
16 Lime 1

Figure 1 shows the obtained during the simulation depending on describing the behavior of manganese and other elements.


pic1

Figure 1 - The behavior of the elements in contact with the slag in the ladle

As can be seen from the graph after the slag is a 5 minute falls into the bucket begins recovery manganese from the slag and this happens until the silicon content reaches the equilibrium values. Next, consider the processes occurring in the case when the issue is preventing the ingress of slag in the ladle. Table 3 lists the materials that are used to achieve a given chemical composition of steel.

Table 4 - materials used in steel production, t
Time Material Weight, t
0 Metal (распл) 100
1 Al (11) 0,2
1 Coke 0,1
2 СМн17 1,550
3 ФС65 0,75
5 Slag (распл) 0
16 Lime 0,4

Figure 2 shows the obtained during the simulation depending on describing the behavior of manganese and other elements.

pic2

Figure 2 - The behavior of the elements of the case prevent the slag in the ladle

Figure 2 shows that in the case when the contact metal and slag is no recovery of manganese does not occur, and to achieve the desired content elements are necessary to introduce an additional amount of alloying material.

Conclusion

As a result of the research found that the technology to hit the ladle furnace slag saves costly silicon manganese, for steel production 10G2S savings of 400 kg melt, but this technology requires an increase in consumption of ferrosilicon in the 450 kg and lime to 600 lbs. In order to show that this technology is justified by the following is a calculation of the economic effect achieved in the production of steel.

pic3

where H1, H2, H3 -, respectively, consumption of silico-manganese, ferrosilicon, and lime, in tons

C1, C2, C3 - respectively, the price of silicon manganese, ferro-silicon and lime, UAH / t

pic4

Since the simulation was performed for 100 tons of metal that economic benefits will be: E/100 = 1.84 UAH / t Also note that getting into the ladle furnace slag leads to the restoration of not only manganese and phosphorus, which leads to the need for deeper dephosphorization in steelmaking in a furnace. Also, the furnace slag with a high FeO content interferes with the normal conduct of desulfurization of the metal. All these factors should be considered when organizing secondary treatment of the metal.

References

1. Термодинамика и кинетика взаимодействия фаз при внепечной обработке. С.А. Храпко. Металлургическая и горнорудная промышленность, 2002, №10, С. 121—123.

2. Влияние массопереноса на взаимодействие металла и шлака в сталеплавильных агрегатах. С.А. Храпко. Металлургия стали, 2004, №9, С. 12—16.

3. Дымнич А.Х., Троянский А.А. Вопросы тепломассообмена в сталеплавильных процессах - Киев; Донецк: Головное изд-во, 2009

4. Рыжонков Д.И., Арсентьев П.П., Яковлев В.В. и др. Теория металлургических процессов - М.:Металлургия. 1989

5. Меджибожский М.Я. Основы термодинамики и кинетики сталеплавильных процессов: учеб. пособие для вузов. - Киев - Донецк: Вища школа.Головное изд-во, 1979. 280с.