CN101880743A - Technology for performing manganese ore alloying by converter less-slag melting - Google Patents

Abstract

The invention relates to technology for performing manganese ore alloying by converter less-slag melting, belongs to the field of converter steelmaking, and mainly relates to addition of the manganese ore in the process of converter steelmaking. A main method comprises that: the slag is reduced by deslagging of a converter halfway. At the initial stage of the smelting, the addition of the manganese ore is 1 to 2.5 kg/t, the slag amount is reduced in the converter smelting process, and over 50 percent of slag is discharged halfway. During tapping, due to the adoption of high catch carbon technology, the carbon content is controlled over 0.08 percent, the air supply intensity is 0.03 to 0.3 Nm<3>/min.t, and the yield of lean manganese ore is over 40 percent. The content of converter end-point metal Mn in the steel is over 0.15 percent.

Description

A kind of technology of performing manganese ore alloying by converter less-slag melting

Technical field:

The present invention relates to iron and steel metallurgical industry converter smelting field, be specially adapted to converter less-slag melting manganese ore alloy prior.

Background technology:

The present invention " a kind of converter less-slag carries out the technology of manganese ore alloying " is mainly the converter smelting manganese ore and reclaims alloying of manganese technology.

Manganese plays the effect that improves intensity in steel, manganese is necessary alloy element, manganese is a large amount of oxidations of initial stage quilt in converter, but the converter smelting later stage because the smelting temperature height, the oxidation of manganese tends to balance, and along with the oxidation of carbon, FeO content reduces in the slag, MnO is reduced, and manganese metal can enter in the steel.Manganese ore mainly consists of: TMn:19%-25%, TFe:8%-10%, SiO ₂: 20%-25%, CaO:8%-10%, P≤0.050%, S≤0.30%.Reduction by carbon in the converter is reduced into metal M n with the MnO in the slag and enters in the steel, thereby makes molten iron contain a certain amount of metal M n during tapping.Under the common situation, single slag melting is adopted in converter, but brings many shortcomings thus, such as, shortcoming such as many, the strong endpoint carbon content height of molten steel oxidation of MnO total amount in the slag that the terminal point quantity of slag is brought greatly.

By adopting less-slag melting, middle deslagging, smelt early stage and control liquid steel temperature about 1350-1450 ℃, adopt poor manganese ore to replace ore control temperature drop, tap to tap time was by 5-6 minute before prolonging deslagging simultaneously, the slag that contains MnO is fully melted and revert in the molten steel, pour out slag amount more than 1/2 during two slag, reduce the slag total amount as far as possible.Adopt the blowing technology of low rifle position, big flow after the deslagging, the molten bath is fully stirred reducing slag MnO content, and catch carbon when adopting high-carbon content.By this technology finally realized the converter terminal quantity of slag reduce, by prolonging tap to tap time before the converter smelting deslagging, make that MnO fully melts in the manganese ore, when deslagging, only have a small amount of MnO pour out outside the stove, by improving two slag melting later stage bottom blowing gas intensities, reduce FeO and MnO content in the steel, improved Mn content in the steel.

Summary of the invention:

Purpose of the present invention is exactly to overcome in the slag that the terminal point quantity of slag is brought greatly in the prior art shortcomings such as the MnO total amount is many, the strong endpoint carbon content height of molten steel oxidation.

In order to realize goal of the invention, the present invention relates to the technology that a kind of converter less-slag carries out manganese ore alloying, the manganese ore reduction mechanism is studied, and innovated alloying technology, the control carbon content of molten steel also reduces the quantity of slag and it is characterized by to reduce the sendout of manganese element in slag:

(1) converter less-slag melting adopts the mode of deslagging midway to reduce the converter quantity of slag, and at converter smelting initial stage lime add-on 25kg/t iron-50kg/t iron, adding the manganese ore amount is 1kg/t-2.5kg/t iron; Stop using ore simultaneously, manganese ore main component mass percent consists of TMn:19%-25%, TFe:8%-10%, SiO ₂: 20%-25%, CaO:8%-10%, P≤0.050%, S≤0.30%.

(2) before the converter deslagging, the lime add-on is pressed 20kg/t-50kg/t, and the main mass percent of lime consists of CaO:85%-90%, SiO ₂: 1%-2%, MgO:5%-10%, CaF ₂:≤5%;

(3) be controlled at 5-6 minute tap to tap time before the converter deslagging, smelts end temp at 1300 ℃-1450 ℃;

(4) top blast oxygen supply gas intensity 2.5-3.3Nm ³/ min.t, oxygen lance position adopts 1.4-1.7 rice;

(5) bottom gas-feeding: to top blast oxygen supply 70%, bottom blowing is for nitrogen intensity 0.03-0.3Nm ³/ min.t; Back top blast oxygen supply 30%, bottom blowing is for argon intensity 0.03-0.3Nm ³/ min.t, during top blast oxygen supply 30%-60% in, adopt low air supply intensity, other times adopt high air supply intensity;

(6) slag more than 1/2 is outwelled in deslagging, and the lime add-on is at 10kg/t-20kg/t after the deslagging;

(7) during the converter terminal catch carbon, carbon content of molten steel is controlled at more than 0.08%.

Adopt the advantage of this technology as follows:

1, the quantity of slag is few about half during converter terminal, and the quantity of slag is reduced to the 25-50kg/t steel, makes metal M n content in steel increase;

2, the converter terminal carbon content is controlled at more than 0.08%, makes the slag oxidation reduction, and manganese partition ratio in steel increases;

3, by converter less-slag melting, the converter terminal basicity of slag is improved and finally reaches 4-6;

4, final by adding manganese ore, the content of converter terminal metal M n in steel reaches more than 0.15%.

Embodiment:

Embodiment 1:

Smelting molten iron Si content is 0.45%, and 1350 ℃ of molten iron temperatures adopt few slag method operation, and the slag melting time is controlled at 5 ' 37 before the deslagging midway, deslagging ", control head is criticized the slag temperature at 1355 ℃, and the initial stage adds 2.1 tons of manganese ores, lime 40.6kg/t; The stove slag quantity of slag about 1/2 of turning round during deslagging reinforcedly after the deslagging is controlled according to the half steel composition, adds lime 15.2kg/t, adopts big flow bottom blowing, and bottom blowing gas intensity is at 0.03Nm ³About/min.t, smelt 1.5 meters of later stage oxygen lance positions, the top blast air supply intensity is at 3.0Nm ³/ min.t, carbon content is controlled at 0.11% o'clock catch carbon, converter terminal Mn content 0.15%.

Table 1 smelting situation

Table 2 is smelted the result

Heat

The total confession

Half steel

Catch carbon

	The oxygen amount	Temperature	Tap to tap time	Catch carbon C	??Mn
						Case one	??5130	??1355	??5’37”	??0.08％	??0.15％

Table 3 slag composition

Heat	??TFe	??FeO	??SiO 2	??CaO	??MgO	??Al 2O 3	??MnO
								Case one	??13.72	??11.51	??10.62	??49.17	??8.80	??0.79	??4.78

Embodiment 2:

Smelting molten iron Si content is 0.36%, and 1320 ℃ of molten iron temperatures adopt few slag method operation, and be controlled at 5 ' 11 tap to tap time before the deslagging midway, deslagging ", liquid steel temperature is at 1390 ℃ during deslagging, and the smelting initial stage adds 2.23 tons of manganese ores, lime 36.1kg/t; Outwell the converter slag quantity of slag about 1/2, two batches reinforced controls according to the half steel composition, adds lime 16.7kg/t, adopts big flow bottom blowing as far as possible, and bottom blowing gas intensity is at 0.08Nm ³About/min.t, smelt 1.4 meters of later stage oxygen lance positions, the top blast air supply intensity is at 3.1Nm ³/ min.t, carbon content is controlled at 0.10% o'clock catch carbon, converter terminal Mn content 0.17%.

Table 4 smelting situation

Table 5 is smelted the result

Table 6 slag composition

Heat	??TFe	??FeO	??SiO 2	??CaO	??MgO	??Al 2O 3	??MnO
								Case two	??15.74	??9.62	??12.65	??48.15	??8.82	??0.76	??5.78

Embodiment 3:

Smelting molten iron Si content is 0.62%, and 1350 ℃ of molten iron temperatures adopt few slag method operation, and be controlled at 5 ' 22 tap to tap time before the deslagging midway, deslagging ", temperature is at 1405 ℃ during deslagging, and the initial stage adds 2.42 tons of manganese ores, lime 58.0kg/t; Outwell the converter slag quantity of slag about 1/2, two batches reinforced controls according to the half steel composition, adds about lime 14.9kg/t, adopts big flow bottom blowing as far as possible, and bottom blowing gas intensity is at 0.10Nm ³About/min.t, smelt 1.7 meters of later stage oxygen lance positions, the top blast air supply intensity is at 2.9Nm ³/ min.t, carbon content is controlled at 0.09% o'clock catch carbon, converter terminal Mn content 0.16%.

Table 7 smelting situation

Table 8 is smelted the result

Table 9 slag composition

Heat	??TFe	??FeO	??SiO 2	??CaO	??MgO	??Al 2O 3	??MnO
								Case three	??15.60	??12.62	??12.39	??43.12	??9.00	??0.81	??5.40

Claims (1)

1. the technology of a performing manganese ore alloying by converter less-slag melting is characterized by:

(1) converter less-slag melting adopts the mode of deslagging midway to reduce the converter quantity of slag, and at converter smelting initial stage lime add-on 25kg/t iron～50kg/t iron, adding the manganese ore amount is 1kg/t-2.5kg/t iron; Stop using ore simultaneously, manganese ore main component mass percent consists of TMn:19%-25%, TFe:8%-10%, SiO2:20%-25%, CaO:8%-10%, P≤0.050%, S≤0.30%;

(2) before the converter deslagging, the lime add-on is pressed 20kg/t-50kg/t, and the main mass percent of lime consists of CaO:85%-90%, SiO2:1%-2%, MgO:5%-10%, CaF2 :≤5%;

(3) be controlled at 5-6 minute tap to tap time before the converter deslagging, smelts end temp at 1300 ℃-1450 ℃;

(4) top blast oxygen supply gas intensity 2.5-3.3N m ³/ min.t, oxygen lance position adopts 1.4-1.7 rice;

(5) bottom gas-feeding: to top blast oxygen supply 70%, bottom blowing is for nitrogen intensity 0.03-0.3Nm ³/ min.t; Back top blast oxygen supply 30%, bottom blowing is for argon intensity 0.03-0.3N m ³/ min.t, during top blast oxygen supply 30%-60% in, adopt low air supply intensity, other times adopt high air supply intensity;

(6) slag more than 1/2 is outwelled in deslagging, and the lime add-on is at 10kg/t-20kg/t after the deslagging;

(7) during the converter terminal catch carbon, carbon content of molten steel is controlled at more than 0.08%.