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A slag control method for dephosphorization foam slag in converter double slag method steelmaking

A double-slag method and foamed slag technology, which is applied in the field of iron and steel metallurgy, can solve the problems of no operation process, no operation guidance scheme, and description of key process operation parameters.

Active Publication Date: 2016-05-25
TIANJIN IRON & STEEL GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] Chinese patent (application number CN103805732A) converter smelting slag pressing method proposes to use high-pressure nitrogen to purge the foamy slag, but does not explain the key process operating parameters, and has no operability and repeatability
[0004] When domestic steel mills adopt the double slag method for steelmaking (optimization of 150t converter slag + double slag smelting technology [J]. Liuzhou Iron and Steel Science and Technology, 2014, 4:5-7), the technology of nitrogen purging and slag pressing is adopted, but The operation process is not given, and no feasible operation guidance scheme is given for different converter slag conditions

Method used

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  • A slag control method for dephosphorization foam slag in converter double slag method steelmaking
  • A slag control method for dephosphorization foam slag in converter double slag method steelmaking
  • A slag control method for dephosphorization foam slag in converter double slag method steelmaking

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Effect test

Embodiment 1

[0024] The 120t top-bottom compound blowing converter (furnace volume ratio 2.0) adopts double slag and slag smelting. The main components of molten iron are: C: 4.10-4.50%, Si: 0.36-0.47%, P: 0.14-0.18%. The amount of slag-making auxiliary materials and temperature-controlled cold materials in the dephosphorization period is: limestone 10-12kg / ton steel, lime 8.5-10kg / ton steel, dolomite 10-13kg / ton steel, magnesium balls 0-5kg / ton steel, iron sheet Ball 12.5~18.5kg / ton steel. The oxygen lance is a 4-hole oxygen lance with a throat diameter of 39.3mm, a throat angle of 12°, and a Mach number of 2.02. During the blowing process, when the dephosphorization period is over, that is, when the decarburization reaction begins, a small amount of foamy slag overflows the furnace mouth, and the gun is lifted quickly. When the oxygen lance nozzle is lifted to the furnace mouth, the oxygen blowing is stopped immediately, and the oxygen is switched to nitrogen. The nitrogen pressure is st...

Embodiment 2

[0028] The 110t top-bottom compound blown converter (furnace volume ratio 1.9) adopts double slag and slag smelting. The main components of molten iron are: C: 4.30-4.80%, Si: 0.42-0.55%, P: 0.10-0.11%. The amount of slag-making auxiliary materials and temperature-controlled cold materials in the dephosphorization period is: limestone 9-11kg / ton steel, lime 9-10kg / ton steel, dolomite 8-12kg / ton steel, magnesium balls 0-5kg / ton steel, iron sheet The ball is 14.5~20kg / ton of steel. The oxygen lance is a 4-hole oxygen lance with a throat diameter of 38.1mm, a throat angle of 12°, and a Mach number of 2.0. During the blowing process, when the dephosphorization period is over, that is, when the decarburization reaction starts, the foamy slag does not overflow the furnace mouth, and the gun is lifted quickly. When the oxygen lance nozzle is lifted to the furnace mouth, the oxygen blowing is stopped immediately, and the oxygen is switched to nitrogen, and the nitrogen pressure is sta...

Embodiment 3

[0032] Smelting with double slag and leaving slag on a 50t top-bottom double-blown converter (furnace volume ratio 1.72), the main components of molten iron are: C: 4.20-4.80%, Si: 0.39-0.60%, P: 0.09-0.10%. The general addition amount of slagging auxiliary materials and temperature control cold materials in the dephosphorization period is: limestone 16-22kg / ton steel, lime 0-10kg / ton steel, dolomite 6-12kg / ton steel, magnesium balls 0-4kg / ton steel, Iron ball 16~30kg / ton of steel. The oxygen lance is a 4-hole oxygen lance with a throat diameter of 25.3 mm, an included angle of the throat of 11°, and a Mach number of 1.97. During the blowing process, when the dephosphorization period is over, that is, when the decarburization reaction begins, a small amount of foamy slag overflows the furnace mouth, and the gun is lifted quickly. When the oxygen lance nozzle is lifted to the furnace mouth, the oxygen blowing is stopped immediately, and the oxygen is switched to nitrogen. The n...

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Abstract

The invention discloses a slag control method of dephosphorization foaming slag in converter double-slag-process steel making. The slag control method comprises the following steps: if slag does not overflow or a small amount of slag overflows from a converter opening during a dephosphorization period, rapidly lifting a lance to the converter opening and switching a gas when the dephosphorization period is ended, unloading the lance at a speed of 1-7mm per ton steel, blowing nitrogen and cooling the slag, and setting a nitrogen slag-control time according to an experience guide formula that t=45m-40P, wherein t is the nitrogen slag-control time, s; m is the total adding amount of limestone, lime, dolomite and magnesium balls, t; P is a nitrogen pressure with a unit MPa; if lots of the slag overflows from the converter opening during the dephosphorization period, carrying out the following operations before the dephosphorization period is ended: a, if slag foaming is not found timely, adding 2-5kg of slag pressing agent per ton steel in 0-30s before the dephosphorization period is ended; and b, if the slag foaming is found timely, adding 2-5kg of lime per ton steel or 2-5kg of ferric oxide skin balls per ton steel in 30-60s before the dephosphorization period is ended. The slag control method disclosed by the invention is used for carrying out cooling treatment on the dephosphorization foaming slag during a converter double-slag-process smelting process by using a top lance for blowing nitrogen or (adding cold materials and blowing nitrogen), thus ensuring the dephosphorization slag deslagging rate.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular to a slag control method for dephosphorization foam slag in converter double slag method steelmaking. Background technique [0002] The converter has a good stirring effect in the molten pool, which provides a guarantee for efficient dephosphorization and decarburization. With the improvement of market requirements for product quality and the increase of smelting cost and environmental protection pressure, double slag steelmaking has gradually become one of the important smelting processes of converters. Efficient dephosphorization in the dephosphorization stage and high slag dumping rate of high phosphorus slag in the double slag smelting process are the key factors to ensure the smooth operation of the double slag method. How to use the existing equipment and materials in the converter workshop to optimize the high efficiency and low consumption to realize the d...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/36
Inventor 潘贻芳曾加庆侯葵任茂勇杨利彬林腾昌
Owner TIANJIN IRON & STEEL GRP