A steel slag modification process in the dephosphorization stage of the converter

Abstract

The invention discloses a modification technology for steel slag in converter dephosphorization stage. The modification technology comprises the following steps: adding an SiO2 material or a material taking SiO2 and Al2O3 as main components, or a Al2O3 material into a furnace from an overhead bunker so as to modify furnace slag before the blowing in the converter dephosphorization stage is finished, so that the basicity of the furnace slag is reduced and the foaming slag is pressed into thinned slag without foam. After the modification of the furnace slag is finished, foaming slag is not formed when the blowing in the converter dephosphorization stage is finished, the content of FeO in the slag is not required for addition in advance near the finishing of the blowing to form proper foaming slag to improve the mobility of the furnace slag, iron loss can be reduced, slag can be poured as soon as stopping of blowing, the slag pouring speed is fast, the slag discharging time is short and the melting period is shortened; the furnace slag is not foamed, so that a slag pressing agent is not required for being added in a slag tank when the slag is discharged, so that the cost is lowered, the labor intensity is reduced, and the operation rate of the slag tank can be improved; after being modified, the furnace slag is blast-furnace slagged, the utilization routes of the slag can be widened, the additional value is greatly increased, and the environment-friendly and utilization problems of the steel slag can be thoroughly solved; the dephosphorization slag can be fast and adequately poured out, so that the terminal full-remaining slag and continuous cycle of converter remaining slag-double slag technology can be guaranteed, so that the advantage of the converter remaining slag-double slag technology can be played to the greatest extent.

Description

technical field [0001] The patented technology of the invention relates to the field of steelmaking, in particular to an in-furnace on-line upgrading process of steel slag in the dephosphorization stage of converter steelmaking. Background technique [0002] In the past two years, the process of leaving slag in the converter and double slag has been widely used in the industry because of its huge cost reduction and efficiency increase. However, at the end of the dephosphorization stage of this process, the slag often foams seriously, the slag dumping time is long, and the amount of slag dumping is insufficient, which cannot meet the process requirements, which not only increases the smelting auxiliary time, but also makes the process unable to continue. In the prior art, iron ore is usually used to press the slag and then extract the slag. The patented technology "A Low-cost Smelting Process of Converter" (201310248732.8) developed a sludge pellet pressing technology, which...

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Problems solved by technology

This process not only increases the loss of FeO in the slag, but also needs to add a slag pressure agent to the slag pot to control the overflow of the foamy slag in the slag pot due to the foaming of the slag, which not only increases the cost but also increases the labor intensity. +Double slag 'steelmaking process research" "China Metallurgy" 2013 04

In addition, the patent "Recovery of Phosphorus Elements in Converter Duplex Dephosphorization Slag" [201010171945.1] developed a method of adding SiO to converter dephosphorization slag 2 or Al 2 o 3 The oxide material can modify the slag, and promote the P in the slag 2 o 5 Enrichment to the non-metallic phase, by adding an appropriate amount of SiO 2 material, when reducing the slag alkalinity from 1.5 to 1.0, P 2 o 5 The distribution ratio Lp of non-magnetic phase and magnetic phase in dephosphorization slag rises from 1.34 to 2.35, which can make 72% of P 2 o 5 Enriched in the non-magnetic phase with the addition of Al 2 o 3 The material gets better results, and then the P-rich 2 o 5 The non-magnetic phase and the magnetic phase are recycled separately, but this method requires a slag heating device, which consumes a lot of energy, and the added materials have a single effect

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