System and method for steel making by spraying limestone powder to bottom of converter

Abstract

The invention discloses a system and method for steel making by spraying limestone powder to the bottom of a converter. The system includes a powder tank truck, a ring-slot valve group, a main blowingvalve group, a powder spray tank and the converter. The feeding end of the powder spray tank is provided with a safety Valve and a pressure relief valve, a fluidizing device is arranged at the lowermiddle part of the powder spray tank, the fluidizing device is connected to the ring-slot valve group through a fluidizing tube, an injector is arranged at the discharging end of the bottom of the powder spray tank, a discharging control valve is arranged between the injector and the powder spray tank, one end of the injector is connected with the main blowing valve group through a main blowing air pipe, and the other end of the injector is connected with a double-layer sleeve-type bottom blowing spray gun installed at the bottom of the converter through a conveying pipe. The passivated limestone powder is sprayed into the converter from the bottom of the converter by means of the double-layer sleeve-type bottom blowing spray gun, the limestone powder spray quantity is adjusted according to the early, medium and later stages of the smelting processe of converter smelting, the direct contact area between limestone and molten steel is greatly increased, the stirring conditions of the converter greatly improved, and the utilization efficiency of the limestone is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgical technology, and in particular relates to a method for making steel by spraying limestone powder at the bottom of a converter. Background technique [0002] As the country adopts energy-saving and emission-reduction policies for iron and steel enterprises, how to better undertake the tasks of low energy consumption and low pollution in the converter process, which is the core link of the steelmaking industry, has become the focus of people's attention. Based on the concept of energy-saving and emission The method of "converter limestone instead of lime slag making steel" proposed by Hong just meets the smelting requirements of low cost, low energy consumption and low emission. Dozens of domestic steel companies have applied this method to make steel and achieved good smelting results. effects and economic benefits. [0003] Modern converter steelmaking generally uses active lime as slagging ...

AI Technical Summary

Problems solved by technology

However, the blocky limestone added through the high-level silo generally has a particle size of 10-80 mm, and the decomposition rate of the limestone block is relatively slow. The calcination of the limestone is completed in the converter slag or at the interface of the steel slag, and the direct contact area with the molten steel is small, and the limestone decomposition reaction produced CO 2 Gas above the slag interface, CO 2 The stirring effect of the gas on the molten pool is not fully exerted, resulting in a low utilization rate of limestone, and the limestone powder produced during the mining, processing and transportation of limestone cannot be effectively utilized

[0013] Patent No. 201210298401.0, which is a Chinese invention patent for a method of side-blowing powdered limestone slag in the top-bottom double-blowing converter to make steel. The limestone powder is sprayed from the side of the converter trunnion to the converter molten pool, which promotes the process to a certain extent. In order to improve the stirring effect of the molten pool and the utilization efficiency of limestone, the lime powder is injected from the side, the carrier gas and lime powder stay in the molten pool for a limited depth and time, and the injection range is limited to a local area, which cannot make full use of the rich heat of converter smelting and the impact on the melting. well agitate the pool

Images