Study on the melting characteristics of steel scrap in molten steel

Abstract

Steel scrap is of great benefit for environmental protection. In converter steelmaking, bottom carbon injection was applied to enhance the scrap ratio and in EAF steelmaking, submerged carbon powder injection was used to accelerate the smelting of scrap. In these two cases, carbon powder is directly injected into molten metal to improve the scrap melting with effective carburization capacity and intense stirring effect. In this study, the induction furnace experiments were carried out to study the melting characteristics of steel scrap with different carbon contents and bottom-blowing gas flow rates. The results show that larger carbon content and faster fluid flow can promote scrap melting because the carburizing reaction can be accelerated by larger carbon concentration gradient and the heat transfer can be enhanced by larger stirring intensity. Finally, the convective mass transfer coefficient and heat transfer coefficient between steel bar and molten metal were also calculated.

Melting Characteristics of Multipiece Steel Scrap in Liquid Steel

“…In these studies, the melting characteristics of an individual steel bar with simple geometries, such as cylindrical and square, were observed. [5][6][7][8][9][10][11] And the factors, such as initial temperature and initial size of the steel bar, and the liquid steel temperature, on the melting of the individual steel bar, were also investigated. [1][2][3][4][12][13][14] In addition, the mass and heat transfer coefficients between the liquid steel and the steel bar under different experimental conditions were also analyzed.…”

A Review of Mathematical Process Models for the Electric Arc Furnace Process

“…The melting of scrap that is submerged within a liquid steel bath is not only relevant to the EAF but also to the basic oxygen furnace (BOF) and has been studied thoroughly both through experiments and numerical simulations. [ 55–60 ] By submerging samples and observing the change in mass and composition, the relevant phenomena and numerical models can be derived for specific geometries under controlled conditions. The carbon content of the sample and metal bath, their temperatures, flow conditions within the bath, and the geometrical arrangement of the samples have a significant influence on the resulting rates of mass, temperature, and composition changes.…”

“…The carbon content of the sample and metal bath, their temperatures, flow conditions within the bath, and the geometrical arrangement of the samples have a significant influence on the resulting rates of mass, temperature, and composition changes. [ 55,56,59,60 ] Numerical models have been developed to reproduce both the behavior in experiments with specific sample types [ 56,59,60 ] and the conditions within a BOF converter [ 58 ] or EAF. [ 57 ] For the EAF, additional phenomena such as the melting of scrap around the arcs and sources of chemical energy such as burners need to be considered.…”

Evaluation of Mass Transfer Coefficient during Scrap Melting

“…Upon increasing the stirring energy density of the molten pool from 3500 and 12,000 W/t, k increased from 8.3 × 10 −5 to 19.4 × 10 −5 m/s. Wei et al [6] performed scrap melting experiments at T = 1673 K. The carbon content of the hot metal and the bottom-blowing flow rate ranged between 2.1 and 4.03 wt% and 3 and 7 L/min, respectively, and the calculated k values ranged between 8.0 × 10 −5 and 10.0 × 10 −5 m/s. In addition, the empirical formulas derived using the analogy method were used to analyze mass transfer [7,8].…”