摘要
The high-carbon ferrochrome is an essential raw material for producing stainless steel,and the demand of it increases with the increase of stainless steel.So increasing Cr recovery rate from chromite is essential for lower costs and higher economic benefits in high-carbon ferrochrome production process.This study calculated the activity of CrO_(x)in slag and investigated the distribution behavior of Cr between slag and alloy.Theω(MgO)/ω(Al_(2)O_(3))was 1.0,and the w(CaO)/w(SiO_(2))was from 0.2 to 0.6 in this study.The calculation and experimental results showed that the main phases of the slag were chrome-containing spinel,magnesium-aluminum spinel,olivine and melilite.The content of spinel in slag decreased with the increasing w(CaO)/w(SiO_(2)),and the w(CrO_(x))in spinel also reduced,but the content of melilite increased.The distribution ratio of Cr between slag and alloy decreased with the increase of slag basicity at 1600℃,meansning that increasing the w(CaO)/w(SiO_(2))of slag can improve the recovery of Cr in chromite smelting process.
高碳铬铁是生产不锈钢的主要含铬原料,随着不锈钢需求量及产量的增加,对高碳铬铁的需求也日益提高。目前主要采用电炉冶炼法生产高碳铬铁,但该过程存在元素回收率低等问题。炉渣的物化性能对于高温冶炼过程元素回收及渣铁分离效果具有重要影响。因此,研究铬铁矿冶炼过程中Cr在炉渣和高碳铬铁合金之间的分配行为,优化渣系组成,提高元素回收率,对保障我国不锈钢产业的可持续发展意义重大。本论文以高碳铬铁合金电炉冶炼过程的Al_(2)O_(3)-SiO_(2)-MgO-CaO-CrO_(x)渣系为基础,研究了w(CaO)/w(SiO_(2))对Al_(2)O_(3)-SiO_(2)-MgO-CaO-CrO_(x)炉渣黏度的影响以及Cr在炉渣与高碳铬铁合金间分配行为的影响。采用Fact Sage 8.1计算了不同炉渣碱度条件下渣中Cr_(2)O_(3)与CrO的活度变化规律,以及不同温度下炉渣的相平衡关系和含铬物相中铬含量。在理论分析的基础上,开展了Cr在炉渣与高碳铬铁合金间分配行为的高温平衡验证实验,利用XRD、SEM-EDS等分析方法对渣铁样品进行了物相及微观结构分析。研究结果表明,Al_(2)O_(3)-SiO_(2)-MgO-CaO-CrO_(x)炉渣的主要物相为含铬尖晶石、镁铝尖晶石、镁橄榄石和钙镁橄榄石,随着炉渣中w(CaO)/w(SiO_(2))的提高,渣中尖晶石含量和尖晶石中CrO_(x)含量下降,钙镁橄榄石的含量增加,镁橄榄石含量降低,炉渣的黏度降低,铬在Al_(2)O_(3)-SiO_(2)-MgO-CaO-CrO_(x)渣与铬铁合金间的分配比降低,且主要存在于尖晶石物相中。结果表明,提高炉渣的w(CaO)/w(SiO_(2))有利于促进Cr的还原迁移,降低炉渣中的Cr含量,有利于提高铬铁矿电炉冶炼过程Cr的回收率。
基金
Project(2023XQLH055)supported by Central South University Graduate Research Innovation Project(University-Enterprise Joint Project),China。
作者简介
Corresponding author:WANG Shuai,PhD,Associate Professor,E-mail:wang_shuai@csu.edu.cn,ORCID:https://orcid.org/0000-0002-5120-7752。
