Specular hematite concentrate,characterized by predominantly intermediate particle size distribution with minimal ultrafine fractions and a dense,smooth surface texture,exhibits poor granulation performance,resulting ...Specular hematite concentrate,characterized by predominantly intermediate particle size distribution with minimal ultrafine fractions and a dense,smooth surface texture,exhibits poor granulation performance,resulting in a significantly lower proportion in sinter mixtures.The granulation behavior of iron ore blends containing 40%Canadian specular hematite concentrate was systematically investigated,focusing on the effects of nuclei types,adhering fines and binders on the packed bed permeability and adhesion load,and solutions were developed for improving its granulation performance.The results revealed that the granulation effectiveness of specular hematite concentrate is influenced more significantly by the type of adhering fines than by the type of nuclei.Specifically,adhering fines with higher maximum molecular moisture content(e.g.,goethite-type LO-F)and elevated proportions of−0.01 mm ultrafine particles help improve the adhering performance,while particles with higher microhardness(e.g.,magnetite MO-F)hinder adhesion.The addition of quicklime and bentonite as binders further enhances the adhesion,and the specular hematite concentrate adhesion load increases by 4.4%with a combination of quicklime and bentonite,accompanied by 33%enhancement in packed bed permeability.An optimized strategy recommends selecting adhering fines with high molecular water content and low microhardness,combined with binders,to improve sintering efficiency and support low-carbon ironmaking transitions.展开更多
The mechanism of high pressure roll grinding on improvement of compression strength of oxidized hematite pellets was researched by considering their roasting properties. The results indicate that oxidized hematite pel...The mechanism of high pressure roll grinding on improvement of compression strength of oxidized hematite pellets was researched by considering their roasting properties. The results indicate that oxidized hematite pellets require higher preheating temperature and longer preheating time to attain required compression strength of pellets compared with the common magnetite oxidized pellets. It is found that when the hematite concentrates are pretreated by high pressure roll grinding （HPRG）, the compression strengths of preheated and roasted oxidized hematite pellets get improved even with lower preheating and roasting temperatures and shorter preheating and roasting time. The mechanism for HPRG to improve roasting properties of oxidized pellets were investigated and the cause mainly lies in the increase of micro-sized particles and the decrease of dispersion degree for hematite concentrates, which promotes the hematite concentrate particles to be compacted, the solid-phase crystallization, and finally the formation of Fe203 bonding bridges during subsequent high temperature roasting process.展开更多
基金financial support of the China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202216).
文摘Specular hematite concentrate,characterized by predominantly intermediate particle size distribution with minimal ultrafine fractions and a dense,smooth surface texture,exhibits poor granulation performance,resulting in a significantly lower proportion in sinter mixtures.The granulation behavior of iron ore blends containing 40%Canadian specular hematite concentrate was systematically investigated,focusing on the effects of nuclei types,adhering fines and binders on the packed bed permeability and adhesion load,and solutions were developed for improving its granulation performance.The results revealed that the granulation effectiveness of specular hematite concentrate is influenced more significantly by the type of adhering fines than by the type of nuclei.Specifically,adhering fines with higher maximum molecular moisture content(e.g.,goethite-type LO-F)and elevated proportions of−0.01 mm ultrafine particles help improve the adhering performance,while particles with higher microhardness(e.g.,magnetite MO-F)hinder adhesion.The addition of quicklime and bentonite as binders further enhances the adhesion,and the specular hematite concentrate adhesion load increases by 4.4%with a combination of quicklime and bentonite,accompanied by 33%enhancement in packed bed permeability.An optimized strategy recommends selecting adhering fines with high molecular water content and low microhardness,combined with binders,to improve sintering efficiency and support low-carbon ironmaking transitions.
基金Project(50725416) supported by the National Natural Science Funds for Distinguished Young Scholars of China
文摘The mechanism of high pressure roll grinding on improvement of compression strength of oxidized hematite pellets was researched by considering their roasting properties. The results indicate that oxidized hematite pellets require higher preheating temperature and longer preheating time to attain required compression strength of pellets compared with the common magnetite oxidized pellets. It is found that when the hematite concentrates are pretreated by high pressure roll grinding （HPRG）, the compression strengths of preheated and roasted oxidized hematite pellets get improved even with lower preheating and roasting temperatures and shorter preheating and roasting time. The mechanism for HPRG to improve roasting properties of oxidized pellets were investigated and the cause mainly lies in the increase of micro-sized particles and the decrease of dispersion degree for hematite concentrates, which promotes the hematite concentrate particles to be compacted, the solid-phase crystallization, and finally the formation of Fe203 bonding bridges during subsequent high temperature roasting process.
