采用热重法研究石灰存在条件下铁闪锌矿的直接碳热还原,以确定生产Zn(g)而没有SO2(g)污染的技术可行性。部分反应的样品X射线衍射分析表明,还原反应是通过形成ZnCaOS和Ca2Fe2O5中间产物进行的,最终产物为Zn(g)、固体Fe和CaS。温度对还...采用热重法研究石灰存在条件下铁闪锌矿的直接碳热还原,以确定生产Zn(g)而没有SO2(g)污染的技术可行性。部分反应的样品X射线衍射分析表明,还原反应是通过形成ZnCaOS和Ca2Fe2O5中间产物进行的,最终产物为Zn(g)、固体Fe和CaS。温度对还原速率存在重要影响。在1100℃下,对于300 mg(Zn,Fe)S:CaO:C比为1:1:1的样品,10 min左右可实现铁闪锌矿的完全转化。用ln(1-X)=-kt模型分析总还原反应的动力学,发现在1000~1150℃、转化率不超过0.95时,该模型很好地描述试验数据,在此温度范围内确定的活化能为257 k J/mol。研究结果证实该方法生产Zn(g)而不产生有害的SO2(g)排放的技术可行性。展开更多
Aiming at prolonging the service life of refractories for direct reduction of laterite nickel ores in rotary kilns,the slag resistance of ten materials(corundum bricks,chrome corundum bricks,silicon nitride bonded sil...Aiming at prolonging the service life of refractories for direct reduction of laterite nickel ores in rotary kilns,the slag resistance of ten materials(corundum bricks,chrome corundum bricks,silicon nitride bonded silicon carbide bricks,high alumina silicon carbide bricks,high alumina bricks,magnesia chrome bricks,magnesium aluminate spinel bricks,spinel chrome corundum bricks,chrome corundum castables and magnesia alumina chrome composite spinel bricks)was evaluated by rotary slag tests,which simulate the service conditions in rotary kilns.The corroded residual bricks were analyzed by SEM and EDS.The results show that the magnesia alumina chrome composite spinel brick possesses the advantages of magnesium aluminate spinel bricks and chrome corundum bricks;MgO-rich spinel can absorb the penetrated ferric oxide,and forms a dense zeylanite layer,which prevents the penetration of the molten laterite nickel ores;therefore,it is an ideal lining of rotary kilns for direct reduction of laterite nickel ores.展开更多
A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced ti...A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced time of 5 h,and CaO content of 2.5wt%,a DRI with a metallization rate of 96.5%was obtained through coal-based direct reduction of ultra-high-grade iron concentrate.Then,an HPI with a Fe purity of 99.95%and C,Si,Mn,and P contents as low as 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.The product of the pilot test with a scale of 0.01 Mt/a had a lower impurity content than the Chinese industry standard.An HPI with a Fe purity of 99.98wt%can be produced through the direct reduction?smelting separation of ultra-high-grade iron concentrate at relatively low cost.The proposed process shows a promising prospect for application in the future.展开更多
基金the financial support of Juan Yamid CARVALLO during his graduate studies。
文摘采用热重法研究石灰存在条件下铁闪锌矿的直接碳热还原,以确定生产Zn(g)而没有SO2(g)污染的技术可行性。部分反应的样品X射线衍射分析表明,还原反应是通过形成ZnCaOS和Ca2Fe2O5中间产物进行的,最终产物为Zn(g)、固体Fe和CaS。温度对还原速率存在重要影响。在1100℃下,对于300 mg(Zn,Fe)S:CaO:C比为1:1:1的样品,10 min左右可实现铁闪锌矿的完全转化。用ln(1-X)=-kt模型分析总还原反应的动力学,发现在1000~1150℃、转化率不超过0.95时,该模型很好地描述试验数据,在此温度范围内确定的活化能为257 k J/mol。研究结果证实该方法生产Zn(g)而不产生有害的SO2(g)排放的技术可行性。
文摘Aiming at prolonging the service life of refractories for direct reduction of laterite nickel ores in rotary kilns,the slag resistance of ten materials(corundum bricks,chrome corundum bricks,silicon nitride bonded silicon carbide bricks,high alumina silicon carbide bricks,high alumina bricks,magnesia chrome bricks,magnesium aluminate spinel bricks,spinel chrome corundum bricks,chrome corundum castables and magnesia alumina chrome composite spinel bricks)was evaluated by rotary slag tests,which simulate the service conditions in rotary kilns.The corroded residual bricks were analyzed by SEM and EDS.The results show that the magnesia alumina chrome composite spinel brick possesses the advantages of magnesium aluminate spinel bricks and chrome corundum bricks;MgO-rich spinel can absorb the penetrated ferric oxide,and forms a dense zeylanite layer,which prevents the penetration of the molten laterite nickel ores;therefore,it is an ideal lining of rotary kilns for direct reduction of laterite nickel ores.
基金the National Natural Science Foundation of China(No.51904063)the Fundamental Research Funds for the Central Universities,China(Nos.N172503016,N172502005,and N172506011)the China Postdoctoral Science Foundation(No.2018M640259).
文摘A new process for preparing high-purity iron(HPI)was proposed,and it was investigated by laboratory experiments and pilot tests.The results show that under conditions of a reduced temperature of 1075°C,reduced time of 5 h,and CaO content of 2.5wt%,a DRI with a metallization rate of 96.5%was obtained through coal-based direct reduction of ultra-high-grade iron concentrate.Then,an HPI with a Fe purity of 99.95%and C,Si,Mn,and P contents as low as 0.0008wt%,0.0006wt%,0.0014wt%,and 0.0015wt%,respectively,was prepared by smelting separation of the DRI using a smelting temperature of 1625°C,smelting time of 45 min,and CaO content of 9.3wt%.The product of the pilot test with a scale of 0.01 Mt/a had a lower impurity content than the Chinese industry standard.An HPI with a Fe purity of 99.98wt%can be produced through the direct reduction?smelting separation of ultra-high-grade iron concentrate at relatively low cost.The proposed process shows a promising prospect for application in the future.