In order to utilize the iron resource effectively in red mud, a laboratory experiment based on the orthogonal method was carried out. Nuggets were gotten by directly reducing the carbon-bearing pellets of red mud and ...In order to utilize the iron resource effectively in red mud, a laboratory experiment based on the orthogonal method was carried out. Nuggets were gotten by directly reducing the carbon-bearing pellets of red mud and coal. The results showed that the strongest influencing factor is temperature, and the separation between liquid iron and slag is thoroughly. The nuggets can be gotten when the pellets, in which xC/xO is 1.6 and the basicity is 1.0, were maintained in 30 min at 1 400 ℃. The nuggets have a high TFe content which is higher than that in the hot metal produced in BF. It also has a low content of Si and Mn, but a high content of S and P. The main compositions of the slag are amorphous phase mainly containing SiO;and unreduced Fe;SiO;. Of course, a little reduced iron retains in it.展开更多
To recycle residual iron efficiently in Bayer red mud, three-factor three-level orthogonal experiments on carbon-bearing pellets of Bayer red mud were conducted on the basis of their characteristics. The influences of...To recycle residual iron efficiently in Bayer red mud, three-factor three-level orthogonal experiments on carbon-bearing pellets of Bayer red mud were conducted on the basis of their characteristics. The influences of CaO dosage, temperature and roast- ing time on total iron content and iron recovery of reduced iron powder were studied. Results showed that these factors slightly influenced iron recovery, but significantly influenced total iron content. The principal factor influencing total iron content was CaO dosage, followed by temperature and roasting time. An increase in CaO dosage could decrease total iron content, whereas an increase in temperature and an extension of roasting time could improve total iron content. The reduced iron powder with total iron content of 88.4 l% and iron recovery rate of 97.97% can be obtained under the optimal conditions of temperature of 1 275 ℃, roasting time of 60 min and CaO dosage of 7.5%. The X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses of the reduced pellets showed that iron minerals in red mud were almost completely reduced to metallic iron. The principal factor influencing the total iron content of reduced iron powder was the grain size of metallic iron particles. An increase in CaO dosage hindered the growth of metallic iron particles, whereas an increase in temperature and an extension of roasting time could neutralise the effect of CaO dosage. Therefore, CaO dosage should be decreased when iron minerals in red mud can be adequately reduced into metallic iron.展开更多
Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface met...Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface methodology was used to study the effects of process parameters, such as FC/O （the molar ratio of fixed carbon in coal to reducible oxygen of iron oxide in red mud）, reduction temperature, reduction time, and their interaction on the iron recovery rate and total iron content in magnetic product obtained from the process of direct reduction-magnetic separation. The relevant assessment model was established. The model could predict the changing rules of iron recovery rate and total iron content in the magnetic product affected by the process parameters. The results show that the iron recovery rate is significantly influenced by three factors and reduction temperature plays the most important role. The iron recovery rate and total iron content in magnetic product could be up to 98.37 and 82.52%, respectively, under the numerically optimal process parameters condition of reduction temperature of 1400 ℃, FC/O of 0.80 and reduction time of 100 min obtained by the assessment model. The predicted values are in good agreement with the experimental values.展开更多
目的 回顾性分析474例高胆红素血症新生儿的临床资料,探讨ABO胎儿新生儿溶血病(hemolytic disease of the fetus and newborn, ABO-HDFN)所致高胆红素血症的临床特征及蓝光治疗影响因素。方法 本研究纳入2019年1月至2023年1月期间在兰...目的 回顾性分析474例高胆红素血症新生儿的临床资料,探讨ABO胎儿新生儿溶血病(hemolytic disease of the fetus and newborn, ABO-HDFN)所致高胆红素血症的临床特征及蓝光治疗影响因素。方法 本研究纳入2019年1月至2023年1月期间在兰州大学第一医院接受治疗的474例高胆红素血症新生儿作为研究对象。所有患儿均接受血型鉴定及新生儿溶血三项试验。收集并分析其基线临床资料。根据溶血三项试验结果,将患儿分为溶血性黄疸组和非溶血性黄疸组。对2组患儿的血红蛋白水平、住院时间及蓝光治疗持续时间等临床指标进行比较分析。同时,采用多元线性回归模型探讨影响蓝光治疗时间的相关临床因素。结果 474例高胆红素血症新生儿中,354例确诊为ABO-HDFN(溶血病组),120例未发生ABO-HDFN(非溶血病组)。A型新生儿中ABO-HDFN发生率(55.93%,198/354)高于B型新生儿(44.07%,156/354),差异有统计学意义(P<0.05)。此外,二胎及以上新生儿ABO-HDFN发生率(81.56%,146/179)高于首胎新生儿(70.51%,208/295),差异有统计学意义(P<0.05)。溶血病组患儿的血红蛋白水平(170.67±21.86)g/L低于非溶血病组(178.99±22.05)g/L(P<0.001),红细胞计数(4.66±0.63)×10^(12)/L低于非溶血病组(4.89±0.59)×10^(12)/L(P<0.05),红细胞压积(50.05±6.56)%低于非溶血病组(52.61±6.75)%(P<0.05)。溶血病组患儿的住院天数[6(5,9)d]、蓝光治疗时间[62(38,84.25)h]及黄疸发病次数[9(7,13)次]均高于非溶血病组[住院天数6(4,8)d、蓝光治疗时间53(34.25,64.77)h、黄疸发病次数8(6,12)次],差异均有统计学意义(P值均<0.05)。回归分析显示,游离抗体试验阳性及胎次(二胎及以上)是蓝光治疗时间延长的独立危险因素(P<0.05)。结论 ABO血型不合是新生儿溶血病的主要病因,应对母亲为O型、新生儿为A型者,加强对该人群胆红素水平的动态监测。多次妊娠增加了同种免疫性溶血风险,临床应针对二胎及以上新生儿缩短胆红素监测间隔,并在必要时开展产前干预措施。同时,应重视血红蛋白水平、红细胞计数等指标的变化对溶血性贫血及胆红素升高的预警作用。展开更多
基金Sponsored by National Science and Technology Support Plan of China(2012BAB14B00)
文摘In order to utilize the iron resource effectively in red mud, a laboratory experiment based on the orthogonal method was carried out. Nuggets were gotten by directly reducing the carbon-bearing pellets of red mud and coal. The results showed that the strongest influencing factor is temperature, and the separation between liquid iron and slag is thoroughly. The nuggets can be gotten when the pellets, in which xC/xO is 1.6 and the basicity is 1.0, were maintained in 30 min at 1 400 ℃. The nuggets have a high TFe content which is higher than that in the hot metal produced in BF. It also has a low content of Si and Mn, but a high content of S and P. The main compositions of the slag are amorphous phase mainly containing SiO;and unreduced Fe;SiO;. Of course, a little reduced iron retains in it.
基金Sponsored by National High Technology Research and Development Program of China(2012AA06A109)
文摘To recycle residual iron efficiently in Bayer red mud, three-factor three-level orthogonal experiments on carbon-bearing pellets of Bayer red mud were conducted on the basis of their characteristics. The influences of CaO dosage, temperature and roast- ing time on total iron content and iron recovery of reduced iron powder were studied. Results showed that these factors slightly influenced iron recovery, but significantly influenced total iron content. The principal factor influencing total iron content was CaO dosage, followed by temperature and roasting time. An increase in CaO dosage could decrease total iron content, whereas an increase in temperature and an extension of roasting time could improve total iron content. The reduced iron powder with total iron content of 88.4 l% and iron recovery rate of 97.97% can be obtained under the optimal conditions of temperature of 1 275 ℃, roasting time of 60 min and CaO dosage of 7.5%. The X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses of the reduced pellets showed that iron minerals in red mud were almost completely reduced to metallic iron. The principal factor influencing the total iron content of reduced iron powder was the grain size of metallic iron particles. An increase in CaO dosage hindered the growth of metallic iron particles, whereas an increase in temperature and an extension of roasting time could neutralise the effect of CaO dosage. Therefore, CaO dosage should be decreased when iron minerals in red mud can be adequately reduced into metallic iron.
基金The authors are especially thankful to the National Natural Science Foundation of China （51374058 and 51704061 ）, China Postdoctoral Science Foundation （2016M601321 ） and Fundamental Research Funds of the Central Universities of China （N162503003）.
文摘Red mud, the waste generated during alumina production, contains iron and other valuable metals. To recover the iron efficiently from red mud, a three-factor five-level central composite design in response surface methodology was used to study the effects of process parameters, such as FC/O （the molar ratio of fixed carbon in coal to reducible oxygen of iron oxide in red mud）, reduction temperature, reduction time, and their interaction on the iron recovery rate and total iron content in magnetic product obtained from the process of direct reduction-magnetic separation. The relevant assessment model was established. The model could predict the changing rules of iron recovery rate and total iron content in the magnetic product affected by the process parameters. The results show that the iron recovery rate is significantly influenced by three factors and reduction temperature plays the most important role. The iron recovery rate and total iron content in magnetic product could be up to 98.37 and 82.52%, respectively, under the numerically optimal process parameters condition of reduction temperature of 1400 ℃, FC/O of 0.80 and reduction time of 100 min obtained by the assessment model. The predicted values are in good agreement with the experimental values.
文摘目的 回顾性分析474例高胆红素血症新生儿的临床资料,探讨ABO胎儿新生儿溶血病(hemolytic disease of the fetus and newborn, ABO-HDFN)所致高胆红素血症的临床特征及蓝光治疗影响因素。方法 本研究纳入2019年1月至2023年1月期间在兰州大学第一医院接受治疗的474例高胆红素血症新生儿作为研究对象。所有患儿均接受血型鉴定及新生儿溶血三项试验。收集并分析其基线临床资料。根据溶血三项试验结果,将患儿分为溶血性黄疸组和非溶血性黄疸组。对2组患儿的血红蛋白水平、住院时间及蓝光治疗持续时间等临床指标进行比较分析。同时,采用多元线性回归模型探讨影响蓝光治疗时间的相关临床因素。结果 474例高胆红素血症新生儿中,354例确诊为ABO-HDFN(溶血病组),120例未发生ABO-HDFN(非溶血病组)。A型新生儿中ABO-HDFN发生率(55.93%,198/354)高于B型新生儿(44.07%,156/354),差异有统计学意义(P<0.05)。此外,二胎及以上新生儿ABO-HDFN发生率(81.56%,146/179)高于首胎新生儿(70.51%,208/295),差异有统计学意义(P<0.05)。溶血病组患儿的血红蛋白水平(170.67±21.86)g/L低于非溶血病组(178.99±22.05)g/L(P<0.001),红细胞计数(4.66±0.63)×10^(12)/L低于非溶血病组(4.89±0.59)×10^(12)/L(P<0.05),红细胞压积(50.05±6.56)%低于非溶血病组(52.61±6.75)%(P<0.05)。溶血病组患儿的住院天数[6(5,9)d]、蓝光治疗时间[62(38,84.25)h]及黄疸发病次数[9(7,13)次]均高于非溶血病组[住院天数6(4,8)d、蓝光治疗时间53(34.25,64.77)h、黄疸发病次数8(6,12)次],差异均有统计学意义(P值均<0.05)。回归分析显示,游离抗体试验阳性及胎次(二胎及以上)是蓝光治疗时间延长的独立危险因素(P<0.05)。结论 ABO血型不合是新生儿溶血病的主要病因,应对母亲为O型、新生儿为A型者,加强对该人群胆红素水平的动态监测。多次妊娠增加了同种免疫性溶血风险,临床应针对二胎及以上新生儿缩短胆红素监测间隔,并在必要时开展产前干预措施。同时,应重视血红蛋白水平、红细胞计数等指标的变化对溶血性贫血及胆红素升高的预警作用。
