流态化气基还原高铝铁矿的研究

利用可视流化床,研究了流态化气基还原高铝铁矿的粘结行为和还原过程。结果表明,温度低于1223 K时,由于矿石铝铁相互嵌布的复杂结构,流态化还原高铝铁矿没有发现粘结失流现象。但是,当温度高于1223 K时,由于局部复杂相出现液相或软化,气基流化还原过程发生了粘结失流。流态化气基还原高铝铁矿,其金属化率高达30%以上。热力学分析表明,只有当CO/(CO+CO2)高于99%时,CO才可以将FeO·A1_2O_3和2FeO·SiO_2进一步还原,从而造成气基还原高铝铁矿金属化率提高困难

Heavy Metal Contamination and Health Risk Assessment in the Zinc Mine Set Area of Youxi,China

为研究典型铅锌矿集区的重金属分布情况,同时对居民区的潜在健康影响程度进行评价,采用现场采样及室内测试方法对尤溪铅锌矿集区内表层土壤中5种重金属(铬、铜、汞、锌、铅)的含量进行分析,同时应用非致癌风险模型对5种重金属进行了健康风险评价.单因子健康风险评价结果表明,铬、铜、汞、锌的健康风险指数在10-2~10-3水平,对当地居民身体健康不会产生危害.铅的平均健康风险指数为0.529,表明人均铅摄入量接近美国EPA公布的慢性参考值;在梅仙东南部矿区出现最大值(2.30),可能会对当地居民身体健康产生不利影响.健康总风险评价结果显示,梅仙镇采矿区和选矿区的健康风险指数均大于1,且铅所引起的健康风险占总健康风险比例最大,说明该地区存在以铅污染为主的重金属污染.越靠近矿区,重金属污染对周围居民人体的健康风险越大.该地区来源于矿冶活动的健康风险远远高于来源于尾气排放(汽油燃烧)的重金属健康风险,成为当地铅锌污染的主要来源.This study focused on the heavy metal contamination and health risk assessment of Cr,Cu,Hg,Zn and Pb in the typical zinc mine set area of Youxi,Fujian province,China.The results of single factor assessment showed that the health risk indexes of Cr,Cu,Hg,Zn were in the range of 10-2-10-3,which will not cause harm to the health of local residents.The mean health index of Pb was 0.529,indicating the intakes of Pb was close to the chronic reference level proposed by EPA in the USA;the maximum(2.30) emerged in the mine area of southeast Meixian town,exceeding the chronic reference level.The results of total assessment showed that the mean health index in the mining area of Meixian town was more than 1,and the health risk caused by Pb occupied the largest proportion of total health risk,showing the existence of heavy metal pollution in the region,especially the Pb contamination.The heavy metal environmental quality near to the mining area had higher risk and might bring potential risk to local residents.The health risk caused by mining activities is much larger than that caused by exhaust emissions of vehicle.Compared with exhaust emissions,mining activity is a major source of Pb and Zn pollution.福建省国土资源厅专项基金(FJDZHJ50309);中国地质调查局项目基金(1212010310307

变载荷激励下含裂纹风电行星轮系疲劳强度分析

随机风载引起的外部激励会极大地影响风电传动系统的疲劳寿命。利用考虑尾流效应的四分量模型模拟风电场随机风速，结合有限元法分析得到风电行星轮系的疲劳寿命。在此基础上，基于子模型法研究了太阳轮单齿和双齿根裂纹深度、长度和延伸角对风电行星轮系疲劳强度的影响。最终发现裂纹尺寸参数对风电行星轮系疲劳寿命的影响程度为：裂纹深度>裂纹长度>裂纹延伸角。双齿根裂纹对疲劳寿命的影响远大于单齿根裂纹的影响，且双齿根裂纹状态下先啮入齿的疲劳寿命远小于单齿根裂纹状态，后啮入齿疲劳寿命略大于单齿根裂纹状态。相关研究为优化风机服役性能提供了理论依据