生物质热解特性及其还原铁精矿研究

生物质低碳环保,用于铁矿石还原可以实现钢铁企业绿色发展,为探究一种快速高效的直接还原方法,本文对其热解特性和铁精矿的还原进行了研究.结果表明,生物质在较低温度下可快速热解,热解温度为693℃时,失重率达到66.76％,最大失重速率可达7.85 min;生物质热解生成的气相产物主要有CO、CO2、CH4、C2H4、H2等...     

氮气流速对废旧电视电路板热解的影响

研究了废旧印刷电视电路板的热解,探索了氮气流速对热解产物产率和成分的影响,并采用SEM、XRF、GC、GC/MS等检测手段对热解产物进行了分析表征。结果表明,液体产率随着氮气流速的增大而减少,气体产率随氮气流速增大呈上升趋势,两者分别在0.3L/min时达到最小值10.85%和最大值14.4%。Cu、Sn和Ag等金属在固体产物中得到富集,随氮气流速增大而波动,可作为铜冶炼的原材料;H_2是气体产物中的主要成分,在氮气流速为0.3L/min时含量最大,达到68.21%,H_2、CO、CH_4的总含量在80.12%～82.39%,是富氢的优良燃气;液体产物主要产物是苯酚、4-异丙基苯酚等,可作为化工原料。废旧印刷电视电路板热解得到的气、液、固产物可实现综合高效利用。     

沥青燃料的热解特性研究

利用热重分析系统对沥青燃料的热解特性进行了详细的研究。实验在一个大气压、氮气环境下进行 ,加热速率为 5 0℃ /min和 80℃ /min。同时建立了一个描述沥青热解的分阶段一级反应模型。在该模型中 ,两个不同阶段沥青的活化能不同 ,但与加热速率变化和沥青种类无关 ;沥青热分解的频率因子与加热速率有关 ,与沥青的种类无关 ;沥青的最终挥发分产量与沥青的种类有关。通过实验结果验证 ,计算结果与实验符合得较好     

碳酸锰热解—酸洗制备高纯化学二氧化锰试验研究

研究了以软锰矿脱硫吸收液碳化所得碳酸锰为原料,通过热解—酸洗工艺制备高纯化学二氧化锰,考察了热解过程中热解温度、空气流量和热解时间对碳酸锰中锰元素形态转化及酸洗过程中洗涤温度、搅拌速度和硝酸浓度对焙烧产物中锰洗出量的影响。结果表明:在热解温度450℃、空气流量0.4 m~3/h、热解时间11 h条件下,碳酸锰热解产物中四价锰占比达54.92%;将热解产物在反应温度80℃、搅拌速度300 r/min条件下,用浓度为0.14 mol/L的硝酸溶液洗涤,产物中MnO_2质量分数可达95.79%。     

废旧电脑印刷电路板的热解特性及动力学分析

为了分析废旧电脑印刷电路板热解过程中的反应机理,研究废旧电脑印刷电路板(DN)在常规热解条件下的升温特性和热解动力学.研究发现,DN粉末主要的质量损失发生在热解温度为553～773 K时的有机物分解阶段,且可分为主要热解和残渣分解两个过程,其相应的平均活化能分别为137.12 kJ/mol和31.31 kJ/mol.通...     

生物质松木锯末中低温还原高铁拜耳法赤泥

对生物质松木锯末和烟煤还原焙烧高铁拜耳法赤泥进行对比试验研究,包括还原温度、还原时间、还原剂用量对还原效果的影响.生物质松木锯末还原高铁拜耳法赤泥所需还原温度低而且还原时间短最终还原效果较好.试验通过热分析和X射线衍射、动力学研究结果揭示出生物质松木锯末中低温还原高铁拜耳法赤泥机理.同时确定了生物质松木锯末中低温还原的最佳还原条件.研究表明生物质松木锯末为赤泥质量分数的20%,还原温度为650℃,还原时间为30 min可将赤泥完全磁化.生物质松木锯末热重试验分析表明250~375℃温度区间为锯末热解的主要阶段,350℃左右热解速率达到最大,450℃后热解反应趋于平缓;烟煤热重试验表明300~700℃温度区间为烟煤热解的主要阶段,450℃左右热解速率达到最大,650℃后热解反应趋于平缓.动力学研究表明锯末在300~400℃区间热解表观活化能比烟煤热解表观活化能要低很多,说明在此温度范围内锯末比烟煤更加容易发生热解反应.生物质能够中低温还原高铁拜耳法赤泥,还原温度比煤基还原的还原温度低200℃左右.     

氧烛中锰金属粒径对氯酸钠热解的催化作用

分别制备了两组粒径的Mn金属燃料(平均粒径分别为18.73和5.24 μm),利用激光粒度分析仪测试了其粒径分布,扫描电镜分析了表面形貌,能谱仪确定了所含元素.对NaClO₃,NaClO₃与Co₃O₄,NaClO₃、Co₃O₄与Mn的混合物分别进行了热重与示差扫描量热联合分析实验(TGA-DSC),通过对比各混合物热解起始温度及其他特征温度,探究了Mn金属粒径对NaClO₃热解的催化强度与热解稳定性的影响.研究结果表明:Co₃O₄虽对NaClO₃热解具有催化性,热解开始温度(T_o)由512.3℃下降为333.0℃,但其可导致NaClO₃热解的不稳定,热解阶梯由1个变为3个;Mn金属燃料对NaClO₃中间产物具有明显的催化性,且随着粒径减小,催化强度逐渐增加,热解终止温度(T_f)由419.8℃下降为351.9℃,同时NaClO₃热解阶梯减少,热解温度区间变窄(由180.6℃减小为19.4℃),热解更加稳定.     

毛细管柱气相色谱法测定粗蒽中蒽和菲

选用N,N-二甲基乙酰胺为溶剂溶解样品,采用外标法进行定量,建立了毛细管柱气相色谱法测定粗蒽中蒽和菲的方法。实验确定了色谱柱的程序升温条件为:柱温起始温度120 ℃,保留4 min;再以40 ℃/min升温至180 ℃,保留5 min;再以40 ℃/min升温至200 ℃,保留5 min。采用实验方法测定蒽和菲的含量,蒽和菲在10～100 mg/L范围内呈良好的线性关系,蒽和菲的检出限分别为2.12×10^-2 mg/L和1.76×10^-2 mg/L。将方法应用于3个粗蒽样品中蒽和菲的测定,结果的相对标准偏差(RSD, n=8)为0.59%～1.3%。对6个粗蒽样品按照实验方法进行分析,测定结果与紫外分光光度法测定菲含量及化学滴定法测定蒽含量的结果基本一致。     

闪锌矿氧化氨浸行为研究

在NH_3-(NH_4)_2SO_4体系中,采用氧化氨浸出工艺研究了不同氧化剂(Na_2S_2O_8和BaO_2)对闪锌矿氧化氨浸行为的影响。结果表明,在110℃、常压、总氨浓度4mol/L、[NH_3]/[NH_4~+]=5/3、转速500r/min、液固比25、粒度0.063mm、浸出时间4h的条件下,以Na_2S_2O_8和BaO_2为氧化剂时,锌浸出率分别为28.4%和82%。     

富集渣中钽的回收提纯研究

以钽富集渣为原料,进行了浸出及萃取试验研究。结果表明:采用65%HF浸出、温度60℃、时间1h、液固比4∶1,钽浸出率大于99%;选用MIBK-HF-H2SO4萃取体系,在钽质量浓度25g/L、温度25℃、萃取时间3min,H2SO4浓度2.5mol/L、相比O/A=1/2时,钽、铪、钛、钨萃取率分别为86%、1.6%、0.2%和5.8%,可实现钽与铪、钛、钨等金属离子的萃取分离。     

锚杆及木柱联合支护采矿法

蓬莱市大柳行金矿庄官矿区3号脉上盘围岩不稳固，应用普及浅孔留矿采矿法开采，矿石贫化、损失指标一直很高。1998年底试验采用锚杆、木柱联合支护采矿法后，获得了满意的效果。损失率由过去的31％－52％降到12％，贫化率由47％－75％降到20％。     

Pneumoconiosis and exposure to wood

The authors report a case of an employee in the wood processing industry. The clinical presentation was respiratory with dyspnoea on effort. The chest x-ray showed bilateral interstitial changes. Following bronchioalveolar lavage electron microscopic studies showed evidence of silica particles. Respiratory function tests showed pulmonary performance of 51%-64% of theoretical values depending on the test used. His working position involved the up keep of the boilers and also the drainage of the silos for wood dust. The wood used was corupixa, a brazilian wood containing crystalline silica; 0.1% in fresh wood dust. Numerous analyses have specified the percentage of silica in the ashes in magma. The diagnosis of pneumoconiosis of the silicotic type was sustained. The occupational risk linked to using this type of wood should be understood and the need to take protective measures for the employees concerned.     

Contact eczema caused by pine wood

A 34 year-old woman, working with pine wood treated with sodium hydroxide and pyrogallol, developed dermatitis on arms, face and neck. Patch testing showed allergic reaction to colophony and pine wood, but not to sodium hydroxide or pyrogallol. Pine wood contains colophony. Since avoiding pine wood, she has had no further attack of dermatitis.     

钢梁结构井架在竖井改造中的应用

主要阐述了钢梁结构井架的优缺点 ,介绍了钢梁结构井架在夹皮沟金矿二道沟分矿竖井改造中的应用及其材料消耗和施工工艺。     

Thermal Behavior and Kinetics of Raw/Pyrolytic Wood and Coal Blends during Co-combustion Process

The thermal properties of raw wood (RW)biomass,corresponding pyrolytic wood (PW)biomass,and their blends with anthracite coal (AC)were evaluated under combustion conditions with a thermogravimetric analysis (TGA)method.The blending ratios of the biomass with AC ranging from 0 to 100 mass% were taken into consider-ation to investigate the thermal behavior and kinetics of these blends during their co-combustion.For blends with dif-ferent ratios of the RW to AC and 100% AC (100 AC),two distinct mass loss peaks related to the release or com-bustion process of the volatiles and the combustion of the char were noted.The addition of a higher ratio of RW or PW into AC can improve the combustion process of the blends.The thermal behavior of the RW/AC or PW/AC blends could not be characterized by a simple linear correlation of their pure material thermal behavior.With the RW/PW addition ratios varying from 25 mass% to 80 mass%,the apparent activation energy of the blends gradually decreased from 48.46 to 34.93 kJ/mol and from 82.74 to 37.81 kJ/mol for the RW/AC and PW/AC blends,re-spectively,with high correlation coefficient (R2 )values ranging from 0.995 6 to 0.998 4.     

设备基础预留螺栓孔施工的几种方法——鞍钢1780热连轧技改工程专题报道之十二

实践中摸索出了几种制模、取模的方法 ,经工程使用 ,效果较好 ,节省了劳动力 ,保证了质量。对具体做法作了介绍 ,可供各单位施工设备基础预留螺栓孔时参考。     

Tissue residues of dietary cadmium in wood ducks

One-week-old wood ducks were fed cadmium in diets containing 18 or 30% protein for a period of three months. Seven drakes from each group were sacrificed, and blood, brain, muscle, kidney, liver, and wing feather tissues were collected and analyzed for cadmium. Highest cadmium concentrations were found in the kidney, liver, and feather tissues; blood, muscle, and brain cadmium residue levels were undetectable. Except in the kidney tissue, protein level of the diet did not affect cadmium residue levels. For birds that were changed to a cadmium-free, high-protein ration at 13 weeks of age, regression analysis indicated a significant decrease in cadmium residue levels for the kidney tissue only. Growth, as measured by bodyweight at 13 weeks of age, was not affected by the various cadmium treatment levels. Histopathological examination revealed lesions in the kidney tissues of the 100 ppm cadmium treatment groups, which were more severe in those birds receiving the 18% protein diet. Vacuolation of the pancreatic acinar cells was observed in all groups, but tended to occur more frequently in the higher cadmium level groups.     

Intraorbital wood foreign body mimicking air at CT

Computed tomography (CT) revealed a 2-cm linear area of extremely low attenuation in the left orbit of a boy who had been poked in the eye with a tree branch. The appearance and attenuation of the area suggested air, so a diagnosis of orbital emphysema was initially considered. Further research indicated that wood mimics the CT attenuation and appearance of air. A wood splinter was surgically removed from the orbit.