硫铁矿废水制备铁黑颜料的工艺

采用湿法氧化沉淀法,通过调节反应溶液初始pH值(7～12)、反应温度(70～95℃)、反应时间(1～4.5h)和搅拌速度(50～250r/min),探索了硫铁矿废水制备铁黑颜料的工艺条件。结果表明:在pH值为9.5、反应温度为85℃、反应时间为2.5h、搅拌速度为150r/min的条件下,能制备得到较优的铁黑颜料。其经XRD、SEM及铁黑颜料技术指标检测分析,表明该铁黑颜料粒径在60nm左右,Fe3O4含量在95%以上,各项指标均能达到氧化铁黑颜料行业标准中一级品的要求。     

铁粉硫化产物氧化自燃性研究

模拟含硫油品储罐硫腐蚀铁生成硫铁化物的过程,对生成硫铁化物的氧化自燃性进行研究,考察了铁粉含水量、硫化反应时间及蓄热条件对硫化反应产物自然氧化升温的影响,通过氧化升温速率和最高温度值评价其氧化自燃性。结果表明,硫化反应产物能自然氧化升温,并且在最高氧化升温处极易形成温度平台区;随着硫化反应时间的延长,硫化反应产物初期自然氧化升温速率增加,当硫化反应时间超过6 h后,再延长硫化时间对其初期氧化升温速率影响不大;铁粉试样的含水量对硫化反应产物的自燃性有重要影响,干燥铁粉试样的硫化反应产物自燃性低,铁粉试样中的适量水可以增加硫化反应产物的自燃性;蓄热条件好,反应放出的热量散失少,硫化反应产物的自燃性高。     

铁粉硫化产物氧化自燃性研究

模拟含硫油品储罐硫腐蚀铁生成硫铁化物的过程,对生成硫铁化物的氧化自燃性进行研究,考察了铁粉含水量、硫化反应时间及蓄热条件对硫化反应产物自然氧化升温的影响,通过氧化升温速率和最高温度值评价其氧化自燃性。结果表明,硫化反应产物能自然氧化升温,并且在最高氧化升温处极易形成温度平台区;随着硫化反应时间的延长,硫化反应产物初期自然氧化升温速率增加,当硫化反应时间超过6 h后,再延长硫化时间对其初期氧化升温速率影响不大;铁粉试样的含水量对硫化反应产物的自燃性有重要影响,干燥铁粉试样的硫化反应产物自燃性低,铁粉试样中的适量水可以增加硫化反应产物的自燃性;蓄热条件好,反应放出的热量散失少,硫化反应产物的自燃性高。     

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren

The effect of iron fortification is generally assumed to be less than iron supplementation; however, the magnitude of difference in effects is not known. The present study aims to compare the efficacy of these two strategies on anaemia and iron status. After screening on low Hb, 425 anaemic children in six primary schools in Tam Nong district of Phu Tho province were included in a randomized, placebo-controlled trial comparing two groups receiving iron fortified instant noodles or iron supplementation for 6 months and a control group, with children in all groups having been dewormed. Blood samples were collected before and after intervention for haemoglobin, serum ferritin (SF), serum transferrin receptor (TfR), C-reactive protein (CRP), and haemoglobinopathies analysis. Regression analysis was used to assess the effect of iron fortification and iron supplementation on haemoglobin concentration, SF, TfR, body iron, and anaemic status as outcome variables. The improvement of haemoglobin, SF, and body iron level in the group receiving iron fortification was 42% (2.6 g/L versus 6.2 g/L), 20% (23.5 μg/L versus 117.3 μg/L), and 31.3% (1.4 mg/kg versus 4.4 mg/kg) of that in the iron supplementation group. The prevalence of anaemia dropped to 15.1% in the control group, with an additional reduction of anaemia of 8.5% in the iron supplementation group. The additional reduction due to iron fortification was 5.4%, which amounts to well over 50% of the impact of supplementation. In conclusion, the efficacy of iron fortification based on reduction of prevalence of anaemia, and on the change in haemoglobin level, is about half of the maximum impact of supplementation in case of optimal compliance. Thus, in a population of anaemic children with mild iron deficiency, iron fortification should be the preferred strategy to combat anaemia.     

Efficacy of iron fortification compared to iron supplementation among Vietnamese schoolchildren

Background  

Parents of six children are facing a trial on charges of aggravated manslaughter in the care a 5 1/2 month old infant who died suddenly and neglect of their four older children for causing them to be malnourished by feeding them all an exclusively raw foods vegan diet. Both parents declined plea bargains and plan to defend themselves in court.     

Tris(dithiocarbamato)iron(III) complexes as precursors for iron sulfide nanocrystals and iron sulfide-hydroxyethyl cellulose composites

Iron(III) complexes of dimethyldithiocarbamate and imidazolyl dithiocarbamate were synthesized and characterized by elemental analyses, FTIR, UV–VIS and the ligands by NMR spectroscopy. The complexes were thermolysed as single molecule precursors at 180°C to prepare octadecylamine (ODA) capped iron sulfide nanocrystals and iron sulfide-hydroxyethyl cellulose (HEC) composites. UV–VIS, PL, FTIR, P-XRD, HRTEM, FESEM and EDS were used to characterize the iron sulfide nanocrystals and corresponding HEC nanocomposites. XRD confirmed iron sulfide nanocrystal (NP1) from dimethyldithiocarbamate to be hexagonal pyrrhotite-5H, Fe₉S₁₀ crystalline phase while iron sulfide nanocrystals (NP2) from imidazolyl dithiocarbamate is in pyrrhotite, Fe₁₁S₁₂ crystalline phase. TEM images show that the iron sulfide nanocrystals have particle sizes in the range 24–32?nm for NP1 and 18–25?nm for NP2 iron sulfide nanocrystals. The optical band gaps of the iron sulfide nanocrystals obtained from Tauc plots are 3.83 and 4.16?eV for NP1 and NP2, respectively. IR spectra, FESEM surface morphology and EDS spectra of iron sulfide/HEC composites confirmed dispersion of the iron sulfide nanocrystals within the hydroxyethyl cellulose (HEC) matrix.     

铁泥氧化制备颜料铁红的研究

以工业废渣铁泥为原料,经拌酸氧化制备铁红颜料,探讨了酸的种类、浓度及用量和氧化温度及时间对产品质量的影响。结果表明,较佳的工艺条件为:硫酸浓度60%,硫酸与铁泥质量比1∶1.2,氧化温度800℃,氧化时间2.0 h,得铁红产品,质量符合油漆、涂料等对铁红颜料的要求。     

用唐钢石人沟铁精矿生产超级精矿

以石人沟铁矿精矿粉为原料生产超级铁精矿，进行了磨矿—反浮选、分级—反浮选和分级—低磁场磁选等试验，并按磨矿—反浮选方案建成了生产超级铁精矿的选矿厂。实践证明阳离子反浮选是生产低硅高纯铁精矿的可靠工艺。     

由含铁酸洗废液制备钾铁蓝的研究

以含铁酸洗废液为主要原料,用铁粉对其作除酸处理后,与亚铁氰化钾反应,生成白浆,用氯酸钾氧化,经过滤、洗涤、干燥、研磨,制备出了深蓝色无机颜料——钾铁蓝。通过正交实验和单因素分析,研究由含铁酸洗废液制备钾铁蓝的最佳工艺条件。结果表明,在Fe2+和亚铁氰化钾的量比1.15∶1,反应温度90℃,含铁酸洗废液p H=1,相对酸度为3的反应条件下,得到了含铁量为30.32%,吸油量为0.45 m L/g的钾铁蓝产品,颗粒大小均匀,粒径100²00 nm,钾铁蓝的结构与Fe4[Fe(CN)6]3相似,且各项指标均符合化工行业标准HG/T 3001—1999。     

由含铁酸洗废液制备钾铁蓝的研究

以含铁酸洗废液为主要原料,用铁粉对其作除酸处理后,与亚铁氰化钾反应,生成白浆,用氯酸钾氧化,经过滤、洗涤、干燥、研磨,制备出了深蓝色无机颜料——钾铁蓝。通过正交实验和单因素分析,研究由含铁酸洗废液制备钾铁蓝的最佳工艺条件。结果表明,在Fe2+和亚铁氰化钾的量比1.15∶1,反应温度90℃,含铁酸洗废液p H=1,相对酸度为3的反应条件下,得到了含铁量为30.32%,吸油量为0.45 m L/g的钾铁蓝产品,颗粒大小均匀,粒径100~200 nm,钾铁蓝的结构与Fe4[Fe(CN)6]3相似,且各项指标均符合化工行业标准HG/T 3001—1999。     

Enamel for cast iron

Data on the effect of the components of grey cast iron on its capacity for being enameled are generalized. A composition of enamel for cast iron is suggested and its manufacturing technology is described. The physicochemical properties of the enamel are investigated.Translated from Steklo i Keramika, No. 4, p. 27, April, 1995.     

Acceleration of zinc corrosion in alkaline suspensions containing iron oxides or iron hydroxides

Fast zinc dissolution is of industrial interest in recycling galvanised steel scraps. An acceleration of zinc corrosion in alkaline solutions was observed in the presence of various iron oxides or iron hydroxides. This corrosion was investigated by weight loss, measurements of hydrogen evolution and variation of current in a galvanic cell. The mechanism of this fast zinc corrosion was investigated by electrochemical means and by X-ray diffraction and scanning electron microscopy observations of zinc surface after immersion in alkaline suspensions of iron oxides or iron hydroxides. These insoluble iron compounds were involved in a reduction step leading to iron containing microparticles characterised by a low hydrogen overpotential and which acted as cathodic areas in a galvanic corrosion of zinc.     

钢铁件涂装前铁系磷化工艺研究

通过正交试验优选出一种新的常温铁系磷化工艺:氧化锌0.5g/L,磷酸5mL/L,酒石酸0.5g/L,马日夫盐0.5g/L,氟钛酸5.0g/L,氟锆酸1.5g/L,铬明矾5.0g/L,硫脲2.0g/L,钼酸钠0.75g/L,成膜时间6.0min。该磷化液游离酸度为3,总酸度为17。经此磷化液磷化后的冷轧钢铁试片表面磷化膜的致密性和耐腐蚀性与普通铁系磷化相比均有提高,耐硫酸铜点滴时间达50s,后续漆膜的附着力为0级,冲击强度为50kg·cm。该磷化液不含亚硝酸钠,可常温处理,沉渣少,成本低,可与各种涂装工艺配合使用。     

黄钠铁矾渣及其浸取液中铁的测定

黄钠铁矾渣中铜的含量较高,用重铬酸钾容量法来测定其中的铁时,干扰铁的测定,需预分离才能准确测量。但在用铁还原法浸取黄钠铁矾渣后的浸出液中,由于部分铜被除去,铜的含量降低,不干扰铁的测定,无须预分离,直接测定。试验结果表明,当铜的含量占铁量的4%时,干扰铁的测定。