Immobilization of A cidithiobacillus ferrooxidans and ferric iron production

1 Introduction Acidithiobacillus ferrooxidans is a kind of Gram negative, aerobic, acidophilic and chemolitho- autotrophic bacteria which is mainly applied in bioleaching of sulphide ores for metal recovery[1]. Compared with the traditional metallurgy techniques, biohydrometallergy technology has the advantages of short process, less energy consumption, environment friendly and lower cost. Thus, biohydrometallurgy is one of the most important aspects in the process of sulphide ores. A. ferro…     

含砷铁矿石脱砷过程的热力学

采用HSC Chemistry 5.0热力学分析软件研究不同气氛和温度条件对华南含砷铁矿石中砷平衡组成及脱砷率的影响,并结合实验进行验证.结果表明:在惰性气氛中,增加Ar及初始As含量能降低体系的O2分压、提高脱砷率；在还原性气氛中,铁矿石脱砷体系气氛需要适宜的CO含量.当CO含量较高时,O2及CO2能削弱体系的强还原性气氛,促进脱砷；当CO含量较低时,O2的存在不利于脱砷,但CO2的影响微弱.不论在何种气氛中,提高温度均有利于脱砷,实验结果与热力学分析结果基本吻合.在氧化性气氛或强还原性气氛中,由于受动力学条件的限制,仍能获得一定的脱砷率.     

钢铁中温黑色磷化新工艺

介绍了一种Zn-Ni系黑色磷化新工艺。它可在50－60℃下形成均匀细致、耐蚀性好、具有防腐装饰、减摩、吸光、消光、吸散热、绝缘等优良性能的黑色磷酸盐转化膜,且工艺稳定、流程简单、成本低廉,成膜速度快。     

单片机控制温度的一种新型电烙铁

介绍了一种采用单片机控制的新型电烙铁,给出了单片机控制系统的组成及工作原理,通过使用该电烙铁,可使操作更加便捷、安全,同时也可节约一部分能源。     

A new method for chill and shrinkage control in ladle treated ductile iron

P revious investigations have shown that rare earth metals (REM) such as cerium (Ce), lanthanum (La), praseodymium (Pr) and neodymium (Nd) can either have a beneficial or a detrimental effect on the microstructure and properties of ductile iron, depending on the casting conditions. For example, small additions of REM are frequently used to restore the graphite nodule count and nodularity in ductile irons containing subversive elements such as Sb, Pb, Ti etc [1-3]. On the other hand, rare …     

Effect of arsenic on spatial pattern of radial oxygen loss and iron plaque formation in rice

The effects of different arsenic (As) treatments on spatial pattern of radial oxygen loss (ROL), iron (Fe) plaque formation and As accumulation in rice were investigated using three rice genotypes, planted under greenhouse conditions. Arsenic was applied to soil at 50 and 100 mg/kg, with untreated soil used as a control having an average As concentration of 8.5 mg/kg. It was demonstrated that the ratio of ROL in root tips to that at the root base slightly decreased with increasing As concentration, suggesting that the spatial ROL patterns in these groups may be shifted from the “tight” barrier towards the “partial” barrier form. Furthermore, increasing As concentration led to a increase in Fe plaque formation on root surfaces. In addition, root As concentrations of genotypes in 50 and 100 mg/kg As treatments were significantly higher than that of control treatment (P<0.05). Grain As concentration of genotype Nanyangzhan (with lower ROL) was significantly higher (P<0.05) than that of genotype CNT87059-3 with higher ROL.     

新型含铝高铬铸铁的耐热腐蚀性能研究

对比研究了新型含铝高铬铸铁的高温耐腐蚀性能。利用失重法测绘了合金的腐蚀动力学曲线;用扫描电子显微镜对热腐蚀后氧化膜(腐蚀膜)的形貌进行观察,并分析其化学成分分布;借助旋转阳极衍射仪对热腐蚀产物进行物相分析;并讨论了新型含铝高铬铸铁的热腐蚀机理。结果表明,与普通高铬铸铁相比,在长时间高温热腐蚀过程中,新型含铝高铬铸铁表面的氧化膜具有更好的完整性和致密性,使得基体在热腐蚀过程中一直保持很低的腐蚀速率,使腐蚀介质无法扩散到基体,不易造成进一步腐蚀破坏。     

A high Cr-Mo alloy iron

The structure, hardness, abrasion, and erosion wear of Cr-Mo white iron (containing approximately 28 % Cr and 1 % Mo) heat treated at certain temperatures were studied. Results show that the heat treatment of white iron changes the structures and properties; that is morphology, amount, size, and distribution of secondary phases are affected. When white iron was heated at 800 to 850 ‡C the secondary phase precipitated at the phase boundary, making the abrasion and erosion wear worse. When the iron was heated at 900 to 950 ‡C, the secondary phase precipitated dispersively at the matrix, and the corrosion wear was optimum. If the iron is heated at 1000 to 1050 ‡C, the resistance of abrasion is inhibited, as the secondary phases precipitate in large amounts, and the hardness is increased. When the white iron is tempered at 500 to 600 ‡C, the resistance of abrasion is better.     

A study on controlled cooling process for making bainitic ductile iron

In the present research, TTT curve of bainitic ductile iron under the condition of controlled cooling was generated. The cooling rate of grinding ball and its temperature distribution were also measured at the same time. It can be concluded that the bainitic zone of TTT curve is separated from the pearlitic zone. As compared to the water-quenching condition, more even cooling rate and temperature distribution can be achieved in the controlled cooling process. The controlled cooling can keep away from pearlitic zone in the high temperature cooling stage and produce similar results to the process of traditional isothermal cooling with a low cooling rate in the low temperature cooling stage.     

铝合金铁相团球化熔剂的研制

研制了一种铝合金铁相团球化熔剂，在含铁量较高（１．０％－４．０％Ｆｅ）的铝合金中加入该熔剂后，可使针片状的铁相变为团球状或颗粒状组织。从而大幅度提高原合金的机械性能，δｂ和δ分别提高２０％－９０％和４０％－１００％。生产实验表明：该熔剂团球化效果好（具有长效性），极便于在生产中推广应用。     

A study of electrical chloride extraction of iron artifacts

The chloride extraction rule of iron artifacts was studied by electrical methods. The effect of the current and potential value on the desalination result of simulated iron artifacts was studied through the galvanostatic and potentiostatic experiments; the ingredients of the rust before and after treatments were also analyzed by the X‐ray diffraction (XRD). It has been found that the optimal current density was between ?0.50 and ?0.75 mA/cm² and the optimal potential was between ?1.175 and ?1.200 V. The phase of the samples rusts transformed after treatment, as well as the anti‐corrosion performance improved.     

Corrosion behavior of iron thin film in deaerated phosphate solutions by an electrochemical quartz crystal microbalance

The corrosion rates of iron thin film in deaerated phosphate solutions were measured by an electrochemical quartz crystal microbalance as a function of solution pH or phosphorus concentration in solutions. The dependences of corrosion rate and corrosion potential on solution pH and phosphorus concentration have suggested that the corrosion mechanism changes in the vicinity of pH 5 and H₂PO₄⁻ contributes to both anodic dissolution of iron and hydrogen evolution. The corrosion mechanism which contains iron-phosphate-hydroxide complex ion as an adsorbed intermediate was proposed to explain the experimental results.     

灰铸铁磷化工艺研究

灰铸铁经成分不同的中温磷化液处理后，磷化膜层的 结晶形态差别较大.分析认为Zn-Ca系比较适合用于灰铸铁的磷化，所处理的工件色泽呈深灰到黑色，耐蚀性好，溶液稳定，沉渣少.     

Kinetics of crystal growth on seeded precipitation of sodium aluminate solutions with new device

A new device was designed, which can effectively avoid the undesired nucleation and agglomeration of fine particles on the experimental results during the seaded precipitation of sodium aluminate solution, and moreover, the experimental conditions are nearly kept constant during the experiment. With the new device, it is proven that a good result can be obtained on the kinetics study of the crystal growth in seeded precipitation of sodium aluminate solution. Experiments were carried out with the concentration of Na2O (Nk)170 g/L, the mole ratio of Na2O to Al2O3(ak) all between 1.52 to 2.01, at 65, 70, 75℃, respectively. And the kinetics equation of crystal growth of gibbsite was deduced.     

烧结添加剂和晶种对新型陶瓷刚玉磨料烧结的影响

本文对烧结添加剂和晶种对新型陶瓷刚玉磨料烧结的影响进行了研究。研究结果表明：晶种的加入能有效地促进刚玉磨料的烧结,细化晶粒,使晶粒粒度分布范围较窄;烧结添加剂的引入能更有效地促进了烧结过程的进行,提高磨料单颗粒抗压强度,同时抑制晶粒的长大;烧结添加剂和晶种的复合添加对于促进刚玉磨料的烧结和提高磨料颗粒的强度作用最为明显,得到的晶粒更细（平均约150nm）。     

新型含碳化物马氏体球墨铸铁的热处理工艺

设计了一种新型含碳化物马氏体球墨铸铁材料,并对该材料进行了不同奥氏体化温度的热处理。结果表明：经不同温度奥氏体化后,新型铸铁的组织均为细针状马氏体+孤立分布的硼-铬碳化物+球状石墨组织。奥氏体化温度在820～890 ℃范围变化时,随奥氏体化温度的升高,该铸铁的硬度增大,冲击韧度减小;奥氏体化温度高于890 ℃时,硬度和冲击韧度均减小。奥氏体化温度为890 ℃时,试验铸铁硬度和冲击性能达到良好的匹配。     

Oil quenched malleable iron,the strength of an old material in a “green cast” development and a new future

Malleable iron lost the interest and the development stopped in the turbulent seventies of tremendous developments of new technologies.The personal computer,emission spectrometer,thermal analysis,cold-box core system and automatic vertical moulding were introduced into the foundry industry.Experience shows that these new technologies do not always match up with malleable iron.Solidification and mould filling simulation programs are not always capable to handle a low carbon equivalent iron like malleable iron.Recent developments show however by using these new technologies and combined with practical experience,it is possible to increase the casting yield of malleable iron to the same level as ductile iron.The mechanical properties,especially the yield strength of malleable iron according to the standard are equivalent to those of ductile iron,however the yield strength of oil quenched malleable iron is significantly higher than that of ductile iron.An extensive investigation is made between ductile iron,air quenched and oil quenched malleable irons based on the properties of more than 350 test bars produced under the same conditions.The results are compared with the existing international standards and discussed.Other properties like fatigue strength and response to surface treatments as induction hardening are also discussed.The costs of malleable iron are reviewed and compared with other ferro alloys.These recent developments in increasing the casting yield,the understanding of the strength,makes malleable iron competitive with ductile iron and cheaper than the first grade of ausferritic ductile iron,or steel qualities.It is possible to design lighter and save weight which is essential in the automotive industry.An example of"green cast"development for typical applications,used in automotive transmissions and engines are shown.     

铸态铁素体低碳球墨铸铁的研究

对铸态铁素体低碳球墨铸铁进行了研究.试验中所选择低碳球墨铸铁的化学成分为:1.2%～2.2%C,2.8%Si,＜0.4%Mn,＜0.05%P,＜0.04%S.铁液采用无芯感应电炉熔炼后,铁液的出炉温度控制在1480～1550℃之间,经过主要由某些公认的反球化元素组成的Sx变质剂进行一次性变质处理.本文分析了铁液的化学成分、变质剂的种类和加入量对铸态铁素体低碳球墨铸铁形成的影响.试验的结果表明:当C1.2%～1.8%,Sx1变质剂的加入量为0.8%或1.0%,可以得到球状石墨 珠光体 少量铁素体组织,Sx1加入量为1.2%,基体中无球状石墨,而且随着含碳量和变质加入量的提高铁素体数量基本不变.当C2.0%～2.2%,Sx1和Sx2变质剂都不能使石墨球化,Sx3变质剂加入量为0.8%,石墨被部分球化;Sx3加入量为1.2%,基体中无球状石墨,Sx3入量为1.0%,可以得到球化良好,铁素体数量大于85%和少量珠光体组织的低碳球墨铸铁,其机械性能主要为:σb≈400MPa、δ≈15%、αk≈22J/cm2,HB≈200.     

离子型稀土矿中铝铁杂质的浸出与抑制规律

通过红外光光谱测定、XRD检测等测试方法分析了稀土矿浸出过程中各种矿物表面性质的变化,稀土离子及铝、铁杂质离子与浸出剂和抑制剂的浸出交换过程及规律。结果表明,抑制剂的添加会与稀土矿中的铝、铁等杂质离子反应,形成化合物,从而降低浸出母液中铝、铁杂质离子含量,但不会影响离子型稀土的交换浸出过程。在机理分析的基础上,采用对铝铁杂质有高效抑制效果的抑杂剂LG-01进行离子型稀土矿抑制铝铁杂质的浸出实验研究。结果表明,在不影响离子型稀土矿稀土离子浸出率的情况下,LG-01能有效降低离子型稀土矿浸出母液中铝、铁等杂质离子含量,去除率可达92%。     

新型Fe72.7Si17B6.8Nb2.6Cu0.9纳米晶铁芯的磁场热处理工艺与软磁性能

为满足高频变压器对铁芯低损耗的需求,研究了新型Fe_72.7Si₁₇B_6.8Nb_2.6Cu_0.9纳米晶铁芯的热处理工艺,探讨了铁芯动态、静态软磁性能随无磁场退火保温时间与施加不同磁场强度的横磁磁场退火时的变化规律。结果表明,不加磁场时,保温时间为60 min时铁芯的损耗最低,为P_{20 kHz/0.5 T}=11.82 W/kg,而其静态软磁性能在保温30 min处于最优状态,H_{c30 min}=1.86 A/m。施加横向磁场后,其直流磁性能剩磁和矫顽力显著降低,H_{c40 mT}=0.64 A/m,而其损耗在磁场强度为50 mT达到最低,为P_{20 kHz/0.5 T}=10.53 W/kg。高频范围内涡流损耗在铁芯损耗中起主导作用,新型纳米晶铁芯经横向磁场热处理后高频损耗大幅降低,同时磁导率表现优异。