Feasibility and cost of creating an iron-phosphate coating on pyrrhotite to prevent oxidation

 Acid mine drainage (AMD) occurs when sulfide minerals are exposed to an oxidizing environment. Most of the methods for preventing AMD are either short-term or high cost solutions. Coating with iron phosphate is a new technology for the abatement of AMD. It involves treating the sulfide with a coating solution composed of H₂O₂, KH₂PO₄, and sodium acetate as a buffer agent. The H₂O₂ oxidizes the sulfide surface and produces Fe³⁺ so that iron phosphate precipitates as a coating on the sulfide surface. Experiments performed under laboratory conditions prove that an iron phosphate coating can be established on pyrrhotite surfaces with optimal concentrations of the coating solution in the range of: 0.2M/0.01M H₂O₂, 0.2M KH₂PO₄, and 0.2M sodium acetate NaAc, depending on the experimental scale. Iron phosphate coating may be a long-term solution to the problem of AMD. The method would be easy to implement; the reagent cost, however, is not low enough, although it is lower than the conventional treatment with lime. Received: 30 March 1995 · Accepted: 6 September 1995     

磷对金刚石增强型硬质合金复合齿性能的影响

在金刚石增强型硬质合金复合齿基体中添加不同量红磷，可降低复合齿烧结温度，实现低温活化烧结。研究表明：添加0．3％(ωB)P的复合齿基体性能最好，采用化学镀Ni-P合金添加P和球磨添加0．1％P的方式，复合齿超硬部分的磨耗比和复合齿的抗冲击功优于单纯通过球磨添加0．3％P的超硬复合齿。为了实现金刚石增强型硬质合金复合齿的低温活化烧结，磷元素最优的添加方式是化学镀结合球磨的添加方式。     

国际油气井钻头进展概述 (四)——PDC钻头发展进程及当今态势（下）

近年来,非平面PDC切削齿,如浅凹面PDC齿、Stinger毒牙中心锥形齿、Stinger毒牙刀翼锥形齿、AxeBlade斧式脊形PDC齿和StayCool保持冷却PDC齿等制造的钻头,逐步在油气钻井中得到有效的应用。这些钻头能够以较高的钻进效率和工作寿命钻进某些硬岩和研磨性地层。为了满足水平钻井,特别在页岩气水平井中能够强力排除岩屑,并具有优良的钻井导向性能,国际著名公司推出了许多新型钻头,如ONXY Ⅱ矛式PDC钻头、Seeker导向PDC钻头、CounterForce反力PDC钻头、Speed快速PDC钻头等用于当代油气钻井,取得了良好的效果。文章还介绍了Defyer DPA套管钻头与CuttPro PDC防剪切保护帽。提出了以下建议：继续深入研究PDC钻头,以提高其性能,更好地满足油气钻井的要求;组合化钻头是油气钻头发展的重要趋势;比金刚石性能更好的钻头切削材料有可能今后发现或合成,可用于制作更佳钻井钻头;我国钻头企业需重组和发展状大;各种钻头技术创新应该加强。     

ZT-TG500推管机的研制

介绍了ZT-TG500型推管机的参数、工作原理、主要结构构成及其功能、关键技术、用途。推管机在非开挖施工过程中,对非开挖设备起到了辅助的作用,能够“营救”施工中卡死的管线,也可以协助非开挖设备推动管线前进,保证工程的成功。该推管机采用电液比例控制技术,能够实现零到最大无级调速,给施工带来了很多的益处;卡瓦橡胶硫化涂覆技术,保证了卡瓦夹紧时不损坏钢管表面的防腐层,同时保证了足够的夹持力而不打滑;双油缸同步防扭技术,采用滑动导轨与大型分流阀的机液控制方法,来实现油缸的零阻力,使油缸的推力能有效地应用到工程中。通过青州水管铺设与穿越松花江的自来水管铺设的现场应用,取得了良好的效果。     

曹娥江大闸钢结构防腐蚀试验研究

根据曹娥江大闸的环境特点,对不同厂家的喷涂金属涂层和富锌涂料进行了浪溅区、潮差区和大气区的室外近2年的暴露试验以及室内近10 500 h的盐雾试验、盐水周期性浸泡试验和盐水浸泡试验.研究结果表明,喷涂金属层耐腐蚀性能普遍优于富锌涂料层;在试验采用的富锌涂料中,高锌粉含量的富锌涂料防腐蚀性能优于低锌粉含量的富锌涂料;从长效防腐蚀角度考虑,建议采用喷涂金属防腐蚀措施.     

Hydrophobic and electrostatic parameters in bacterial adhesion

Recently it has been shown that the initial stages of bacterial adhesion to a model-surface of sulphated polystyrene can best be described using hydrophobic and electrostatic parameters. In the present study it is tested whether these parameters can generally be applied to predict bacterial adhesion by using (i) glass, as a model for hydrophilic and natural surfaces of silicates and oxides, (ii) polystyrene coated with proteins, as a model for a surface coated with an organic layer, and (iii) river Rhine sediment, as an example of a natural surface. Adhesion to glass was dominated by electrostatic interaction, whereas adhesion to polystyrene coated with various types of proteins depended on the surface characteristics of the bacteria and the type of protein. By relating Van der Waals interactions to hydrophobicity of the interacting species, the adhesion of bacteria to the various surfaces including the river Rhine sediments could be interpreted in terms of the DLVO-theory. It is therefore concluded that the conceptual principles of the DLVO-theory (interplay of Van der Waals and electrostatic interactions) are suitable to describe, at least qualitatively, the initial processes of bacterial adhesion to a wide range of surfaces.     

扫描电镜分析各类微体化石样品最佳镀膜的探讨

根据多年的工作经验和试验对比,总结出了非导电微体化石－放射虫,硅藻,竹节石,有孔虫,介形虫,轮藻,牙形石,海绵骨针等的最佳镀膜方法和最佳镀膜厚度。     

用传输矩阵方法研究多层介质增透膜的透射特性

利用麦克斯韦方程组和边界条件,推导出由高低折射率介质组成周期性的多层增透膜系的传输矩阵,用传输性矩阵求出增透膜系的反射率和透射率表示式,采用Maple语言和数值计算方法得到4层和8层高反射膜系的反射率随入射光波长变化曲线,分析和讨论入射光的入射角对反射率和透射率的影响.得到的结果有利于对多层介质增透膜系结构的理解,为光学仪器镀膜的设计提供了理论依据.     

Sol－gel法制取Al_2O_3系陶瓷涂层的组织与性能

用多种分析手段分析了Ｓｏｌ－ｇｅｌ法制取的Ａｌ２Ｏ３系陶瓷涂层在烧结过程中的组织变化以及烧结后涂层的成分和组织结构；对涂层的高温抗氧化性、耐蚀性、耐磨性以及涂层与金属基体的结合力进行了测试，结果表明，Ｓｏｌ－ｇｅｌ法制取的Ａｌ２Ｏ３系陶瓷涂层由氧化物晶体、过渡相和玻璃体混合而成，涂层与基体之间有很好的结合力，金属基体的抗氧性、耐蚀性、耐磨性能有明显提高．     

Insights into the formation of rock varnish in prevailing dusty regions

The characteristics of rock varnish from the Campo de Piedra Pomez (CPP, Andes Argentina) provides new insights into the development of rock varnish under severe dusty conditions. The CPP varnish has been analysed using SEM‐EDAX and Raman techniques. The rock coating is tens of microns in thickness and under the microscope shows a micro to cryptocrystalline appearance and a general granular texture. Silica (quartz, cristobalite and amorphous silica) is the main phase forming these coverings followed by Al, K and Na compounds. Minor Fe oxides and Mn oxides are the source for the orange (Fe) and brown (Fe and Mn) hues of the coating. The results obtained for the CPP coating show that desert varnish developed under dusty circumstances does not have the appearance of typical rock varnish. Textural characteristics include high crystallinity and granular arrangement of the components. Moreover the absence of typical microlaminations is related to the presence of aeolian mineral grains which inhibit their development. The main mechanism of formation of rock varnish under such environmental circumstances is the direct incorporation of aeolian mineral grains into the varnish. However, other physicochemical processes are also required to explain the formation of varnish components such as amorphous silica or iron oxides phases. Although the development of the desert varnish may act as a protector of the underlying pyroclastic rock, the extreme and persistent windy conditions in the CPP field are high enough to weather and erode not only the rock coating but also the original ignimbrite. As other warm desert sites on Earth, the CPP area can also be considered as possible terrestrial analogue to Mars. Some environmental attributes might be similar to those expected on the Martian surface and thus, textural similarities between the CPP varnish and the rock varnish‐like coating of Mars are likely. Copyright © 2014 John Wiley & Sons, Ltd.