碳钢的苛性碱破坏

碳钢的苛性破坏包括碳钢在浓烧碱中的腐蚀和碱脆。一般来说,碳钢对烧碱有较好的耐蚀性,在温度低于80℃、浓度低于50％的NaOH溶液中可以放心地使用。但在高温高浓度的NaOH中却有相当大的腐蚀率,特别是在受力的情况下,会发生严重的苛性开裂,这种碱性介质中的应力腐蚀破裂称为碱脆。我省很多碳钢制的碱液蒸发器使用几     

延长高温浓碱罐的使用寿命

我厂的浓碱贮罐是用全碳钢制造的。在生产过程中,以30％的液碱为原料,经浸没蒸发(燃烧氢气)制得45％的浓碱,温度高达135℃,而后放到浓碱冷却罐中,进行循环冷却至25℃以下,分离盐合格     

热钾碱法脱除CO_2系统中钒缓蚀剂防腐蚀机理的电化学研究

本文用电化学方法,研究了国内外大型合成氨厂脱除合成氨原料气中CO_2时,广泛采用的几种热钾碱溶液中钒缓蚀剂防止碳钢设备腐蚀的机理。在除去了溶解氧的各种热钾碱溶液中加入钒缓蚀剂前后测得的碳钢的阳极极化曲线和电位-时间曲线表明,在K_2CO_3溶液、K_2CO_3+KHCO_3溶液,G-V溶液、Benfield溶液、Catacarb溶液和二乙撑三胺热钾碱溶液中,钒缓蚀剂都是一种氧化性钝化剂。它是通过其氧化作用使碳钢的电极电位由活化区转移到钝化区内,使碳钢由活化状态转变为钝化状态而防止腐蚀的。     

小联碱厂苯菲尔脱碳溶液中腐蚀与控制的经验

苯菲尔(Benfield)溶液是以二乙醇胺为活化剂的热钾碱脱碳液(脱除CO_2),是用于合成氨气体净化中的一种溶液。它具有吸收速度快,气体净化度高,CO_2回收率高,纯度高,溶液无毒,原料易得,价格便宜,操作简便等优点,是目前合成氨厂较好的脱碳溶液之一。苯菲尔溶液的主要成份是碳酸钾的水溶液。吸收大量CO_2气体后,对碳钢设备有很强的侵蚀作用。腐蚀主要发生在高温和CO_2高浓度区域以及气体、液体冲刷和节流部位。Bien-stock和Field的研究表明,在浓度为40％,没有吸收CO_2的热钾碱沸腾溶液中,碳钢的腐蚀     

不透性石墨换热设备在联碱行业的应用前景

腐蚀问题是联碱生产中较突出的问题，由于联碱母液是主要含氯化钠、氯化铵、碳酸铵、碳酸氢铵、碳酸氢钠等盐类的多元混合溶液，属强电解质，较利于电化学腐蚀的进行，尤其在溶液中游离氨含量较高且溶液具有一定流速的条件下，腐蚀更严重。因此，联碱生产中的设备及管道常选用经过严格防腐处理的碳钢、铸铁和不锈钢材料甚至钛材。     

热钾碱溶液中钒酸盐缓蚀剂的致钝作用

<正> 目前,我国大多数大中型合成氨厂采用热钾碱(热的碳酸钾)溶液脱除合成气中的CO_2,并用钒酸盐或五氧化二钒作缓蚀剂。本文用旋转电极,从而在流体力学条件稳定的热钾碱溶液中研究碳钢的阳极溶解特性和钒酸盐缓蚀剂的致钝作用。这方面的工作迄今未见有文献报道。结果与讨论一、热钾碱溶液中碳钢阳极溶解的特     

国产WC-1型外磁式除垢器试用总结

受国家经委能源局委托,包头市磁性材料厂试制成功了WC—1型外磁式除垢器。此产品于八三年七月始在我厂氯碱车间浓碱板式螺旋冷却器上进行了试用,阻垢、除垢效果良好,同时也有一定的缓蚀作用。现总结如下: 一、基本试验条件 1.冷却器:碳钢,板式螺旋冷却器(新)。连接管(即冷却水出口管):碳钢,     

双氧水蒸碱系统优化改造总结

0前言目前,国内蒽醌法双氧水生产工艺中使用碳酸钾溶液(碱液)处理双氧水工作液,浓碳酸钾溶液吸收工作液中的水分后,造成密度下降,达不到生产的要求,需将其浓缩去除水分、提高密度后循环利用。安徽晋煤中能化工股份有限公司双氧水蒸碱装置原碳酸钾溶液浓缩工艺为间歇式操作法。该法由人工操作,稀、浓碳酸钾溶液的补加、排放需人工手动控制,且需要2个楼层的操作人员配合才能完成;因此,易出现碱液跑料、碱蒸发     

浓碱溶液中氯化钠的吸附分离

用自制的新型吸附剂从浓氢氧化钠溶液中吸附分离氯化钠,确定了吸附时间、碱液浓度、吸附剂用量、吸附温度等因素对吸附的影响.结果表明,该吸附剂对浓碱溶液中的氯化钠有良好的吸附分离效果,且容易洗脱,重复使用10次以上仍具有较好的吸附性能.     

电渗析处理后油田污水在聚合物驱和复合驱中的应用

利用电渗析法处理油田污水,研究了处理前后3种水所配制的聚合物溶液的流变性;淡水所配制的聚合物溶液黏度最高;指出矿化度和阳离子是造成3种水聚合物溶液流变性不同的根本原因,淡水可以作为聚合物驱的配注水。通过3种水在不同质量分数碱(0．4％、0．6％、0．8％、1．0％、1．2％)的三元复合体系的界面张力曲线,得出浓水三元复合体系达到超低界面张力时碱的质量分数范围最宽(0．4％～1．1％)。根据现场三元复合体系配方(聚合物质量浓度为1350mg／L,ORS-41的质量分数为0．3％,碱的质量分数为1％)选择了浓水三元复合体系碱的质量分数为0．6％时,两个三元复合体系黏度相近。对两个三元复合体系配方在光刻模型上进行了微观驱油实验,结果表明：浓水低碱三元复合体系也能驱替各种残余油,具有良好的驱油效果。     

PTA加氢反应器在碱洗条件下的安全分析

通过用SUS304L不锈钢制作的楔形张开加载预裂纹试样,在280℃、质量分数为3．0%的NaOH溶液的条件下进行应力腐蚀试验,以模拟对苯二甲酸(PTA)装置的加氢反应器PD-201不停车碱洗工作过程中SUS304L不锈钢在该介质环境下的抗应力腐蚀性能。结果表明：SUS304L不锈钢在此条件下经720h的浸泡,未发生应力腐蚀开裂现象,设备泵用SUS304L不锈钢作为内衬复合层是安全的。     

Electrochemistry and surface chemistry of stainless steels in alkaline media simulating concrete pore solutions

Despite the increased use of stainless steel for concrete reinforcement in harsh chloride environments, comparatively little is known about the surface chemistry of these materials in alkaline media simulating concrete pore solutions. This work is concerned with a combined electrochemical and XPS surface analytical investigation on austenitic, ferritic and duplex stainless steels in simple NaOH and more complex alkaline concrete pore solutions. The results show that the passive films on these materials change with immersion time, the ferritic and duplex stainless steels becoming enriched in chromium oxy-hydroxide, the austenitic steel strongly enriched in nickel hydroxide. The composition of the metal layer beneath the surface film is strongly enriched in nickel and depleted in chromium and iron. The results are discussed with respect to the relation between the Fe(II) content in the films and the open circuit potential (OCP) during exposure, the film growth mechanism and localized corrosion resistance.     

Nickel-free manganese bearing stainless steel in alkaline media—Electrochemistry and surface chemistry

The use of austenitic nickel-containing stainless steels as concrete reinforcement offers excellent corrosion protection for concrete structures in harsh chloride bearing environments but is often limited due to the very high costs of these materials. Manganese bearing nickel-free stainless steels can be a cost-effective alternative for corrosion resistant reinforcements. Little, however, is known about the electrochemistry and even less on surface chemistry of these materials in alkaline media simulating concrete pore solutions. In this work a combined electrochemical (ocp = open circuit potential) and XPS (X-ray photoelectron spectroscopy) surface analytical investigation on the austenitic manganese bearing DIN 1.4456 (X8CrMnMoN18-18-2) stainless steel immersed into 0.1 M NaOH and more complex alkaline concrete pore solutions was performed. The results show that the passive film composition changes with immersion time, being progressively enriched in chromium oxy-hydroxide becoming similar to the conventional nickel-containing stainless steels. The composition of the metal interface beneath the passive film is strongly depleted in manganese and enriched in iron; chromium has nearly the nominal composition. The results are discussed regarding the film growth mechanism (ageing) of the new nickel-free stainless steel in alkaline solutions compared to traditional austenitic steels. Combining the results from pitting potential measurements with the composition of the passive film and the underlying metal interface, it can be concluded that the resistance against localized corrosion of the new nickel-free stainless steel relies on the strong chromium(III) and molybdenum (VI) oxy-hydroxide enrichment in the passive film.     

不锈钢在氟硼酸清洗剂中的腐蚀行为研究

通过X-射线衍射仪（XRD）对经过不同表面处理的两种不锈钢（1Cr18Ni9Ti）表面进行物相分析,采用失重法测定其在氟硼酸清洗剂中的腐蚀速度,同时借助扫描电镜及电子扫描探针观测浸泡过程中不锈钢的表面腐蚀形貌及其表面粗糙度的变化特征。结果表明：不锈钢在沸腾的浓硝酸中形成一层氧化物后作为模拟污染物相对于未处理前表面含有较...     

电化学聚合导电聚苯胺膜的研究

分析了恒电位法在酸性和碱性溶液中于不锈钢基体上电聚合聚苯胺的过程及其影响因素,测定了聚苯胺膜与基体的附着力、膜的导电性和防腐性.结果表明:该膜在空气中呈绿色,稳定、完整致密,导电性好,与基体的结合情况较好.阳极极化曲线测定表明,在碱性溶液中预镀后酸性溶液中聚合聚苯胺膜,其点蚀电位比酸性溶液中聚合聚苯胺膜升高1 V左右,表明前者的导电聚苯胺膜可显著提高不锈钢的抗点蚀性能,具有良好的点腐蚀防护效果.     

磷酸盐分步沉淀不锈钢酸洗污泥浸出液铬铁镍

不锈钢酸洗污泥含有高浓度的Fe、Cr、Ni金属离子,属于危险固体废弃物。本文对不锈钢酸洗污泥浸出液有价组分梯级分离展开研究,探讨了磷酸钠用量、浸出液初始pH、反应温度、搅拌时间对酸洗污泥中浸出液中Fe、Cr、Ni分离效果的影响。确定Cr³⁺沉淀的最佳工艺条件：P/Cr摩尔比为1.00,初始pH为1.00,反应温度为90℃,反应时间70min。Cr³⁺平均沉淀率为94.47%,Fe²⁺、Ni²⁺平均沉淀率为0.88%、0.78%。Fe³⁺优化条件为P/Fe体积比0.80、初始pH为1.00、反应温度为45℃、搅拌时间为60min,Fe³⁺沉淀率最高为99.83%、Ni²⁺沉淀率稳定在0.68%,证明了磷酸盐沉淀法可以有效分离不锈钢酸洗污泥浸出液中Fe、Cr、Ni,为不锈钢酸洗污泥铁、镍、铬分离提供理论依据和技术应用参考。     

Semiconducting behavior of passive film formed on stainless steel in borate buffer solution containing sulfide

The semiconducting behavior of passive film formed on 316L stainless steel in borate buffer solution containing sulfide was studied by capacitance measurements (Mott–Schottky approach), electrochemical impedance spectroscopy and potentio dynamic polarization curves. The results reveal that the measured capacitance values of the stainless steel electrode have frequency dependence and hysteresis, which shows amorphous or highly doped semiconductor property of the passive film. The Mott–Schottky plots indicate p-type semiconducting behavior related to chromium oxide and n-type semiconducting behavior to iron oxide at different potential range of stainless steel electrodes. The existence of sulfide in the solution increases the acceptor densities obviously which increase more than five times with the sulfide concentration of 9 mg L⁻¹ and enables a more conductive behavior. The presence of sulfide also decreases the impedance values and enlarges the passive current of the electrode.     

Chiral-selective growth of single-walled carbon nanotubes on stainless steel wires

Single-walled carbon nanotubes (SWCNTs) were successfully grown on calcined stainless steel wires at 700 °C using CO as the carbon source. By contrast, the raw stainless steel wires produced only necklace-like multi-walled carbon nanotubes. Photoluminescence spectroscopy studies showed that SWCNTs grown from calcined stainless steel have a narrow diameter distribution and a high chiral selectivity of (6,5) nanotubes. The pre-growth heat treatment of the stainless steel leads to formation of iron and chromium oxides. The reduction of iron oxide results in formation of Fe nanoparticles which, anchored by chromium oxide, account for the chiral-selective growth of SWCNTs.     

超低碳炼铁技术路径分析

2060年碳中和目标既使我国钢铁工业未来发展面临巨大挑战，又为其提供了换道超车的发展机遇。本文对绿氢直接还原、氧化铁熔融还原、碱性溶液电沉积铁、酸性溶液电沉积铁的发展历史和技术现状进行了综述。在全绿电炼铁场景下，本文对各种技术路线的理论和实际耗电进行了估算，从技术成熟度、电耗、技术难度、应用前景等方面，对各技术路径进行了对比分析，发现碱性溶液电沉积铁电耗最低，酸性溶液电沉积铁和电供热氢气熔融还原次之。从技术难度上看，氢气直接还原、酸性溶液电沉积铁技术难度较小，且都已完成一定规模的中试，氢气熔融还原炼铁、碱性溶液电沉积铁和氧化铁熔融电解炼铁技术都还处于概念或技术发展早期阶段。综合来看，氢气直接还原、酸性溶液电沉积铁和氢气熔融还原炼铁路线可望发展成为有竞争力的超低碳炼铁技术，而碱性溶液电沉积铁和氧化铁熔融电解炼铁技术难度较大，短期内恐难以取得较大突破。     

钢铁钼系无毒常温发黑液的维护及后处理工艺

介绍了两步法钢铁钼系无毒常温发黑工艺。与高温碱性发黑相比,常温发黑膜的结合力和耐蚀性较差,发黑液稳定性差。在此探讨了常温钢铁钼系发黑液的维护方法,采用调整酸度和密封保存方式可延长发黑液的使用寿命,再生处理可降低成本、减轻环境污染。此外,提出了一种新型低毒钝化工艺。大大提高了发黑膜的附着力和耐蚀性。