铬铜钼马氏体磨球的研制

本文分析了水泥磨机对研磨体性能的要求,介绍了铬铜钼磨球的成分、性能、金相组织。并通过模拟试验对各种磨球作磨损对比试验,证实了铬铜钼磨球的磨损远低于中锰球铁及低碳白口磨球,而稍高于高铬球,但经济效益高于高铬球。     

氰化镀液电镀全光亮,高整平的铜锡合金新工艺

铜-锡合金/铬镀层优良的抗蚀性,已为50～60年代我国装饰性电镀领域中广泛应用所证明,铜-锡合金/镍/铬多层电镀经研究证明,其防护、装饰性至少不亚于双层镍/铬镀层。但是,过去的电镀铜-锡合金工艺,只能获得无光的镀层,镀后必须抛光,不能在自动线上一步法生产,所以为了实现光亮电镀,电镀工作者进行了大量研究,也取得过一些成就,例如采用二价锡盐的氰化镀液,可镀出比较光亮的铜-锡合金镀层。可是,整平能力不够,不能直接镀装饰铬,直接镀镍也很困难,因而未能在行业中大规模应用。我们经过长时间研究,采用二种相辅相成的添加     

三价铬镀液中铜杂质的分析

利用铜试剂与Cu2 的特效显色反应,采用分光光度法测定三价铬镀铬溶液中铜的质量浓度。用EDTA掩蔽镍和铁,在氨性条件下显色,显色液pH=9.20。以镀液底色作参比,在波长450 nm处测定。测定结果的相对平均偏差不大于1.3%,回收率为100%~103%,能够满足监控三价铬镀液中铜杂质的要求。     

电镀铜两则

使用磷铜阳极的一种镀铜方法;一种镀铜的整平剂;电镀双层硬铬的方法。     

铜及不锈钢件直接镀装饰铬若干问题的探讨

铜及不锈钢件直接镀装饰铬若干问题的探讨在铜镍铬体系中，镀装饰铬是不需要“前处理”的，操作者只需从镀镍槽中取出零部件，经清水洗后，迅速地将其置入镀铬槽中便可。但是，有些零部件，如铜件、不锈钢件，往往镀装饰铬而无预镀层，这就需要有“严格”而独特的前处理了...     

铁铬系变换催化剂中铜含量的测定

用碘氟法测定变换催化剂中铜的含量，即可排除铁，铬对测定铜时的干扰，又可得到较好的精确度和准确度，其方法易行，结果稳定。     

铬化砷酸铜防腐处理木材对环境安全的影响综述

对长期以来在木材防腐市场居于主导地位的铬化砷酸铜(CCA)处理木材对环境的影响进行了较为系统、全面的介绍,其中包括CCA防腐剂中铜、铬、砷等元素对环境的影响,以及CCA防腐处理木材使用过程中对环境的影响,旨在促进CCA处理木材的科学生产,保证CCA防腐处理木材的使用安全。     

催化光度法测定痕量铜的研究

1　前言铜是生命机体中不可缺少的微量元素之一 ,广泛分布于植物、动物组织及所有食品及饮用水中 ,因此环境及生命组织中痕量铜的测定及研究日趋引起人们的重视[1 ] 。用催化动力学方法测定微量铜的反应体系已有报道 ,但基于Ｈ2 Ｏ2 氧化三苯甲烷类酸性染料的铬天青Ｓ(ＣＡＳ)为指示反应的催化光度法测定痕量铜 (Ⅱ )尚未见报道。本文研究了在活化剂邻菲罗啉 (ｐｈｅｎ)存在下 ,铜 (Ⅱ )对Ｈ2 Ｏ2 氧化ＣＡＳ的催化褪色反应 ,找到了影响催化褪色反应的最佳条件 ,建立了测定痕量铜 (Ⅱ )的新方法 ,测定的线性范围为 0～ 40ｎｇ/ｍＬ ,用于测…     

用铜泥制铜液的工艺

本文介绍了回收铜洗工序中的沉淀铜泥,並制备成铜液,重新用于铜洗中,取得了较好的经济效益。     

碘量法测定废旧线路板中铜含量的过程研究

对碘量法测定废弃线路板回收液中铜含量的过程条件进行了研究。通过6个粗产品中铜的含量测定,研究了共存铅、锰、铬、镍、锡对测定结果的影响,并与ICP-OES分析结果进行比对,发现碘量法相对标准偏差(n=3)在0.0010%～0.2905%,与ICP-OES法结果一致,该方法适用于废弃线路板回收液中铜含量的测定。     

FT-IR and Temperature-programmed Desorption (TPD) Study of the Adsorption of Probe Molecules Used to Model Epoxy Resin Adhesion to Chromium,Iron and Stainless Steel Substrates

In this study, we investigated the reactivity of chromium, iron, and surface-treated 304L stainless steels (SS) toward molecules representing model epoxy resins. These molecules were ammonia (a basic probe molecule also representative of the hardener amine group), 1,2-epoxybutane (for epoxy groups) and 2(methylamino)ethanol (for the β-amino alcohol resulting from the reaction of epoxy with amine). These molecules were analyzed in the adsorbed state by either FT-IR or temperature-programmed desorption (TPD).

Surface analysis showed that the top surface of the treated 304L samples only contains chromium and iron as metallic elements. The chromium/iron ratio can be varied within a wide range according to the SS surface treatment used. When increasing the SS surface chromium enrichment, we show a simultaneous increase of (i) both density and strength of surface acid sites, (ii) the amount of β-amino alcohol adsorbed. In addition, there is a marked improvement of the epoxy resin/304L bond strength when the SS surface is more chomium-enriched.     

Pilot plant investigation on petrochemical wastewater treatmentfor the removal of copper and chromium with the objective of reuse

There has been great demand for development of technologies that remove toxic heavy metal ions from wastewater. Chemical precipitation operation is known to remove heavy metal ions from water. In this study applicability of alkaline reagents such as Ca(OH)₂ (lime) and NaOH (caustic soda) in removing copper and chromium ions were evaluated. Separation of heavy metals such as chromium compounds from petrochemical industries' cooling water wastes was achieved by conversion of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III). Maximum conversion occurred in the pH range of 2.0 and 2.3, adjusted by ferrous sulfate and sulfuric acid. Maximum precipitation of Cr(III) occurred at pH 8.7 with addition of Ca(OH)₂, followed by mixing and 2-h sedimentation. At the end, the concentration of chromate was reduced from 30 ppm to 0.01 ppm. In the case of copper, which is found in the form of cupro-ammonia in ammonia plant wastes, it was observed that the presence of ammonia in wastewater prevents effective chemical precipitation. Therefore, the quantity of ammonia was reduced by aeration. The optimum aeration rate was determined to be 70 L/min, and it was found that ammonia concentration reached equilibrium after 5.0 h o f aeration. Furthermore, hydroxide and carbonate methods were evaluated with respect to precipitation of heavy metals at bench scale, and the former was selected as the method of choice. The results obtained in the Jar test were then applied to pilot scale, and it was determined that the optimum pH for maximum copper precipitation was about 12.0 for both lime and caustic soda used in the hydroxide precipitation method. Lime was preferred due to economics and its high speed of precipitation. Finally, using established methods described here, the concentration of copper followed by coagulation with lime, mixing, 2-h sedimentation and filtration through Whatman 0.45 Am filters was reduced from 48.51 mg/L to 0.694 mg/L, which is below the environmental standards for water resources.     

FT-IR and Temperature-programmed Desorption (TPD) Study of the Adsorption of Probe Molecules Used to Model Epoxy Resin Adhesion to Chromium, Iron and Stainless Steel Substrates

In this study, we investigated the reactivity of chromium, iron, and surface-treated 304L stainless steels (SS) toward molecules representing model epoxy resins. These molecules were ammonia (a basic probe molecule also representative of the hardener amine group), 1,2-epoxybutane (for epoxy groups) and 2(methylamino)ethanol (for the β-amino alcohol resulting from the reaction of epoxy with amine). These molecules were analyzed in the adsorbed state by either FT-IR or temperature-programmed desorption (TPD).

Surface analysis showed that the top surface of the treated 304L samples only contains chromium and iron as metallic elements. The chromium/iron ratio can be varied within a wide range according to the SS surface treatment used. When increasing the SS surface chromium enrichment, we show a simultaneous increase of (i) both density and strength of surface acid sites, (ii) the amount of β-amino alcohol adsorbed. In addition, there is a marked improvement of the epoxy resin/304L bond strength when the SS surface is more chomium-enriched.     

镀铬液中铁的测定

根据氨性溶液的特性,向镀液中加入过量的氨水与铁作用生成氢氧化铁沉淀,从而与镀铬液及杂质金属,如:铜、锌、镍等分离。用稀王水溶解氢氧化铁,使铁离子全部氧化为三价而与硫氰酸铵生成深红色的硫氰酸铁配位物,借此进行比色测定。方法简单,准确。     

Afterchrome dyeing of wool. Part A — chromium in the effluent,analytical determination and characterisation of influencing factors

As a consequence of increasing legal restrictions on the concentration of chromium in industrial discharges, afterchrome dyeing of wool has been re-evaluated. Special regard was given to the distribution of trivalent and hexavalent chromium species in the individual process stages (chroming, rinsing and ammonia aftertreatment baths) of afterchrome dyeing. Recommendations are outlined to give minimum chrome residues in the effluent and to avoid the distribution of the toxic hexavalent chromium species into the environment. The effiency of the thiosulphate procedure is doubtful for improving the exhaustion of total chromium. Subsequent alkaline treatments of chrome-dyed wool lead to a desorption of chromium compounds that are probably fibre-bonded chromium—tetrathionate (sodium thiosulphate) complexes.     

水泥窑用镁铬砖中Cr6+化合物的化学性质和解毒

研究了K2CrO4的化学稳定性。K2CrO4中的Cr^6 不能或难于被乙醇、乙醛、柠檬酸、酒石酸、葡萄糖甚至草酸还原，仅发现FeSO4与MnSO4可将K2CrO4的Cr^6 转化成Cr^3 。镁铬残砖产生的Cr^6 物质很难在环境中被破坏，很多情况下将长期存在自然界中，持续性地危害人体的健康。因此，水泥窑应优先使用无铬耐火材料，如使用镁铬砖，须用FeSO4或MnSO4等方法将残砖解毒。     

酸化-预热处理方法解离去除高浓度络合态铬

金属铬络合染料废水中的铬Cr(Ⅲ)与偶氮类有机配体结合,呈络合状态,结构非常稳定。采用常规的中和混凝法对黑色、黄色和橙色三种铬络合物的废水进行处理,均不能有效地去除铬。研究表明．温度和酸度是影响络合态铬离子热力学稳定性的主要因素。对于黄色或橙色铬络合物,将废水进行预热以提高处理温度,或加酸酸化,都会使络合态铬离子结构破坏;而对于黑色铬络合物,其结构更为稳定,必须酸化并同时提高处理温度．才能有效地破坏黑色铬络合物的结构,游离出的铬离子极易通过投加石灰乳中和沉淀去除。因此,通过酸化、预热、中和混凝等步骤,可将该类高浓度络合态铬离子完全解离并去除,处理后含铬质量浓度降至1．0mg／L以下,达到了重金属处理排放要求。     

云南胶磷矿选矿脱铬试验研究

对云南胶磷矿进行了铬元素分析,结果表明铬在胶磷矿中是一种痕量元素.多种选矿工艺试验研究结果表明,铬元素没有赋存于胶磷矿的主要脉石矿物白云石和硅质矿物中,无法利用选矿的方式有效脱除.从磷精矿粒度分布来看,粗粒级中铬质量分数较低,而细粒级中铬质量分数较高,利用该分布规律可以对磷精矿进行分级利用.     

硫酸盐体系三价铬镀液中六价铬离子的积累及去除

绘制了分光光度法测定六价铬的标准曲线,研究了硫酸盐体系三价铬镀液中六价铬的积累规律,并测试了不同的去除方法.结果表明,添加有机醛类稳定剂或溴化铵可以降低六价铬的生成速率,使用小电流电解和添加过氧化氢能降低三价铬镀液中六价铬的质量浓度.     

三价铬镀铬液中三价铬的碘量法分析

改进了三价铬镀铬液中三价铬的分析方法。在弱酸性条件下,用过硫酸铵作氧化剂将三价铬氧化成六价铬,用碘量法测定六价铬,得到三价铬的质量浓度。实验表明,在弱酸性条件下,不加硝酸银作催化剂,用过硫酸铵能将三价铬完全氧化成六价铬。分析结果的相对平均偏差为0.13%。本法简单而准确,分析成本低,标准溶液稳定,优于传统方法。