Chrome free surface treatments for galvanized steels—present and future

As the galvanized steels used for electrical and office appliances has achieved a complete chrome-free production worldwide,surface treatment technologies have entered a new phase of development.Grenter effort will be made in exploring new frontier for future surface treatment technologies.A greater contribution will be made for environmental protection,energy-saving and resource-saving,to prevent globalwarming.

Clean Production for Chrome Free Leather by Using a Novel Triazine Compound

Based on a novel triazine compound,the properties of tanned leather and commercial feasibility in pilot scale have been investigated.Then this novel approach tanning was compared with conventional chrome tanning:in the condition of less-salt pickling and chrome free,the physicochemical properties including thermal stability and mechanical strength were analyzed.Meanwhile,the surface roughness and fiber dispersion were evaluated as well.The results show that the thermal stability and mechanical strength of the triazine compound tanned leather are similar to conventional chrome tanned leather,the fiber bundle is well-dispersed and much evener than that of chrome treating.The optimized tanning approach has obvious reduction in environmental impact and leads an excellent biodegradability of tanning liquor.In industrial application,the cost of materials and water treatment are reduced effectively.The production of chrome free leather can encourage the sustainable development of leather industry and protects ecological environment in some extent.

Investigation of Formation Process of the Chrome-free Passivation Film of Electrodeposited Zinc

The feasibility was investigated to substitute chrome-free passivation treatment of electrodeposited zinc in a titanium bath for chromate passivation treatment. The formation mechanism of the chrome-free passivation film was further analyzed. The surface mor- phologies and the elemental compositions of the treated samples with varied immersion times were observed by scanning electron mi- croscopy （SEM） and determined by energy dispersion spectrometry （EDS）, respectively. The electrode potential of the sample surface was recorded in the film formation process. The changes of the electrode potential are in accordance with that of SEM and EDS of the sample surface. The results of X-ray photoelectron spectroscopy （XPS） show the chrome-free passivation film composed ofZnO, SiO2, TiO2, Zn4Si207（OH）2, and SrF2. The anode zinc dissolution and the local pH value increase due to the cathode hydrogen ion reduction process result in the formation of the chrome-free passivation film. The macro-images of the chrome-free passivation films formed on electrodeposited zinc show that the color of the film changes from blue to iridescence with the increase of the immersion times.

Development and Application of Chrome-free Refractory Materials for RH Degasser

The research progress and industrial application of chrome-free refractories for RH degasser were introduced in the paper.It is proved that unburned magnesia-spinel refractories used for RH throat and snorkel in Baosteel have longer service life compared with traditional direct bonded fused magnesia-chrome materials.The new developed chrome-free unburned magnesia-spinel composite can fully meet the present demand for RH operation and can be applied extensively for RH processing.At present,instead of chrome-containing materials,chrome-free refractories have been applied widely for RH in Baosteel.Super low carbon MgO-C material with high mechanical properties at mild and high temperatures can be an alternative chrome-free material for RH.

High Temperature Interactions of Chrome Oxide Free Refractories with Coal Slag Under Simulated Gasification Conditions

Chrome oxide free refractories have significant economic benefits for the development of gasification technology.Spinel based and SiC based refractories are corroded by coal slag at 1500℃under reducing atmosphere.Moreover,interactions between refractory materials and molten slag are also predicted by thermodynamic calculations under the same conditions.The results indicate that spinel based refractories are corroded by dissolution of molten slag,while SiC based refractories are corroded by oxidation of CO and FeO.Both of the spinel and SiC based refractories show good corrosion resistance against coal slag by the present experimental tests.Finally,preliminary developed spinel-SiC composite materials are prepared and corroded by coal slag as well,the research of which shows great potential to be used in slagging gasifiers.

Corrosion resistance evaluation of highly dispersed MgO–MgAl2O4–ZrO2 composite and analysis of its corrosion mechanism: A chromium-free refractory for RH refining kilns

The corrosion resistance behavior of a highly dispersed MgO-MgAl2O4-ZrO2 composite refractory material is examined by testing with high-basicity and low-basicity RH(Ruhrstahl-Hereaeus)slags.The composite material exhibits greater resistance to the RH slags than the traditional MgO-Cr2O3 composite,MgO-ZrO2 composite,and MgO-MgAl2O4-ZrO2 composite.On the basis of the microstructural analysis and mechanisms calculations,the corrosion resistance behavior of the MgO-MgAl2O4-ZrO2 composite is attributable to its highly dispersed structure,which helps protect the high activity of ZrO2.When in contact with the slag,ZrO2 reacts with CaO to form the stable phase CaZrO3,which protects MgAl2O4 against corrosion,thereby enhancing the corrosion resistance of the composite.

加速老化的无铬鞣革中游离苯胺的FIA-UV法分析

采用流动注射分析-紫外光谱法(FIA-UV),基于苯胺与亚硝酸盐在酸性条件下发生的重氮化反应及其在碱性条件下的偶合显色反应,实现苯胺的有效检测.通过实验参数的优化,确定495 nm为最大吸收波长,建立了苯胺质量浓度在0.002~2.0 mg/L范围内与峰高具有良好线性关系的模型(R^(2)=0.9997),检出限为1.62μg/L,重复性(RSD)为0.71%.该方法在加速老化后皮革萃取液中的应用表现出97.8%~103.8%的加标回收率,相较国标法具有更优的抗干扰能力和更高的检测精度.成功建立的苯胺检测新方法,为无铬鞣革产品的质量控制及环境监测提供了重要的技术支持,有助于提高公共健康和环境保护水平.

6063铝合金中性无铬转化膜制备及膜层性能分析

目的提高铝合金微小器件的耐蚀性,开发一种条件温和可控的转化膜成膜工艺。方法采用中性无铬转化工艺,在6063铝合金表面制备转化膜。通过研究NaF、NH_(4)HF_(2)、KMnO_(4)、十二烷基硫酸钠(SDS)和没食子酸等几种添加剂对转化膜外观与耐蚀性的影响,确定NH_(4)HF_(2)为最佳添加剂。采用电化学方法分析膜层的耐蚀性,用SEM和EDS分析表面形貌及元素组成,并采用XRD和XPS表征膜层晶态结构和化合物组成。基于检测结果,简要分析转化膜的成膜过程。结果最终得到了中性转化处理的最佳成膜工艺为EDTA-2Na8.0g/L,单宁酸1.0g/L,Na_(2)WO_(4)6.0g/L,H_(2)ZrF_(6)4.0g/L,NH_(4)HF_(2)3.0g/L,pH6.6,成膜温度为30℃,成膜时间为15 min。该工艺所制备的转化膜外观致密均匀,颜色为浅黄色。电化学测试结果表明,转化膜具有良好耐蚀性,自腐蚀电流密度由基体铝合金的16.22µA/cm^(2)下降为转化处理后的0.87µA/cm^(2)。EDS能谱分析结果表明,膜层主要由Al、C、F、O、Na、Zr和W元素组成。XRD结果显示,膜层中含有Na_(3)AlF_(6)晶体。XPS分析结果表明,膜层中还含有Al_(2)O_(3)、AlF_(3)、WO_(3)、ZrF_(4)以及金属有机络合物。结论采用中性转化处理工艺,可以在6063铝合金表面制备有色均匀、耐蚀性良好的转化膜,膜层主要由Al的难溶化合物组成。

生物质基无铬鞣剂在可持续皮革制造中的研究进展

鞣制是使生皮变成革的关键工序。目前,铬鞣剂因其优良的性能仍占据鞣剂市场的90%。但是Cr3+存在转化为具有致癌性Cr6+的潜在危害,铬鞣废水的排放对生态系统的潜在风险不容忽视。因此,无铬鞣剂成为研究的热点。其中生物质材料因其来源广泛、可再生和生物可降解好等优点而备受关注。文章对多糖类、蛋白类等生物质材料进行了介绍,并对多糖、蛋白质的功能改性及其在皮革鞣制和复鞣的应用进行了归纳。同时,对生物质基鞣剂的发展前景及推广应用进行了展望。

基于单因素法的植物鞣剂-沸石鞣剂结合鞣革研究

为改善植物鞣白湿革性能,引入了沸石鞣剂,以湿热收缩温度和物理机械性能(撕裂强度和抗张强度)为评价指标,采用单因素法,优化出基于植物鞣剂的沸石结合鞣的最佳工艺。试验结果表明,植物鞣剂-沸石结合鞣最佳条件为:沸石鞣剂的用量为5%,鞣制时间50 min,提碱终点p H为5.5,鞣制终点温度30℃,所得白湿革的收缩温度达到94.55℃,撕裂强度达到55.75 N/mm,抗张强度达到11.44 N/mm^(2),部位差显著降低。该工艺对植鞣白湿革的改善效果明显,为无铬结合鞣技术提供了新思路。

有机配体对铝-锆配合物鞣制性能及环境效益的影响

采用氧化木质素磺酸钠(OSL)、酒石酸(TA)和氧化淀粉(OST)与铝锆盐(AZ)进行配位鞣制,并与传统铬(Cr)鞣进行对比,评估了4种鞣制技术的鞣革性能、坯革性能和环境效益。OSL-AZ与皮胶原以配位键结合为主,辅以OSL的磺酸基、羧基、酚羟基和苯环与皮胶原间的离子键、氢键和疏水键作用,促使OSL-AZ在皮胶原间形成大分子刚性交联网络,鞣革的收缩温度高达88.4℃,等电点达到7.54,对染整化学品吸收率超过84%,最终获得的坯革物理性能优良,仅次于Cr鞣坯革。TA和OST无磺酸基、酚羟基和刚性苯环,与皮胶原的相互作用弱,故其铝-锆配合物的鞣制性能不及OSL-AZ。OSL-AZ鞣革和废水的生物降解性明显优于传统Cr鞣革和废水。综上,OSL-AZ鞣制技术是一种实用环保的制革技术。

无铬鞣废革屑胶原提取物与PBAT共混成膜性能

利用稀酸法分别从沸石、TWS鞣废革屑中提取胶原,以提取率、特性粘数等为指标优化提取工艺,对纯化后的胶原水解物进行表征。随后选取TWS鞣废革屑提取的胶原水解物(C-TWS)与聚己二酸对苯二甲酸丁二醇酯(PBAT)共混成膜,探究二者的成膜性能。结果表明:两种胶原水解物均含有17种氨基酸,元素组成以C、N、O为主,矿物盐含量低,是优质的生物可降解蛋白基材。PBAT/C-TWS共混过程为简单的物理共混,C-TWS组分含量的增大使复合膜的水蒸气透过量提高43.05%~182.5%。C-TWS组分含量为30%时,薄膜的最大热降解温度由405.4℃降低至386.5℃,所有比例共混膜都具有良好的透光率,共混体系中C-TWS组分含量小于50%时具有较好的相容性。

三聚氯氰与氨基葡萄糖反应产物的鞣革性能

以三聚氯氰和氨基葡萄糖为原料,合成了N,O-二-(4,6-二氯-1,3,5-三嗪基)-氨基葡萄糖(CG)。通过FTIR和1HNMR对CG的结构进行了表征。并将其用于生皮鞣制实验,以脱灰软化状态的绵羊皮为材料,以单因素实验确定了适宜的鞣制工艺条件为:CG鞣剂用量为7.5%(以灰皮质量计,下同),并采用30、40、45℃阶梯控温模式进行鞣制,各温度对应下的鞣制时间为1、1.5、2 h。结果表明,CG初鞣的坯革收缩温度可达78.9℃,革面洁白细腻,身骨柔软;坯革具有良好的染色性能,经过染整的坯革也具有优异的卫生性能和物理机械性能。

制革无铬鞣体系中高分子化学品的构造设计研究进展

制革中无铬鞣的发展使其配套的高分子化学品开发成为热点.就高分子而言,高分子链的构造对分子结构有着重要影响,将直接影响其作为皮革化学品在工艺中的应用范围及作用效果.但目前以高分子链构造为依据的无铬鞣皮革化学品综述仍鲜有报道.基于此,本文按照线型、支化和交联等主要构造方式分类对无铬鞣配套高分子化学品进行综述.归纳探讨了不同构造的特点、影响该构造的主要因素以及对应构造在无铬鞣配套化学品制备当中的特点,以期为无铬鞣体系高分子化学品的开发提供理论支持,从而进一步推动传统皮革产业的转型升级和可持续发展.

铝鞣法的演变:从传统技术到绿色制革

铝鞣作为最古老的鞣法之一,一直被用于制革。近年来,由于制革行业面临着Cr(Ⅵ)和含铬固废带来的环境与健康风险,铝鞣法在生态皮革制造中再次被重点关注。本文全面综述了铝鞣技术的研究现状,具体包括铝单独鞣、植-铝结合鞣、铝与其他鞣剂结合鞣以及新型铝鞣技术;对未来铝鞣技术的发展方向进行了展望,有助于生态皮革制造技术的发展。

基于均匀设计的无铬复鞣工艺设计与优化

为提高皮革复鞣工艺的生态性能,以锆-铝-钛鞣白湿革为原料皮,以皮革的热收缩温度、撕裂强度、感官性能和复鞣排放废液中的COD含量作为评价指标,设计并优化基于改性戊二醛、锆铝钛配合鞣剂和阳离子油的无铬复鞣工艺。结果表明,当改性戊二醛鞣剂用量为2%、锆-铝-钛配合鞣剂用量为2%、阳离子油用量为0.4%时,复鞣效果和生态性能好,复鞣后的坯革也具有较好的耐热性能、感官性能和物理性能。这为皮革的生态设计提供了一种新思路。

基于CH/β-CD的无铬鞣白湿革长效抗菌性能研究

以β-环糊精(β-CD)醛基衍生物和盐酸环丙沙星(CH)作为抗菌剂,应用于无铬鞣白湿革(MCFL),开发了一种新型长效抗菌白湿革。采用傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、热重分析仪(TGA)对所得皮革的结构和性能进行表征,并考察其对大肠杆菌和金黄色葡萄球菌的抑菌效果。结果表明,与未经β-CD改性和CH处理的MCFL相比,该方法制备的皮革的Ts、Td和Tp分别提高了5.7℃、4.9℃和6.9℃;在贮藏90 d时,经CH处理后,对大肠杆菌和金黄色葡萄球菌的抑菌率仍分别达到99.7%和97.4%,比未经β-CD处理的分别提高了29.8%和34.4%。这说明改性后的MCFL具有更好的热稳定性能,且引入β-CD空腔可以包合抗菌剂,能改善因小分子抗菌剂释放导致的抗菌持久性差的问题。利用β-环糊精多醛基衍生物和CH对MCFL进行抗菌改性,可满足白湿革生产需求,为实现白湿革长效抗菌提供了一种新工艺。

艾力特AT鞣剂在浸酸与不浸酸工艺体系下的鞣制性能

以绵羊酸皮为实验对象,使用新型有机鞣剂艾力特AT分别在常规浸酸和不浸酸两种工艺体系下进行鞣制,通过坯革的收缩温度、纤维形貌及其热力学性能等分析测试,主要考察艾力特AT鞣剂在浸酸与不浸酸工艺体系下鞣制性能的差异性。实验结果表明:在两种工艺体系中,鞣制工艺条件的变化对鞣制效果产生了相似的影响;在艾力特AT鞣剂用量6%时,两种不同工艺体系下鞣制的坯革收缩温度都可以达到89℃。此外,鞣制坯革粒面饱满,毛孔清晰,热稳定性和力学性能基本接近。因此,艾力特AT鞣剂在浸酸与不浸酸工艺条件下,基本鞣制效应差异性不明显,这对于推广和应用基于艾力特AT鞣剂的无铬鞣制技术具有一定的理论指导意义。

鳄鱼皮制革工艺的研究进展

由于鳄鱼皮具有骨骼架构等特点,鳄鱼皮革加工对技术要求苛刻。近几十年,国内外不少研究者对鳄鱼皮制革加工的技术进行了不断探索。本文阐述了鳄鱼皮的特点,并重点对鳄鱼皮制革工艺在无铬鞣制、涂饰、加工和其他方向上进行了总结和展望。

铝合金表面无铬化学转化膜的制备及其性能

采用正交实验优化铝合金稀土转化处理液的配方,采用点滴腐蚀法、极化曲线、交流阻抗研究铝合金表面稀土转化膜的耐腐蚀性能,利用硬度计、SEM、EDS研究转化膜的表面硬度、形貌与组成。结果表明:处理液中添加成膜促进剂可提高转化膜的生长速度,并且添加铵盐、氯化物后转化膜的铈含量从5.93%改变为4.15%和9.27%;还发现添加成膜促进剂铵盐、氯化物后转化膜耐腐蚀性提高为原来的2.6和5.6倍,其中后者的耐点滴腐蚀能力优于传统铬酸盐转化膜,并且还可将铝合金表面的显微硬度从HV68.8增大至HV389和HV450。