制革工业关键清洁技术的研究进展

应用制革清洁技术能够从制革生产的源头削减/消除污染。COD_Cr、氨氮和总铬是制革工业的典型污染物,研发和推广应用其源头减排技术对制革工业实现清洁生产具有重要意义。本文较系统地综述了保毛脱毛技术、鞣前过程废液循环利用技术、无氨脱灰技术、无氨软化技术、高吸收铬鞣技术、铬鞣废液循环利用技术、逆转铬鞣技术和无铬鞣制技术等清洁技术的研究进展及实际应用情况。介绍了这些技术的应用方法和重要控制参数,以及这些技术对源头减少典型污染物的作用。同时,对已有清洁技术的优点和尚存在的问题进行了分析。指出进一步提高单元清洁技术的成熟度和经济实用性,加强单元清洁技术之间的工艺平衡研究,重视单元清洁技术的集成链接,是制革工业清洁技术的未来发展方向。     

制革固体废弃物资源化利用现状及展望

制革是将生皮鞣制成皮革的过程,这个过程会产生大量有高价值和危险的固体废弃物。因此,本文概述了关于制革废弃物的来源、产生情况和危害以及国内外对皮革废弃物管理的举措,总结了脱毛、铬鞣这两个主要制革过程产生的毛发、含铬废革屑的国内外资源化利用研究,其中包括角蛋白、胶原蛋白和铬提取,最后对制革固体废弃物回收利用中存在的问题进行总结和展望。     

制革废水中铬的形态及其沉淀过程研究进展

在制革过程中,有机络合态的铬是主鞣段和复鞣染色段废水中铬的主要赋存形态。在主鞣废水中,主要存在低分子有机酸及胶原水解产物的铬络合物,除了具有强稳定性的多元有机酸外,传统的蒙囿剂及胶原水解产物不会影响铬的碱沉淀去除效果。染整工段废水中的铬与该工段的各类皮革化学品形成络合物,其主要以水溶性、憎液溶胶以及颗粒物等多种形式存在,其中,水溶性铬-有机物络合物主要以阴离子型存在,通常的加碱沉淀法很难将其有效去除。系列研究表明,探索制革染整废水中水溶性阴离子铬配合物的去除是制革含铬废水脱铬的关键。     

基于铬物料资源化利用的制革含铬废水处理技术现状及对策建议

制革含铬废水处理及铬物料资源化利用是制约制革行业持续健康发展的瓶颈问题。文章综述了当前制革含铬废水处理及资源化利用技术现状,指出制革含铬废水处理存在的问题主要是含铬废水深度处理及回用技术、铬泥中铬物料回收及对皮革制品质量影响等方面,进而从加强技术盲点研究消除技术应用障碍、加强技术耦合以促进工程示范推广、加强企业源头削减与末端治理的主体责任以落实含铬废水减排与资源化利用三个方面提出了对策建议。     

制革铬鞣清洁生产技术研究

传统的制革铬鞣生产工艺会引入铬等有毒重金属,对环境造成污染。在生产中必须严格控制制革原材料中重金属等有害物质的限量,通过使用高效的铬鞣助剂,改进生产工艺,提高铬的吸收率,采用无铬或少铬鞣制的清洁化生产技术,从源头解决皮革制品生产中有毒重金属铬的污染问题。     

皮革含铬废水处理技术分析

皮革含铬废水主要来自于铬鞣、复鞣等工序。在这些工艺中,铬的利用率较低,而且铬本身具有毒性,因此加强废水处理并回收铬资源十分必要。皮革含铬废水回收和利用的方法很多,本文主要介绍了皮革含铬废水处理的常用方法以及近年来兴起的新工艺技术,分析了各类技术中的优缺点和存在的问题,并探讨了铬资源的回收再利用问题。     

铬鞣革生产明胶的中间控制

<正> 利用制革工业废料铬鞣革皮制造工业明胶,为制胶工业开创了新的原料来源,既可变废为宝,又有利于环境保护。那么,如何制取优质的低含铬量的明胶呢?这就必须通过中间检测和控制手段,对原材料在生产过程中形成的半成品质量严格加以控制把关,并根据生产过程中的具体情况进行调整,为提高产品质量提供可靠的保证。铬鞣革皮(蓝矾皮)制取工业明胶的生产工艺流程为: 铬鞣革皮→碱处理→水冼→酸处理→水冼中和→熬胶→过滤→浓缩→干燥→粉碎。依据我厂在生产过程中的中间控制状况,就如何加强铬鞣革皮制取明胶的中间控制介绍如下: 一、中间控制人员的配备中间控制人员必须要有较高的文化水平和较强的责任感,有丰富的实践经验和专业技术,人员需要保持相对的稳定。     

制革废水处理技术探讨

根据我国实际情况,总结了一套适合我国国情的制革工业废水的处理方法。对当前制革废水中最大的铬鞣废液,毁毛液、综合废液的处理方法进行了论述,利用目前最常用和实用的物化、生化处理技术,使制革废液得到有效处理,使排放废水达到国家规定标准。最突出的一点是生产过程中尽可能减少或消除污染,达到清洁生产的目的。     

制革工业中铬鞣废水的治理和回收利用

制革工业中铬鞣废水的治理和回收利用河南省环保所鲁东霞，何新胜，高粉娥铬污染是制革工业中唯一的重金属污染，铬及其化合物是一种致癌、致敏物质．它可以通过空气、水、食物进入人体，危害人类的健康。因此，如何消除铬污染带来的危害是目前各国正在探索而没有解决的问...     

含铬制革废弃物处理的研究现状和研究思路

含铬制革废弃物经过适当处理可以回收其中的能量、重金属铬和胶原蛋白,但目前不合理的处置造成了环境污染及资源浪费。本文简述了含铬制革废弃物的来源和处置现状,综合国内外最新的含铬制革废弃物处理的文献,系统总结了含铬制革废弃物处理方式的相关研究,将处置方式分为直接处理和间接处理两大类分别进行阐述,详细介绍了吸附剂、热解、焚烧这3种直接处理方式及氧化法、酸水解法、碱水解法、酶水解法这4种间接处理方式,分析了每种处置方式的原理、存在的优缺点和应用前景,简述了各种处置方式的主要作用以及优缺点对比。最后提出了含铬制革废弃物处置的研究思路,特别是开展含铬制革废弃物热解和焚烧过程中燃烧和污染物排放机理研究。     

镀铬废水中铬的回收及在铬鞣中的应用

将电镀废水中的六价铬还原成Cr(III),用化学沉淀法和絮凝法将其转化为Cr(OH)3沉淀,通过硫酸酸化,结晶为高纯硫酸铬,作为皮革工业的铬鞣剂。分析了镀铬废水的絮凝效果、Cr(III)溶液絮凝前后杂质的含量及硫酸铬的纯度,选定了最佳pH。结果表明,使用回收后的硫酸铬进行铬鞣与使用标准铬粉进行铬鞣达到了同等水平,废水中铬的回收率高达92.8%。     

端羧基超支化聚合物-铝无铬鞣剂的制备及应用

根据超支化聚合物官能团度大,反应活性高的特点,利用端羧基超支化聚合物(HPAE-C)的末端羧基与Al3+络合,制备一种新型的无铬鞣剂(HPC-Al),通过单因素实验考察了反应条件对成革收缩温度的影响,确定了最佳合成条件:m(HPAE-C)∶m〔Al2(SO4)3〕=2∶1,反应温度30℃,pH=3,反应时间3 h。采用IR、XRD对产品分子结构进行表征,并采用热重分析仪测试了产品的热性能,HPC-Al的热分解温度为243℃。将产品应用于皮革鞣制中,其单独鞣革收缩温度为76.6℃,铬复鞣后收缩温度大于95℃,且物理力学性能明显提高。     

Synthesis and characterization of a carboxyl‐terminated waterborne hyperbranched polymer and its coordination behavior with chromium(III)

Despite its irreplaceable position in the leather industry, chrome tanning has been listed in the procession of limitation. The serious environmental pollution caused by chrome tanning through the residual chrome it leaves in wastewater has attracted great attention. To improve the absorption of chrome and reduce chromium emission, a novel hyperbranched ligand was synthesized and characterized. The impact elements of the coordination process between the hyperbranched oligomer and Cr(III) was investigated, and the characteristics of the complex are also discussed. This hyperbranched oligomer had a low molecular weight (weight‐average molecular weight = 2125) and narrow molecular weight distribution (PDI = 1.21). The time required for the coordination process between the hyperbranched oligomer and Cr(III) was around 6 h, and the optimum pH was 4.0. Moreover, the complex exhibited alkali resistance and fair resistance to oxidation; this suggested that this developed hyperbranched ligand is a potential masking agent or tanning auxiliary for chrome tanning and will enable improvements in chromium absorption. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40117.     

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.     

Hide tanning with modified natural tannins

Tannin from “Acacia Mearnsii” usually called Mimosa, is largely employed in vegetal tanning of hide even if the quality of the leather is poorer than that obtained using chromium as tanning agents. However, taking into account the natural resources of this product and its reduced environmental impact, mimosa tannin has been modified to obtain leather having improved properties. Tannin was modified using formaldehyde, urea, a sulfonic acid and a sulfiting agent: The new products show a higher molecular weight than mimosa tannin but maintain a good solubility in water. Modified tannins were characterized through physicochemical and technological tests and evaluated as tanning agents. The properties of tanned leathers obtained using the new tannin products and mimosa were compared. Some of the polymers containing phenolsulfonic acid are good tannin agents, especially those with a suitable molecular weight. The technological and sensorial properties of the leather obtained using modified tannins (distension and strength of grain, tensile strength, elongation, and tear load) are better than those obtained using mimosa when an appropriate ratio of the reagents were employed. At the same time the feeling of the tanned leather was improved and the final products show fullness, elasticity, fluency, reactivity, and a thin and fine grain. Some of the tannins modified with naphtalensulfonic acid show poor tanning properties but good penetration in the leather suggesting their use as auxiliary sintans in the pretanning process. A simple procedure to prepare these modified tanning agents in the course of the tannin extraction is suggested. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

An eco‐efficient rationalized leather process

BACKGROUND: The leather industry is under pressure to develop environmentally efficient leather‐making processes to comply with modern pollution and discharge legislation. Conventional leather‐processing methods are known to contribute significant pollution loads in tannery wastewaters. The rationalized process described here involves a salt‐free curing, lime and sulfide‐free beamhouse process and post‐tanning followed by tanning employing a reverse leather‐processing technique. RESULTS: Scanning electron microscopy (SEM) analysis substantiated that the grain surface, fibre separation and tight packing of fibres are similar for leathers from conventional and rationalized processes. The functional performance of the leathers is found to be on par with that of conventionally processed leathers. The rationalized leather process reduces the usage and discharge of chemicals by 68% and 82%, respectively. It also enjoys the reduction in biochemical oxygen demand (BOD), chemical oxygen demand, Cl^?, SO₄^2? and total solids loads by 58%, 62%, 95%, 66% and 85%, respectively. The rationalized process also results in reduction of water consumption and discharge and energy by 37%, 37% and 38%, respectively. CONCLUSION: The rationalized process utilizes resources efficiently with reduced environmental impact without compromising leather qualities and can be seen as being eco‐efficient compared to the conventional leather process. Copyright © 2007 Society of Chemical Industry