电渗析法回收铅酸蓄电池化成工序废硫酸的研究

本研究采用单价阳离子交换膜电渗析法,对北方某铅酸蓄电池厂化成车间产生的含低浓度铁离子的废酸进行回收实验。比较了单价阳离子交换膜和普通阳离子交换膜的分离性能,并且考察了操作电流密度、初始铁离子浓度以及初始硫酸浓度对硫酸回收率的影响。结果表明,当硫酸回收率达到80%时,单价阳离子交换膜对金属离子和氢离子的分离系数约为普通阳离子交换膜的7.5倍。在电流密度0.06 A·cm-2的条件下,采用单价阳离子膜对工厂化成废酸(初始硫酸浓度约2.25 mol·L-1,初始铁离子浓度约12 mg·L-1)电渗析,当废酸回收率达到80%时,金属铁离子的透过率小于10%,可控制回收酸中铁离子的浓度在2 mg·L-1以下,满足该蓄电池厂对化成硫酸中铁离子浓度的限值要求。通过对H+传质过程进行动力学分析的结果表明:其传质过程符合零级反应动力学,电迁移传质在传质过程中占主要地位。回收得到的硫酸重新回用于蓄电池的化成工序,不仅能够实现资源的回用,还可避免废酸进行中和处理时对碱的消耗,具有较好的环境效益及技术可行性。     

铝型材阳极氧化液的酸回收装置

铝型材的阳极氧化处理,根据溶液及膜层性质的不同,可分为硫酸、铬酸、草酸、硬质及瓷质阳极氧化等五类。本文以硫酸阳极氧化处理为例。氧化膜的成长过程,取决于膜的溶解和生长速度的比率,随着硫酸溶液浓度的增高,氧化膜的溶解速度也增大,因此氧化槽中溶解的铝也越来越多,当溶液中铝离子的含量超过25g/L 时,往往使制件表面呈现白点或块状白斑,并使膜层的吸附性能下降,造成染色     

扩散渗析法从含铬废酸中分离硫酸和Cr(VI)离子

以还原红染料生产过程中产生的含铬废酸为研究对象,采用扩散渗析法分离回收含铬废酸中的Cr(VI)和硫酸。通过实验,确定了合适的膜材料,确定装置运行稳定的时间,得出酸的回收率、Cr(VI)回收率和Cr(III)截留率随酸浓度和流量的变化趋势;优化实验条件时:定制的均相全氟阴离子交换膜在料液(稀释1倍的含铬废酸)与去离子水的体积流量比为1:1、体积流量为50mL/h、室温的工艺条件下,硫酸回收率达到75%,Cr(VI)回收率达到92.8%以上,Cr(III)截留率达到99.8%。     

扩散渗析法回收钛白废酸中的硫酸

采用DF120阴离子交换膜,通过扩散渗析法对钛白废酸中的硫酸回收进行了研究,考察了扩散时间、流量及流量比等因素对硫酸回收率及金属离子截留率的影响。动态扩散渗析结果表明,当废酸流量为10 m L/min,酸水流量比为0.5时,硫酸回收率可达到93.5%,金属离子截留率均在95%以上。将上述条件下所得渗析残液进行二次回收,硫酸回收率可提高到96.7%。可见,扩散渗析对于酸和金属盐的分离是一个极其有效的工艺。     

氧化槽中硫酸浓度的自动控制

<正> 铝阳极氧化过程中,电解液硫酸的浓度影响着涂件的膜厚及膜层性能。在电流密度、温度、氧化时间达到规定工艺指标的前提下,实现铝阳极氧化槽中硫酸浓度的自动控制,可以保证氧化膜厚度,并确保氧化膜的染色性、耐磨性、耐碱性等,涂出优质产品。上海制笔电化厂采用低温硬质铝阳极氧化工艺。工艺规定:硫酸浓度160～170克/升;温度0～3℃;氧化时间根据厚度需要而定;电流密度0.4～0.6安培/分米~2。在氧化过程中,硫酸浓度的变化影响着氧化膜厚度和性能。硫酸浓度变化的原因是:(1)涂件进槽时,带进一部分蒸馏水;(2)化学溶膜反应;(3)氧化槽液位偏低时,灌进蒸馏水;(4)阳极放氧、阴极放氢的电化学反应。基于上述工艺规定和电解液硫酸浓度的变化原因,我们研制了硫酸浓度自动控制系统。现介绍如下:     

第十三次 电镀基础常识智力测验

请迅速回答下列问题(填空) 〔1〕通常经铬酸阳极化的铝氧化膜层很薄,只有__微米,而经硫酸阳极化的铝氧化膜层一般可达__微米。〔2〕铝的硫酸阳极化溶液中主要有害杂质是__离子、__离子和过量的__离子。〔3〕当氯离子含量超过__g/l以后,硫酸阳极化后的铝氧化膜层,就可能产生大量的__腐蚀斑点。〔4〕硫酸阳极化时,温度过高,氧化膜生成速度将__,而溶解速度__,所生成的膜层疏松、有粉末。〔5〕铝及铝合金铬酸阳极化溶液中的有害杂质主要是__和__离子。〔6〕铬酸阳极化溶液中的__价铬含量也不能太高,否则,氧化膜层发__。     

铝合金阳极氧化膜耐蚀性的研究

在硫酸电解液中,采用直流电源对铝合金进行阳极氧化处理。通过电化学测试和点滴实验,探讨了硫酸的质量浓度和氧化时间对阳极氧化膜耐蚀性的影响。结果表明:随着硫酸质量浓度的增加和氧化时间的延长,阳极氧化膜的耐蚀性有所提高;当硫酸的质量浓度为60g/L,氧化时间为30min时,阳极氧化膜的耐蚀性最好。     

以铝氧化废液酸蚀代替除油

铝件装饰性阳极氧化大多采用硫酸电解液。随着电解液中铝离子(Al~(+3))不断增多,铝氧化膜层质量就会恶化而需要调整电解液成份。当Al~(+3)离子积累到一定限度,比如超过28克/升时,电解液就基本失效,需要更换。我厂利用这些硫酸废液对铝工件进行酸蚀,代替了一向沿用的铝件氧化前的碱性化学除油工序。经过硫酸废液酸蚀后的铝工件表面均匀润     

13X分子筛去除废水中镍离子的性能研究

研究了13X分子筛用量、吸附时间、溶液pH值、初始镍离子浓度对废水中镍离子去除效果的影响.结果表明,在25℃、pH=5.9、13X分子筛质量浓度10 g/L、吸附时间30 min时,对初始质量浓度小于250 mg/L的镍离子去除率均可达到98%以上.13X分子筛重复使用5次,对废水中镍离子的去除率保持不变,再生性能良好...     

铝合金硫酸氧化槽液的测定

通过多年来与客户的接触发现国内许多铝氧化厂是根据铝阳极氧化槽液的波美度来控制硫酸氧化槽中硫酸质量浓度的，使其氧化膜质量很不稳定。分析了波美度与槽液硫酸质量浓度和Al^3 质量浓度的关系，证明了此法的不准确并介绍了化学分析控制槽液硫酸质量浓度和Al^3 质量浓度的方法。     

减压蒸馏法从生物质水解液中分离提纯乙酰丙酸

以乙酰丙酸（LA）/硫酸溶液模拟生物质水解液,探讨了硫酸用量、氢离子物质的量、硫酸根物质的量以及蒸馏温度对LA提纯效果的影响,并进一步考察了碱中和对LA提纯的促进作用。实验结果表明：硫酸的存在不利于LA的分离提纯,模拟水解液中氢离子物质的量是影响LA回收率的主要因素;在氢离子物质的量一定时,较高的硫酸根物质的量有利于LA的分离;最佳的蒸馏温度为170~180℃,利用氢氧化钠中和模拟水解液中的氢离子,可以得到较高纯度和回收率的LA。在100 mL水、0.1 mol LA、0.03 mol硫酸、0.06 mol NaOH（碱中和）和蒸馏温度170℃下,LA的回收率为84.5%,纯度为93.3%。在固体碱活性氧蒸煮（CAOSA）竹浆制得的LA水解液中,加入氢氧化钠中和后进行LA的减压蒸馏分离提纯,当NaOH与硫酸根的物质的量比值为1.4时,LA回收率高达91.8%（纯度93.5%）。     

Performance of a synthetic resin for lithium adsorption in waste liquid of extracting aluminum from fly-ash

In this study, we investigated the performance of a synthetic resin for the adsorption of Li from pre-desilicated solution which is the waste liquid produced by extracting aluminum from fly ash. The adsorption kinetics and isotherms of the resin were obtained and analyzed. The saturated adsorption sites of the resin were in agreement with the quasi-second-order kinetic model. Then, the pore diffusion model (PDM) was applied to represent the lithium adsorption kinetics which confirming that the external mass is the limiting step. Moreover, we evaluated the adsorption properties of this resin in fixed-bed mode. We established a feasible extraction process for Li from strong alkaline solutions with low Li concentrations. The process parameters, such as the flow rate, initial adsorption solution concentration, water washing process, desorption agent concentration, and flow rate were studied. The desorption rate of the Li⁺ ions was directly proportional with the concentration of the desorption agent. The time required to accumulate Li decreased as the hydrochloric acid concentration and flow rate increased. Time of the peak appeared increased from 0.5 bed volume (BV) to 2.5 BV as the concentration was increased from 1 to 3 mol·L^-1, and the peak increased from 231 to 394 mg·L^-1. The resin presented good selectivity for Li⁺ ions and could effectively separate impurity ions from the pre-desilication solution.     

高铁煤矸石酸浸液合成氧化铁红的实验研究

以高铁煤矸石为原料,先用硫酸酸浸的方法获得含有铝离子的硫酸铁溶液;采用分步沉淀的方法,使Fe3+完全转化为氢氧化铁凝胶而与Al³⁺分离;再将获得的氢氧化铁凝胶烘干后高温煅烧;最后将煅烧产物磨粉过筛,获得了氧化铁红。确定了合成氧化铁红的工艺条件是：酸浸液中铁离子的浓度为0.31 mol/L;分离Fe³⁺与Al³⁺时,氢氧化钠溶液的浓度为1 mol/L,且控制终点pH在3.0左右;干凝胶焙烧温度为800 ℃,时间为60 min。XRD及化学分析结果表明：所得产物为氧化铁红,符合GB/T 1863-2008《氧化铁颜料》的相关要求。     

REMOVAL OF TOXIC Pb2+ IONS BY SYNTHETIC HYDROXYAPATITES

The removal behavior of toxic Pb²⁺ ions from aqueous and nonaqueous solutions by two synthetic hydroxyapatites (S-1 and S-2) has been investigated by using both batch and column methods.

It was found that Pb²⁺ ions in the both solutions were easily removed to the apatite samples mainly by cation-exchange reactions between the Pb²⁺ ions in the solutions and Ca²⁺ ions of the samples at room temperature. Further, in the system of aqueous PbF₂ solutions, anion-exchange reactions between F^- ions in the solutions and OH ^- ions of the samples occurred simultaneously and the liberated OH ^- and Ca²⁺ ions influenced removal behavior of Pb²⁺ and F^- ions. The maximum removal amount of Pb²⁺ ions from the aqueous solutions was 400 mg per g of S-1. Pb^- ions in the waste water from lead plating factories were completely removed to the apatite samples. In this manner, it was found that the apatites, especially S-1 can be employed as a new removal agent for the treatment of poisonous Pb²⁺ ions in waste water.     

Investigation of solution chemistry to enable efficient lithium recovery from low-concentration lithium-containing wastewater

In the production of lithium-ion batteries (LIBs) and recycling of spent LIBs, a large amount of low-concentration lithium-containing wastewater (LCW) is generated. The recovery of Li from this medium has attracted significant global attention from both the environmental and economic perspectives. To achieve effective Li recycling, the features of impurity removal and the interactions among different ions must be understood. However, it is generally difficult to ensure highly efficient removal of impurity ions while retaining Li in the solution for further recovery. In this study, the removal of typical impurity ions from LCW and the interactions between these species were systematically investigated from the thermodynamic and kinetics aspects. It was found that the main impurities (e.g., Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺) could be efficiently removed with high Li recovery by controlling the ionic strength of the solution. The mechanisms of Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺ removal were investigated to identify the controlling steps and reaction kinetics. It was found that the precipitates are formed by a zero-order reaction, and the activation energies tend to be low with a sequence of fast chemical reactions that reach equilibrium very quickly. Moreover, this study focused on Li loss during removal of the impurities, and the corresponding removal rates of Fe³⁺, Al³⁺, Ca²⁺, and Mg²⁺ were found to be 99.8%, 99.5%, 99%, and 99.7%, respectively. Consequently, high-purity Li₃PO₄ was obtained via one-step precipitation. Thus, this research demonstrates a potential route for the effective recovery of Li from low-concentration LCW and for the appropriate treatment of acidic LCW.     

酸性废水体系中硫酸钙反应结晶过程研究(英文)

The present work focused on the recycle of the sulfate and the metal ions from acidic wastewater dis charged by nonferrous metallurgical industry. The effects of the temperature, the reactant concentration, the stirring speed and the metal ions on the reactive crystallization process of calcium sulfate between sulfuric acid and lime were systematically investigated. The morphology of the precipitated crystals evolved from plateletlike and nee dlelike shape to rodlike shape when the temperature was increased from 25 to 70 ℃. An increase in the agglom.     

镁铝离子共存硅酸体系的聚合行为

通过对镁铝离子共存硅酸体系中硅酸胶凝时间、单硅酸聚合反应速率以及凝胶热性能的研究,得出：在pH<;4的微酸性条件下,硅酸体系的胶凝时间随镁铝离子共存浓度的增大而减小,且铝离子在对硅酸体系的促凝过程中起主要作用。镁铝离子共存硅酸体系的单硅酸反应速率常数比不含金属离子硅酸体系的有所增大,计算得出MA_0.1+0.1硅酸体系的单硅酸平均速率常数为：k₀=7.28×10^-4,k₁=5.62×10^-4。镁铝离子共存硅酸体系凝胶的晶化转变温度与晶型转变温度,相较于不含金属离子硅酸体系的均有所降低,根据热重曲线计算出MA_0.1+0.1硅酸体系水合二氧化硅的化学式为：SiO₂·0.556 H₂O。     

用于分离酸性废液中铯的连续性循环系统

针对核工业回收U、Pu过程所产生的放射性废液中Cs⁺的分离与富集,设计了连续电渗析富集分离技术(CEEST)。在不同温度下通过水热法合成一系列的多金属氧酸盐Na[Co₉-POM],通过SEM、XRD等方法对其进行了表征,并评价Na[Co₉-POM]材料的Cs⁺分离性能。探究不同的恒定电流、溶液pH值和共存离子存在下对分离Cs⁺过程的影响。实验结果表明,120℃下合成的材料Na[Co₉-POM]-120具有最佳的Cs⁺分离和回收能力,在恒定电流为0.03 A且pH<1的高酸性环境中,Cs⁺的分离率在150 min左右可达到96%以上。其共存离子对分离过程的影响较小,分离率仍可达到70%以上。为此提出了一种综合性连续循环的Cs⁺分离系统,成功实现了高酸放射性废液中Cs⁺的分离,并分析其在工业上的应用前景。     

聚合硅酸硫酸铁铝混凝剂的制备表征与混凝性能

引言聚合硅酸硫酸铁铝(PAFSS)是近十年来发展起来的一种新型无机高分子混凝剂,它不但综合了聚铝、聚铁和聚硅酸混凝剂的多重优点,还克服了聚铝处理后水样残余铝浓度高、聚铁残余色度大和聚硅酸稳定性差的缺点,在废水的处理过程中可同时发生电中和、吸附架桥和网捕等多种功能,产生比单一聚铁、聚铝和聚硅酸更好的混凝效果,因而得到了国内外研究人员的广泛关注。如文献[1-4]以硅酸钠、硫酸铝和硫酸铁为原料,通过硅酸钠的酸化得到聚硅酸(PSA),通过硫酸铝和硫酸     

不锈钢老化着色液预还原草酸沉淀除杂过程研究

为实现不锈钢老化着色液杂质离子的分离与回收,采用预还原-草酸沉淀法对老化液中铁、镍、锰沉淀除杂过程进行研究。通过溶液化学计算及条件优化实验,考察铁、镍、锰离子沉淀效率,并使用X射线衍射仪、扫描电子显微镜、X射线光电子能谱仪对草酸沉淀物进行物相及形貌结构的表征。结果表明,通过控制溶液pH及草酸用量可有效实现溶液中铁离子、锰离子、镍离子与草酸根络合,形成草酸盐沉淀,实现杂质离子与溶液铬离子分离,杂质离子沉淀顺序依次为锰离子、镍离子、铁离子。老化液预还原后,在草酸过量系数为1.2、溶液pH为2、反应温度为25℃的条件下沉淀反应2 h,铁、锰、镍离子沉淀率分别可达98.12%、99.35%、87.26%,沉淀物主要为二水草酸亚铁及少量草酸镍、草酸锰。