铁锰氧化物对稀土离子的吸附行为研究

采用化学共沉淀法制备铁锰复合氧化物作吸附剂，通过静态和动态吸附实验探究了不同吸附条件对铁锰氧化物吸附稀土离子的影响，对铁锰氧化物吸附稀土离子过程进行了等温吸附模型拟合和吸附动力学、吸附活化能分析，探究了稀土离子在铁锰氧化物上的吸附机理。结果表明，稀土离子在铁锰氧化物上的吸附过程符合Langmuir等温吸附模型；稀土离子在铁锰氧化物上的吸附过程符合准二级动力学模型，属于单层均匀的化学吸附过程，吸附速率控制步骤由化学吸附决定，且温度对吸附动力学影响程度最大；吸附热力学分析表明铁锰氧化物吸附稀土离子是吸热的化学吸附过程，吸附活化能分别为E₍La³⁺)=11.04 kJ/mol、E₍Gd³⁺)=16.85 kJ/mol和E₍Y³⁺)=16.67 kJ/mol;稀土离子与铁锰氧化物上的羟基发生了交换形成了内层络合物，稀土离子取代表面羟基是主要的吸附机制。     

浸矿液pH对离子吸附型稀土浸出行为影响实验研究

为了探究浸矿液pH对离子吸附型稀土浸出行为的影响,从宏观和微观相结合的角度对离子吸附型稀土浸出行为进行了研究。实验采用不同pH硫酸镁溶液作为浸矿液对离子吸附型稀土进行室内模拟柱浸实验,同时采用核磁共振技术测定浸矿过程试样的横、纵两向反演图像及T₂图谱、孔隙结构等参数,分析了不同pH(2～4.5)对离子吸附型稀土浸矿行为的影响规律。结果表明,当pH>2.5时,随浸矿液pH降低,稀土浸出率增加,浸矿过程中试样内部孔隙结构由大孔隙和超大孔隙向小中孔隙演化;当pH<2.5时,随浸矿液pH降低,稀土浸出率减小,浸矿过程中试样内部孔隙先由大孔隙和超大孔隙向小中孔隙演化,随着离子交换反应结束,小中孔隙又向大孔隙和超大孔隙演化。分析认为,这种差异是由于稀土矿体微细颗粒在孔隙表面沉积和释放动态转化过程导致,受离子置换反应引发浸矿液离子强度变化等因素影响。     

农业废弃物吸附稀土离子的研究进展

稀土元素在工业上大量应用的同时, 给人类身体健康和生态环境带来了危害, 近年来引起了广泛关注.研究发现吸附法相比其他传统水处理方法具有效果较好、操作简单、成本较低等优点, 它是消除稀土离子危害的最具潜力的方法之一; 而农业废弃物吸附剂因是农业副产物具有廉价的特性, 且部分农业废弃物吸附稀土离子时吸附量大、反应速率快, 可作为主要研究对象.文中对农业废弃物吸附材料吸附稀土离子的机理、吸附影响因素、吸附应用与吸附模型研究进展进行总结评述, 并对农业废弃物吸附稀土离子的发展方向进行展望.      

离子吸附型稀土总量快速容量法测定的研究

本文研究了0.2—0.01％范围内离子吸附型稀土矿中稀土总量的直接测定法,其回收率96～102％,变异系数0.96～3.56。方法简便,终点明显,结果稳定可靠。     

螺旋藻对模拟矿山废水中稀土镱 离子的吸附性能

通过Zarrouk培养液获得了螺旋藻，并以其为生物质吸附剂，对模拟矿山废水中稀土镱离子的吸附性能进行研究.通过单道扫描电感耦合等离子体发射光谱（ICP-AES）、扫描电镜（SEM）、傅里叶红外光谱仪（FTIR）、多功能成像电子能谱仪（XPS）等分析方法对螺旋藻的结构和吸附性能进行研究.通过Freundlich，Langmuir，Redlich-Peterso和Dubinin-Radushkevich等温吸附模型，以及伪一级、伪二级、Elovich方程和颗粒内扩散动力学模型，对该过程的吸附动力学和热力学规律进行探讨，以了解该吸附过程的机理.结果表明:当被处理液的pH值为5、螺旋藻的剂量为2.0 g/L、初始镱离子浓度为100 mg/L和吸附时间为60 min时，螺旋藻对模拟矿山废水中的稀土镱离子的吸附去除率为77 %，且解吸附率可达到92.3 %，表明螺旋藻的吸附速率快、吸附效果较为理想.研究表明:该过程的吸附动力学行为符合伪二级动力学模型（R2>0.99），主要受化学吸附控制；且吸附等温线能较好用Langmuir方程进行模拟（R2>0.99），属于自发吸热型吸附过程.      

啤酒酵母对镉离子的吸附特性及机理研究

文章在啤酒酵母吸附镉离子试验的基础上,用吸附等温线对吸附特性进行了描述,用Langmuir吸附模型对啤酒酵母的吸附行为进行了评价.并对啤酒酵母吸附镉离子的机理进行了探讨.研究表明:啤酒酵母对Cd2 离子的吸附主要发生在细胞壁,酵母对Cd2 离子的吸附可能与离子交换有关.     

半风化离子吸附型稀土的浸取实验

针对龙南某矿山的半风化离子型稀土进行浸取试验研究.矿样中全相品位为 0.11 %,其中离子相稀土含量为 0.083 7 %.考察了浸取剂种类,浸取剂浓度,淋洗液固比以及尾水液固比对浸取的影响,其最佳柱浸浸取条件为:HT-13 浓度 2 %,淋洗液固比（指质量比,下同）为 0.4:1,尾液水液固比为0.6:1, 在此条件下稀土离子相浸出率为 98.06 %. 在放大试验中 HT-13 浸出液中稀土离子浓度为1.14 g/L,铝浓度为 10.8 mg/L,铁浓度为 7.8 mg/L,且 HT-13 可以循环使用.      

Cyanex 272浸渍树脂对稀土吸附特性的研究

将6种不同型号的苯乙烯型大孔吸附树脂浸渍于用石油醚稀释了的Cyanex 272（二（2，4，4-三甲基戊基）次膦酸）溶剂中，制取6种Cyanex272浸渍树脂，对其进行比较，制得了最佳的Cyanex272浸渍树脂。研究了Cyanex272对稀土离子的吸附特性，其吸附的最佳pH值为3，平衡时吸附容量为20．0436mg／g树脂，最佳吸附温度为40℃，达到最大吸附容量平衡时仅需要35min。     

某螯合树脂对钒(Ⅳ)离子的吸附行为研究

研究了某螯合树脂A对钒(Ⅳ)离子的吸附行为,考察了pH值、树脂用量、反应时间、反应温度、钒标准溶液浓度对静态吸附效果的影响。实验结果表明,在pH=4、树脂用量1.0g、反应时间4h、温度60℃条件下,螯合树脂A对钒(Ⅳ)的吸附量为184.2mg/g。对螯合树脂A的解吸、共存阳离子的影响等进行了分析。     

Luminescence enhancement of rare earth ions by metal nanostructures

Well-ordered metal structures, i.e. arrays of nanosized tips on silver surface for studies of the luminescence enhancement of absorbed media with rare earth ions were used. These arrays were prepared by the metal evaporation on track membranes. Calculations of resonance frequencies of tips regarded as semispheroids were done taking into account the interaction between dipoles of tips. They were used to discuss experimental results for media with Eu(NO₃)₃·6H₂O salt basing on data for bulk silver dielectric function.     

Enhancing leaching efficiency of ion adsorption rare earths by ameliorating mass transfer effect of rare earth ions by applying an electric field

Improving the seepage of leaching solution in the ore body and strengthening the mass transfer process of rare earth ions during in-situ leaching are two critical methods to improve the leaching efficiency of rare earth.In this study,2 wt% MgSO₄ solution was used for the indoor simulated column leaching experiment on rare earth samples and an electric field was applied at both ends of the samples.Then the effects of different intensities,initial application time and duration of the el...     

稀土负载生物炭的制备及其对低浓度氨氮的吸附特性

对微波/稀土元素铈吸附剂的制备条件及其吸附降解低浓度氨氮的反应条件进行优化,并采用XRD、SEM和FTIR对负载型吸附剂进行了表征。实验结果表明,负载型吸附剂内部结构发生变化,比表面积增大,羟基数量增多;负载后的生物炭对氨氮的处理效果明显优于原生物炭,其较为合适的制备条件为固液比(指原生物炭质量与氯化亚铈溶液体积之比,单位g/mL)1:25,浸渍pH 10;在氨氮溶液浓度为50 mg/L,初始pH为10,反应温度为50℃,反应时间为120 min,吸附剂投加量为5 g/L条件下,氨氮吸附量达到最大,为11.297 mg/g,且反应过程符合准二级动力学模型。      

A novel polystyrene-poly(hydroxamic acid) interpenetrating polymer network and its adsorption towards rare earth ions

A novel polystyrene-poly(hydroxamic acid)interpenetrating network resin(PS-PHA IPNs)was successfully synthesized by suspension polymerization and interpenetrating network technology.The effects of various experimental parameters,including pH,contact time and initial concentrations of rare earth ions on the adsorption capacity were discussed in detail.Under the condition of pH 4.0(La³⁺),1.0(Ce³⁺)and 3.0(Y³⁺),respectively,PS-PHA IPNs can reach equilibrium adsorption in 6 h and get maximum adsorption capacities(1.08,1.43 and 1.36 mmol/g).The adsorption process of PS-PHA IPNs for La(Ⅲ),Ce(Ⅲ)and Y(Ⅲ)ions can be described by liquid membrane diffusion,particle diffusion and chemical reaction.The adsorption process is a spontaneous and endothermic process and can be better simulated by Langmuir adsorption isotherm.The studies of SEM-EDS indicate that rare earth ions are adsorbed on the surface of PS-PHA IPNs.Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS)analysis further prove that rare earth ions are chemisorbed on the surface of PS-PHA IPNs.These results reveal that the as-prepared PS-PHA IPNs is a promising adsorbent for adsorption of rare earth ions due to their higher adsorption capacity than other adsorbents.     

Insight into leaching of rare earth and aluminum from ion adsorption type rare earth ore: Adsorption and desorption

Clay minerals are inferred to be the primary host materials for ion-exchangeable rare earth in ion adsorption type rare earth ore(IAREO).During the rare earth leaching process,the adsorption and desorption reactions of the cations controlling the leaching process continue to occur at the clay minerals-leaching agent solution interface.In order to understand the leaching mechanism and behavior of rare earth and co-leached aluminum,adsorption,competitive adsorption,and desorption experiments were ...     

Progress in green and efficient enrichment of rare earth from leaching liquor of ion adsorption type rare earth ores

Ion adsorption type rare earth ores (IATREOs) are a valuable strategic mineral resource in China, which feature a complete composition of fifteen rare earth elements and are rich in medium and heavy rare earth (RE) elements. In the leaching process for recovering rare earth elements from IATREOs, many impurities will be leached together with rare earth elements and enter the leaching liquor. An impurity removal-precipitation enrichment technique is currently applied to selectively recovery rare earth elements from the leaching liquor with the high content of impurities and low concentration of rare earth elements by using ammonium bicarbonate in the industry. However, a high loss of rare earth elements and severe ammonia nitrogen pollution are caused by this process. Therefore, more beneficial impurities removal technologies, mainly for aluminum, and green enrichment technologies with lower pollution are now urgently needed. For this purpose, this paper analyzed two aspects of research progress in recent decades: the green separation of rare earth elements and aluminum from leaching liquor and the green and efficient enrichment of rare earth elements. Finally, an approach for the high-efficiency and green enrichment of rare earth elements from leaching liquor of the IATREOs is proposed in several aspects, including impurity inhibition leaching, neutralization and impurity removal, alkaline calcium and magnesium salt precipitation enrichment, and centrifugal extraction enrichment.     

Element migration and phase distribution characteristics during crystallization of rare earth phase in rare earth slag

The crystallization experiment of molten rare earth (RE) slag under different cooling rates was carried out. The characteristics of element migration and phase distribution during RE phase crystallization were studied by using different equipment. The experimental results show that there are two RE phases in the RE slag, namely (Ca, Ce, La)₅(SiO₄)₆F and (Ca,Ce,La,Mg)₃(Ti,Al,Nb)₂O₇. During the cooling crystallization process of molten RE slag, Ca and P elements in the RE phase of (Ca,Ce,La)₅(SiO₄)₆F migrate from inside to outside, and finally gather at the outer edge of the phase to form phase Ca₃(PO₄)₂. The RE phase (Ca,Ce,La)₅(SiO₄)₆F is distributed inside the furnace-cooled slag, and the RE phase (Ca,Ce,La,Mg)₃(Ti,Al,Nb)₂O₇ is distributed in the surface layer of the furnace-cooled slag. And based on the phase distribution characteristics, the central hollowing method is proposed to realize the preliminary enrichment of valuable elements Ti, Nb and RE in RE slag.