Separation of cobalt and nickel by non-equilibrium solvent extraction

The separation of cobalt and nickel in the ammoniacal sulfate solution by non equilibrium solvent extraction with a phosphate (P303) as extractant was studied. In the experiment, the effects of equilibrium pH value in aqueous phase, contact time of the two phases, the air blowing time for feed liquor in the open beaker on percentage extraction of cobalt and nickel and percentage reextraction of nickel from the loaded organic phase with dilute H 2SO 4. etc were studied. The results showed that: Co(Ⅱ) can be oxidized to Co(Ⅲ) ammino complex by adding (NH 4) 2S 2O 8 or blowing air to the aqueous phase, and Co(Ⅲ) ammino complex is a kind of kinetically inert complex. Its extractive speed is very slow, while the nickel′s is much faster than that of cobalt. By controlling the contact time of the two phases, nickel can be separated from cobalt by non equilibrium solvent extraction. Then nickel was reextracted from the loaded organic phase with dilute H 2SO 4.

Dialkyl phosphinic acids:Synthesis and applications as extractant for nickel and cobalt separation

Three kinds of dialkylphosphinic acids(DAPAs),i.e.dihexylphophinic acid(DHPA),di-(2,4,4-trimethylpentyl) phosphinic acid(DTMPPA)and didecylphophinic acid(DDPA),were synthesized through free radical addition reaction.The influence of the types of initiator,reation time and reaction temperature on the yield of DAPAs were investigated.The products were characterized by NMR and MS.By using DHPA,DTMPPA and DDPA(10%in kerosene)as extractants,the extraction of Co2 +and Ni2 +in sulphate medium at different equilibrium pH values were measured.The results show that the maximum yield of DHPA, DTMPPA and DDPA can all be achieved at about 130℃under the initiation of di-tert-butyl peroxide(DTBP).All the extraction of cobalt with respect to DHPA,DDPA and DTMPPA precedes that of nickel.The difference in pH1/2 value(defined as the pH at which 50%metal extraction occurs)between cobalt and nickel increases in the following sequence from large to small:DHPA,DDPA and DTMPPA,which indicates that the separation ability for cobalt and nickel ascends from DHPA,DDPA to DTMPPA.

Pretreatment study on chloridizing segregation and magnetic separation of low-grade nickel laterites

The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated.The nickel laterites were characterized by microscopic investigations,using X-ray diffractometry(XRD)and energy dispersive spectrometry(EDS)techniques.The pellets,which were prepared with magnesium chloride and coke as chloride agent and reductant respectively,were heated to a high temperature,and the pellets after cooling were crushed for magnetic separation.A series of experiments were conducted to examine the effect of chlorinating agent dosage,reductant dosage,chloridizing temperature and chloridizing time on enrichment grade of Ni and Co.The results indicate that the four factors have significant effects on the extractions of Ni and Co.The optimum conditions are as follows:the amounts of magnesium chloride and coke are 6%and 2%,respectively,chloridizing temperature is 1 253 K,and chloridizing time is 90 min.Under the conditions,extractions of Ni and Co reach 91.5%and 82.3%,respectively.

Electrochemical performance of a nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material for lithium-ion batteries under different cut-off voltages

A spherical-like Ni0.6Co0.2Mn0.2(OH)2precursor was tuned homogeneously to synthesize LiNi0.6Co0.2Mn0.2O2as a cathode material for lithium-ion batteries. The effects of calcination temperature on the crystal structure, morphology, and the electrochemical performance of the as-prepared LiNi0.6Co0.2Mn0.2O2were investigated in detail. The as-prepared material was characterized by X-ray diffraction, scanning electron microscopy, laser particle size analysis, charge–discharge tests, and cyclic voltammetry measurements. The results show that the spherical-like LiNi0.6Co0.2Mn0.2O2material obtained by calcination at 900°C displayed the most significant layered structure among samples calcined at various temperatures, with a particle size of approximately 10 μm. It delivered an initial discharge capacity of 189.2 mAh•g−1at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V. The as-prepared cathode material also exhibited good rate performance, with a discharge capacity of 119.6 mAh•g−1at 5C. Furthermore, within the cut-off voltage ranges from 2.7 to 4.3, 4.4, and 4.5 V, the initial discharge capacities of the calcined samples were 170.7, 180.9, and 192.8 mAh•g−1, respectively, at a rate of 1C. The corresponding retentions were 86.8%, 80.3%, and 74.4% after 200 cycles, respectively. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

Continuous Separation of Cesium Based on NiHCF/PTCF Electrode by Electrochemically Switched Ion Exchange

Nickel hexacyanoferrate (NiHCF) film was synthesized on porous three-dimensional carbon felt (PTCF) substrate by repetitious batch chemical depositions, and the NiHCF/PTCF electrode was used as electrochemically switched ion exchange (ESIX) electrode in a packed bed for continuous separation for cesium ions. The morphologies of the prepared electrodes were characterized by scanning electron microscopy and the effects of solution concentration on the ion-exchange capacity of the electrodes were investigated by cyclic voltammetry technique. Cycling stability and long-term storage stability of NiHCF/PTCF electrodes were also studied. The NiHCF/PTCF electrodes with excellent ion-exchange ability were used to assemble a diaphragm-isolated ESIX reactor for cesium separation. Continuous separation of cesium and regeneration of NiHCF/PTCF electrode based on the diaphragm-isolated reactor were performed in a laboratory-scale two-electrode system.

Synthesis and electrochemical characterization of layered Li[Ni_(1/3)Co_(1/3)Mn_(1/3)]O_2 cathode materialfor Li-ion batteries

Layered LiNi1/3Co1/3Mn1/3O2 materials were synthesized using a nickel-cobalt-manganese carbonate precursor obtained by chemical co-precipitation. The [Ni1/3Co1/3Mn1/3]CO3 precursor and the LiNi1/3Co1/3Mn1/3O2 powders were characterized by X-ray diffraction（XRD） and scanning electron micrograph（SEM）. The SEM analysis shows that these particles possess uniform and spherical morphology. The electrochemical properties of the (LiNi1/3-)(Co1/3Mn1/3O2) cathode material for rechargeable lithium-ion batteries such as the galvanostatic charge-discharge performance and cyclic voltammetry（CV） were measured. The results show that an initial discharge capacity of 190.29mA·h·g-1 is obtained in the voltage range of 2.54.6V and at a current rate of 0.1C at 25℃.The discharge capacity increases linearly with the increase of the upper cut-off voltage limit.

Synthesis and Electrochemical Property of Calcium Doped LiNi0.8Co0.2O2 Solid Solution

A divalent ion doped LiNi0.8Co0.2O2 solid solution, LiNi0.79Co0.20Ca0.01O2, was synthesized in air at 720℃. The structure and electrochemical property as cathode material of lithium ion batteries were measured by XRD and charge-discharge system. The solid solution showed high capacity and good cycle-ability. The second discharged capacity reached 190 mAh穏-1 at the current density of 100 mA穏-1.

Recovery of valuable metals from spent lithium ion batteries by smelting reduction process based on FeO-SiO_2-Al_2O_3 slag system

NA novel smelting reduction process based on FeO-SiO2-Al2O3 slag system for spent lithium ion batteries with Al cans was developed, while using copper slag as the only slag former. The feasibility of the process and the mechanism of copper loss in slag were investigated. 98.83% Co, 98.39% Ni and 93.57% Cu were recovered under the optimum conditions of slag former/battery mass ratio of 4.0：1, smelting temperature of 1723 K, and smelting mass ratio of time of 30 min. The FeO-SiO2-Al2O3 slag system for the smelting process is appropriate under the conditions of m（FeO）：m（SiO2）=0.58：1？1.03：1, and 17.19%？21.52% Al2O3 content. The obtained alloy was mainly composed of Fe-Co-Cu-Ni solid solution including small amounts of matte. The obtained slag mainly consisted of fayalite and hercynite. Meanwhile, the mechanism of copper loss is the mechanical entrainment from strip-like fayalite particles in the main form of copper sulfide and metallic copper.

MOFs基铁钴镍氧化物及其复合材料在锂离子电池中的应用

锂离子电池(LIBs)具有较高能量密度且无记忆效应,广泛应用于电动汽车、便携式电子产品。目前锂离子电池的商业石墨负极材料的容量已经接近理论值,限制了动力电池的发展,所以开发容量高、稳定性好、循环寿命长和倍率性能优良的负极材料显得尤为重要。金属有机骨架化合物(MOFs)基氧化物及其复合材料具有形貌均匀、多孔结构和高比表面积等优点,是理想的锂离子电池负极材料之一。本文总结以铁、钴、镍这3种金属为中心离子的MOFs基氧化物及其复合材料的性质、合成方法以及在锂离子电池中的研究应用。MOFs基氧化物及其复合材料能够提高电子与电荷的传输效率,缓解体积膨胀和电极粉碎,从而提高电池的循环性能和倍率性能。

过渡金属比例对锂离子电池LiNi_(x)Co_(y)Mn_(z)O_(2)层状材料电化学性能及热特性的影响

为了揭示LiNi_(x)Co_(y)Mn_(z)O_(2)(NCM)的性能随过渡金属(TM)成分的变化规律,系统研究TM比例对不同NCM材料的结构、形貌、电化学性能和热行为的影响。镍含量的增加能够提高可逆容量,但速率性能和循环稳定性变差。在富镍NCM中,Li^(+)的动力学抑制和电子导电性差是容量损失的主要原因。通过原位和非原位微量热法对不同NCM的热行为进行对比。结果表明,随着Ni含量的降低,材料的热稳定性显著提高。通过对NCM中Li剩余量的分析,对相变相关的氧释放量进行评估。结果表明,富镍材料在脱锂后出现更严重的结构恶化,起始温度更低,热释放量更多。综合表征表明,LiNi_(0.5)Co_(0.3)Mn_(0.2)O_(2)在电化学性能和安全性能间实现良好的平衡。

双重改性三元正极材料及其性能研究

为提高三元正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM523)的可逆比容量和循环稳定性,通过表面包覆聚并苯(PAS)复合钾氯共掺杂对NCM523材料进行双重改性,利用XRD､SEM､TEM等分析方法和恒电流充放电性能测试,研究了不同PAS包覆量复合K､Cl共掺杂NCM523材料的结构､形貌和电化学性能。结果表明,2%PAS包覆复合1%K和Cl共掺的NCM523材料在0.1 C首次放电容量为209.5 mAh/g;1 C倍率下充放电循环100次后放电容量保持率比未改性的NCM523提高了19%;5 C倍率下的放电比容量为158.1 mAh/g,比未改性的NCM523提高了13%。

高镍无钴正极材料研究进展

高镍无钴正极材料具有低毒性、低成本、高比能的特点,是目前锂离子电池正极材料的研究热点之一。介绍了高镍无钴正极材料制备方法及其改性研究进展,指出通过优化制备工艺可以提高正极材料的结构稳定性;利用体相掺杂和表面包覆改性可以改善材料的电化学性能。未来应注重高镍无钴正极材料失效机理和复合改性机理的研究,解决其结构不稳定和倍率性能差等问题。

锂离子电池镍-锰二元正极材料LiNi_(0.5)Mn_(1.5)O_(4)的研究进展

尖晶石型LiNi_(0.5)Mn_(1.5)O_(4)因无钴,具有高能量密度和高电压平台而受到人们的广泛关注,是具有潜力的正极材料之一。其制备方法有固相法、溶胶-凝胶法、水热法和共沉淀法等。综述了各种制备LiNi_(0.5)Mn_(1.5)O_(4)正极材料方法的优缺点,以及近年来针对LiNi_(0.5)Mn_(1.5)O_(4)正极材料改性的研究进展,并对未来LiNi_(0.5)Mn_(1.5)O_(4)正极材料的改性方法进行了展望。

无钴富镍正极材料的火焰辅助喷雾热解合成与性能研究

锂离子电池富镍三元正极材料因其成本低、容量高的优势受到广泛关注,受限于钴的高毒性、低储量,富镍正极材料无钴化成为锂离子电池未来的发展趋势。传统液相法制备无钴富镍材料存在步骤繁琐、耗时长、副产物多等问题。火焰辅助喷雾热解(FASP)方法可一步合成正极材料,具有设备简单、耗时短、环境友好等优点。采用FASP方法制备LiNi_(0.8)Mn_(0.2)O_(2)(NM82)无钴富镍正极材料,探究合成条件对NM82结构、形貌和电化学性能的影响。结果表明,FASP可一步合成NM82正极材料,且其在载气流速1.5L/min、锂过量10%、退火温度800℃条件下的锂镍混排水平最低,放电比容量最高,在0.1C倍率下达到180.2mA∙h/g。

三元镍钴锰酸锂的制备、电化学反应和研究进展

化石能源广泛地使用,在全球范围内造成了广泛的环境问题,开发新能源技术已经十分紧迫。循环使用的化学电源是能将电能和化学能进行相互转换。锂离子电池是依靠锂离子在电源正负极之间转移实现充放电过程,因工作电压高,电池体积小,电池质量轻,电池能量密度高,循环寿命长,因而受到广泛的关注。锂离子电池正极材料的制备工艺包括高温固相法,溶胶凝胶法,水热法和溶剂热法等。镍钴锰三元化合物材料存在的问题包括阳离子混排,不可逆相变和热失控等,解决的方法包括材料结构形貌的有效控制,掺杂和修饰改性。镍钴锰三元化合物材料用在锂离子正极材料时,其充放电过程与钴酸锂类似。目前LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)已经运用到圆柱电池和动力电池上,部分代替钴酸锂等材料。目前三元化合物具有非常广阔的应用前景。

不同正极材料的大容量锂离子电池热失控实验研究

为探究不同正极材料大容量锂离子电池的热失控特性,针对不同荷电状态(SOC)下相同容量的不同正极材料大容量52 Ah磷酸铁锂电池(LFP)和53 Ah三元锂离子电池(NCM)的热失控进行实验,通过热失控行为、热失控特征参数等参数对比二者的宏观行为与特征。实验结果表明:NCM热失控比LFP更剧烈;SOC越大,NCM与LFP更易发生热失控且热失控更剧烈,NCM热失控对SOC的变化更敏感。

镍钴锰酸锂三元正极材料的改性研究进展

锂离子电池的容量、循环寿命和安全性等性能很大程度上依赖于正极材料。镍钴锰酸锂(NCM)三元正极材料具有能量密度高、成本低、相对安全等优点而备受关注。但阳离子混排、界面副反应、不可逆相变等问题的存在严重影响了电池的循环和倍率等性能。综述了NCM正极材料的结构特点、问题成因,并从掺杂、表面包覆、单晶和浓度梯度结构等角度探讨了其改性研究情况,对其未来研究方向进行了展望。

镍钴资源及冶炼技术现状

分析了全球镍钴资源分布状况,归纳总结了镍钴冶炼技术现状。近年来,新发现的大型硫化镍钴矿较少,红土镍矿冶炼技术进步比硫化镍矿要快,特别是回转窑—电炉(RKEF)生产镍铁技术和高温高压浸出技术(HPAL)得到推广应用以来,红土镍矿获得大规模开发利用。钴产量主要来源于铜钴矿和红土镍矿湿法冶炼副产的钴,铜钴分离和镍钴富集技术也已得到广泛应用。最后对我国镍钴冶炼技术未来发展趋势进行了预测。

镍钴锰酸锂离子电池的制备及特性研究

研究锂离子电池在不同放电倍率、不同温度情况下放电电压随容量的变化,发现在高倍率3 C和低温-10℃时,电压变化最大。同时,不同放电倍率及温度下,锂离子电池的荷电状态与电压关系和容量与电压关系类似。锂离子电池在0.5 C充电1 C和3 C放电时,锂离子电池的循环寿命分别达1636周和819周,循环寿命优异。放电倍率越大,对锂离子电池的循环寿命越不利。

膜分离技术脱除废水中镍离子的研究进展

膜分离技术具有高效、节能、环保等诸多优点,顺应国家“双碳目标”和“乡村振兴”等相关政策,具有广阔的发展空间与应用前景。进入21世纪,世界各国都将膜分离技术列入优先发展的高新技术,促使膜分离技术进入了全面发展的崭新时期。本文结合传统的废水处理技术,综述了微滤、超滤、纳滤、反渗透、电渗析和新型有机-无机杂化膜在脱除废水中重金属镍离子方面的有关研究内容,分析并比较了各种废水处理方法的优点和缺点。针对相应的问题,提出了相关见解,并进行了展望。