废锂电池负极全组分绿色回收与再生

以三氟乙酸溶液为溶剂,对废锂电池负极片中的铜箔、石墨及锂元素进行了综合回收试验研究,考察了不同实验条件对各组分回收效果的影响,并采用 XRD、SEM 和 FTIR 等手段对再生产物进行了表征。结果表明,经酸浸后,铜箔表面干净光亮,其回收率可达100%;石墨(锂离子浸出最佳酸浸条件下过滤所得的石墨)呈现出典型的层状结构特征,且纯度高、无杂质,其回收率约为 96.3%;在三氟乙酸浓度为 15%(体积分数)、固液比为 60 g/L、浸出温度为 40 ℃、浸出时间为 30 min的实验条件下,浸出液中锂离子的最大浸出质量分数为1.08%。经除杂后浸出液中锂元素的再生产物为纯相碳酸锂,其产率为 95.6%。实验中三氟乙酸溶剂可通过蒸馏的方式循环利用。整个工艺流程简单,绿色环保。     

油页岩灰渣中金属元素的赋存状态及醋酸浸出规律研究

采用醋酸有机酸分离法对油页岩灰渣中的金属元素进行转化分离,利用醋酸的高选择性和低污染性,将Ca、Mg、Na、K等金属元素转化为醋酸盐,实现高效分离。采用Tessier法和BCR法研究油页岩灰渣中金属元素的赋存状态,结果表明,油页岩灰渣中Ca、Mg、Na、K四种元素主要以可交换态、碳酸盐结合态和氧化物结合态等醋酸可提取态赋存,适于醋酸浸取分离法;而Fe元素的赋存状态不是醋酸可提取态,仅有少量以氧化物结合态赋存,不适于醋酸浸取分离法。研究了不同反应条件(反应时间、反应温度和醋酸浓度)对油页岩灰渣中金属元素醋酸浸出率的影响规律,优化反应条件可提高其醋酸浸出率,选择醋酸浓度为30%,醋酸浸取反应温度为30℃,反应时间为2.0h。     

NH_3-NH_4Cl-H_2O体系浸出氧化锌矿的试验研究

研究了用NH_3-NH_4Cl-H_2O体系浸出氧化锌矿,进行了正交试验和单因素试验,并对浸出渣进行了物相和能谱分析。通过正交试验得出浸出氧化锌矿工艺,影响锌浸出率的主要因素的较佳组合为:液固比4.5mL/g、浸出时间60min、浸出温度20℃、总氨浓度6.0mol/L。由正交试验结果适当调整工艺参数,进行单因素试验研究,考察液固比、浸出时间、温度及总氨浓度对锌浸出率的影响,得到优化工艺条件为:液固比5mL/g、浸出时间60min、浸出温度20℃、总氨浓度6.0 mol/L。在优化条件下,锌的浸出率达到88.1%,物相分析表明浸出渣主要成分是SiO2、针铁矿(FeOOH),含锌物相为ZnS,实现了锌选择性高效溶出,与铁、铝、硅等杂质元素的有效分离。     

某金矿石中金浸出率的实验

目前,该矿采用全泥氰化炭浆法进行生产。由于金以超微粒金存在褐铁矿中,金的氰化浸出率较低。试验拟定了一个提高金氰化浸出率的工艺方法,在氰化浸出时,加入一种自行研制的高效助浸剂,可有效地提高金的氰化浸出率,使金的氰化浸出率达93.75%,比现行生产中工艺方法提高14%。该工艺方法操作简便,药剂成本低,设备投资小,见效快,具有较好的经济效益和社会效益,值得推广。     

高铁闪锌矿精矿加压浸出半工业试验研究

高铁闪锌矿经二段加压浸出，锌浸出率97.09%，铁浸出率15.2%，元素硫产率93%，浸出液残酸3.95g/L，经简单中和、净化，生产合格硫酸锌新液供应锌电积。为了研究比较，闪锌矿经一段加压浸出，锌的浸出率98.09%，铁浸出率37.88%，元素硫产率96%，浸出液残酸高（46.4g/L），可并入现有传统湿法炼锌工艺流程处理。     

酸浸法提取粉煤灰中铝铁及纳米氧化铁的制备北大核心CSCD

硫酸加压浸出法提取粉煤灰中的铝、铁等金属元素是一种有效利用粉煤灰的方法。硫酸浓度、浸出温度、反应时间等对铝、铁元素的浸出率具有显著影响,优化条件下铝元素浸出率超过90%,铁元素浸出率超过98%;利用伯胺N_(1923)-TBP萃取滤液中的铁,以2mol/L氯化钠溶液反萃,有效分离了浸出液中的铝、铁离子。在室温条件下,采用沉淀-超声波辅助结晶法制备了α-FeOOH纳米颗粒,经过350℃煅烧4h制得了短棒状纳米α-Fe_2O_3。     

废脱硝催化剂钒、钨的浸出-搅拌对浸出率的影响

实现废脱硝催化剂高效综合再利用具有重大的社会和经济效益。本文采用NaOH浸出废脱硝催化剂中钒钨离子并考察其浸出影响因素,对比研究了搅拌和不搅拌作用下废脱硝催化剂中的钨离子浸出动力学。结果表明,提高浸出温度和NaOH浓度均有利于钒、钨的浸出;在搅拌条件下(350 r/min),液固比3.5∶1,浸出温度160℃,NaOH浓度40%,浸出时间3.5 h,钒、钨浸出率均达到100%。动力学研究结果钨离子浸出过程属于固膜扩散控制,搅拌条件下钨浸出表观活化能为29.28 kJ/mol,而不搅拌时,其表观活化能仅为1.26 kJ/mol,搅拌强化可增加扩散速率,减小扩散阻力,强化钒钨的浸出。     

钠化焙烧法回收废SCR催化剂中钒和钨的浸出机理及浸出动力学研究

鉴于废烟气脱硝催化剂具有浸出毒性的危险特性,环境保护部明确将废烟气脱硝催化剂纳入危险废物进行管理,同时由于废催化剂中含有高价值的钒钨钛成分,对废脱硝催化剂的资源化回收技术的研究成为近年来环保领域的热点。钠化焙烧可以破坏废催化剂原有的组织结构,使其中钒钨发生相变而提高浸出率,工艺简单,因此适用性广。2012年Kim等就采用钠化焙烧-水浸工艺回收废SCR催化剂中的钒和钨,并对焙烧过程机理进行研究,但目前对于钒钨浸出过程机理尚未有人研究。本工作是为了探究废SCR催化剂焙烧后浸出过程的反应机理,研究反应过程的控制条件,并进一步研究浸出过程动力学,从而使钒钨浸出反应的过程清晰明了,为提高浸出经济性提供理论基础。利用X射线衍射(XRD)和扫描电镜(SEM)对焙烧后样品的物相和形貌进行了分析,基于此设计了浸出过程的动力学模型,推导反应过程浸出方程,并通过浸出过程实验结果对浸出方程的参数进行推导。研究结果表明,焙烧后的试样呈柱状烧结相和针状非烧结相,两种相间几乎是完全分离的,钒、钨等主要存在于柱状烧结相中,因此适合对其进行直接水浸处理,使钒和钨溶出;根据焙烧形貌和假设,采用非端面柱状缩合模型推导了浸出过程动力学方程,得出浸出率和时间的函数关系。通过单因素实验确定了最佳的浸出条件为:液固比3∶1,浸出温度为80℃,搅拌速率为350 r/min,时间为30~40 min,此时钒和钨的回收率分别为90.07%和84.57%;通过回收率与浸出时间的关系换算出浸出率和时间的关系,并推导出钒、钨的浸出动力学方程为ηV=0.001 05t~2+0.066 2t+0.014 66和ηW=0.001 00t~2+0.064 12t+0.014 91。     

低温酸浸高铁铝土矿中铁和铝的溶出规律研究

采用低温酸浸法对广西高铁铝土矿中的铝和铁的溶出规律进行了研究,考察了硫酸浓度、浸出温度、浸出时间及液固比因素对铝土矿中铝和铁溶出率的影响.结果表明,最优浸出条件为浸出时间60min,浸出温度100℃,液固比5∶1,硫酸浓度20％.此条件下铁的浸出率为98.68％,铝的浸出率为3.02％,溶出比为32.68,可实现高铁铝土矿中铁和铝的分步溶出.对该浸出过程进行动力学分析研究表明,此条件下浸出过程属化学反应控制,其控制动力学方程为:lgk=3-1.83×10-31/T反应活化能Ea=35.11kJ/mol.     

钠化富硼渣中硼化物析晶动力学分析与实验研究

富硼渣经熔态钠化—热处理析晶—水浸工艺可制得硼砂晶体。硼的浸出率与渣中硼组分析出形态直接相关,若以NaBO2为主晶相析出,硼浸出率高;若以玻璃态存在,硼浸出率低。根据非晶固体形成动力学理论,计算富硼渣钠化过程中NaBO2成核速度(I)和晶体长大速度(IL),获得了NaBO2晶体在熔体中的最佳形成温度。采用化学分析方法研究了热处理温度对渣中硼浸出率的影响。结果表明,钠化渣的最佳热处理温度与理论计算所得最佳温度一致。     

Nickel hydroxide ageing time influence on its solubility in water acidified with sulphuric acid

Nickel hydroxide samples freshly settled as well as stored over 1 month, 2 months and 6.5 years were examined for their solubility rate in diluted H2SO4 solutions of pH 1.9 and 2.8 as a function of time. Samples with a longer ageing history dissolved less readily than freshly settled ones. It was determined that the resistance to dissolving rose with sample ageing time and the solubility of the 6.5 years stored sample was particularly low. X-ray examination evidenced that during storage the crystallinity of Ni(OH)2 subsequently rose. The parallelity of both time-dependent phenomena allows the conclusion that with nickel hydroxide ageing the transformation of disordered nickel hydroxide species into crystalline Ni(OH)2 (without phase changes) is responsible for increasing nickel hydroxide resistance to dissolving in acidic solutions. Such decrease of nickel hydroxide solubility with ageing in case of waste nickel hydroxide, is worth to notice in a view of environment protection against pollution with electroplating waste.     

电池用正极材料纳米Ni(OH)2的研究进展

综述了电池正极材料Ni(OH)2的几种主要制备方法,介绍了各种制备方法的工艺条件及主要特点,描述了制备Ni(OH)2过程中的影响因素,指出氢氧化镍作为电池正极材料具有光明的前景,但对生产技术还需进一步研究.     

Effect of binder properties on the strength,porosity and leaching behaviour of single nickel laterite pellet

Nickel laterite pellets with controlled mass, porosity and binder were made by using a pellet press. Both water and sulphuric acid solution were used as binders. The wet pellets were then dried at different conditions and their mechanical strength was measured. Leaching tests were also conducted on single pellet with irrigation of sulphuric acid solution from the top of the pellet. The leached out solutions were collected and nickel recoveries were analysed. The time taken for the pellets to disintegrate during leaching test was also recorded. It was found that the mechanical strength of the pellets was directly related to their dryness, with completely dried pellets having much higher strength. The dry pellet strength was found to increase with increasing binder content and decreasing pellet porosity. The time taken for the pellets to disintegrate during leaching test increased with increasing pellet strength. In comparison to sulphuric acid solution-bound pellets at the same condition, water-bound pellets exhibited higher mechanical strength. Although the nickel leaching rate for water-bound pellets was low at the beginning of the leaching test, the pellets lasted for more than 200 h without disintegration, with 70% of nickel recovered.     

The structural transitions during leaching of Ni2Al3 phase in a Raney Ni-Al alloy

The microstructure transitions during leaching of a rapidly solidified Ni-Al alloy have been investigated by means of X-ray diffraction, transmission electron microscopic (TEM) and high resolution electron microscopic (HREM) techniques. Ni₂Al₃ was the main phase in the starting Ni-Al alloy. The microstructure of the Raney nickel catalyst consists of nano-scale nickel crystallites, residue of source phases surrounded by nano-scale boundary regions. The transformation during leaching of Ni₂Al₃ phase was an advancing interface type process. Clusters of AuCu-structure type face-centrered tetragonal Ni₃Al₂ as an intermediate phase seems to appear in the reaction front. Based on an analysis of the atomic configurations of phases Ni₂Al₃, Ni₃Al₂ and nickel, a reasonable explanation for the transition mechanism during leaching of Ni₂Al₃ phase and the arc characteristic of diffraction spots was proposed. The nickel crystallites generated during leaching obey an orientation relationship with the source Ni₂Al₃ phase, which is consistent with the Delannay's orientation relationship proposed for nickel and NiAl phases. The nano-scale structural characteristic of the Raney nickel catalyst, especially its porous structure at the boundary regions, provides an excellent hydrogenation catalytic activity and selectivity of the catalyst.     

高灰分碳粉的碱酸法提纯

对某电解铝企业废旧阴极材料进行浮选-酸洗-磨碎处理后获得含灰分高达27.3%的碳粉,然后采用加NaOH焙烧活化-水洗-盐酸酸浸-水洗工艺对该碳粉进行除灰提纯研究。考察了氢氧化钠加入量、焙烧温度、焙烧时间、盐酸酸浸温度对碳粉灰分脱除的影响。结果表明:当设定氢氧化钠/碳粉为0.4,在1000℃焙烧1h,然后采用浓度为1mol/L的盐酸在60℃酸浸1h,可使碳粉中的灰分由27.3%降低到4.04%,碳含量由68.4%提高至94.6%,处理后的碳粉可重返阴极配料利用。     

Structural transitions during aluminum leaching of NiAl<Subscript>3</Subscript> phase in a Raney Ni–Al alloy

Structural transitions during aluminum leaching of the NiAl₃ phase in a Raney nickel–aluminum alloy have been investigated by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray energy dispersive spectroscopy. We observed that NiAl₃ grains cracked into crystalline nano-fragments at the initial stage of leaching. A possible mechanism for the grain fragmentation was proposed based on the crystal structure of NiAl₃. We discovered that fcc nickel, the known active phase, coexisted with another active nickel phase with an orthorhombic structure in the Raney-Ni catalyst. The orthorhombic nickel phase was generated directly from its source phase, NiAl₃, and further transformed to the fcc nickel phase during aluminum leaching     

Bioleaching of spent Ni-Cd batteries by continuous flow system: effect of hydraulic retention time and process load

Spent Ni–Cd batteries bring a severe environmental problem that needs to be solved urgently. A novel continuous flow two-step leaching system based on bioleaching was introduced to dissolve heavy metals in batteries. It consists of an acidifying reactor which was used to culture indigenous thiobacilli and a leaching reactor which was used to leach metals from spent batteries. The indigenous acidophilic thiobacilli in sewage sludge was used as the microorganisms and the sludge itself as culture medium. Bioleaching tests at different hydraulic retention time (HRT) and process load in the leaching reactor were performed. The results showed that the longer the HRT (1, 3, 6, 9 and 15 days) was, the more time required to achieve the complete leaching of Ni, Cd and Co. The maximum dissolution of cadmium and cobalt was achieved at higher pH values (3.0–4.5) while the leaching of nickel hydroxide and nickel in metallic form (Ni⁰) were obtained separately in different acidity (pH 2.5–3.5). It cost about 25, 30 and more than 40 days to remove all of the three heavy metals with the process load of two, four and eight Ni–Cd batteries under the conditions that the ingoing bio-sulphuric acid was 1 L d⁻¹ and HRT was 3 days.     

Mechanical strength and rewetting stability of nickel laterite pellets

The stability of agglomerated/pelletized ores is one of the key properties for successful heap leaching of complex, low-grade nickel laterite minerals. In this paper, single pellets of saprolitic and goethitic nickel laterite with controlled binder type (tap water and 44 wt.% H₂SO₄), binder content and pre-set porosity were made by a pellet press and subjected to mechanical strength and rewetting stability tests. The effect of fine/coarse particles ratio on the mechanical strength was also investigated using siliceous goethitic ore. The failure strength of the pellets under different drying conditions was measured and the time taken for the pellets to disintegrate under saturated (soaking) and leaching conditions was recorded. The results showed that, with the same type of nickel laterite, the time taken to disintegration during leaching test is proportional to the pellets tensile strength. Pellets with water as binder are more stable under soak conditions. Furthermore, failure strength for oven dried pellets is greater than that of air dried. With saprolitic nickel laterite (SAP) pellets, their mechanical strength and re-wetting stability can be enhanced by drying the wet pellets or by increasing the binder content in the pellets. The pellets mechanical strength was found to be a good indication of their stability under leaching conditions as well. However, no relationship between the two was observed for goethitic nickel laterite pellets.     

Recovery and reuse of Ni(II) from rinsewater of electroplating industries

Discharge of nickel compounds, which may occur in both liquid and solid phases, can cause severe environmental problems. In this work, 'point of source' treatment strategy is followed and reduced the nickel content of rinsewater to about less than 1 mg L(-1) by ion-exchange method using a packed column involving batch recirculation mode of operation and to recovered Ni(II) content by desorption. The treated water could be recycled for rinsing operation. The nickel from resin is first precipitated as nickel hydroxide to synthesize positive active material and that was used in Nickel/Metal hydride cell. The performances in terms of electrochemical utilization of nickel hydroxide, specific capacity as a function of discharge current density and cycle life were examined and the nickel hydroxide electrode with 5% CaCO(3) addition, having 200 mAh g(-1) specific capacity, could be subjected to charge/discharge cycles at C/5 rate for more than 200 cycles without the capacity fading.     

火法焙烧蛇纹石制取氢氧化镁工艺研究

改变传统的酸浸取法,研究添加硫酸铵火法焙烧蛇纹石以浸出镁的适宜工艺条件,并用该法制备超细氢氧化镁,对试验中消耗的硫酸铵进行回收,并测试回收后的焙烧再用效果。结果表明,在本实验设计的工艺流程下蛇纹石中镁元素的一次烧出率可以达到62.42%,制备的超细氢氧化镁的白度可达99.8%,二次粒径d50≤10μm,硫酸铵回收率为55%,但返回焙烧再用效果较好。