Study concerning the recovery of zinc and manganese from spent batteries by hydrometallurgical processes

Used batteries contain numerous metals in high concentrations and if not disposed of with proper care, they can negatively affect our environment. These metals represent 83% of all spent batteries and therefore it is important to recover metals such as Zn and Mn, and reuse them for the production of new batteries. The recovery of Zn and Mn from used batteries, in particular from Zn–C and alkaline ones has been researched using hydrometallurgical methods. After comminution and classification of elemental components, the electrode paste resulting from these processes was treated by chemical leaching. Prior to the leaching process the electrode paste has been subjected to two washing steps, in order to remove the potassium, which is an inconvenient element in this type of processes. To simultaneously extract Zn and Mn from this paste, the leaching method in alkaline medium (NaOH solution) and acid medium (sulphuric acid solution) was used. Also, to determine the efficiency of extraction of Zn and Mn from used batteries, the following variables were studied: reagents concentration, S/L ratio, temperature, time. The best results for extraction yield of Zn and Mn were obtained under acid leaching conditions (2 M H₂SO₄, 1 h, 80 °C).     

Fixation and partitioning of heavy metals in slag after incineration of sewage sludge

Fixation of heavy metals in the slag produced during incineration of sewage sludge will reduce emission of the metals to the atmosphere and make the incineration process more environmentally friendly. The effects of incineration conditions (incineration temperature 500-1100°C, furnace residence time 0-60min, mass fraction of water in the sludge 0-75%) on the fixation rates and species partitioning of Cd, Pb, Cr, Cu, Zn, Mn and Ni in slag were investigated. When the incineration temperature was increased from 500 to 1100°C, the fixation rate of Cd decreased from 87% to 49%, while the fixation rates of Cu and Mn were stable. The maximum fixation rates for Pb and Zn and for Ni and Cr were reached at 900 and 1100°C, respectively. The fixation rates of Cu, Ni, Cd, Cr and Zn decreased as the residence time increased. With a 20min residence time, the fixation rates of Pb and Mn were low. The maximum fixation rates of Ni, Mn, Zn, Cu and Cr were achieved when the mass fraction of water in the sludge was 55%. The fixation rate of Cd decreased as the water mass fraction increased, while the fixation rate of Pb increased. Partitioning analysis of the metals contained in the slag showed that increasing the incineration temperature and residence time promoted complete oxidation of the metals. This reduced the non-residual fractions of the metals, which would lower the bioavailability of the metals. The mass fraction of water in the sludge had little effect on the partitioning of the metals. Correlation analysis indicated that the fixation rates of heavy metals in the sludge and the forms of heavy metals in the incinerator slag could be controlled by optimization of the incineration conditions. These results show how the bioavailability of the metals can be reduced for environmentally friendly disposal of the incinerator slag.     

Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO(2) and CoO directly as CoC(2)O(4)·2H(2)O with 1.0 M oxalate solution at 80°C and solid/liquid ratio of 50 g L(-1) for 120 min. The reaction efficiency of more than 98% of LiCoO(2) can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.     

Laboratory study on the behaviour of spent AA household alkaline batteries in incineration

The quantitative evaluation of emissions from incineration is essential when Life Cycle Assessment (LCA) studies consider this process as an end-of-life solution for some wastes. Thus, the objective of this work is to quantify the main gaseous emissions produced when spent AA alkaline batteries are incinerated. With this aim, batteries were kept for 1h at 1273K in a refractory steel tube hold in a horizontal electric furnace with temperature control. At one end of the refractory steel tube, a constant air flow input assures the presence of oxygen in the atmosphere and guides the gaseous emissions to a filter system followed by a set of two bubbler flasks having an aqueous solution of 10% (v/v) nitric acid. After each set of experiments, sulphur, chlorides and metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were analyzed in both the solutions obtained from the steel tube washing and from the bubblers. Sulphur, chlorides and metals were quantified, respectively, using barium sulfate gravimetry, the Volhard method and atomic absorption spectrometry (AAS). The emissions of zinc, the most emitted metal, represent about 6.5% of the zinc content in the batteries. Emissions of manganese (whose oxide is the main component of the cathode) and iron (from the cathode collector) are negligible when compared with their amount in AA alkaline batteries. Mercury is the metal with higher volatility in the composition of the batteries and was collected even in the second bubbler flask. The amount of chlorides collected corresponds to about 36% of the chlorine in the battery sleeve that is made from PVC. A considerable part of the HCl formed in PVC plastic sleeve incineration is neutralized with KOH, zinc and manganese oxides and, thus, it is not totally released in the gas. Some of the emissions are predictable through a thermodynamic data analysis at temperatures in the range of 1200-1300K taking into account the composition of the batteries. This analysis was done for most of potential reactions between components in the batteries as well as between them and the surrounding atmosphere and it reasonably agrees the experimental results. The results obtained show the role of alkaline batteries at the acid gases cleaning process, through the neutralization reactions of some of their components. Therefore, LCA of spent AA alkaline batteries at the municipal solid waste (MSW) incineration process must consider this contribution.     

Characterization of spent AA household alkaline batteries

The aim of this work is identification of the structural components of actual domestic spent alkaline AA batteries, as well as quantification of some of their characteristics. Weight, humidity, ash content, zinc and zinc oxide on anode, manganese on cathode and other metals, potassium hydroxide on the internal components and heating values for papers, anode and cathode were determined in several batteries. As expected, cathode, anode and the steel can container are the main contributors to the 23.5 g average weight of the batteries. Cathode is also the major contributor to the positive heating value of the batteries as well as to the heavy metals content. Mercury was detected in very low levels in these mercury-free batteries. Zinc and zinc oxide amounts in the anodes are highly variable. Results obtained were compared to information on alkaline batteries in the literature from 1993 to 1995; and a positive evolution in their manufacture is readily apparent. Data from the producer of batteries shows some small discrepancies relative to the results of this experimental work.     

Survey of mercury,cadmium and lead content of household batteries

The objective of this work was to provide updated information on the development of the potential impact of heavy metal containing batteries on municipal waste and battery recycling processes following transposition of the new EU Batteries Directive 2006/66/EC. A representative sample of 146 different types of commercially available dry and button cells as well as lithium-ion accumulators for mobile phones were analysed for their mercury (Hg)-, cadmium (Cd)- and lead (Pb)-contents. The methods used for preparing the cells and analysing the heavy metals Hg, Cd, and Pb were either developed during a former study or newly developed. Several batteries contained higher mass fractions of mercury or cadmium than the EU limits. Only half of the batteries with mercury and/or lead fractions above the marking thresholds were labelled. Alkaline–manganese mono-cells and Li-ion accumulators, on average, contained the lowest heavy metal concentrations, while zinc–carbon batteries, on average, contained the highest levels.     

Evaluation of heavy metal leaching from spent household batteries disposed in municipal solid waste

Batch leaching tests and simulated landfill lysimeter tests were performed to evaluate the contents of heavy metals leached from spent batteries in the municipal solid waste. The toxicity characteristic leaching procedure was utilized to perform the batch leaching tests of 36 spent batteries. Four lysimeters were prepared with battery contents ranging from 0% to 100% by weight for column tests, and the experiments were performed at ambient temperature. The age of all the batteries used in the study ranged from freshly disposed up to approximately 3 years old. The results from the batch tests showed that the type of battery influenced the heavy metal concentrations in the leached solutions. The lysimeter experiment results illustrated that at lower pH levels more metals are leached than at higher pH levels. The increasing amount of batteries disposed in landfills can contribute to the leaching of more metals, especially Mn and Zn, into the environment. These results indicate that the direct disposal of spent household batteries into a MSW landfill can increase the heavy metal contents in the landfill leachate.     

失效动力锂离子电池再利用和有用金属回收技术研究

动力锂离子电池以其贮电能力大、充放电速度快等优点被广泛应用在电动汽车上,近年来失效电动汽车动力锂离子电池报废量不断增加,但未得到有效处理回收,造成了巨大的资源浪费和环境污染.失效电池还有80％左右的容量可以使用,可以在场地车或者储能电站进行再利用,以达到材料和电池的最大利用率;同时电池中含有多种有用金属（如Co,Al,Ni,Li等）且相对含量较高,极具回收价值.针对失效动力锂离子电池的再利用和有用金属的各种回收方法进行了评述.     

Metal separation from mixed types of batteries using selective precipitation and liquid-liquid extraction techniques

The purpose of this paper is to study metal separation from a sample composed of a mixture of the main types of spent household batteries, using a hydrometallurgical route, comparing selective precipitation and liquid-liquid extraction separation techniques. The preparation of the solution consisted of: grinding the waste of mixed batteries, reduction and volatile metals elimination using electric furnace and acid leaching. From this solution two different routes were studied: selective precipitation with sodium hydroxide and liquid-liquid extraction using Cyanex 272 [bis(2,4,4-trimethylpentyl) phosphoric acid] as extracting agent. The best results were obtained from liquid-liquid extraction in which Zn had a 99% extraction rate at pH 2.5. More than 95% Fe was extracted at pH 7.0, the same pH at which more than 90% Ce was extracted. About 88% Mn, Cr and Co was extracted at this pH. At pH 3.0, more than 85% Ni was extracted, and at pH 3.5 more than 80% of Cd and La was extracted.     

Tannic acid as a novel and green leaching reagent for cobalt and lithium recycling from spent lithium-ion batteries

Tannic acid–acetic acid is proposed as novel and green chemicals for cobalt and lithium recycling from spent lithium-ion batteries through a leaching process. The synergism of both acids was documented through batch and continuous studies. Tannic acid promotes cobalt dissolution by reducing insoluble Co³⁺ into soluble Co²⁺, while acetic acid is critical to improve the dissolution and stabilize the metals in the pregnant leach solution. Based on batch studies, the optimum conditions for metal recovery at room temperature are acetic acid 1 M, tannic acid 20 g/L, pulp density 20 g/L, and stirring speed 250 rpm (94% cobalt and 99% lithium recovery). The kinetic study shows that increasing temperature to 80 °C improves cobalt and lithium recovery from 65 to 90% (cobalt) and from 80 to 99% (lithium) within 4 h at sub-optimum condition (tannic acid 10 g/L). Kinetic modeling suggests the leaching process was endothermic, and high activation energy indicates a surface chemical process. For other metals, the pattern of manganese and nickel recovery trend follows the cobalt recovery trend. Copper recovery was negatively affected by tannic acid. Iron recovery was limited due to the weak acidic condition of pregnant leach solution, which is beneficial to improve leaching selectivity.

     

Vitrification for reclaiming spent alkaline batteries

The object of this study is to stabilize spent alkaline batteries and to recover useful metals. A blend of dolomite, limestone, and cullet was added to act as a reductant and a glass matrix former in vitrification. Specimens were vitrified using an electrical heating furnace at 1400 °C and the output products included slag, ingot, flue gas, and fly ash. The major constituents of the slag were Ca, Mn, and Si, and the results of the toxicity leaching characteristics met the standards in Taiwan. The ingot was a good material for use in production of stainless steel, due to being mainly composed of Fe and Mn. For the fly ash, the high level of Zn makes it economical to recover. The distribution of metals indicated that most of Co, Cr, Cu, Fe, Mn, and Ni moved to the ingot, while Al, Ca, Mg, and Si stayed in the slag; Hg vaporized as gas phase into the flue gas; and Cd, Pb, and Zn were predominately in the fly ash. Recovery efficiency for Fe and Zn was >90% and the results show that vitrification is a promising technology for reclaiming spent alkaline batteries.     

Recovery of manganese oxides from spent alkaline and zinc–carbon batteries. An application as catalysts for VOCs elimination

Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO₄ solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO_x synthesized in our laboratory.The characterization by XRD, FTIR and XPS reveal the presence of Mn₂O₃ in the EMO and the CMO samples, together with some Mn⁴⁺ cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn₃O₄.The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO₂.The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs.     

Nickel and cobalt recycling from lithium-ion batteries by electrochemical processes

The presence of LiCoO(2) and LiCo(x)Ni((1-x))O(2) in the cathodic material of Li-ion and Li-polymer batteries has stimulated the recovery of Co and Ni by hydrometallurgical processes. In particular, the two metals were separated by SX method and then recovered by electrochemical (galvanostatic and potentiostatic) processes. The metallic Ni has been electrowon at 250 A/m(2), pH 3-3.2 and 50 degrees C, with 87% current efficiency and 2.96 kWh/kg specific energy consumption. Potentiostatic electrolysis produces a very poor Ni powder in about 1 h with current efficiency changing from 70% to 45% depending on Ni concentration in the electrolyte. Current efficiency of 96% and specific energy consumption of 2.8 kWh/kg were obtained for Co at 250 A/m(2), pH 4-4.2 and 50 degrees C, by using a solution containing manganese and (NH(4))(2)SO(4). The Co powder, produced in potentiostatic conditions (-0.9 V vs. SCE, pH 4, room temperature) appears particularly suitable for Co recycling as cobaltite in new batteries.     

Leaching studies for tin recovery from waste e-scrap

Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50g/L and temperature 90°C in mixing time 165min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60min and pulp density 50g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.     

Recycling nickel from spent catalyst of Phu My fertilizer plant as a precursor for exhaust gas treatment catalysts preparation

In this study, a very promising way of treating and recycling spent nickel catalysts of fertilizer plants in Vietnam was proposed. Firstly, nickel was recovered from spent catalyst using HNO₃—leaching process. Results show that nickel recovery of over 90% with a purity of over 90% can be achieved with HNO₃ 2.1–2.5 M at 100?°C in 75 min. The residue after leaching is not considered as a hazardous waste according to the Vietnamese regulations. Then, the leachate solution was used as a precursor to prepare a model catalyst for exhaust gas (CO, HC, NO_x) treatment. In comparison with the catalyst prepared from the commercial nickel nitrate solution, the catalyst synthesized from recovered nickel exhibits similar properties and activities. The influence of Ni loading of Ni/alumina catalyst as well as the modification of active phase by some metals addition (Mn, Ba, Ce) was also investigated. It is feasible to modify active phase by transition metals such as Mn, Ba, and Ce for complete oxidation of CO and HC at 270?°C and a reduction of NO_x below 350?°C at high volumetric flow condition (GHSV?=?110.000 h^?1).     

Reclaiming the spent alkaline zinc manganese dioxide batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi0.5Mn1.5O4 materials

A process for reclaiming the materials in spent alkaline zinc manganese dioxide (Zn–Mn) batteries collected from the manufacturers to prepare valuable electrolytic zinc and LiNi_0.5Mn_1.5O₄ materials is presented. After dismantling battery cans, the iron cans, covers, electric rods, organic separator, label, sealing materials, and electrolyte are separated through the washing, magnetic separation, filtrating, and sieving operations. Then, the powder residues react with H₂SO₄ (2 mol L^?1) solution to dissolve zinc under a liquid/solid ratio of 3:1 at room temperature, and subsequently, the electrolytic Zn with purity of ?99.8% is recovered in an electrolytic cell with a cathode efficiency of ?85% under the conditions of 37–40 °C and 300 A m^?2. The most of MnO₂ and a small quantity of electrolytic MnO₂ are recovered from the filtration residue and the electrodeposit on the anode of electrolytic cell, respectively. The recovered manganese oxides are used to synthesize LiNi_0.5Mn_1.5O₄ material of lithium-ion battery. The as-synthesized LiNi_0.5Mn_1.5O₄ discharges 118.3 mAh g^?1 capacity and 4.7 V voltage plateau, which is comparable to the sample synthesized using commercial electrolytic MnO₂. This process can recover the substances in the spent Zn–Mn batteries and innocuously treat the wastewaters, indicating that it is environmentally acceptable and applicable.     

Mercury flows in a zinc smelting facility in South Korea

To prepare for the international mercury convention, the characteristics of mercury emissions from a zinc smelting facility in South Korea have been reviewed and a material flow analysis (MFA) has been conducted in this research. As inputs into the mercury MFA study, zinc ores and sulfuric acid were examined, whereas wastewater sludge, effluence water, spent catalyst, and emissions from the casting and roasting processes were examined as outputs. Mercury concentrations extracted from end products like zinc ingots, cadmium ingots, and sulfuric acid were then analyzed. Our results showed that the wastewater sludge discharged from the zinc smelting process had a relatively higher concentration of mercury, indicating that the concentration of mercury was further enriched in the wastewater sludge. The wastes discharged through the zinc smelting process should be thoroughly controlled, as results of the MFA showed that approximately 89 % of the mercury contained in the original input was later found in the waste. According to this study, the higher the concentration of mercury within zinc ores at the input stage, the higher is the mercury concentration found in the wastewater sludge at the output stage.     

黄钠铁矾法氧化去除废锂电池硫酸浸出液中的铁

废锂电池中含有的Co、Ni和Cu等金属具有回收价值,Fe的存在降低了有价金属的回收效率。为去除废锂电池硫酸浸出液中的Fe,采用黄钠铁矾法分别以氯酸钠和过氧化氢作为氧化剂氧化除Fe,并优化了过氧化氢作为氧化剂的除Fe工艺参数。实验结果表明:过氧化氢作为氧化剂的除Fe效果好于氯酸钠;在n(H2O2)∶n(Fe)=0.5、初始溶液pH为1.8、终点pH为2.5、反应时间为2.0 h、搅拌速率为500 r/min的最佳工艺条件下,初始ρ(Fe)为0.212g/L的硫酸浸出液经除Fe处理后ρ(Fe)小于0.004 g/L,Fe去除率达98.0%,Co、Ni和Cu的损失率分别为1.04%、2.17%和1.41%。     

溶剂萃取法提取废旧碱性电池中的有价成分

为回收利用废旧电池，进行了溶剂萃取法提取碱性废弃电池中锌、锰金属的试验研究。选择南孚（AA）碱性废电池为处理样品，通过粉碎、水浸、酸浸等步骤，获得含锌、锰离子的稀溶液，并利用模拟体系得到的萃取结果进行浸出液的萃取性能试验研究。结果表明，每个废电池填充物中含锌和锰分别为0.25g和0.36g，具有可观的回收价值；采用完全皂化的二（2－乙基己基）磷酸（D2EHPA）／煤油为萃取剂提取含锌锰的酸浸出液，一级萃取就可获得60％以上的提取率。     

The BATINTREC process for reclaiming used batteries

The Integrated Battery Recycling (BATINTREC) process is an innovative technology for the recycling of used batteries and electronic waste, which combines vacuum metallurgical reprocessing and a ferrite synthesis process. Vacuum metallurgical reprocessing can be used to reclaim the mercury (Hg) in the dry batteries and the cadmium (Cd) in the Ni-Cd batteries. The ferrite synthesis process reclaims the other heavy metals by synthesizing ferrite in a liquid phase. Mixtures of manganese oxide and carbon black are also produced in the ferrite synthesis process. The effluent from the process is recycled, thus significantly minimizing its discharge. The heavy metal contents of the effluent could meet the Integrated Wastewater Discharge Standard of China if the ratio of the crushed battery scrap and powder to FeSO4.7H2O is set at 1:6. This process could not only stabilize the heavy metals, but also recover useful resource from the waste.