Recovery of Nickel and Cobalt from Spent NiMH Batteries by Electrowinning

For nickel and cobalt recovery from spent NiMH batteries by electrowinning, the effect of different electrowinning parameters as boric acid concentration, temperature, current density, and pH were studied using different synthetic solutions. The optimized operational parameters were applied in an electrowinning test with a solution achieved by leaching the electrodes of NiMH batteries. The electrowinning tests were performed galvanostatically in a two‐compartment cell separated by an anionic membrane. A platinum/iridium‐coated titanium anode and a stainless‐steel cathode were used. A sodium sulfate solution served as anolyte. The results demonstrate the technical viability of nickel and cobalt recovery. The chemical composition of the obtained deposit presented high nickel and cobalt concentrations.     

聚酯材料表面化学镀镍的研究

研究了聚酯材料表面化学镀镍的实验操作方法、工艺控制条件,讨论了各种因素对镀层质量的影响,确定了聚酯材料表面化学镀镍的工艺流程和最佳实验条件。实验结果表明,聚酯材料经过预处理及敏化、活化处理后,化学镀镍溶液的pH值控制在5.5,镀镍温度在45℃,反应时间25min,可以得到较好的聚酯材料化学镀镍镀层。     

Separation of cadmium(II) from spent nickel/cadmium battery by emulsion liquid membrane

Experiments were conducted to investigate the separation of cadmium(II) from spent nickel/cadmium battery by emulsion liquid membrane. Liquid membrane mainly consisted of a diluent (kerosene), a surfactant (Span 80), a carrier (di(2‐ethylhexyl) phosphoric acid, D2EHPA) and an internal phase (sulfuric acid). Main research effort was focused on the identification of optimal parameters affecting the separation process, such as D2EHPA (4.4 vol%), Span 80 (6.6 vol%), pH in the external phase (3.0), treat ratio (0.4), agitation time (10 min), and sulfuric acid concentration (1500 mol / m³). With the selected emulsion liquid membrane to separate cadmium(II) from the leaching solution of spent nickel/cadmium battery, the fraction extracted of cadmium(II) ions (0.963) was much more than that of nickel(II) ions (0.026). The organic membrane phase after demulsification was re‐mulsification and recycled up to eight times.     

化学镀镍液的再生与回用

采用可溶性钙盐沉淀法去除化学镀镍废液中的亚磷酸根，用氟化物去除残余的钙离子，同时研究了PH值，处理温度及钙离子与亚磷酸根的浓度对绎亚磷酸根去除率的影响，采用再生处理液施镀可以得到具有优良性能的镀层，本方法具有经济可行的特点。     

化学镀镍-铜-磷三元合金工艺的研究

为提高化学镀镍－磷合金镀层的性能及获得多种性能的合金镀层以拓宽其应用范围。在化学镀镍－磷合金液中加入硫酸铜制得镍－铜－磷三元合金。研究了镀液中硫酸镍、次磷酸钠、柠檬酸钠、硫酸铜、稳定剂、光亮剂的含量以及pH值和温度等因素对合金镀层的外观、沉积速度及铜含量的影响。通过5％氯化钠溶液和10％硫酸溶液浸泡试验比较了所得镍－铜－磷合金镀层与镍－磷合金镀层以及前人制得的镍－磷合金镀层的耐蚀性，同时比较了上述镀层的其它性能。结果表明，所得镍－铜－磷合金镀层的耐蚀性、外观、结合力、孔隙率、沉积速度、硬度和耐磨性等性能优于镍－磷合金及前人制得的镍－铜－磷合金镀层。     

化学镀镍老化液的生物处理

以葡萄糖为碳源、污水处理厂厌氧池的活性污泥为种源,处理化学镀镍老化液中的亚磷酸盐和次磷酸盐.通过正交试验考察了葡萄糖添加量、菌种培养温度和初始pH、接种比及培养时间对磷去除率的影响.获得了最佳处理条件:葡萄糖0.8 g/L,培养液初始pH为6.5,温度35 ℃,接种比1.5:1,培养时间4 d.在此条件下处理化学镀镍老...     

陶器材料表面化学镀镍

实验研究了普通陶器材料化学镀镍的操作方法、工艺条件及各种因素对镀层的影响,实验结果表明,普通陶器材料经过预处理及敏化、活化处理后,化学镀镍的pH值在7.0,镀镍温度在80°C,反应时间40~45 min,镀层品质较好。     

电渗析法再生化学镀镍老化液的实验研究

应用电渗析技术,再生化学镀镍老化液以降低镀液成本,减少环境污染。在采用非均相离子交换膜条件下,考察了4种工艺条件对电渗析的选择去除效果的影响,得出了优化工艺条件,在去除副产物的同时限制了有效物质的流失。     

Electrical conductivity and density of NiSO4/H2SO4 solutions in the range of modern nickel electrorefining and electrowinning electrolytes

The density and electrical conductivity of nickel sulfate electrolytes as a function of nickel and sulfuric acid concentration and electrolyte temperature have been experimentally measured. Models have been developed to explain the effects of temperature, nickel and sulfuric acid concentration on the electrical conductivity and density. Empirical equations to mathematically quantify the reported values have also been derived to allow reasonable extrapolation. These models maybe used to enhance the electrorefining and electrowinning processes.     

Recovery of nickel from spent catalyst from palm oil hydrogenation process using acidic solutions

In this study, recovery of nickel from spent catalyst from palm oil hydrogenation process is carried out via extractive leaching process using sulfuric and hydrochloric acids. The effects of acid concentration, solid-liquid ratio, temperature and digestion time on the recovery (acid dissolution) process are investigated. It is found that sulfuric acid is the better leaching solution as compared to hydrochloric acid for recovery (dissolution) of nickel from the spent catalyst. Results from speciation modelling using VMINTEQ further imply that nickel can form sulfate complexes which are more stable than chloride complexes at concentrations higher than 1 M. The optimum conditions for maximum recovery at 85% are achieved at 67% sulfuric acid concentration, digestion time of 140 min, solid-to-liquid ratio of 1:14 and reaction temperature of 80 °C. At solution temperatures higher than 80 °C, the percentage nickel extraction is reduced. The optimization study presented here is useful for spent catalyst generators in the palm oil industry intending to recover valuable metals which may assist in reducing palm oil processing costs.     

从含镍磷铁中提镍的初步研究

以蛇纹石为原料生产钙镁磷肥副产含镍磷铁。为了提取含镍磷铁中的镍同时综合回收磷和铁,采用氨浸法以及酸浸法进行多种工艺组合实验。结果表明,含镍磷铁加纯碱经过850℃灼烧2 h后,水浸分离磷酸三钠,滤渣再加氨水在50℃浸取4 h,可以提取50%的镍;用硫酸处理含镍磷铁,可以一步生成硫酸镍和磷酸并进入溶液中,与铁分离,再经过过滤、沉淀、结晶等操作,最后分离出碳酸镍、磷酸氢二钠及氢氧化铁。     

工程塑料表面化学镀镍工艺的研究

给出了一种在工程塑料表面上利用化学方法进行镀镍的工艺,探讨了化学镀镍的工艺条件。结果表明:在钯离子活化作用下,控制溶液pH值(pH=4.7~4.9)和反应温度(85~90℃),用次磷酸钠还原可溶性硫酸镍,生成的金属镍牢固地沉积在工程塑料的表面,达到了化学镀镍的目的。     

丝纤维表面化学镀镍的研究

实验研究了丝纤维化学镀镍的操作方法、实验控制条件,讨论了各种因素对化学镀层的影响,试验了化学镀层与丝纤维的结合力,确定了丝纤维化学镀镍的工艺流程和最佳实验条件,实验结果表明,丝纤维经过预处理及敏化、活化处理后,化学镀镍溶液的pH值控制在8．0,镀镍温度在75℃,反应时间30min,可以得到较好丝纤维化学镀镍镀层。     

II. Electrodeposition/removal of nickel in a spouted electrochemical reactor

An investigation is presented of nickel electrodeposition from acidic solutions in a cylindrical spouted electrochemical reactor. The effects of solution pH, temperature, and applied current on nickel removal/recovery rate, current efficiency, and corrosion rate of deposited nickel on the cathodic particles were explored under galvanostatic operation. Nitrogen sparging was used to decrease the dissolved oxygen concentration in the electrolyte in order to reduce the nickel corrosion rate, thereby increasing the nickel electrowinning rate and current efficiency. A numerical model of electrodeposition, including corrosion and mass transfer in the particulate cathode moving bed, is presented that describes the behavior of the experimental net nickel electrodeposition data quite well.     

镁合金化学镀镍前植酸活化工艺

通过植酸活化可提高AZ31镁合金化学镀层的耐蚀性能。采用正交试验优化植酸活化工艺,利用金相显微镜观察了植酸膜的微观形貌,测定了植酸膜在质量分数为3.5%的NaCl溶液中的极化曲线及在化学镀镍液中的开路电位。结果表明,当植酸质量浓度为20g/L、温度为50°C、pH=8时处理25min,植酸膜具有良好的耐蚀性能,并且能够作为化学镀的活化层。     

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。     

Acid Precipitation and Purification of Wheat Straw Lignin

ABSTRACT

The acid precipitation and purification of lignin from wheat straw soda pulping effluent were studied. Prior to lignin precipitation, the suspended solids and dissolved silica were removed from the effluent to avoid lignin contamination. Suspended solids and dissolved silica were removed by centrifugation and selective precipitation at pH 5, respectively. After these treatments, the pH of the effluent was reduced to an optimum pH value of 3.5 with sulfuric acid in order to precipitate lignin. About 80% of the total lignin was recovered. Effluent color and COD were simultaneously reduced by 82 and 71%, respectively. Lignin precipitate purification was carried out by washing with aqueous acidic solutions. Only the time and the agitation rate influenced the washing process. The purity of the lignin was very high when the time and rate of agitation during washing were low. Under optimum conditions, lignin with a purity of 99.5% can be obtained.     

玻璃表面无钯活化化学镀镍的研究

利用热还原方法制备活性镍,取代了玻璃表面化学镀镍用钯活化的方法;探索了活化液的组成和制取活性镍的工艺条件,同时获得了在玻璃表面进行化学镀镍的镀液配方;通过ＳＥＭ对镀层的形貌和组成进行了观测。实验结果表明：所得镀液稳定、镀速好,镀制的镍层均匀、光亮;这说明玻璃表面用镍活化以取代用钯活化是一种可行的方法。     

超细氢氧化铝中氯离子的测定

研究了用硫酸溶解超细氢氧化铝并测定氯离子的方法.控制硫酸的加入量,调节溶液的pH值在2～3之间,以二苯偶氮碳酰肼作为指示剂,用标准硝酸汞溶液滴定.测定超细氢氧化铝中氯离子的相对平均偏差在3.40 %～6.63 %,加标回收率在95.50 %～109.10 %之间,此方法准确度高,结果稳定,操作简便.     

Preparation of nickel coating on ZTA particles by electroless plating

With the aim to effectively improve the interface between ZrO₂ toughened Al₂O₃ (ZTA) particles and metal matrix, nickel was deposited on the surface of ZTA particles by electroless plating method. Formation mechanism of nickel coating and effects of the solution pH, loading capacity of ZTA particles and temperature on the nickel deposition were investigated. Microstructures, thickness and element distributions of nickel coating were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the nickel was successfully deposited on the surface of ZTA particles by electroless plating without noticeable defects. The process of electroless nickel plating could be explained by combination of atomic hydrogen and electrochemistry theories. The interfacial nucleation of nickel is easier to form than spontaneous nucleation in the solution. Deposited Nickel has priority on the surface of ZTA particles comparing to that in solution. The optimal conditions to coat nickel on the surface of ZTA particles are: solution pH 4.7–4.8, loading capacity 15–20?g/L, and electroless plating temperature 85?°C. The ZTA particle reinforced iron matrix composites prepared by powder metallurgy could have better interfacial bonding between ZTA particle and iron matrix because of the nickel coating on the surface of ZTA particle. Nickel diffuses into the iron matrix during the sintering preparation of composite materials. The interface between ZTA particle and iron matrix presents the evidence of non-chemical bonding.