Recovery of Co（Ⅱ） and Ni（ Ⅱ） from hydrochloric acid solution of alloy scrap

A hydrometallurgical process was developed for recovery of nickel and cobalt from the hydrochloric acid leaching solution of alloy scraps. The process consists of five maj or unit operations： 1） leaching with 6 mol/L hydrochloric acid under the L/S ratio of 10：1 at 95 ℃ for 3 h; 2） copper replacement by iron scraps under pH value of 2.0 at 80 ℃, and stirring for 1 h, 3） removal of iron and chromium by chemical precipitation： iron removal under pH value of 2.0 at 90 ℃ by dropwise addition of sodium chlorate and 18% sodium carbonate solution, then chromium removal under pH value of 4.0 at 70 ℃ by addition of nickel carbonate solution, stirred by air flow for 2 h; 4） selective separation of cobalt from nickel by extraction using 30% trialkyl amine＋50% kerosene （volume fraction） and tri-n-butylphosphate （TBP） as a phase modifier with the O/A ratio of 2：1, and stripping of cobalt with 0.01 mol/L HCl; 5） crystallization of nickel chloride and electrodeposition of cobalt. It is found that the nickel recovery of 95% and the cobalt recovery of approximately 60% with purity over 99.9% are obtained by this process.     

Extraction of palladium（Ⅱ） with OTMSO from acidic media

The extraction of palladium(Ⅱ) from acidic media with cyclic sulfoxide deriva-tive-α-octyl-tetrahydrothiophene-Ⅰ-oxide (OTMSO) was investigated. The extraction efficiency of palla-dium(Ⅱ) with OTMSO is 97.1% at 0.3mol·L~(-1) OTMSO. The plots of the extraction efficiency for palla-dium(Ⅲ) appear to lie on a convex curve having a minimum of extraction efficiency at 1-2 mol·L~(-1) HCl. Theextraction reaction of palladium(Ⅱ) with OTMSO is endothermic, and ΔH_(OTMSO)~=12.2kJ·mol~(-1). The coor-dination number was studied with slope method. The result indicates that coordination number is 2. FT-IRspectra were used to analyze the structure of complex and coordinated atom in complex. Pd is coordinated withboth oxygen and sulfur atom in S=O group in OTMSO. The situation and intensity of peaks contributed bycomplex prepared from various acidity were different. The recovery of palladium(Ⅱ) with OTMSO from scrapcontaining palladium was discussed. After silver and bismuth were removed, the feed solution w     

Adsorption and removal of cadmium （ Ⅱ ） from aqueous solutions by bio-formulation

A novel sorbent, bio-formulation（BF）, was prepared and employed for the adsorption of cadmium（Cd） ion from aqueous system. The process of adsorption follows the pseudo second-order kinetic equation and the adsorption behavior is fitted with a Freundlich isotherm. The removal rate of Cd is slightly dependent on the initial pH value over a wide range of 4-11. The addition of Zn^2＋ and Cu^2＋ ions hardly affects the Cd adsorption, whereas the coexisting Pb^2＋ ion greatly interferes with the adsorption. The adsorption mechanism is supposed as a cation-exchange process between Cd^2＋ and calcium and Mg^2＋ present on the surface of BF, and somewhat as adsorption in a hydrolyzed form. The adsorbed Cd ions are desorbed effectively by a 0.1 mol/L HCl solution.     

Synthesis, characterization, and biological activities of Pt（Ⅱ） and Pd（Ⅱ）complexes with 2′,3′,4′,5,7-pentahydroxy flavone

Pt(Ⅱ) and Pd(Ⅱ) complexes with 2′,3′,4′,5.7-pentahydroxy-flavone were synthesized and characterized by ele-mental analysis, molar conductance, IR, ′HNMR, TG-DTA, UV-Vis spectroscopic techniques, and fluorescence analysis.The scavenging effect on the superoxide radical (O2) and the inhibitory effect on lipid peroxides were also investigated. Both the ligand and the complexes exhibit scavenging effect on superoxide radicals, and the effect of the complexes is greater than that of the ligand. The Pt(Ⅱ) complex exhibits the strongest scavenging efficiency. Both Pt(Ⅱ) and Pd(Ⅱ) com-plexes have the inhibitory effect on lipid peroxides, and the effect of the complexes is greater than that of the ligand, but the Pt(Ⅱ) complex has a high effect of promoting lipid peroxides.     

Thermoelectric properties of Bi_（1.5）Pb_（0.5）Sr_（2-x）La_xCo_2O_y polycrystalline materials

Polycrystalline samples of Bi 1.5 Pb 0.5 Sr 2-x La x Co 2 O y (x = 0.1, 0.2, 0.3) with a layered structure were prepared by solid-state reaction method. All samples are p-type semiconductors. The thermoelectric properties, namely, the electric resistivity (ρ), Seebeck coefficient (S), and power factor (S 2 /ρ) of the samples are dependent on chemical composition. The values of ρ, S, and S 2 /ρ increase with an increase in temperature for all samples. The substitution of Pb 2+ for Bi 3+ and La 3+ for Sr 2+ improves the thermoelectric properties of the Bi 2 Sr 2 Co 2 O y system owing to the simultaneous decrease of electric resistivity and increase of Seebeck coefficient. As a result, the optimal thermoelectric property has been obtained in Bi 1.5 Pb 0.5 Sr 1.7 La 0.3 Co 2 O y and the power factor can reach 2.1 × 10-4 W·m-1 K-2 at 998 K.     

Thermodynamics of Cu（ Ⅱ ）-NH3-NH4Cl-H20 system

The thermodynamics of a complex solution system, Cu（ Ⅱ ）-NHa-NH4Cl-H2O, was presented both theoretically and experimentally. Firstly, according to the principles of simultaneous equilibrium and aqueous electronic charge neutrality of the system, a nonlinear mathematical thermodynamic model with multi-members was set up. In this model, there were six unknowns： pH value, concentration values of free Cl^- , free NH3 , total concentration values of Cu^2＋ , Cl^- and NHa, four equilibrium equations and three equilibrium equations of total quantum of Cu^2＋ , Cl^- and NH3 , as well as an equilibrium equation of electric charge, were involved in the model. Then after specifying the values of total concentrate of NH3 and Cl^- , the model was solved precisely using MATLAB language, and the other four unknowns were obtained. According to the values obtained above, various valuable figures regarding thermodynamic relation of the system were protracted also with MATLAB, including two and three dimensions figures. These figures and data can supply the theoretic conference for optimizing the ratio of leaching reagents in copper extraction through ammonia hydrometallurgy. Finally, the solubility of CuO were measured in the system of NHa-NH4Cl-H2O. The results show that the model and the thermodynamic data obtained are reliable.     

Extraction of palladium （Ⅱ） from hydrochloride solutions with 2-n-octyl-4-isothiazolin-3-one as novel extractant

Solvent extraction of palladium （Ⅱ） from hydrochloric acid solution with 2-n-octyl-4-isothiazolin-3-one （OIT）/cyclohexane was studied. Effects of different parameters on extraction efficiency were evaluated. 99.96 % and 98.26 % palladium （Ⅱ） could be effectively extracted with 0.018 mol·L^-1 OIT/cyclohexane of 0.1 and 4.0 mol·L^-1 HCl medium, respectively. Nonpolar solvent and low acidity could improve the extracting efficiency, and successfully strip palladium （Ⅱ） from the loaded organic phase was achieved with 0.5 mol·L^-1 （NH2）2CS solution. It was proposed that the extraction of Pd com-plexes from HCl medium proceeded through the ion-association mechanism by slope method, NMR and FF-IR spectra.     

Oxidation behavior of Ni（Co）CrAlYHf（Si） coatings on DS superalloy at 1150℃

Two Ni（Co）CrAlY coatings were deposited by EB-PVD method on a DS superalloy of Ni-Al-Cr-Co-W-Mo-Ta-Hf system. SEM, XEDS and XRD were used to study the oxidation behavior of the coatings. The two coatings show a good protection for the DS superalloy. The results of the isothermal oxidation test at 1150 ℃ for 100 h show that the oxidation tendency obeys the parabolic law, and the oxidation rate constant Kp of the coated specimens decreases to about 1/3 of that for the bare superalloy. After oxidation, a continuous alumina-based scale is formed at the surfaces of the coated samples. Y2O3, NiO and SiO2 are also detectable in the oxide scale. A large number of Al in the coating is consumed due to high-temperature diffusion and oxidation reactions, and the NiAl phases in the coating are almost completely transformed to Ni3Al phases. For the Hf-bearing coating, some HfO2 particles exist at the interface between the coating and the substrate. Although internal oxidation occurs, the coating still shows a good adhesion with the superalloy substrate even after oxidation for 100 h. For the bare DS superalloy, after 100 h oxidation at 1 150℃, only discontinuous alumina-based oxide particles exist on the surface. Oxide spallation occurs for the bare alloy.     

Anodic reaction kinetics of electrowinning zinc in system of Zn （Ⅱ）-NH3-NH4Cl-H2O

The anodic reaction kinetics of zinc electrowinning was investigated on the titanium base RuO2 anode in the system of Zn(Ⅱ)-NH3-NH4Cl-H2O. The effects of stirring speed, ammonium chloride concentration and tem-perature on anodic reaction rate were studied through the curve measurement of potentiostatic polarization. The re-sults reveal that the electrochemically controlled anodic reaction obeys Tafel equation and the anodic reaction order for ammonium chloride is 1. 056, with the apparent activation energy of 40. 17 kJ/mol. The general equation of a-nodic reaction kinetics was obtained.     

Accelerated Gas Carburizing （URX Gas Carburizing）

URX gas carburizing is an accelerated gas carburizing method with 50% CO 50% H2 gas which comes from CH4 gas CO2 gas. By using this gas composition, the carburizing reaction rate increases to the maximum and the controllability of carbon potential improves. A carbon mass flow rate is the product of the carburizing reaction rate multiplied by the difference of carbon percent between carbon potential of the gas and the carbon content of the surface of treated steel parts. We have obtained excellent results from the experimental tests at our laboratory as mentioned bellow. 1) Carburizing time can be shortened by 40% for 0.5 - 0.9 mm effective case depth. 2) Uniform carburizing case depth 3) Less internal oxidation with the same case depth. We have already developed the new roller hearth type continuous carburizing furnace and the new URX gas generator.     

Recovery of Mn^2＋, Co^2＋ and Ni^2＋ from manganese nodules by redox leaching and solvent extraction

The recovery of Mn, Co and Ni from deep-sea manganese nodules was conducted by acid oxidative leaching and solvent extraction. The results indicate that pyrrhotite used during leaching can effectively facilitate the leaching out of manganese, cobalt and nickel. The leaching behaviors of Mn, Ni and Co were determined and the influences of temperature, leaching time and sulphuric acid concentration on leaching rate were also investigated. Co and Ni are precipitated from the leaching liquor by adding sodium sulfide into solution with agitation for 2 h at 50 ℃, and the manganese sulphate is obtained by concentrating the resulting solution. By re-dissolving the precipitates of cobalt and nickel, the separation of cobalt and nickel is performed using di（2-ethylhexyl） phosphoric acid （D2EHPA） for impurities elimination with 8 stages at organic-to-aqueous（O/A） volume ratio of 3：5, and 2- ethylhexyl phosphonic acid mono-2-ethylhexyl ester （known as PC88A or P507） for cobalt extraction with 3 stages counter-current operations at O/A volume ratio of 2：3 followed by their scrubbings and strippings, respectively. The final maximum recovery rates for manganese, cobalt and nickel are 85%, 75% and 78%, respectively.     

Selective recovery of cobalt,nickel and lithium from sulfate leachate of cathode scrap of Li-ion batteries using liquid-liquid extraction

This paper focuses on the extractive separation and selective recovery of cobalt, nickel and lithium from the sulfate leachate of cathode scrap generated during manufacture of lithium ion batteries (LIBs). The conditions for extraction, scrubbing and stripping of cobalt from nickel and lithium are optimized with an aqueous feed containing 25.1 g·dm^?3 cobalt, 2.54 g·dm^?3 nickel and 6.2 g·dm^?3 lithium using Na-PC-88A. 99.8% Co is extracted with 60% Na-0.56 mol·dm^?3 PC-88A in two counter-current stages at an O/A phase ratio of 3/1 and an equilibrium pH of 4.5. The “crowding effect” shown for the first time provides effective scrubbing of impurities (Ni and Li) with 2.0 g·dm^?3 CoSO₄ solution. The McCabe-Thiele diagram predicts the scrubbing of 99.9% Ni and 99.9% Li at an equilibrium pH of 4.75 and O/A of 2/1 in two stages. High purity (99.9%) cobalt sulfate along with Ni and Li from the leach liquor of cathode scrap is recovered by solvent extraction. The proposed process ensures complete recycling of the waste of the manufacturing process of LIBs.     

EDTA—铋盐联合测定硬质合金中钴和镍

本文以二甲酚橙作指示剂，首先在pH5的HAc－NaAc介质中，用EDTA滴定Co－Ni合量，继而调节试液pH至2左右，用Bi（NO3）3返滴定测定Co分量．应用该方法测定硬质含金中Co－Ni含量，获得满意结果．     

Recovery of valuable metals from anode material of hydrogen-nickel battery

Simultaneous recovery of rare earth, nickel and cobalt resources from the anode material of hydrogen-nickel battery was performed through a hydrometallurgical process. Most of rare earth elements are separated from nickel and cobalt in the form of sulfates when the anode material is firstly leached with sulfuric acid. Then, the precipitated rare earth sulfates are dissolved with sodium hydroxide to form rare earth hydroxides. The rare earth element, zinc and manganese ions in the lixivium are also separated from nickel and cobalt by using PC-88A extractant system, and the organic phase loaded rare earth is stripped with hydrochloric acid. By neutralizing the stripping solution with rare earth hydroxide, the rare earth chloride is obtained. Under the suitable leaching conditions of sulfuric acid 3 mol/L, leaching time 4 h and temperature 95 ℃, 94.5% of rare earth in the anode material is transformed into the sulfate precipitates, and the leaching ratios of nickel and cobalt can approach 99.5%. When the pH value of the extractive system is controlled in the range of 3.0-3.5, the rare earth elements in the lixivium can be extracted completely into the organic phase, and the stripping recovery of the rare earth can reach 98% in the extraction stage. The total recoveries of rare earth, nickel and cobalt are 98.9%, 98.4% and 98.5%, respectively.     

Transport processes in passivity breakdown—II. Full hydrolysis of the metal ions

Transport process analysis shows that passivity breakdown can be associated with a depletion of OH^? ligands at the metal-solution interphase. In a previous publication (J. electrochem. Soc., 123, 464 (1976)), assuming only the first step of cation hydrolysis, important pH changes were shown to be possible at the initial steps of pitting. A calculation based on full hydrolysis is attempted in the present paper. New relations between pitting potential and pH were found, which could not be explained by the previous simplified treatment. The pitting potential of bivalent metals, such as iron, nickel, cadmium, zinc and cobalt was found to be pH-independent up to a pH value of around 9 to 10, but pH-dependent for higher pH-values. This pH dependence should be equal to the Tafel slope for those metals in the pit-like solution. In the case of trivalent metal ions, such as aluminium, on the other hand, the external pH contribution is buffered by the various hydrolysis steps of the metal ion. As a result of this, the condition for pitting is not affected by the external pH value over a wide range of pH values, an observation that though reported by previous authors, has not so far been theoretically explained.     

Separation of precious metals using selective mesoporous adsorbents

The mesoporous NH₂-MCM-41 adsorbent prepared by grafting aminopropyls on MCM-41 is selective towards gold and palladium adsorptions and can separate these precious metals from complex solutions containing other metal ions such as cobalt, nickel, copper and zinc. Adsorption is rapid and the adsorbent’s capacity for gold is better or comparable to most carbonaceous adsorbents including activated carbons. Furthermore, NH₂-MCM-41 can separate palladium from gold solution at pH1.0 with excellent selectivity and capacity. Thus, it is possible to design a two steps separation process for the separation of palladium and then gold from the complex solution. A simple acid wash was sufficient to recover the adsorbed palladium and gold as concentrated, high purity (i.e., > 95%) metal salt solutions and the regenerated adsorbent was reused without lost of performance.     

Process for cobalt separation and recovery in the presence of nickel from sulphate solutions by Cyanex 272

The present paper deals with the extraction of cobalt from a solution containing cobalt and nickel in a sulphate medium similar to the leach liquor obtained by the dilute sulphuric acid pressure leaching of the Pacific Ocean nodules matte followed by copper extraction. The commercial extractant Cyanex 272 (bis (2, 4, 4-trimethylpentyl) phosphinic acid) is used for this purpose. The leach liquor used for the present study contains Co =1.78 g/L and Ni=16.78 g/L. Before cobalt extraction, impurities, such as copper and iron, are removed from the leach liquor by the precipitation method. Increasing the concentration of Cyanex 272 increased the extraction percentage of cobalt due to the increase of equilibrium pH. Cobalt extraction efficiency of >99.9 % is achieved with 0.20 M Cyanex 272 in two counter-current stages at an aqueous: organic (A:O) phase ratio of 1.5∶1. Complete stripping of cobalt from the loaded organic containing 2.73 g/L Co was carried out at pH 1.4 by a synthetic cobalt spent electrolyte in two stages at an A:O ratio of 1∶2. The enrichment of cobalt during extraction and stripping operations was about 3.5 times. A complete process flowsheet for the separation and recovery of cobalt is presented.     

Some Possible uses of Alternating Currents in Electrodeposition

Some possible causes of discontinuities in nickel and cobalt deposits have been investigated. The results suggest that neither hydrogen bubbles clinging to the surface of the cathode, nor impurities present on the surface of the basis metal (including those deposited from the electrolyte during electrolysis) can be main causes of pores. The important cause appears to be the surface contour of the basis metal. Work is proceeding to decide whether internal stresses in the deposit or in the basis metal can cause discontinuities.

Changes of current density or pH in nickel baths were not found to influence the number of pores in the deposits, but a rise in temperature of the bath increased the number of pores per unit area.

Cathode polarisation curves for nickel and cobalt deposition from different solutions showed a high value of dη/dI to be associated with a small number of pores, where η is the overpotential and I the current density. Concentration polarisation was observed when nickel was deposited from an ammoniacal complex salt solution at a very low current density.

Composite plates consisting of (1) nickel and copper (in alternate layers), (2) cobalt and nickel, and (3) cobalt and chromium, showed no promise as a means of avoiding pinholes.

The authors wish to make clear that some of the results given in this paper must be regarded as preliminary, and the interpretation as tentative. But for the Silver Jubilee Conference, the work would not have been published until later.     

Selective separation of Cu(II), Zn(II), and Cd(II) by solvent extraction

An experimental investigation was presented on the separation of Cu (II), Zn (II), and Cd (II) from a rich sulfate leachate of zinc slag by solvent extraction. The results of orthogonal experiments indicate that LIX 984N is highly selective and very efficient in the extraction of Cu (II), and the analysis of variance indicates that the sequence of parameters according to their influence on the separation efficiency is phase ratio>LIX 984N concentration>pH value>extraction time. The optimal condition for copper extraction is obtained as 25% of LIX 984N concentration, 7 min of extraction time, 3:2 of phase ratio O/A, and pH=1.7. The separation of Zn (II) and Cd (II) was performed after the copper extraction from the raffinate. Comparative analysis of the separation with di-2-ethylhexyl phosphoric acid (D2EHPA), D2EHPA-tributyl-phosophate (TBP) synergistic extracting system, and 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester (HEHEHP) was made at pH=2.0. It is demonstrated that the extraction efficiency with D2EHPA is improved after being saponified by sodium hydroxide, and D2EHPA-TBP synergistic extracting, as well as HEHEHP, has a superior selectivity to Zn (II) over Cd (II).