Electrolytic Sampling from Pure Copper and Common Brasses Ⅰ: Calculation of the Mass Dissolved from the Samples according to Faraday's Law

In a procedure for electrolytic dissolving pure copper and common brasses, the approximate electrochemical mole mass(k) of the sample was determined in accordance with the brand of the sample, a stitable electrolyte was selected to make the current efficiency equal to 100%, and then the dissolved mass of samples was calculated according to Faraday's law(m=klt).Three representative samples were sampled by the electrolytic dissolution method and the calculated dissolved amounts were equal to the values by weighing the anode.The cxperimental results of zinc and copper in the anode liquor are in agreement with certified values.

ELECTROLYTIC REMOVAL OF COPPER FROM GUANYL-O-ALKYL-ISOUREA COPPER COMPLEX

A facile method for removing copper from guanyl-0-alkylisourea copper complex was found by using electrolysis.The complex was electrolyzed at a copper cathode in dilute hydrochloric or nitric acid to give guanyl-O- alkylisourea salt in high yield and current efficiency.

ON-LINE ELECTROLYTIC DISSOLUTION OF SOLID METAL SAMPLE AND DETERMINATION OF COPPER IN ALLOY BY AAS

On-line dissolution of solid metal sample can be carried out by electrolysis under the control of flow injection analyzer(FIA),and the dissolved sample can be transferred to atomic spectrometer for the direct analysis.The hyphenated technique of FIA on-line electrolytic dissolution of alloy and atomic absorption spectrometer(AAS)detection is developed.The research is focused on the effects of electrolyte composition and electrolysis parameters on the sample dissolving,as well as the quantitative analysis of Cu in Al alloy samples.

Role of Sb(V) in removal of As, Sb and Bi impurities from copper electrolyte

The function mechanism of Sb（V） in As, Sb and Bi impurities removal from copper electrolyte was investigated by adding Sb（V） ion in a synthetic copper electrolyte containing 45 g/L Cu2＋, 185 g/L H2SO4, 10 g/L As and 0.5 g/L Bi. The electrolyte was filtered, and the precipitate structure, morphology and composition were characterized by chemical analysis, SEM, TEM, EDS, XRD and FTIR. The results show that the precipitate is in the shape of many irregular lumps with size of 50-200 μm, and it mainly consists of As, Sb, Bi and O elements. The main characteristic bands in the FTIR spectra of the precipitate are As-O-As, As-O-Sb, Sb-O-Bi, Sb-O-Sb and Bi-O-Bi. The precipitate is the mixture of microcrystalline of AsSbO4, BiSbO4 and Bi3SbO7 by XRD and electronic diffraction. The removal of As, Sb and Bi impurities by Sb（V） ion can be mainly ascribed to the formation of antimonate in copper electrolytes.

Separation and recovery of Cu and As during purification of copper electrolyte

Cu, As, Sb and Bi in copper electrolyte could be efficiently removed by reducing with SO2 followed by evaporative crystallization. As2O3 and CuSO4·5H2O were obtained after crystallized product was treated by dissolution, oxidation, neutralization, sedimentation, filtration and evaporative crystallization. The removal rates of Cu, As, Sb and Bi are 87.1%, 83.9%, 21.0% and 84.7%, respectively, when As （Ⅴ） in copper electrolyte is fully reduced to As （Ⅲ） by SO2, and the H2SO4 in concentrated copper electrolyte is 645 g/L. The removal rate of As is 92.81% when 65 g crystallized product is dissolved in 200 mL water at 30 ℃. The CuSO4·5H2O content is 98.8% when the filtrate is purified under the conditions that n（Fe）：n（As） is 1.2, the dosage of H2O2 is 19 times the stoichiometric needed, temperature is 45 ℃, time is 40 min, pH is 3.7, and then is evaporation crystallized.

Separation and recovery of Cu and As from copper electrolyte through electrowinning and SO_2 reduction

Cu and As were separated and recovered from copper electrolyte by multiple stage electrowinning, reduction with SO2and evaporative crystallization. Experimental results showed that when the current density was 200 A/m2, the electrolyte temperature was 55 °C, the electrolyte circulation rate was about 10 mL/min and the final Cu concentration was higher than 25.88 g/L, the pure copper cathode was recovered. By adjusting the current density to 100 A/m2 and the electrolyte temperature to 65 °C, the removal rate of As was 18.25% when the Cu concentration decreased from 24.69 g/L to 0.42 g/L. After As（V） in Cu-depleted electrolyte was fully reduced to As（Ⅲ） by SO2, the resultant solution was subjected to evaporative crystallization, then As2O3 was produced, and the recovery rate of As was 59.76%. The cathodic polarization curves demonstrated that both Cu2＋ concentration and As（V） affect the limiting current of Cu2＋ deposition.

Reduction and deposition of arsenic in copper electrolyte

The influences of temperature, H2SO4 concentration, CuSO4 concentration, reaction time and SO2 flow rate on the reduction of arsenic（V） with SO2 were studied and the deposition behavior of arsenic （III） under the effect of concentration and co-crystallization was investigated in copper electrolyte. The results indicate that reduction rate of arsenic （V） decreases with increasing temperature and H2SO4 concentration, but increases with increasing SO2 flow rate and reaction time, and it can reach 92% under appropriate conditions that reaction temperature is 65 °C, H2SO4 concentration is 203 g/L, CuSO4 concentration is 80 g/L, reaction time is 2 h and SO2 gas flow rate is 200 mL/min. To remove arsenic in the copper electrolyte, arsenic （V） is reduced to trivalence under the appropriate conditions, the copper electrolyte is concentrated till H2SO4 concentration reaches 645 g/L, and then the removal rates of As, Cu, Sb and Bi reach 83.9%, 87.1%, 21.0% and 84.7%. The XRD analysis shows that crystallized product obtained contains As2O3 and CuSO4·5H2O.

Sb(Ⅴ) removal from copper electrorefining electrolyte: Comparative study by different sorbents

Removal of Sb（V） from copper electrolyte by different sorbents such as activated carbon, bentonite, kaolin, resin, zeolite and white sand was investigated. Adsorption capacity of Sb（V） removal from copper electrolyte was as follows： white sand 〈 anionic resin 〈 zeolite 〈 kaolin 〈 activated carbon 〈 bentonite. Bentonite was characterized using FTIR, XRF, XRD, SEM and BET methods. The results show specific surface area of 95 m2/g and particles size of 175 nm for bentonite. The optimum conditions for the maximum removal of Sb are contact time 10 min, 4 g bentonite and temperature of 40 ° C. The adsorption of Sb（V） on bentonite is followed by pseudo-second-order kinetic （R2=0.996 and k=9×10？5 g/（mg· min））. Thermodynamic results reveal that the adsorption of Sb（V） onto bentonite from copper electrolyte is endothermic and spontaneous process （ΔGΘ=？4806 kJ/（mol· K）. The adsorption data fit both the Freundlich and Langmuir isotherm models. Bentonite has the maximum adsorption capacity of 10000 mg/g for adsorption of Sb（V） in copper electrolyte. The adsorption of Zn, Co, Cu and Bi that present in the copper electrolyte is very low and insignificant.

Separation and recovery of Ni from copper electrolyte by crystallization of nickel ammonium sulfate double salt

The separation and recovery of Ni from the copper electrolyte by crystallization of nickel ammonium sulfate double salt were studied.It is found that the solubility of copper sulfate at the same temperature is less than that of nickel sulfate,while the solubility of copper ammonium sulfate is greater than that of nickel ammonium sulfate.So,by adding(NH_(4))_(2)SO_(4),the Ni can be selectively crystallized from the copper electrolyte.By adding(NH_(4))_(2)SO_(4)at the molar ratio of(NH_(4))_(2)SO_(4)/NiSO_(4)≤0.8,and crystallizing at−15℃for 10 h,the Ni in the copper electrolyte can be crystallized in the form of Ni(NH_(4))_(2)(SO_(4))_(2)×6H_(2)O.The qualified product of NiSO_(4)×6H_(2)O can be obtained by pyrolyzing the crystals,dissolving the pyrolysis product in water,and then concentrating the dissolved solution for crystallization.The method of double salt crystallization is a clean,environmentally-friendly,cost-effective and efficient method for separating and recovering nickel from copper electrolyte.

Industrial experiment of copper electrolyte purification by copper arsenite

Copper electrolyte was purified by copper arsenite that was prepared with As2O3.And electrolysis experiments of purified electrolyte were carried out at 235 and 305 A/m2,respectively.The results show that the yield of copper arsenite is up to 98.64% when the molar ratio of Cu to As is 1.5 in the preparation of copper arsenite.The removal rates of Sb and Bi reach 74.11% and 65.60% respectively after copper arsenite is added in electrolyte.The concentrations of As,Sb and Bi in electrolyte nearly remain constant during electrolysis of 13 d.The appearances of cathode copper obtained at 235 and 305 A/m2 are slippery and even,and the qualification rate is 100% according to the Chinese standard of high-pure cathode copper(GB/T467-97).

Single-crystallization of electrolytic copper foils

Depending on the production process,copper(Cu)foils can be classified into two types,i.e.,rolled copper(r-Cu)foils and electrolytic copper(e-Cu)foils.Owing to their high electrical conductivity and ductility at low cost,e-Cu foils are employed extensively in modern industries and account for more than 98%of the Cu foil market share.However,industrial e-Cu foils have never been single-crystallized due to their high density of grain boundaries,various grain orientations and vast impurities originating from the electrochemical deposition process.Here,we report a methodology of transforming industrial e-Cu foils into single crystals by facet copy from a single-crystal template.Different facets of both low and high indices are successfully produced,and the thickness of the single crystal can reach 500μm.Crystallographic characterizations directly recognized the single-crystal copy process,confirming the complete assimilation impact from the template.The obtained single-crystal e-Cu foils exhibit remarkably improved ductility(elongation-to-fracture of 105%vs.25%),fatigue performance(the average numbers of cycles to failure of 1600 vs.200)and electrical property(electrical conductivity of 102.6%of the international annealed copper standard(IACS)vs.98.5%)than original ones.This work opens up a new avenue for the preparation of single-crystal e-Cu foils and may expand their applications in high-speed,flexible,and wearable devices.