Catalytic anodes in chromium deposition

Catalytic anodes based on Ir02 catalyst has been investigated as a substitute for lead in chromium deposition from chromic acid electrolyte. Oxygen evolution characteristics and ability to oxidise the trivalent chromium are some of the aspects examined in this context. Comparison has also been made with conventional lead anode

Activated lead electrodes for electrowinning operations

The need for new technology to recover metals with more energy efficiency has created increasing interest in sulphate electrowinning systems. Development of electrocatalytic . . anodes for oxygen evolution conditions is a subject of current interest. A kind of . . activated elmrode with an electrocatalyst dispersed and embedded within a matrix of lead has been investigsted. Cyclic voltammetric studies and anodic polarisation studies . under oxygen evolution condition have been carried out in HzSOs~o lutions. The effects of catalyst loading and acid concentration on anode potential have been discussed. RuOn and lrOp ar&?Felectrocatalysts studied

Catalytic anodes in electrowinning - inhibition of poisoning :part I. Cyclic voltammetric studies

Poisoning of the catalytic anodes of Mn2+ ion in metal winning electrolytes has been investigated. Addition of soluble phosphorous (V) and arsenic (Ill) compounds has been examined as a deterrent for MnOz deposition using cyclic voltamrnetric technique. Probable role of these compounds in the inhibition of anodic formution of MnOz is discussed. Platinum, RuOz film electrode and Ru02 powder compact electrode have been studied in this context

Activated lead electrodes for electrowinning operations

The need for new technology to recover metals with more energy efficiency has created increasing interest in sulphate electrowinning systems. Development of electrocatalytic . . anodes for oxygen evolution conditions is a subject of current interest. A kind of . . activated elmrode with an electrocatalyst dispersed and embedded within a matrix of lead has been investigsted. Cyclic voltammetric studies and anodic polarisation studies . under oxygen evolution condition have been carried out in HzSOs~o lutions. The effects of catalyst loading and acid concentration on anode potential have been discussed. RuOn and lrOp ar&?Felectrocatalysts studied

Catalytic anodes for electrowinning-part:I effect of methanol addition

A significant reduction in energy consumption in metal electrowinning from sulphate solutions can be achieved by the use of catalyti: anodes in combination with methanol addition to the electrolyte. The effect of current density on methanol oxidation has knst udied on different types of catalytic anodes like Ru4f ilm electrode and sponge electrode. The effect of periodic current reversal on the anodic process has also been investigate

Electrorefining of lead from scrap lead acid battery

Lead acid battery finds application system and the disposal of its scraps is one of the environmental problems all over the world. Pyrometallurgical operation currently employed generates emission of oxides of sulphur and particulate lead causing atmospheric pollution. Electrolytic route is investigated as an alternative to recover lead. The route comprises breaking the scrap batteries and separating the portions of metallic lead and lead compounds. The metallic portion is cast into anodes and electrorefined in lead fluoborate medium. The purity of final cathode is analysed by mass spectroscopy. Addition of leveling agent and grain refiner in proper proportion avoids dendritic growth. Over potential measurement is found to be useful in monitoring the concentration of additive in the electrolyte during electrorefining of lea

Activated lead electrode for electrowinning of metals

Rising costs of power forecast for the future emphasis the need for the effective energy saving measures in the electrolytic extraction of metals, Introduction of newer anode materials in the electrolytic cells avoid problems like high energy consumption and anode corrosion associated with the conventional lead anodes. A new type of catalytic anode, known as activated lead electrode, has been investigated for its possible application in the electrolytic recovery of metals from their aqueous solutions. The anode consists of a lead substrate and an etectrocatalyst like IrO2 supported on the titanium sponge particles. Voltage saving anodic stability, ability to tolerate the chloride impurity in the electrolyte and catalyst poisoning, associated with the new anode system, have been examine

Recovery of lead from battery sludge by leaching and electrowinning

Spent lead acid batteries are a rich source for the production of secondary lead. Pyrometallurgical operation currently practised exploiting this resource produces a lot of emission of oxides of sulphur and lead particulates causing atmospheric pollution. This paper examines an alternative approach for the extraction of lead avoiding environmental hazards. Lead in the compound form is not amenable for recycling to a large extent. This investigation is concerned particularly with recovery of lead from non-metallic portion of the spent battery plates viz. lead sulphate and lead dioxide of active material. Lead was extracted as fluoborate and aspects like desulphurisation, reduction and leaching were examined for maximum recovery. Finally lead was electrowon from the lead fluoborate solutio