During electro-oxidative metal removal on a semiconductor substrate, the substrate having a metal layer is anodically biased and the metal is electrochemically dissolved into an electrolyte. Metal particles (e.g., copper particles when the dissolved metal is copper) can inadvertently form on the surface of the substrate during electrochemical metal removal and cause defects during subsequent semiconductor processing. Contamination with such particles can be mitigated by preventing particle formation and/or by dissolution of particles. In one implementation, mitigation involves using an electrolyte that includes an oxidizer, such as hydrogen peroxide, during the electrochemical metal removal. An electrochemical metal removal apparatus in one embodiment has a conduit for introducing an oxidizer to the electrolyte and a sensor for monitoring the concentration of the oxidizer in the electrolyte.

The present disclosure relates to the use of a wetting agent such as a non-ionic wetting agent and a reagent comprising a thiocarbonyl functional group, for example, in a method/process or use for extracting a base metal such as copper from a material comprising the base metal. Such methods/processes can comprise contacting the material under acidic conditions with the wetting agent and the reagent comprising the thiocarbonyl functional group; and optionally recovering the base metal.

An electrochemical process implements, in a decoupled manner, a first step of electrolysis of an electrolyte to produce gaseous oxygen in a chamber and a second step of electrochemical conversion of H+ ions into gaseous hydrogen in a chamber which contains a liquid phase and a gas phase not dissolved in the liquid phase. Gaseous hydrogen produced in the conversion step is partly present in the gaseous headspace of chamber and as bubbles in the electrolyte, and partly dissolved in the electrolyte which is saturated with hydrogen. The electrolyte has at least one redox pair (A/B) forming at least one intermediate vector enabling the decoupling of the first and second steps. The interface between the gas and liquid phases is increased during the second step to accelerate the diffusion, from liquid phase to gas phase, of the dissolved hydrogen able to supersaturate the electrolyte. Pressurized gaseous hydrogen is then collected.

An alternating current electrolysis system, as well as a method and a device for controlling the alternating current electrolysis system are provided. The method includes: acquiring a voltage amplitude at an alternating current side of an electrolysis rectification power supply; and modifying an output parameter of the electrolysis rectification power supply based on the voltage amplitude. Compared with the conventional technology, the problem of oscillation of a power grid due to unbalanced power of the alternating current electrolysis system is effectively solved, thereby facilitating normal operation of a electrolysis station.

Disclosed herein is an electrolyzer comprising a horizontal cathode located below a suspended anode for purposes of performing electrolysis on metal-bearing mixtures or solutions. The horizontal cathode may comprise the bottom surface of a compartment for containing a mixture or solution of metal components, electrolyte, and/or supplemental chemicals. The horizontal anode may engage the upper surface of the mixture or solution in the compartment. A removal mechanism for facilitating removal of the end-products of the mixture or solution from the compartment (and the surface of the horizontal cathode) through the gate may also be employed. These implementations may be used in recycling of lead acid batteries (LABs) without any need for smelting, and also may be applied to a variety of different electrolytical operations.

The present invention is directed to an electrochemical device for at least partially removing or reducing a target ionic species from an aqueous solution using faradic immobilization, the electrochemical device including at least one first electrode and at least one second electrode with different void fraction and surface area properties, due to differences in void fraction (also referred to as void ratio) of the at least one first and the at least one second electrode, water flows through an electrode with a high porosity, while the aqueous solution does not flow through an electrode with a low porosity. The asymmetry of the electrodes provides a desired voltage distribution across the device, which equates to a different voltage at each electrode, to control the speciation of the target ionic species at the anode and the cathode.

Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-ray after heating the metal at 100° C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an α-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-ray after heating the metal at 100° C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an α-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

A circuit for supplying electrical power (20) at a rated direct current of between 20 kA and 100 kA to an electrolysis cell (21) comprising an upstream busbar (25), a downstream busbar (26), the two upstream (25) and downstream (26) busbars being connected to each other by means of a short-circuiting device (22) which, when closed under the action of an actuating mechanism (229), allows the two busbars to be electrically connected to each other in order to cut off the electrical power supply to the cell (21), an anode bar (213) equipped with an anode connection interface (215) for connection to the anode (211) of the cell, and a cathode connection interface (214) for connection to the cathode (212) of the cell. According to the main features of the invention, the cathode connection interface is connected to the downstream busbar by means of a flexible electrical connector (27), the circuit comprises means for absorbing the movement of the various constituent elements of the circuit due to thermal expansion and a disconnector (23) connected, on the one hand, to the upstream busbar (25) and, on the other hand, to the anode bar (213), the disconnector is opened by an actuating mechanism (239) and electrically disconnects the upstream busbar and the anode bar from each other after a non-zero time interval Tm when the short-circuiting device has been closed, the time interval Tm corresponding to the time of establishment of the rated current in the short-circuiting device (22).

An electrowinning cell includes a first anode associated with a first anode compartment, a cathode in a cathode compartment, a second anode associated with a second anode compartment, a first spacer plate between the first anode and the cathode and a second spacer plate between the cathode and the second anode compartment.