Electrode cap with integral tank cover for acid mist collection

Method for acid mist collection for use in a tank having sides confining an electrowinning process having an electrolyte bath containing an electroplating solution containing circulated acid solution passing between side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above a surface of the electrolyte bath, the acid mist collection method comprising the steps of:

• providing a multi-element cover system applied below the electrical connections and above the surface of the electrolyte bath;
• providing a plurality of flexible electrode caps having sufficient dimension to span to adjacent electrodes;
• fastening the electrode caps to at least one side of the electrodes at a location permitting the caps to span to adjacent electrodes to form a continuous, substantially air tight cover over the electrolyte bath;
• providing means for covering the circulated acid solution from the electrodes to the sides of the tank above the surface of electrolyte solution for forming a substantially air tight seal;
• and,
• evacuating a volume below the multi-element cover system and above the bath at a rate exceeding a rate of gas and mist generation to create a negative pressure in the volume whereby any atmosphere leakage that occurs into the volume below the multi-element cover system and above the bath occurs from above the multi-element cover system into the volume below the multi-element cover system thereby preventing acid aerosol from escape.

In a multi-element cover system applied below electrode connections and above a surface of a bath in an electrowinning process having circulated acid electroplating solution containing acid passing between side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above the surface of the bath, the multi-element cover system comprising:

• a plurality of flexible electrode caps fastened to at least one side of the anode electrodes below the electrical connection thereto and above the bath, the flexible electrode caps having an underside exposed to the bath;
• each said flexible electrode caps having sufficient dimension to span to adjacent cathode electrodes to form a continuous, substantially air tight cover between the electrodes of the electrode array;
• the underside of the cap having a first slope having a high end of the slope at a cathode and a low end of the slope at an anode whereby coalesced acid is substantially prevented from passing from the underside of the caps to an adjacent cathode;
• and,
• means for preventing the coalesced acid from running along the underside of the flexible electrode caps whereby during insertion of the cathodes, the coalesced acid is substantially prevented from passing from the underside of the caps to an adjacent cathode during flexure of the caps producing a second slope reversed to the first slope at the underside exposed to the bath toward the cathodes.

In an electrowinning apparatus side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above a surface of an electrolyte bath, an improved electrode comprising:

• means for depending support of the electrodes into the electrolyte bath;
• means for supplying sufficient current to the electrode to cause electroplating to occur between a plurality of the electrodes;
• a plurality of flexible electrode caps fastened to at least one side of the anode electrodes below the electrical connection-thereto and above the bath, each said flexible electrode caps having sufficient dimension to span to adjacent cathode electrodes to form a continuous, substantially air tight cover between the electrodes of the electrode array, the flexible electrode having an underside exposed to the bath;
• the underside of the cap having a first slope having the high end of the slope at a cathode and the low end of the slope at an anode whereby the coalesced acid is substantially prevented from passing from the underside of the caps to an adjacent cathode;
• and,
• means for preventing coalesced acid from running along the underside of the flexible electrode caps whereby during insertion of the cathodes, the coalesced acid is substantially prevented from passing from the underside of the caps to an adjacent cathode during flexure of the caps producing a second slope reversed to the first slope at the underside exposed to the bath toward the cathodes.

An acid mist aerosol collection system for use in a tank having sides to confine an electrowinning process having an electrolyte bath with an electroplating solution containing circulating acid passing between side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above a surface of the electrolyte bath, the acid mist aerosol collection system comprising:

• a multi-element cover system applied below the electrical connections and above the surface of the electrolyte bath including a plurality of flexible electrode caps fastened to at least one side of the electrodes and spanning to adjacent electrodes to form a continuous, substantially air tight cover over the solution;
• means for covering the circulating acid from the electrodes to the sides of the tank above the surface of the circulating acid for forming a substantially air tight seal;
• and,
• means for evacuating a volume below the cover system and above the bath at a rate exceeding a rate of gas and mist generation to create a negative pressure in the volume whereby any atmosphere leakage that occurs into the volume overlying the bath and underlying the multi-element cover occurs from above the multi-element cover into the space below the multi-element cover thereby preventing acid aerosol from escape to the atmosphere;
• the means for evacuating operating at a rate to maintain humidity under the multi-element cover system for retarding evaporation under the cover from the acid mist aerosol.

Method for acid mist collection for use in a tank confined electrowinning process having an electrolyte bath with electroplating solution containing circulating acid passing between side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above a surface of the electrolyte bath, the acid mist collection system comprising in combination:

• providing a multi-element cover system applied below the electrical connections and above the surface of the electrolyte bath including a plurality of flexible electrode caps having sufficient dimension to span to adjacent electrodes;
• fastening the electrode caps to at least one side of the electrodes at a location permitting the caps to span to adjacent electrodes to form a continuous, substantially air tight cover over the electrolyte bath;
• providing means for covering the circulating acid from the electrodes to the sides of the tank above the surface of the circulating acid for forming a substantially air tight seal;
• and,
• evacuating a volume below the cover system and above the bath at a rate exceeding a rate of gas and mist generation to create a negative pressure in the volume whereby any leakage that occurs into the volume overlying the bath and underlying the multi-element cover system occurs from above the multi-element cover system into the volume below the multi-element cover system thereby preventing acid aerosol from escape, the evacuating restricted to at a rate to maintain humidity under the multi-element cover system for retarding evaporation under the multi-element cover system from the acid mist aerosol.

In the combination of:

• a tank for containing electroplating solution for electroplating;
• anode and cathode electrodes within the tank and having electrical connections above the surface of the electroplating solution communicated to a source of current for causing electroplating within the tank;
• an outlet for discharging the electroplating solution from the tank;
• a cover over the tank and outlet;
• and,
• means for evacuation of gas and mist resulting from the electroplating from a plenum under the cover and over the bath, the cover and means for the evacuation of gas and mist comprising:
• the cover including:
• a multi-element cover system applied below the electrical connections and above the surface of the electroplating solution including a plurality of flexible electrode caps fastened to at least one side of the electrodes and spanning to adjacent electrodes to form a continuous, substantially air tight cover over the solution;
• means for covering the circulating electroplating solution from the electrodes to the sides of the tank above the surface of the circulating electroplating solution for forming a substantially air tight seal;
• the means for the evacuation of gas and mist including:
• at least one weir for discharging the electroplating solution to at least one pipe;
• and,
• the weir in combination with the pipe having sufficient flow volume for receiving the outflow of electroplating solution from the tank and gas and mist from the plenum.

In combination:

• a tank having sides for containing electroplating solution;
• anode and cathode electrodes within the tank and having electrical connections communicated to a source of current for causing electroplating within the tank;
• a multi-element cover system applied below the electrical connections and above a surface of the electroplating solution including a plurality of flexible electrode caps fastened to at least one side of the electrodes and spanning to adjacent electrodes to form a continuous, substantially air tight cover over the solution;
• means for covering the circulating electroplating solution from the electrodes to the sides of the tank above the surface of the circulating electroplating solution for forming a substantially air tight seal;
• and,
• an outlet for discharging electroplating solution from the tank, the outlet including at least one weir for discharging the electroplating solution to a pipe;
• and,
• the at least one weir in combination with the pipe having sufficient flow volume for receiving the outflow of electroplating solution from the tank and gas and mist from the plenum.

A method for evacuating aerosol acid mist from a tank having electroplating solution within the tank and having electroplating occurring between anode and cathode electrodes having electrical connections for producing plated metal and gas rising to the surface of the bath in the tank, the gas rising in the tank causing gas and mist aerosols over the surface of the tank, the method comprising the steps of:

• placing a cover over the electrodes, the cover including a multi-element cover system applied below the electrical connections and above the surface of the electrolyte bath including a plurality of flexible electrode caps fastened to at least one side of the electrodes and spanning to adjacent electrodes to form a continuous, substantially air tight cover over the solution;
• covering the circulating electroplating solution from the electrodes to the sides of the tank above the surface of the circulating electroplating solution for forming a substantially air tight seal;
• providing the tank with at least an outflow for circulating electroplating solution through the tank;
• providing the tank with a weir at the outflow;
• out flowing fluid from the tank over the weir;
• and,
• drawing gas and mist aerosol over the weir below the cover and above the surface of the electrolyte for causing the gas and mist to exit the tank and be drawn over the weir to avoid the formation of crystals adjacent the weir.

An acid mist collection system for use in a tank confined electrolysis process having electrolyte electroplating solution containing acid passing between side-by-side planar anode electrodes and cathode electrodes in an array, each electrode having electrical connections above the surface of the electrolyte bath, said acid mist collection system comprising:

• a multi-element cover system applied below the electrode connections and above the surface of the electrolyte bath including a plurality of flexible electrode caps spanning between adjacent electrodes to form a continuous, substantially air tight cover over said solution;
• means for covering said circulated acid solution from the electrodes to the sides and ends of the tank above the surface of the acid solution for forming a substantially air tight seal;
• and,
• means for evacuating the volume below the cover and above the bath at a rate exceeding the rate of gas and mist generation to create a negative pressure in said volume whereby any atmosphere leakage that occurs into the volume overlying the bath and underlying the multi-element cover occurs from above said multi-element cover thereby preventing acid aerosol from escape to the atmosphere.