Process for recovering metal carbide powder from cemented carbides

A process for recovering metal carbide powder from cemented carbide comprising metal carbide grains and a binder phase, such process comprising submerging a plurality of pieces of cemented carbide in a conductive aqueous electrolyte having an anode and a cathode therein, said electrolyte comprises at least 2% concentration by weight of a corrosive agent which in the absence of an applied electrolytic current will corrode and dissolve the binder phase of the cemented carbide pieces while having little if any corrosive effect on the metal carbide grains of such pieces, said corrosive agent being selected from the group consisting essentially of phosphoric acid, acetic acid plus a soluble acetate salt, citric acid plus a soluble citrate salt, tartaric acid, hydrochloric acid, oxalic acid, carbonates, borates, and sulfuric acid, maintaining at least some of said cemented carbide pieces in contact with said anode, passing an electric current between said anode and cathode, controlling at least one of the amperage and potential of said electric current to electrochemically and selectively dissolve at least a portion of the binder phase of said cemented carbide pieces without significant dissolution of the metal carbide grains of said cemented carbide pieces, and recovering metal carbide grains from which the binder phase has been dissolved.

A process for recovering metal carbide powder from cemented carbide comprising metal carbide grains and a binder phase, such process comprising submerging a plurality of pieces of cemented carbide in a conductive aqueous electrolyte having an anode and a cathode therein, said electrolyte comprises phosphoric acid at a concentration of about 1.2 M, maintaining at least some of said cemented carbide pieces in contact with said anode, passing an electric current between said anode and cathode, controlling at least one of the amperage and potential of said electric current to electrochemically and selectively dissolve at least a portion of the binder phase of said cemented carbide pieces without significant dissolution of the metal carbide grains of said cemented carbide pieces, and recovering metal carbide grains from which the binder phase has been dissolved.

A process for recovering metal carbide powder and a binder phase metal from cemented carbide pieces wherein a plurality of pieces of cemented carbide are placed in an electrolytic apparatus containing an aqueous conductive electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, said electrolyte comprising a corrosive agent which in the absence of an applied electrolytic current will corrode and dissolve the binder phase of the cemented carbide pieces while having little if any corrosive effect on the metal carbide grains of such pieces, passing an electric current between said anode and cathode, at least one of the amperage and potential of said electric current being controlled to electrochemically and selectively dissolve the binder phase of said cemented carbide pieces without significantly attacking the metal carbide grains therein, recovering metal carbide grains from which said binder phase has been dissolved, and recovering a metallic value from said dissolved binder phase by precipitation as a compound from said electrolyte.

A process for recovering metal carbide powder and a binder phase metal from cemented carbide pieces wherein a plurality of pieces of cemented carbide are placed in an electrolytic apparatus containing an aqueous conductive electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, said electrolyte comprising a corrosive agent which in the absence of an applied electrolytic current will corrode and dissolve the binder phase of the cemented carbide pieces while having little if any corrosive effect on the metal carbide grains of such pieces, passing an electric current between said anode and cathode, at least one of the amperage and potential of said electric current being controlled to electrochemically and selectively dissolve the binder phase of said cemented carbide pieces without significantly attacking the metal carbide grains therein, recovering metal carbide grains from which said binder phase has been dissolved, and recovering a metallic value from said dissolved binder phase by precipitation as a compound from said electrolyte, said binder phase being essentially cobalt and said compound being essentially a cobalt salt.

A process for recovering metal carbide powder and a binder phase metal from cemented carbide pieces wherein a plurality of cemented carbide pieces are placed in an electrolytic apparatus containing an aqueous conductive electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, said electrolyte comprising a corrosive agent which in the absence of an applied electrolytic current will corrode and dissolve the binder phase of the cemented carbide pieces while having little if any corrosive effect on the metal carbide grains of such pieces, passing an electric current between said anode and cathode, at least one of the amperage and potential of said electric current being controlled to electrochemically and selectively dissolve said binder phase of said cemented carbide pieces without significantly attacking said metal carbide grains therein, recovering metal carbide grains from which said binder phase has been dissolved, and recovering metal values from said dissolved binder phase by electroplating said metal values from said electrolyte onto a cathode.

A process for recovering metal carbide powder and a binder phase metal from cemented carbide pieces wherein a plurality of cemented carbide pieces are placed in an electrolytic apparatus containing an aqueous conductive electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, said electrolyte comprising a corrosive agent which in the absence of an applied electrolytic current will corrode and dissolve the binder phase of the cemented carbide pieces while having little if any corrosive effect on the metal carbide grains of such pieces, passing an electric current between said anode and cathode, at least one of the amperage and potential of said electric current being controlled to electrochemically and selectively dissolve said binder phase of said cemented carbide pieces without significantly attacking said metal carbide grains therein, recovering metal carbide grains from which said binder phase has been dissolved, and recovering metal values from said dissolved binder phase by electroplating said metal values from said electrolyte onto a cathode, said cemented carbide pieces comprising cemented tungsten carbide pieces with a binder phase containing cobalt and said metal values comprising cobalt and tungsten.

A process for recovering metal carbide powder from cemented carbide wherein a plurality of cemented carbide pieces are placed in an electrolytic cell containing an oxalic acid electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, passing an electric current between said anode and cathode, at least one of the amperage and potential of said current being controlled to electrochemically and selectively dissolve the binder phase of said cemented carbide pieces without significantly attacking the metal carbide grains therein, and recovering at least a portion of said metal carbide grains from which said binder phase has been dissolved along with cobalt oxalate.

A process for recovering metal carbide powder from a cemented carbide containing a binder phase, first metal carbide grains having an active anodic polarization at a higher positive potential than said binder phase, and second metal carbide grains having an active anodic polarization at a higher positive potential than said first metal carbide grains, such process comprising placing a plurality of said cemented carbide pieces in an electrolytic apparatus containing an aqueous conductive electrolyte, an anode and a cathode and wherein at least some of said cemented carbide pieces are in contact with said anode, passing an electric current between said anode and cathode, at least one of the amperage and potential of said electric current being controlled to electrochemically and selectively dissolve said binder phase and said first metal carbide grains of said cemented carbide pieces without significantly attacking said second metal carbide grains therein, and recovering at least a portion of said second metal carbide grains from which said binder phase and said first metal carbide grains have been dissolved.