A method for separating an amount of osmium from a mixture containing the osmium and at least one other additional metal is provided. In particular, method for forming and trapping OsO.sub.4 to separate the osmium from a mixture containing the osmium and at least one other additional metal is provided.

In an electrodeposition treatment of an iron-group metal ion-containing liquid, without being influenced by the properties of the iron-group metal ion-containing liquid, iron-group metal ions are efficiently removed from the liquid by precipitation. An anode chamber 2A provided with an anode 2 and a cathode chamber 3A provided with a cathode 3 are separated from each other by a cation exchange membrane 5, an iron-group metal ion-containing liquid is charged into the anode chamber 2A, a cathode liquid is charged into the cathode chamber 3A, and by applying the voltage between the anode 2 and the cathode 3, iron-group metal ions in the liquid in the anode chamber 2A are moved into the liquid in the cathode chamber 3A through the cation exchange membrane 5, so that an iron-group metal is precipitated on the cathode 3.

In an electrodeposition treatment of an iron-group metal ion-containing liquid, without being influenced by the properties of the iron-group metal ion-containing liquid, iron-group metal ions are efficiently removed from the liquid by precipitation. An anode chamber 2A provided with an anode 2 and a cathode chamber 3A provided with a cathode 3 are separated from each other by a cation exchange membrane 5, an iron-group metal ion-containing liquid is charged into the anode chamber 2A, a cathode liquid is charged into the cathode chamber 3A, and by applying the voltage between the anode 2 and the cathode 3, iron-group metal ions in the liquid in the anode chamber 2A are moved into the liquid in the cathode chamber 3A through the cation exchange membrane 5, so that an iron-group metal is precipitated on the cathode 3.

A method for extracting the tantalum from an acid aqueous phase A1 comprising at least one step comprising the bringing of the aqueous phase A1 into contact with a phase A2 not miscible with water, and then the separation of the aqueous phase A1 from the phase A2, the phase A2 consisting of one ionic liquid or a mixture of ionic liquids as an extractant. A method for recovering the tantalum that implements this extraction method and to a use of an ionic liquid or of a mixture of ionic liquids as an extractant, in order to extract the tantalum from such an aqueous phase A1.

A method for extracting the tantalum from an acid aqueous phase A1 comprising at least one step comprising the bringing of the aqueous phase A1 into contact with a phase A2 not miscible with water, and then the separation of the aqueous phase A1 from the phase A2, the phase A2 consisting of one ionic liquid or a mixture of ionic liquids as an extractant. A method for recovering the tantalum that implements this extraction method and to a use of an ionic liquid or of a mixture of ionic liquids as an extractant, in order to extract the tantalum from such an aqueous phase A1.

A system for recycling machined metal produced by an electrochemical material removal process. The system includes a machining unit and an electrowinning unit. The machining unit includes an anode to receive a workpiece, a cathode tool, and a first pulse generator to provide a voltage or current waveform between the anode and the cathode tool. The electrowinning unit includes an electrowinning cathode, an electrowinning anode, and a second pulse generator to provide a voltage or current waveform between the electrowinning anode and the electrowinning cathode. The machining unit is in fluid communication with the electrowinning unit.

A system for recycling machined metal produced by an electrochemical material removal process. The system includes a machining unit and an electrowinning unit. The machining unit includes an anode to receive a workpiece, a cathode tool, and a first pulse generator to provide a voltage or current waveform between the anode and the cathode tool. The electrowinning unit includes an electrowinning cathode, an electrowinning anode, and a second pulse generator to provide a voltage or current waveform between the electrowinning anode and the electrowinning cathode. The machining unit is in fluid communication with the electrowinning unit.

A method for recycling metallic material produced by an electrochemical material removal process. The method includes flowing an electrolyte solution between an anode workpiece and a cathode tool in a first electrolytic process, the first electrolytic process including applying a first electrolytic current and voltage between the anode workpiece and the cathode tool and thereby causing metal ions to be removed from the anode workpiece and dissolved and substantially retained in the electrolyte solution. The electrolyte solution with the metal ions therein is passed between an electrowinning cathode and an electrowinning anode in a second electrolytic process, the second electrolytic process including applying a second electrolytic current and voltage between the electrowinning cathode and the electrowinning anode and thereby causing the metal ions to be removed from the electrolyte solution and deposited onto the electrowinning cathode.

A method for recycling metallic material produced by an electrochemical material removal process. The method includes flowing an electrolyte solution between an anode workpiece and a cathode tool in a first electrolytic process, the first electrolytic process including applying a first electrolytic current and voltage between the anode workpiece and the cathode tool and thereby causing metal ions to be removed from the anode workpiece and dissolved and substantially retained in the electrolyte solution. The electrolyte solution with the metal ions therein is passed between an electrowinning cathode and an electrowinning anode in a second electrolytic process, the second electrolytic process including applying a second electrolytic current and voltage between the electrowinning cathode and the electrowinning anode and thereby causing the metal ions to be removed from the electrolyte solution and deposited onto the electrowinning cathode.

A method of producing iron metal by electrolysis of iron ore can include introducing iron ore into an anode chamber. The anode chamber can include a first electrolyte and an anode. The anode can oxidize water to form O.sub.2 gas and H.sup.+ ions in the anode chamber. The iron ore can be dissolved to form Fe.sup.3+ and/or Fe.sup.2+ ions in the anode chamber. The Fe.sup.3+ and/or Fe.sup.2+ ions can be transferred from the anode chamber to a cathode chamber through a cation exchange membrane that separates the anode chamber from the cathode chamber. The cathode chamber can include a second electrolyte and a cathode. The Fe.sup.3+ and/or Fe.sup.2+ ions can be reduced to form iron metal at the cathode.