Electrochemical dissolution of conductive composites

Abstract

A method and apparatus separates recoverable components ( 210 ) from conductive matrix composites ( 200 ) for further use or reuse. In an embodiment, the process uses an electrochemical apparatus that includes a cathode ( 220 ) and an anode. The conductive composite is electrically connected to the anode, and a non-acidic electrolyte ( 250 ) is supplied to an inter-electrode gap between the cathode and the anode.

1 . A process of recovering material from a conductive composite, comprising:
 at least partially dissolving a solid body through electrolytic dissolution, wherein:
 the body comprises a conductive matrix and one or more non-conductive constituents; and 
 the dissolving is conducted at a current having a density that is at least 10 A/cm 2 ; and 
   recovering one or more materials released from the body in the dissolution.   
   
   
       2 . The process of  claim 1 , wherein the dissolution is conducted in the presence of an electrolyte having a pH between about 6 and about 11. 
   
   
       3 . The process of  claim 1 , wherein:
 the electrolytic dissolution uses a cathode;   a gap exists between the cathode and the body; and   the gap is maintained to be less than about 10 millimeters in size by moving the cathode, the body, or both the cathode and the body.   
   
   
       4 . The process of  claim 1 , wherein:
 the electrolytic dissolution uses a cathode; and   an electrolyte flow having a rate greater than 300 milliliters per minute per square centimeter of cathode area is directed into a gap between the cathode and the body.   
   
   
       5 . The process of  claim 1 , wherein the current density is between about 15 A/cm 2  and about 100 A/cm 2 . 
   
   
       6 . The process of  claim 2 , wherein the electrolyte comprises a concentrated alkali metal in solution, an alkaline earth salt in solution or an ammonium salt in solution. 
   
   
       7 . The process of  claim 1 , wherein the non-conductive constituents comprise diamond or graphite, and the process further comprises feeding at least a portion of the released diamond or graphite to a separation device for recovery. 
   
   
       8 . A process for reclaiming one or more components of a composite body, comprising:
 positioning a composite body comprised of one or more conductive materials and one or more non-conductive materials in an apparatus in the presence of an electrolyte so that the body acts as an anode opposite a cathode;   applying a voltage in the range of about 5 to about 50 volts and a current having a density that is at least 10 A/cm 2  and about 100 A/cm 2  so that one or more of the non-conductive materials are released from the body; and   recovering one or more of the released non-conductive materials.   
   
   
       9 . The process of  claim 8 , wherein the current density is about 15 to about 100 A/cm 2 . 
   
   
       10 . The process of  claim 8 , wherein the body is in electrical contact with a conductive anode member via a mechanical, magnetic, pneumatic or electrical device, a gap of at least 1 millimeter exists between the cathode and the body, and the process further comprises maintaining the gap by moving the cathode, the body, or both the cathode and the body. 
   
   
       11 . The process of  claim 8 , wherein the electrolyte comprises an alkali metal in solution, an alkaline earth salt in solution or an ammonium salt in solution. 
   
   
       12 . The process of  claim 8 , wherein the electrolyte has a conductivity that is in excess of about 100 millisiemens at temperatures in the range of about 10° to about 90° C. 
   
   
       13 . The process of  claim 8 , wherein the released non-conductive materials comprise diamond or graphite. 
   
   
       14 . A method of processing a conductive composite body containing diamond comprising:
 providing a conductive composite body in an electrochemical apparatus, the apparatus including an anode and a cathode, so that the composite body is electrically connected to the anode and an inter-electrode gap is located between the cathode and the composite body;   delivering electrolyte to the inter-electrode gap, wherein the electrolyte has a pH of about 6 to about 11; and   applying a current having a density of about 10 A/cm 2  to about 100 A/cm between the cathode and the anode.   
   
   
       15 . The method of  claim 14 , wherein the electrolyte has a pH of about 6.5 to about 9. 
   
   
       16 . The method of  claim 14 , wherein the conductive composite body is comprised of graphite, metal and non-conducting material. 
   
   
       17 . The method of  claim 14 , wherein the current density is about 15 A/cm 2  to about 100 A/cm 2 . 
   
   
       18 . The method of  claim 14 , wherein the electrolyte comprises one or more metal chlorates, metal nitrates, metal chlorides, or mixtures thereof. 
   
   
       19 . The method of  claim 14 , further comprising advancing one or both of the electrodes toward the other as the composite body is processed. 
   
   
       20 . The method of  claim 14 , wherein a layer of conductive material is positioned between the anode and the composite. 
   
   
       21 . The method of  claim 14 , wherein the processing is performed at an electrolyte gage pressure that is about 1 bar to about 5 bar. 
   
   
       22 . An apparatus for recovering non-conductive, non-metallic material from a conductive matrix composite body, comprising:
 an anode, wherein the anode is electrically connected to a conductive matrix composite;   a cathode positioned to form an inter-electrode gap between the composite body and the cathode;   a non-acidic electrolyte supply; and   a non-conductive particle recovery system.   
   
   
       23 . The apparatus of  claim 22 , further comprising a direct current or alternating current power supply that applies a current having a density of about 15 A/cm 2  of electrode area to about 100 A/cm 2  of electrode area. 
   
   
       24 . The apparatus of  claim 22 , further comprising a driver to move one or more of the anode or the cathode, to maintain the gap at a substantially uniform size. 
   
   
       25 . The apparatus of  claim 22 , wherein the recovery system comprises at least one of the following: a settling device and an apparatus for recycling electrolyte. 
   
   
       26 . (canceled)