NU 2020-041

INVENTORS
J Fraser Stoddart*
Huang Wu

ABSTRACT
For well over a century now, 83% of gold production has depended on a cyanide-leaching process, while that remaining in the debris  is often treated  with  mercury.  Both cyanide  and mercury, however, are  highly  toxic, causing  human  health  hazards and serious  environmental  pollution  from  inadequate  handling  and  accidental  spillage.  Therefore, developing environmentally benign, extremely efficient and highly selective processes for gold recovery is urgently desired for maintaining a sustainable ecological environment. Northwestern researchesr have developed a highly efficient gold-recovery protocol on the basis of the instantaneous assembly between cucurbit[6]uril (CB[6]) and [AuX4]−(X = Cl / Br) anions. The use of CB[6] as a gold extractant, not only provides us with a new opportunity to develop more efficient and environmentally friendly processes for  the  industrial  production  of  gold, but  also it  avoids  the  use  of  toxic  cyanide and mercury  employed  in  the  traditional  gold mining industries all around the world.  This approach addresses several critical problems:  (1) the need for extremely efficient and highly selective recovery of gold from gold-bearing raw materials; (2) the need for golf recovery in a environmentally friendly manner, avoiding the use of toxic cyanide and mercury; and (3) the need for adopting a more simple gold recovery protocol for large-scale gold recovery.   Such a gold-recovery strategy based on cucuebit[6]uril, not only leads to a fast, feasible and economic process with a high recovery efficiency,  but  also  is  more  environmentally  friendly  in  comparison  with  the  traditional  cyanidation  process,  demonstrating  its considerable potential for finding wide practical application

APPLICATION

• Gold extraction
• Separation of other previous metals

ADVANTAGES

• Rapid co-precipitation at ambient conditions
• Highly efficient separation of gold (99.2%)
• Selective recovery of gold from complex mixtures of other metal salts
• Achieved in environmentally friendly manner, avoiding the use chemicals

PUBLICATION
Wu H, Jones L, Wang Y, Shen D, Liu Z, Zhang L, Cai K, Chen XY, Jiao Y, Stern C, Schatz T and Stoddart JF (2020) High-Efficiency Gold Recovery Using Cucurbit[6]uril.  ACS Appl Mater Interfaces 12: 38768-38777

IP STATUS
Provisional and PCT applications have been filed.