Synthetic ion-exchange resins offer an attractive alternative to carbon for the recovery of gold from alkaline cyanide solutions. This paper describes an investigation of the kinetics of loading gold onto a new weak-base resin (PAZ-4) designed specifically for gold and silver cyano anions. The uptake of gold was determined at temperatures from 25 degree C to 450 degree C, pH's from 8. 5 to 11. 5, and free cyanide concentrations from 0. 20 g/l to 0. 80 g/l. The adsorption rate increases strongly with decreasing pH and to a lesser extent with increasing free CN** minus concentration. Temperature was observed to have very little effect on the loading kinetics. The initial loading kinetics obey a shell-progressive (shrinking core) diffusion mechanism and can be explained mathematically by the classical diffusion equation for spherical particles. An exchange mechanism involving reaction between aurocyanide and hydrogen cyanide is proposed to explain the results.
|Original language||English (US)|
|Title of host publication||Unknown Host Publication Title|
|Publisher||Metallurgical Soc of AIME|
|Number of pages||16|
|State||Published - Dec 1 1986|
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