An Application Fundamental Study On Recorvery Cyanide By Macroporous Anion Exchange Resin

This paper mainly deals with the performance and mechanics of adsorption and desorption cyanide by macroporous anion exchange resin , it is expected to provide theoretical basis for industrial applications.The experiments in this paper are operated by static and dynamic methods. The effects of acidity, temperature, cyanide concentration, adsorption time, resin dosage and flow rate on D296r and D261 resins adsorption cyanide are systematically investigated. The adsorption isotherm on alkaline anion exchange resin is drawn, the thermodynamic function of adsorption process is deduced, the apparent adsorption rate of cyanide and dynamics parameter is measured, a kind of promising eluant selected and the conditions of elution are determined, at the same time, adsorption mechanism is studied initially by infra-red spectrometry. The test results show that free cyanide, metallic cyanide complexes such as zinc cyanide, copper cyanide, iron cyanide, gold and silver cyanide can be well adsorped by D296r and D261 macro porous strong basic anion exchange resin. The adsorption behavior of two resins for cyanide obeys the Freundlich isotherm and the adsorption process is concluded to be a favorable adsorption. Dynamic data from the static experiment indicate that this adsorption is instantaneous reaction under the room temperature conditions, and main control step of two resins adsorbing cyanide is body liquid membrane diffusion. It is determined that the static and dynamic saturate adsorption capacity of wet D296r resin are 27.58mg/ml and 28.02mg/ml respectively, and those of wet D261 are resin 25.28mg/ml and 26.64mg/ml respectively. The adsorption principles of two resins are both physical adsorption. At the same time, the MN as eluant instead of acid is selected and elution ratio can reach above 96%. 10 circles of the stable experiments show that the resins are stable, and their adsorption ratio could be maintained around 93%. Recovery cyanide using D296r and D261 resins has the advantages of little influence by temperature, high speed, easy elution, simple operation, no secondpollution, high adsorption capacity, and low cost and dosage etc. Therefore, D296r and D261 resins have promising industry application in recovering cyanide.