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Study On Removing Trace Lead And Zinc From Nickel Electrolyte By Continuous Ion Exchange Process

Posted on:2004-05-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:G Q ZhangFull Text:PDF
GTID:1101360125458097Subject:Non-ferrous metallurgy
Abstract/Summary:PDF Full Text Request
Removing trace lead and zinc from nickel electrolyte is an important step in the process of nickel refinery. In view of the disadvantages of traditional method, a brand-new method of removing trace lead and zinc from nickel electrolyte by continuous ion-exchange process is put forward, i.e. method of continuous ion-exchange process with the combination of moving packed bed and fluid bed (CIX-MF). And it has been successfully industrialized. The research covers laboratory trial with fixed bed, study on ion-exchange equilibrium and its kinetics, scaled-up trial of CIX-MF, study on industrialization of CIX-MF, and development on the new method of analyzing trace lead in nickel electrolyte.Macroporous weak-base resin D363 and macroporous strong-base resin D201 have been selected to remove lead and zinc respectively from the nickel electrolyte by ion exchange. The effects of pH value, temperature, contact time on lead and zinc adsorption by ion exchange are inspected respectively in laboratory-scale fixed bed. The adsorption capacities of the resins are examined, and its adsorption property has been inspected. The results show that resin D363 and resin D201 have excellent ability of lead and zinc adsorption respectively, the loaded resin can desorb easily with water, and its desorption property is very good. As far as the adsorption ability of lead and zinc, desorption property , wearability, intensity, and the ability of anti-pollution are concerned, resin D363 and resin D201 perform better than lead-removing resin 331 and zinc-removing resin 201x7, which is employed in the traditional technology of fixed bed.The ion-exchange equilibrium and kinetics of lead adsorption with resin D363 and zinc adsorption with resin D201 have been studied. The results of study on ion-exchange equilibrium illustrate that the Cl" concentration, acidity and temperature of feed have certain effect on the equilibrium of lead adsorption with resin D363, among them, the effect of temperature is great. Both the drop of acidity and rising of temperature have negative impact on lead adsorption. Different from resin D363, acidity and temperature have very little effect on zinc adsorption with resin D201. It has also been shown that the ion-exchange isothermal (q-C Curve) of both lead adsorption with resin D363 and zinc adsorption with resin D201 are straight line within a certain concentration range of lead and zinc. According to the straight linear relationship of lead adsorption with resin D363 and effect of temperature on the isothermal (q-C Curve), A H and A S of lead adsorption with resin D363 are acquired, and the formula for calculating saturation capacity of resin D363 to lead has been obtained. Similarly, the formula for calculating saturation capacity of resin D201 to zinc has also been obtained, according to the linear relationship of zincABSTRACTadsorption with resin D201 and effect of temperature on its isothermal (q-C Curve).The results of study on ion exchange kinetics indicate, the exchange rate of zinc adsorption with resin D201 is lower than that of lead adsorption with resin D363. Both of them are controlled by the diffusion through micro ball of macroporous resin. The apparent sorption rate constant and apparent activation energy of the two ion exchange processes have been acquired according to the experiments.Scaled-up trial on removing lead by CIX-MF has been conducted, and the basic module and operation method for the equipment has been set. The results indicate that moving packed bed can effectively remove lead by adsorption with D363 resin, and the operation capacity of the resin is one time larger than the break through capacity of the resin in fixed bed. The resins in moving packed bed move smoothly, and there is no resin-layer confusion. The duration for desorption and regeneration of loaded resin in the fluid bed is short and water consumption is low. The equipment of the CIX-MF operates easily and stably, and the trial repeatability is good, which manifest that it can basically realize continuous ion excha...
Keywords/Search Tags:ion exchange, moving packed bed, fluid bed, lead, zinc, nickel electrolyte
PDF Full Text Request
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