| Cobalt is an important non-ferrous metal which plays a significant role innational defense and economic construction. China is shortage of cobalt resources,and cobalt ore is low grade, lack of a single mine. Due to the development of specialindustries in recent years, such as batteries, catalysts and superalloys, it has been achallenge to the ability of our production of cobalt. The inappropriate of miningtechnology and recovery methods not only led to a waste of resources but alsoenvironmental issues. The search for crafts of high comprehensive recovery and littleenvironmental pollution is imminent.In this paper, research on the existing recovery process of copper and cobaltwhich have been studied were enumerated. Aiming at the separation of copper andcobalt in the dilute sulfate solution, the separation performance of three chelatingresins for copper and cobalt were studied. One resin with good performance onadsorption of copper and cobalt has been selected. Flame atomic absorptionspectrometry and iodometric method were used for the the detection of metal ions.This method has solved the problem of the difficult recycle of copper and cobalt indilute sulfate solution.The main contents are as follows:1. The separation performance of chelating resin D405, D407, D418for copperand cobalt were investigated by static method. The research results showed that theabsorption capacity of three chelating resins for copper and cobalt was D418> D405> D407, and for each chelating resin, the adsorption capacity of copper is well thanthat of cobalt. The separation performance of three chelating resin for copper andcobalt was D407≈D418> D405. Considering adsorption amount and separation performance, D418was selected to separate copper and cobalt in sulfate dilutesolution.2. The adsorption properties of D418for copper and cobalt in single sulfatedilute solution were investigated by static method. In this paper, the effect of thesolution pH, initial concentration, contact time, temperature on the adsorption wasinvestigated. The experimental results showed that both of the optimum pH valueswere5.0for copper and cobalt for the absorption of copper and cobalt by D418. Themaximum absorption amount were170.65mg/g and132.28mg/g, respectively.Sulfuric acid was used to elute loaded resins. Experimental results showed that, inorder to elute completely, sulfuric acid concentration were1.0mol/L for copperloaded resin and0.6mol/L for cobalt loaded resin.3. In this paper, the results of absorption of D418for copper and cobalt werefitted on Langmuir and Freundlich isotherm equation. Langmuir isotherm equation ismore suitable than Freundlich isotherm equation at the description of the adsorptionbehavior of D418on copper and cobalt. Adsorption of D418for copper and cobalt isan endothermic process. Kinetic studies were used pseudo-first order kinetic model,second-order kinetics model and particle diffusion model. The results showed that, theabsorption of copper was well fitted by pseudo-first order kinetic equation and theabsorption of cobalt was well fitted by second-order kinetics equation. Moreover, bothof absorption process of copper and cobalt were controlled by liquid film diffusionand particle diffusion.4. The separation performance of D418for copper and cobalt was studied bystatic method. The absorption equilibrium experiments showed that an absorptioncompetition have occurred between copper and cobalt in secondary solution. Copperwas selectively absorbed by D418in the presence of cobalt. The pH value was5.0forthe absorption process in secondary solution. The separation performance of D418forcopper and cobalt in the concentration ratios of2000/300,500/100(Cu/Co, mg/L)dilute sulfates solution. With the combined effect of the amount of resin and contacttime, copper and cobalt could been separated. Experimental results showed thatcopper recovery rate could reach more than90%, while all cobalt was reminded in the adsorption raffinate after three adsorption followed by the absorption of cobaltadsorption. For the recovery of cobalt, two programs have been compared in theexperiment. One is complete adsorption of copper and cobalt. Then, by desorption ofloaded resin, cobalt was recoveried from desorption solution. The other is completeadsorption of copper. After the adsorption, a majority of cobalt was recovered fromadsorption raffinate. The data of the recovery and the purity of the product showedthat complete adsorption copper is superior to complete adsorption of copper andcobalt. |
PDF Full Text Request