The Research On The Enrichment Technology Of Low Concentration Nickel Sulphate Solution

Large number of low concentration of nickel sulfate solution will be produced in nickel plating production and the process which is one of the world's leading heavy pollution. To build a resource-saving and environment-friendly society, in this paper, the ion exchange was be used to reuse wastewater containing nickel. Study about the influence factors on the recovery of nickel ions to guide the engineering design and debugging. The following researches have been carried out:The ion exchange resins would be selected though static method. The results revealed that ineffection of resin adsorption controlled by pH value 5⁶ at common temperature. The recovery rate of nickel exceeded 90% if strong acidic ion exchange resin was up to 4g and nickel ions concentration 1g/L and reacted for 60 minutes. Corresponding to the single ion system view, the recovery rate of nickel had different degrees of decline in mixed system because of similar nature and ion combining between Co²⁺and Ni²⁺. So when they coexist in the same system basically the same level when adsorption.The study on reaction kinetics showed that the adsorption process was mainly controlled by liquid film diffusion, and adsorption isotherms corresponded well with the Freundlich equations. Thermodynamics research shows that the adsorption enthalpy was positive at different temperatures. It was indicated that the adsorption process in the ion exchange resin was endothermic and was easier to carry.The dynamic experimental results demonstrate that the optimized conditions of single-column process are as follows: under certain feed concentration and temperature, the ratio of height to diameter 20, the flow rate of feed solution 7ml/min. whereas the adsorption process with mixed columns in series can reduced the ion concentration to 1mg/L, and the ion removal rate will be above 99%. Under this situation, the concentration of the wastewater can meet national emission standards, and the utilization rate of the resin can reach to 80%. So, we can conclude that the effect of the adsorption process is much better than that of the single column.Infrared spectra of saturated ion exchange resin under static test and dynamic test show that the peak of concentration of Ni²⁺ do not change, which indicating that wastewater treatment is just a change for different ions. Combined with the results of research, we enlarge the design of ion exchange equipment, and also completed calculation of the nickel that the daily production is 1kg. When the resins become to be saturated, select the appropriate regenerator to recover exchange performance of the resin, and it will make the resin achieve the utmost exchange capacity. The optimum regeneration condition of the experiment is that: firstly use single column in the case of sulfuric acid as regenerator, then use 3mol / L sulfuric acid under the absorption is cast to 40 minutes when the amount of regeneration is 15 times than recycled resin. The ion adsorption will have good performance under this condition.