Studies On The Capability Of K～+-Ca～(2+) Exchange On Natural Clinoptilolite

The task is the studies on the capability of K+-Ca2+ exchange on natural clinoptilolite, which is based on the predecessor's research. Two parts were studied which included thermodynamics and kinetics. The effect of different surroundings on the ion exchange was investigated. All the work can help us to find the best operation conditions.In the studies of thermodynamics some conclusions had been drawn. The ability of potassium exchange was 164.42meq/100g clinoptilolite. The reaction belongs to incomplete exchange. The isotherm of ion exchange and the diag of Kielland had been got. It showed that the selectivity would be higher with the temperature increasing. The adsorption of potassium in the seawater on the Ca-form clinoptilolite was studied at different temperature and the best operation temperature was 50℃. The functions of thermodynamics had been got, which showed the reaction was endothermic and it can progress spontaneously in the experiment.The studies of kinetics showed that the exchange process was controlled by film diffusion in the conditions of experiment. By the technique of shallow bed, the data and the curve of kinetics had been got under different conditions. The KD.a and D had been calculated. The results of experiments showed the increasing of temperature and concentration was in favor of the exchange of potassium. Although the increasing of flow can also be in favor of the exchange, the effect was not notable. The mass transfer model was founded in the research, and the data got from the model could be fit for the data got from the experiments well.The task can supply the research blank of the Ca-form clinoptilolite, it also can help us to improve the technique of extracting potassium. This method can reduce the cost and cut short the circuit. In a word, this task is an indispensable complement for extracting potassium from seawater.