Study On Ion Exchange Characteristic Of Clinoptilolite On K～+

In the recent years, clinoptilolite , as a kind of ion exchange agent with high property, has been paid more and more attention to, and there were obvious development on the side of researching on structure, characteristic and utilization of clinoptilolite. Since 1970s, the research and utilization of clinoptilolite has got a suitable achievement in our country. It was stated that clinoptilolite had the characteristic of exchange cations, especially a high selectivity to potassium, So the technology extracting kali salt from seawater by clinoptilolite was a outlook way to change the existing situation of the lack of potassium in China. But now, the mechanism of ion exchange on clinoptilolite was not clear in whole world .So the technology that extracting kali salt from seawater by clinoptilolite was restricted. In order to optimize technological parameters, reduce the comsumption of energy, and offer some basis theory for the technology of extracting kali salt by clinoptilolite, ion exchange systems were studied in experiment and theory.In the paper, the thermodynamics and kinetics of ion exchange systems were studied. The thermodynamics is as follows: First, we determined the capacity of ion exchange to K+; Second, we finished the isotherm of ion exchange equilibrium of clinoptilolite under different temperature by static method. Further more, by the figure of isothermal ion exchange equilibrium , we studied the influence of temperature on ion exchange equilibrium, and by the data obtained from experiments we got thermodynamics models which were similar to Langmuir equation, as well as thermodynamics functions. The kinetics is as follows: First, rate-controlling mechanism of ion exchange was found out.That is ,film diffusion control. At the same time, we utilized two ways, which were broken phase contact and shallow-bed tech.,to confirm the correctness of the mechanism, and influence of Mg2+. Second, on the basis of the principles of mass-transfer, we derived model under the conditions of the film diffusion control. The results showed that mass-transfer coefficient obtained from model tallied with experimental results when current velocity increased from 0.02165m/s to 0.0433m/s. Third, under varieties of conditions, such as concentration, temperature, particle radium, current velocity and viscosity of solution, we got the mass transfer coefficient and effective diffusion coefficient, the experimental results were that the mass-transfer coefficient extended when temperature andcurrent velocity of solution rased and when particle radium and viscosity of solution reduced, but the influence of concentration to the mass-transfer coefficient was not obvious. On the other hand, we got kinetics curves under varieties of conditions.The result not only was used in direct production but also consulted some other studies about ion exchange on clinoptilolite. So the domain of this research will be wide.