Study On The New Technology Of Abstracting Potassium Sulfate From Seawater Using Zeolite

The effect of various kinds of factors upon zeolite's ion exchange was discussed in the paper. The phase of the erishment of potassium included the adsorption of potassium ion in seawater,the elution and regeneration of zeolite. In the phase of adsorption, the flux of the seawater had little effect on the ion exchange; we can increase the flux of seawater according to the cost of energy and power. At the same time,The result of expriment showed that the effect on the zeolite's adsorption of potassium was better in the bittern than in the seawater. In the phase of elution, It showed that the higher the temperature and the concentration of ammonium,the better the effect of elution.It also showed that either too low or too high flux of ammonium sulfate was disadvantage to the effect of elution. According to the results of experiment, we choosed 80ml/min as the better flux of ammonium sulfate. In the phase of regeneration, the results of experiment indicated that a higher temperature and a lower flux of salt was advantage to the effect of regeneration. In the industry, considering the cost of energy and power, we choosed 80 ℃ as the better temperature of the elution.To separate potassium sulfate from the solution riched of potassium different methods were tried in the paper. By means of cooling the solution directly and concentrating the solution, the crystal was gained contained low potassium sulfate. When added the Carbinal, Ethanol, Acetone and Ammonia gas in the same weight of 10% separately to the solution, the crystal containing about 25% potassium sulfate was gained. With adding of Ammonia gas, the crystal we gained and the ratio of deposition of potassium was increased, however the ratio of potassium sulfate in the crystal was not changed. Through orthogonal experiment, The effect of the weight of ammonia gas and water on the result of experiment was tested.It showed that when the ratio of the water was 12gH2O/gK.2SO4 and the weight of ammonia gas in the solution was 10%, the effect of crystallization was better. At this time, the ratio of potassium sulfate in the crystal was 81.47% and the ratio of deposition of potassium ion was 80.14%. Complementary experiments were carried out on the base of the orthogonal experiment, the crystal products with the content of potassium sulfate of 91.61 % had been obtained when the content of ammonia gas was 18 % and the content of water was 15gH2O/gK2SO4in the solution riched of potassium. At the sametime, the ratio of deposition of potassium ion was 99.10%.