| Firstly, the exchange equilibrium of K+—NH4+ on the novel ion-sieve for potassium is studied .The ion exchange equilibrium data of K+—NH4+ on the novel ion-sieve for potassium have been determined, and The ion exchange isotherms at the temperature of 0℃,25℃,50℃and 75℃has been drew respectively. The results show that the selectivity of the ion-sieve to K+ is in preference to NH4+, with the going up of the temperature, the selectivity of the ion-sieve to NH4+ increases; At 50℃, the ion exchange capability of the ion-sieve is optimal.Secondly,the technology of extraction potassium sulfate from seawater using the new synthesis ion-sieve was researched on the basis of the predecessor research, including efficient enrichment K+ in seawater and economic separation of potassium sulfate from enriched potassium solution, so as to produce a new process to realize industrialization of producing potassium sulfate from the seawater.The phase of the enrichment of potassium includes the adsorption of potassium ion in seawater, the elution and regeneration of ion-sieve. In the phase of elution, the result showed that the higher the temperature and the concentration of ammonium sulfate, the better the effect of elution. Either lower or higher flux of ammonium sulfate is disadvantageous to the effect of K+ elution. The better is 80ml/min. In the phase of regeneration,the result showed that the higher the temperature and the lower flux of the salt,the better the effect of regeneration.To separate potassium sulfate from the enriched potassium solution, various methods in the experiment were attempted. By means of cooling the solution directly, we found that the ratio of deposition of potassium is 15.90%. When adding the methanol, isopropyl methanol and ammonia to the solution, the crystal containing below 80% potassium sulfate was gained. By the way of potassium chloride transforming,Hign ratio of potassium sulfate in the crystal can be gained. Through orthogonal experiment, the effect of the quantity of potassium chloride and water, and the temperature on the result of experiment was tested .In the optimal condition; the ratio of potassium sulfate in the product can reach 99.25%. |
