Production of Potassium-Enriched Fertilizer Using the Complex Sorption and Membrane Technology

The production of potassium-containing fertilizer using improved, complex method was researched. Cheapness and availability of the raw material (the natural zeolite, clinoptilolite from Dzegvi and Tedzami mines is used as a substrate and seawater – as a source of potassium ions) make this method very interesting and prospective for the countries with clinoptilolite stocks, located in the seaside regions and engaged in agrarian industry (Georgia, Greece, Romania, Bulgaria). It includes two technological processes: sorption and membranes ones. At the first stage, for intensification purpose electrodialysis was used for concentration of sea water. The optimal parameters for concentration of sea water were matched using the electrodialysis apparatus produced in the Institute workshop. In the produced concentrate of sea water, the index of potassium-ion concentration exceeds 4, being twice higher than the natrium-ion concentration index. At the second stage, selection of sea water ions was provided on the natural zeolite by so called dual-temperature ion exchange method: during sorption of potassium by clinoptilolite at low temperature the other ions pass into filtrate. The received potassium-enriched zeolite is a new type fertilizer: potassium containing therein passes into soil “as needed”, when soil is impoverished.