Study On The Production Of Potassium Carbonate By Using Zeolite Ion Exchange Method

The technology of extracting potassium carbonate from seawater using zeolite ion exchange method was researched on the basis of the predecessor research, including efficiency enrichment K~+ in seawater and separation of potassium carbonate from enriched potassium solution, so as to produce a new process to realize industrialization of producting potassium carbonate from seawater.K~+ enrichment working procedure: Some comparation experiments about the effect of K~+ enrichment efficiency were carried out under different technological methods. Compared with the first stage, the average concentration of K~+ in the enriching potassium solution produced by the new technology at second stage is almost one time higher. In the first stage of enriching potassium, the seawater was adsorbed at the normal atmospheric temperature, and the first concentrated solution was obtained by using high temperature saturated brine as elution. In the second stage of enriching potassium, the temperature of adsorbing the first concentrated solution was room temperature. The enriched potassium solution was eluted by the 47g/L ammonium bicarbonate at the flow of 80mL/min and at 25℃(room temperature), K~+ concentration can reach to 19.42g/L.Separation working procedure: Using extraction method, via evaporating and cooling for the solution rich of potassium directly and precipitating by adding 1:0.8 methanol to the enriched potassium solution. Next, we keep going to evaporate the extraction solution until 51.6°Be', and then we carbonize 4h at a low temperature. After twice crystallizations and calcining,we can get at least 99.2% potassium carbonate.Using twice carbonization method, by concentrating the solution rich of potassium to 2.8mol/L and carbonizing, filtrating sodium bicarbonate crystal, continuing to evaporate the solution to 52°Be'. As a result after crystallizating and calcining it for 4h at low temperature, can get at last 99.2% potassium carbonate. Using both of the above methods, the quality of potassium carbonate can both reach the China Standard of GB1587-2000, which belongs toⅠtype first-rate quality(≧99%)。...