| 摘要 |
<p>PURPOSE:A Steffen waste from which the calcium component is previously excluded is combined with about 1/2 equivalent, based on the total cations, of sulfuric acid, concentrated and filtered when sulfate ion does not increase substantially in concentration of the solution, thus producing high-purity potassium sulfate and the condensed mother liquor for feed. CONSTITUTION:A Steffen waste produced in the sugar production is saturated with carbon dioxide to remove the calcium component and combined with about 50, preferably 20-40 equivalent %, based on the total cations in the waste, of sulfuric acid. The resulting waste is concentrated and the precipitated potassium sulfate is separated when the concentration of sulfate ion does not increase substantially and the pH does not lower below 4.5. Then, the mother liquor is concentrated at a temperature of over 70 deg.C to make the pH near 5 and remove completely nitrous acid, resulting in remarkable reduction of amine odor. Therefore, the condensed mother liquor does not cause scours in domestic animals and can be used as feed with good taste. The potassium sulfate obtained contains 45% or more potassium ingredient (as K2O), which exceeds the minimum requirement as the potassium fertilizer.</p> |
