Experimental Study On The Preparation Of Potassium Dihydrogen Phosphate By Dihydrate Wet-process Phosphoric Acid And Potassium Sulfate Extractio

Potassium dihydrogen phosphate is used in industry,agriculture,medicine and food industry broadly with good market prospects as a kind of efficient phosphorus potassium phosphate compound fertilizer and fine phosphate products.In the early 18th century the preparation method of potassium dihydrogen phosphate had been researched,but until the middle 1960s,scientists all over the world began to discuss its theoretical basis and technology.In recent years,the increase in demand for efficient compound fertilizer without chloride in the field of modern medicine,chemistry and food based on high quality of potassium dihydrogen phosphate in the market greatly promotes the researching and development of technology of potassium dihydrogen phosphate.All we know,due to the effect of raw material prices,the cost of production market,the understanding of farmers and other factors,potassium dihydrogen phosphate is always difficult to get promotion.But over recent years in some areas with the applying demonstration of potassium dihydrogen phosphate,the excellent properties of potassium dihydrogen phosphate are gradually understood and accepted by large-scale agriculture areas and the vast majority of farmers,more and more people begin to use,which leads to serious shortage of product.At the same time,the price of product also gradually rises.How to produce potassium dihydrogen phosphate with high efficiency,no pollution,large quantities,high quality and low price and meet the needs of agriculture has become a grim problem for the sustainable development of agriculture.This thesis studies the technical process of producing potassium dihydrogen phosphate with potassium sulfate and wet-process phosphoric acid in extraction method,examines the water bath temperature,stirring speed and reaction time which have the effect on deprivation of fluorine ion and calcium ion on the soluble liquor;Extraction reaction examines the concentration of phosphoric acid,extraction volume ratio,reaction time,stirring speed and reaction temperature on the influence of the preparation of potassium dihydrogen phosphate;Through orthogonal experiment,the optimum process conditions of extraction reaction:the concentration of dihydrate wet process phosphoric acid is 12.0%,extraction volume ratio is 2:1,reaction temperature is 50℃,stirring speed is 175 r/min,the reaction time is 35 min;Optimum process conditions of reverse extraction reaction were:ammonia concentration is 8%,reverse extraction stirring speed is 225 r/min,reverse extraction temperature is 45℃,reaction time is 15 min.On the basis of the above experiments,there will be the enlarger and continuous experiment for producing potassium dihydrogen phosphate with potassium sulfate and wet-process phosphoric acid in extraction method.The research showed that:it is feasible to produce potassium dihydrogen phosphate with potassium sulfate and wet-phosphoric acid as raw materials in extraction method by the process route.This method has the very good industrialization prospect Besides,there is not harmful waste liquid and waste gas which are put out,the production preparation process is very clean and easy to operate.During the enlarger and continuous experiments,qualified products are got by evaporating,cooling,crystallizing the mother liquid of potassium dihydrogen phosphate,the content of the product obtained is over 97%and the SO42-is less than 2.0%.