The Purification Of Wet-process Phosphoric Acid From Alum Mountain Phosphate Ores And The Prepation Of Water Soluble Fertilizer

There are different by raw material and manufacturing technique, make wet-process phosphoric acids contain iron, aluminum, organic matter and other impurities, ammonification reaction process with the preparation of water soluble fertilizer will have a lot of complex chemical reactions to take place, they have a great influence on the quality of the water soluble fertilizer. Therefore, wet process phosphoric acid after removing impurity, it is essential to the preparation of water soluble fertilizer. In this paper, making use of chemical precipitation method purifies Alum Mountain mineral wet-process phosphoric acid that comes from Qinhuangdao a company, then, the purification mechanism is studied, and after purification of wet-process phosphoric acid uses for production the monoammounium phosphate(MAP) water-soluble fertilizers.Choose H was oxidant, K, N, NA was precipitant, through a single variable and orthogonal experiment method studied the influence of process conditions on the effect of removing impurity. Controlling reaction temperature was 45 ℃, K content was 1.00%, H content was 5.00%, N content was 1.50%, NA content was 0.25%, natural sedimentation time was 24 h, removing impurity effect was the best, Iron removal rate and aluminum removal rate could be achieved 37.59% and 6.49% respectively. Through XRD, scanning electron spectroscopy and thermal analysis, atomic absorption and titration method gave an analysis of the precipitation, getting of precipitation containing K2SiF6、Fe(PO3)3、Al(PO3)3、FePO4、KAlSi3O8 and so on.Selection of O and K was precipitating agent, process conditions were studied through the single variable method for removing impurity and decolorizing effects. Control the reaction temperature of 40 ℃, the adding amount of 0.50%O and 0.75% K, the natural sedimentation time for 7 days, under the condition of the above process, wet process phosphoric acid decolorization rate could reach 68.43%. Control the reaction temperature of 60℃, the adding amount of 1.25% O and 1.50% K, the natural sedimentation time for 6 days, Iron and aluminum removal rate reached 37.59% and 1.30% respectively. Through Some characterization methods such as XRD, scanning electron spectroscopy and thermal analysis maked a analysis for the precipitation, getting the precipitation by K2SiF6、Fe(PO3)3、Al(PO3)3、FePO4、 KAlSisO8、(Mg,Fe)2Al4Si5O18、Mg(C2H3O2) and so on mixture composition.After purifying wet-process phosphoric acid, iron and aluminum impurities content was significantly reduced, Using it for ammoniation experiments. Controlling nitrogen and phosphorus ratio was 0.98, the reaction speed was 325 r/min, the reaction temperature was 40 ℃, chelating agent B adding quantity was 4%, In these conditions, Production rate reached 97%, water insoluble content in ammoniation product was about 0.05%. During the industrial production, controlling nitrogen and phosphorus ratio was 0.98, water insoluble content in ammoniation product was about 0.42%.Through characterization means such as XRD,IR and thermal analysis to determine ammoniation products for monoammonium phosphate.