| The contribution rate of chemical fertilizer to the development of agricultural grain production is 40%,which plays a very important role.However,the annual amount of chemical fertilizer in China exceeds 60 million tons,while the nutrient utilization rate of fertilizer is only about 30%.About 360 billion m3 of water is used for agricultural irrigation every year,with a gap of 30 billion m3.Therefore,the model of increasing yield through increasing fertilizer application is no longer applicable,and the increasing yield and increasing efficiency must be realized by improving the quality of fertilizer instead of the quantity.Compared with traditional fertilizers,water soluble fertilizers can save more than 40%of water and more than 20%of fertilizer.But currently on the market often appears in water soluble fertilizer crystallization,precipitation and other issues,it not only affects the utilization rate of fertilizer,but also can cause congestion problems such as mechanical transmission equipment,one of the reasons is the reason for this is that the lack of raw material properties of water soluble fertilizer research and lack of solubility data results in basic theory of the water soluble fertilizer research weak theory research.Combined with the research status of water soluble fertilizer at home and abroad,In this paper,using isothermal dissolution equilibrium method,the CO?NH2?2-KH2PO4-H2O,CO?NH2?2-KH2PO4-containing organic matter and quantitative CO?NH2?2,KNO3 ZnSO4 FeSO4-H2O-organic matter system was studied,with fulvic acid potassium as chelating agent preparation containing a large number of elements and trace elements zinc,iron water soluble fertilizer,using the single factor and response surface method optimization method for water soluble fertilizer with fulvic acid production process conditions are studied,research results provide theoretical basis for the preparation of water soluble fertilizer.The main research contents are as follows:?1?research and application of CO?NH2?2-KH2PO4-H2O system.The solubility,system density and pH of CO?NH2?2 and KH2PO4 in CO?NH2?2-KH2PO4-H2Osystem were determined by isothermal solution equilibrium method using CO?NH2?2 and KH2PO4 as raw materials.According to the phase diagram of water and salt system,the water soluble fertilizer formulation area conforming to GB/T 17419-2018 standard was determined.The addition of organic matter in the system to a certain extent contributes to the dissolution of CO?NH2?2 and KH2PO4,but it has little impact.The study system of aqueous phase is sufficient to meet the requirements for the preparation of N,P2O5 and K2O contents in water-soluble fertilizers containing organic matter.By XRD analysis,no new substance was found.?2?research and application of ZnSO4·7H2O-FeSO4·7H2O-H2O system containing quantitative CO?NH2?2 and KNO3.Using ZnSO4·7H2O and FeSO4·7H2O as raw materials,the solubility,system density and pH of ZnSO4·7H2O and FeSO4·7H2O in ZnSO4·7H2O-FeSO4·7H2O-H2O system containing quantitative CO?NH2?2 and KNO3 were determined by isothermal solution equilibrium method.According to the phase diagram of water and salt system,the water soluble fertilizer formulation area conforming to GB/T 17419-2018 standard was determined.The addition of organic matter in the system to a certain extent contributes to the dissolution of ZnSO4·7H2O and FeSO4·7H2O,but the effect is not significant.Taking the aqueous phase as the research object is enough to meet the preparation requirements of Zn2+and Fe2+contents in the water-soluble fertilizer containing organic matter.?3?Study on the production technology of water soluble fertilizer containing fulvic acid.In order to prevent the precipitation of Zn2+,Fe2+and PO43-in the water-soluble fertilizer system,potassium fulminate was selected as the chelating agent to study the chelating reaction conditions of zinc sulfate and ferrous sulfate in heptahydrate.by single factor experiment and response surface method optimization experiment,get zinc chelating optimized process conditions:the reaction time of 76 min,the reaction temperature is 33?,material ratio was 5.4:1.The optimized process conditions of iron chelation were obtained:reaction time was 70min,reaction temperature was 37?,material ratio was 5.6:1.Considering the energy consumption and production cost,the production process condition of water soluble fertilizer containing fulvic acid is 76min,the reaction temperature is 33? and the material ratio is 5.6:1.According to the phase diagram of water and salt system and the production process conditions of water-soluble fertilizer containing fulvic acid,a water-soluble fertilizer product containing fulvic acid was prepared.The product formula was 100-20-50+20Zn+10B+20Fe+100 organic matter.By means of CO?NH2?2-KH2PO4-H2O?CO?NH2?2-KH2PO4-containing organic matter and ZnSO4·7H2O-FeSO4·7H2O-H2O containing quantitative CO?NH2?2 and KNO3 and fulvic acid potassium and organic matter of Fe2+ and Zn2+ chelating reaction research,determine the formula of area and water soluble fertilizer production process conditions,according to the raw material system phase diagram and water soluble fertilizer production technology,preparation of water soluble fertilizer with fulvic acid product performance is stable,uniform system of no precipitation and of high nutrient content. |
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