Preparation Of Water-Soluble Ammonium Polyphosphate And Starch Polyphosphate

Water-soluble ammonium polyphosphate?APP?is a agricultural good liquid fertilizer and industrial raw material,and its different uses are determined due to its different degree of polymerization,solubility,and thermal stability.According to different raw material sources and process conditions,ammonium polyphosphates with different degree of polymerization can be prepared.At this stage,the main production process of domestic ammonium polyphosphate is thermal reaction of phosphoric acid and urea to produce urea phosphate;and then the reaction of urea phosphate and urea at250-340°C.The degree of polymerization of ammonium polyphosphate produced on this route is 2.The biuret,a by-product,produces phytotoxicity to the crops;during the production process,a large amount of CO₂ and NH₃ is suddenly emitted,and a large amount of heat is released.The material is washed and dangerous,and the production is difficult to master.It stays below 10,000 tons.Therefore,the use of cheaper raw materials and simpler synthetic processes has important practical significance.This article selects cheap and readily available industrial pandemonium phosphate as raw material,and obtains ammonium polyphosphate by high-temperature polymerization of pandemonium phosphate,and then ammoniates ammonium polyphosphate to obtain the required water-soluble ammonium polyphosphate.Single factor experiments were used to analyze the reaction temperature,reaction time,influence of different ammoniating agents on the reaction.And the optimum process conditions were determined:the polymerization temperature was 275?.,the reaction time was 6 hours,when ammonium bicarbonate was used as an ammoniating agent,the average degree of polymerization of the product was 4,the nitrogen content was17.63%,and the phosphorus content was 57.86%.When ammonia was invoked as the ammoniating agent,the average polymerization degree of the product was 9,the nitrogen content was 17.97%,and the phosphorus content was 57.66%.The product was marked by infrared and thermogravimetry.This process is simpler than conventional processes,lower in cost and better in product performance.Based on the preparation of water-soluble ammonium polyphosphate,the application of the intermediate acid ammonium polyphosphate was explored.Ammonium polyphosphate was utilized as an esterification agent to esterify tapioca starch to obtain tapioca starch phosphate.By exploring the experimental conditions univariate analysis of the amount of catalyst,reaction temperature,reaction time on the reaction of esterifying agent.The optimum conditions were as follows:the amount of esterification agent was 10%,the reaction temperature was 120°C,the reaction time was2h,and the amount of catalyst was 5%.Under this condition,the degree of substitution of the product was 0.107 and the reaction efficiency was 74.41%.The products were analysed by infrared,scanning electron microscopy and differential scanning calorimetry,as well as the detection of the gelatinization properties.The product had properties such as decreased gelatinization temperature and greater viscosity,and it could be invoked as a flocculant to treat waste paper deinking wastewater andindustrial wastewater from chemical plants.