Thermal Phosphoric Acid Burning Tower The Conjunctiva Matter Of Research

Phosphoric acid is not only an important chemical product, but also a indispensable chemical raw materials for all kinds of phosphorus chemical products and a variety of phosphate fertilizer. It has a decisive position in inorganic chemicals. the primary means of making phosphoric acid is the hot and wet at home and abroad. Because of restriction on production technology, wet phosphoric acid low concentration, high levels of impurities, making its mainly used for the production of phosphate fertilizer; while the hot phosphoric acid with the advantages of high concentrations, low levels of impurities, mainly used in the production of higher value-added industries Chemical products. However, its application subject to certain restrictions because of the larger energy expenditure and high cost. In the country's vigorously promote energy conservation, the waste heat utilization of phosphate achieved a lot of results. but there are also some problem, such as the corrosion of burning towers, the membrane referred to in this paper has a very connection with these.In this paper, the traditional process of combustion-hydration be improved so that it can accurately control the quantity of phosphorus and the water in the second air. It establishs a controlled environment in the burning tower so as to the production of the membrane. The membrane in the low-temperature, the mid-temperature, high-temperature condition has been made by adjusting the amount of phosphorus. Through the apparent test, thermal chemical tests and X-ray diffraction analysis and verification tests of the membrane, we have know that the membrane in the low-temperature is the phosphorus pentoxide (P2O5) layer and the membrane in the mid-temperature is the mixture of the phosphorus pentoxide (P2O5) layer and the metaphosphoric acid, the the membrane in the high-temperature is the super-phosphate polymer as the main component, an attachment of a mixture of a small amount of phosphorus pentoxide. Analysis of the causes and mechanism of the membrane. The dissolving experiment of the membrane in the 85 percent of the phosphate acid has been made, it shows that the membrane in the hydration tower will not affect the production. These results are different from domestic and foreign reports and is innovative.The preservative effect of the membrane has been made. In the absence of protection of the membrane, the ordinary boiler steel and the 316 L stainless steel will soon be corrosion in the environment of 120℃and high concentration of the phosphate acid. While the burning towers under the protection of membrane were no obvious signs of been eroded. The test of the iron content in the membrane has been made. It is found that the iron content is 4-17 ppm in the membrane and the corrosion rate is less than 0.06mm per year. Therefore we believe that the burning towers will not be corrosion under the protection of membrane.