磷肥厂典型生产设备防腐蚀研究

【作者】 汪林祥；

【导师】 徐人平； 马兴良；

【作者基本信息】 昆明理工大学 ， 机械工程， 2005， 硕士

【摘要】 磷肥是农作物生长的主要肥料,包括普通过磷酸钙、重过磷酸钙、粒状过磷酸钙等几个品种。云南昆阳磷肥厂是采用湿法生产磷肥,俗称湿法磷肥,即用稀硫酸（或湿法磷酸）+磷矿粉混合,产生化学反应,释放出氟化氢气体,经过切削、破碎、造粒、烘干、筛分、包装等工序制造而成。由于在生产过程中都存在酸、碱、盐等介质,其设备不仅遭受无机酸（H₂SO₄、H₃PO₄、HF、SiF₄、H₂SiF₆、HCl）的腐蚀,而且由于磷矿石中夹带一定的石英（SiO₂）,所以设备又遭受以石英为主固体物的磨损,使生产过程腐蚀复杂化。 本课题结合实际,对普通过磷酸钙生产装置、湿法磷酸生产装置以及无熟化粒状过磷酸钙生产装置的流程、工艺进行了介绍,并对其中的三台典型设备——回转化尘室、料浆泵、卧式混合器的结构、腐蚀原因、失效形式进行了分析,找到了问题的关键,同时对各种耐腐蚀材料的性能进行比价分析,选择合适的材料进行实验,运用科学的规范进行施工和制造,从而解决了我厂当前湿法磷肥生产中设备腐蚀问题。有如下结论: 1、室温自硫化丁基橡胶是一种性能非常优异的新型材料,钾水玻璃—KP—1粉胶泥较钠水玻璃—辉绿岩粉胶泥具有许多技术优点。这一复合衬里防腐蚀技术安全可靠,衬里质量稳定,经济合理,特别适用于大面积钢板衬里结构,值得推广应用。 2、高铬镍不锈钢具有较强的耐氟、氯离子综合腐蚀的性能。且具有一定的硬度和耐磨性能。特别适用于湿法磷酸料浆泵的叶轮及过流部件。更多还原

【Abstract】 As the major fertilizer for crops growth, phosphate fertilizer includes ordinary calcium super phosphate, heavy calcium super phosphate and granular calcium super phosphate etc. Wet-process method is adopted to produce the phosphate fertilizer in Yunnan Kunyang Phosphate Fertilize Factory. Its coarse name is wet-process phosphate fertilizer. At first, rare sulphuric acid （or wet-process phosphor acid） and phosphor mine powder are mixed to produce chemical reaction and release HF gas. Then through the process of cutting, breaking, making particulate, drying, selecting & splitting and packing etc., the wet-process phosphate fertilizer is produced. The equipment is not only eroded by inorganic acid （H₂SO₄、 H₃PO₄、 HF、 SiF₄、 H₂SiF₆、 HCl） because of the acid, alkali and salt etc in production course, but also frayed by solid thing mainly with quartz because of SiO₂ carried with phosphor ore. So the corrosion of production course becomes complex.Combined with the practice, the process and technics of the production installation with ordinary calcium super phosphate, wet-process phosphate and unripe granular calcium super phosphate is discussed. Thereinto three typical equipments （rotatory transforming dust room, stuff slurry pump and the horizontal mixer） are analyzed concerning the structure, the cause 0 corrosion and invalidation. And the key of problem has been found. At the same time, the properties of various anti-corrosive materials are compared and analyzed. Suitable materials are selected to carry out experiment. Scientific criterion is adopted in the construction and manufacture. So, the current problem of equipment corrosion in the wet-process phosphate fertilizer production course has been solved. Conclusion is as follows:1. Self-sulfuration butyl rubber in room temperature is a kind of new material that has extremely excellent capability. Potassium water glass-KP-1 whitewash clay has more technical advantage than sodium water glass - brightness green rock whitewash clay has. The kind of compound lining’s anticorrosion technology is safe and reliable. It is worthy of popularizing application especially in the lining structure of steel plate with big area because of the steady quality and reasonable price.2. High chromium nickel stainless steel has comparatively strong corrosion resistance to fluorine ion and chlorine （?）on. It has certain hardness and wear ability. It’s especially suitable to be used in the production of the wet-process phosphoric acid slurry pump impeller and passing liquid parts.3. High alloy Ao body stainless steel, double-phases stainless steel and ferrite stainless steel all have good corrosion resistance in wet-process phosphoric acid. According to the erosion status all of them may be used. But the temperature of medium, the fixed proportion and the content of fluorine ion and chlorine ion should be in consideration.4. In the production of grainy ordinary calcium super phosphate, horizontal mixer suffers the erosion of vitriol, phosphoric acid, hydrofluoric acid and ternary acid in high temperature. So the material of mix machine shell and blade should be heat-resistant （almost 250°C）, erosion-resistant and something wearable. According to the analysis of all kinds of materials’ erosion resistance wear resistance and corrosion resistance in high temperature, only Alloy 825 satisfies technology requirement. The application of Alloy 825 is recommended because it is comparable new and advanced in recent years, and it also has ideal capability and price. According to the New Zealander information, Alloy 825 is used to produce machine shell and blade 0 It is not only high erosion-resistant but also good molten capability, machining capability and heat treatment capability. It is worthy of popularizing application.In conclusion, the equipment erosion is complicated in the production of wet-process phosphoric fertilizer. There are three steps to solve the erosion problem. At first, numerous anticorrosive materials and protection methods are tested and analyzed connected with the practice Then some features including wear resistance, erosion resistance, machining capability, jointing capability and economical property are taken into account. At last suitable material is selected to satisfy the reliability and safety of production equipment.更多还原