Phosphate Fertilizer Plant Typical Production Equipment Corrosion

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.