Phosphorus fertilizer is the only chemical fertilizer which is easy to bring harmful and toxic heavy metal components in resources and processing. At present, there are two main raw materials for the production and processing of phosphate fertilizer, one is phosphate rock, the other is sulfuric acid. This paper intends to open a method of producing low heavy metal content of sanitary phosphate fertilizer. Combined with the actual situation, a set of solutions for the application of vacuum system in phosphate fertilizer manufacturing enterprises are determined, hoping to solve the environmental pollution caused by heavy metals and the quality and safety of crops.
As the raw material of phosphate fertilizer production sulfuric acid and the heavy metals from phosphate rock enter into the soil directly through the way of fertilizer, the accumulation of heavy metals in the soil increases, resulting in the content of heavy metals in crops exceeding the standard, causing food safety and health problems.
The application of vacuum system in phosphate fertilizer manufacturing enterprises is actually vacuum filtration.
The central vacuum station is a complete set of automatic vacuum degree control system which takes the rotary vacuum pump as the vacuum obtaining equipment and the vacuum tank as the vacuum storage equipment. In the case of frequent use of vacuum source and less air volume needed, the system greatly saves energy and effectively improves the service life of vacuum pump compared with direct use of vacuum pump. At present, the rotary vane vacuum pump has been widely used in the vacuum packaging of all kinds of food, the vacuum Blister molding of rubber and plastic industry, the paper transportation of printing industry, the vacuum impregnation leak proof of all kinds of castings, the vacuum fixture, the vacuum drying, the vacuum filtration, the vacuum dynamic test and the vacuum suction of the hospital operating room, etc. within the vacuum range that the rotary vane vacuum pump can reach Li.
As the source of phosphorus for processing phosphate fertilizer, phosphate rock can be divided into two types: igneous apatite and sedimentary phosphorite. The former accounts for 15% of the existing commercial use of phosphate rock, and its heavy metal content is low, especially the toxic substance cadmium which is easily absorbed into rice by rice crops is very small; the latter accounts for 85% of the commercial use of phosphate rock, and its heavy metal content is relatively high. Sulfuric acid, as the main auxiliary raw material of phosphate fertilizer processing, also has different sources of raw materials. The content of heavy metals in sulfuric acid produced by sulfuric acid is different.
vacuum system advantages:
1. When a vacuum source is needed, the required vacuum degree can be achieved in a very short time.
2. The vacuum source is more stable and sufficient.
3. One system can be used by multiple workbenches at the same time without affecting the operation of different units.
4. When the vacuum source stored in the pressure vessel is sufficient, the vacuum pump can stop working / stop working in turn, extending the rest time of the pump, so as to reduce the loss of the pump, parts and oil, reduce the cost of operation and maintenance, and also reduce the noise in the workplace.
5. Easy to operate and master.
The special vacuum system of the phosphate fertilizer manufacturing enterprise can remove the heavy metal elements in the phosphate fertilizer, eliminate the accumulation of heavy metals in the soil caused by sulfuric acid, the raw material of the phosphate fertilizer production, and the heavy metals in the phosphate ore directly entering the soil through the way of fertilizer, which leads to the excessive content of heavy metals in the agricultural crops, causing the unsafe food hygiene and endangering people’s health. At the same time, the heavy metal elements are separated from phosphoric acid and used as resources, which not only solves the pollution of heavy metals to the environment and the quality and safety of crops, but also recovers very useful resources, which not only has significant social benefits, but also has very good resource benefits.