1. Material preparation: The main raw materials of food-grade phosphate are phosphorus ore, such as aphamith, sodium phosphate, etc. Before the process begins, the raw materials need to be screened, broken, and washed to remove the impurities and impure substances in them to ensure that the phosphate obtained meets food-grade standards.
2. Soluble preparation: Add the processed raw materials for treatment to the reactor, and then add a certain amount of water for stirring and heating. The phosphoric acid material in the solution reacts with water to form a phosphoric acid solution. In this process, the temperature and stirring speed need to be controlled to ensure a sufficient and uniform reaction.
3. Filter: The solution may contain some insoluble impurities, which need to be removed by filtering. The solution is transferred from the reaction kettle to the filter equipment, and the solid particulate matter in the solution is filtered through the filter element or filter cloth and other filter medium to obtain a relatively clear phosphoric acid solution.
4. Concentration: The filtered solution is transferred to the concentrated device. By heating and reducing the solvent (usually water), the water in the solution is gradually removed to condense the solution. In this process, the temperature and concentration speed need to be controlled to prevent the phosphate from blocking the device.
5. Crystal: During the concentration, when the phosphoric acid solution reaches a certain concentration, phosphate will start crystallization. At this time, the crystallization response is needed by cooling or adding a crystallizer (such as ammonium sulfate). After the crystallization, the phosphoric acid crystals will be separated in the solution, and it is separated by filtering or centrifugation.
6. Dry: Dry treatment of the obtained phosphate crystals, remove the water in it so that it has a certain water content and meets the standard requirements of food-grade phosphate. Commonly used drying methods include natural dryness, heating and drying, and vacuum drying.
7. Packaging and storage: After drying the phosphate crystals, packaging and storage can be performed. Common packaging forms include plastic bags, barrels, etc. In the process of packaging and storage, we need to pay attention to moisture-proof and dustproofing to ensure the quality and stability of phosphate.