Manganese phosphate is a widely used chemical raw material, mainly used as a phosphating agent for steel products, especially for the phosphating treatment of large mechanical equipment. It can have a rust preventive effect and can also be used as a lubricant and protective agent in the national defense industry. In recent years, manganese phosphate has important application value as a high-quality raw material for lithium manganese phosphate as the positive electrode material of lithium-ion batteries.

At present, there is relatively little research on the preparation methods of manganese phosphate both domestically and internationally. The existing preparation methods mainly include: (I) oxidation precipitation method/hydrothermal synthesis method. For example, the invention patent with publication number CN101673819A discloses a method for preparing lithium manganese phosphate/carbon composite materials from manganese phosphate. In an acidic system, manganese and phosphorus sources are used as raw materials, with an excess manganese source, an excess oxidant added, and stirring reaction for 0.5-24 hours, Alternatively, the manganese phosphate product can be prepared by hydrothermal reaction at 80-200 ° C for 2-72 hours, followed by a series of processes such as washing, filtration, drying, and crushing; (2) The solvent thermal synthesis method, as described in the paper titled "Solvent Thermal Synthesis and Characterization of Novel Titanium Phosphate and Manganese Phosphate Crystals" in 2003, used various organic amines as structural directing agents in the n-butanol system to prepare a layered structure of manganese phosphate formed by manganese oxide octahedra and phosphorus oxides.

When using the existing hydrothermal synthesis method to prepare manganese phosphate, excessive manganese sources are used, and the manganese precipitation rate is only about 50%, or even lower. Compared to phosphorus sources, manganese sources are expensive, have low utilization efficiency of manganese resources, and have high production costs; The preparation of manganese phosphate by oxidation precipitation method is carried out in a single aqueous phase system. The product purity is difficult to control, the amount of water of crystallization is unknown, and the particle size distribution is uneven, thus affecting the electrical performance of the product; When preparing manganese phosphate by solvothermal synthesis method, the reaction system composition is complex, and the composition and structure of manganese phosphate products are complex, and it is not easy to scale production.