[iron phosphate: Chanhen iron phosphate patent] Recently, Guizhou Chanhen Chemical Industry Co., Ltd. announced a patent for "a method of preparing an iron phosphate precursor for LFP." The process first involves purifying the byproduct ferrous sulphate heptahydrate from titanium dioxide using a hydrolysis-based impurity removal principle. After oxidizing the purified ferrous ions to ferric ions, they react with phosphate salts to form amorphous iron phosphate. By controlling different crystallization conditions, slurries of dihydrate iron phosphate with varying particle sizes are obtained. These slurries are then mixed in specific proportions, filtered, washed, and dried to produce anhydrous iron phosphate. This method optimizes powder stacking efficiency, reduces inter-particle voids, and produces more compact iron phosphate, which is used to prepare LFP with high compaction density.