The application relates to the technical field of
iron phosphate preparation, in particular to a preparation method of
iron phosphate dihydrate containing an orthorhombic
crystal form, which comprises the following steps: adding a
mixed solution of a
phosphate and an
oxidizing agent into a
ferrous solution, controlling the amount of the
oxidizing agent, so that there is no
ferrous ion in the reaction solution after the
mixed solution is added; adding an alkali liquor to the reaction solution to adjust the pH value, and keeping the temperature at 50-60 DEG C for 1-2 hours; filtering and washing the prepared
slurry to obtain a
solid; after the
solid is pulped, adding
phosphoric acid to adjust the pH value, and reacting at 80-100 DEG C for 1-2 hours; and filtering, washing and
drying the
reaction product to obtain the
iron phosphate dihydrate containing the orthorhombic
crystal form. The preparation method of the iron
phosphate dihydrate containing the orthorhombic
crystal form is simple in process, short in technological process, low in
reaction temperature, and does not need to add a surfactant in the reaction, so that the iron
phosphate dihydrate containing the orthorhombic crystal form can be prepared.