Method for preparing monopotassium phosphate at constant pH

The invention provides a method for preparing high-purity monopotassium phosphate. The method comprises the following steps: carrying out neutralization reaction on potassium hydroxide (or potassium carbonate) and phosphoric acid, then carrying out gradient cooling crystallization to prepare monopotassium phosphate, and automatically, precisely and accurately adjusting and controlling pH on line in the neutralization reaction process. refining the monopotassium phosphate by adopting the non-ionic macromolecular macroporous adsorption resin, and adopting a gradient cooling crystallization process to make crystals gradually formed and grow up. The sizes of the crystals are uniform, inorganic impurities wrapped in the monopotassium phosphate crystals can be greatly reduced, the product purity can be improved while the product yield is increased, the crystallization yield is increased by 5%, the purity is high, and the requirements of the medicine field are met. 本发明提供一种高纯度磷酸二氢钾的制备方法，本发明的方法采用氢氧化钾(或碳酸钾)与磷酸发生中和反应后再经