Preparation and crystallization method of industrial potassium nitrate

The invention provides a preparation and crystallization method of industrial potassium nitrate, and the preparation method comprises the following steps: adding magnesium nitrate and potassium hydroxide solution into a reaction container to obtain reaction feed liquid, filtering the reaction feed liquid to obtain potassium nitrate mother liquor, and carrying out step-by-step cooling crystallization and centrifugal separation on the potassium nitrate mother liquor to obtain potassium nitrate crystals, and drying to obtain the product industrial potassium nitrate. According to the preparation method provided by the invention, magnesium nitrate and a potassium hydroxide solution are used as raw materials, and the problems of low production efficiency and low product quality of an existing industrial potassium nitrate preparation method are solved through the steps of step-by-step cooling, crystallization and the like. The method is widely applied to the technical field of industrial potassium nitrate synthesis.