Method for preparing potassium nitrate by means of double decomposition

Abstract

The invention discloses a method for preparing potassium nitrate by means of double decomposition. The method comprises the following steps: taking potassium chloride, ammonium nitrate and water solution as raw materials, and controlling the concentrations of Cl<-> and NH4<+> in the reaction solution to be 14-19% and 6-9.6% respectively, wherein the temperature of the reaction solution is 85-95 DEG C; lowering the temperature of a solution obtained from the reaction till a temperature of 0-20 DEG C is realized, crystallizing and precipitating KNO3 semi-finished product, and obtaining a filtrate mother liquor I by means of filtration; flushing KNO3 crystals with water till the Cl<-> concentration is 1-2% and the NH4<+> concentration is 1-3%; and recovering the flushing solution; positioningthe KNO3 crystals in a double decomposition device so that the KNO3 crystals can be fully dissolved, and controlling the solution concentration to be 44-52 Be; lowering the temperature for purpose ofprecipitating the KNO3 crystal, drying the KNO3 crystal till the water content of the KNO3 is less than or equal to 0.1%, and then obtaining the KNO3 finished product. In the method, the double decomposition device is used during the double decomposition reaction process and no stirring device is needed, therefore, the contact reaction of the reaction solution is more complete, and balance, continuous cyclic industrial production, productivity improvement and production cost reduction are realized in the precondition of ensuring 'two highs'.

Description

Technical field: [0001] The invention relates to a method for preparing potassium nitrate, in particular to a method for producing potassium nitrate by double decomposition. Background technique: [0002] Potassium nitrate is colorless transparent orthorhombic crystal or rhombohedral crystal or white powder, odorless, non-toxic, and salty. It is an important raw material for inorganic chemical industry and is widely used in industry, agriculture, medicine, food, etc. The method of potassium nitrate etc. such as Chinese patent number is that the patent number is 01114497.1 " the method for producing potassium nitrate by double decomposition three-step circulation method ", also need to add sodium nitrate as auxiliary agent in its production process, and the potassium nitrate product produced is only suitable for agricultural nitric acid Potassium is used, and its production does not use a metathesis reaction device through the complex reaction process, so the products produce...

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Problems solved by technology

[0002] Potassium nitrate is colorless transparent orthorhombic crystal or rhombohedral crystal or white powder, odorless, non-toxic, and salty. It is an important raw material for inorganic chemical industry and is widely used in industry, agriculture, medicine, food, etc. The method of potassium nitrate etc. such as Chinese patent number is that the patent number is 01114497.1 " the method for producing potassium nitrate by double decomposition three-step circulation method ", also need to add sodium nitrate as auxiliary agent in its production process, and the potassium nitrate product produced is only suitable for agricultural nitric acid Potassium is used, and its production does not use a metathesis reaction device through the complex reaction process, so the products produced are far from the quality standard requirements of more than 99.0% of the national industrial potassium nitrate qualified products, and are far less than the high yield of product production. High rate and high content, that is, potassium nitrate content of more than 99.5% high-quality potassium nitrate quality standard requirements

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