Production method of industrial potassium dihydrogen phosphate

Abstract

The invention provides a production method of industrial potassium dihydrogen phosphate, which comprises the steps of adding phosphoric acid and an extractant into a potassium chloride solution in sequence, cooling to crystallize after extraction, conducting liquid-solid separation, and obtaining potassium dihydrogen phosphate. According to the production method, trialkylamine is compounded with kerosene to form the extractant, as a pH value of the potassium chloride solution and various technological parameters are controlled, the raw materials react fully; the extractant is high in HCI extraction efficiency; a reaction system is in a partial miscible state after the extraction; a lot of potassium dihydrogen phosphate solid is precipitated; potassium dihydrogen phosphate with high quality can be obtained by just conducting the follow-up material crystallization and liquid-solid separation; the whole technological reaction conditions and course are mild; only single phase separation operation is needed; the technological process is simple; the energy consumption and production cost are low; no waste gas, waste water or industrial residue is produced in the whole technology; and the production method is simple in technological process, low in production cost and clean, and can be used for continuous production.

Description

technical field [0001] The invention relates to a production method of industrial potassium dihydrogen phosphate, in particular to a production method of industrial potassium dihydrogen phosphate based on the principle of organic extraction. Background technique [0002] Potassium dihydrogen phosphate is a high-concentration, high-efficiency phosphorus-potassium compound fertilizer, which is widely used in agriculture, industry, medicine, food and other industries. There are many production methods of potassium dihydrogen phosphate, which can be roughly divided into neutralization method, extraction method, ion exchange method, double decomposition method and electrolysis method. At present, the production process of neutralization method is mainly used in China. Although this method has the characteristics of short process flow, mature technology, low equipment investment, high product quality and low energy consumption, this method uses thermal phosphoric acid and potash...

AI Technical Summary

Problems solved by technology

Chinese patent 200610010782.2 "A Continuous Method for Preparing Potassium Dihydrogen Phosphate" uses wet-process phosphoric acid and potassium chloride as raw materials, uses N235, tributyl phosphate and kerosene compound extractant for extraction, and passes through extraction tower and washing tower , The stripping tower constitutes a cyclical continuous production process. This method has a simple process flow and can realize continuous production, but the composition of the extractant is complex, and the extraction capacity and extraction efficiency after stripping and regeneration are reduced.

Chinese patent 201010543993.9 "Method for producing industrial potassium dihydrogen phosphate and nitrogen, phosphorus and potassium compound fertilizers by extraction method using phosphoric acid as raw material" uses phosphoric acid and potassium chloride as raw materials, and the extraction agent is compounded with octylamine and octanol, after extraction and stripping Obtain the potassium dihydrogen phosphate product and the by-product nitrogen, phosphorus and potassium compound fertilizer. Although this method has good selectivity and the extraction agent is easy to strip and regenerate, the extraction agent octanol has a relatively high viscosity and poor fluidity, which has a negative impact on the extraction rate. And octyl ammonium substance has not been reported in the prior art

Chinese patent 201210069524.7 "A Production Method of Potassium Dihydrogen Phosphate" mixes trialkylamine and n-octanol to prepare the extractant, and extracts and back-extracts in different micro-mixers. This method combines the extraction process with the crystallization process through equipment strengthening Decoupling avoids the generation of fine crystals and can produce high-quality potassium dihydrogen phosphate, but the solution requires that the concentration of the mother liquor of the product should not be too high, for example, the concentration of potassium chloride solution must be between 0.2 and 1.5mol / L, in large-scale production In the process, this method has a high demand for process water. At the same time, to obtain a high yield of potassium dihydrogen phosphate, a large amount of water needs to be concentrated, which not only increases energy consumption but also increases the cost of three wastes treatment

On the other hand, the existing organic extraction process for preparing potassium dihydrogen phosphate is to separate the phases once after the extraction, and carry out crystallization treatment to the obtained inorganic phase to obtain potassium dihydrogen phosphate, and to separate the phases for the second time in the stripping process. In order to recover the organic extractant, the whole process requires at least two phase separation operations, and the process is cumbersome

And in the existing process, there is no mention of how to treat the three wastes of the process, especially the distilled water of the concentrated stripping water phase, and there is no clean production technology for the production of potassium dihydrogen phosphate by the extraction method with industrial value