Method for reducing viscosity of nitrophosphate neutralization slurry and application

Abstract

The invention discloses a method for reducing viscosity of neutralized slurry of nitrophosphate fertilizer and application, and relates to the technical field of nitrophosphate fertilizer production.The method comprises the steps that a chelating agent is adopted for mixing the neutralized slurry, so that metal ions in the neutralized slurry exist in a soluble chelate state; wherein the chelating agent is selected from any one or a combination of EDTA, citric acid and oxalic acid. Based on the existing freezing method nitrophosphate fertilizer production process, the chelating agent is added in the neutralization process, and the chelating effect of metal ions in the neutralized slurry and the chelating agent is utilized, so that the metal ions in the neutralized slurry exist in a soluble chelate state in the ammonia neutralization process and do not cause precipitation, thereby achieving the goal of effectively reducing the consistency of the slurry. Moreover, the method is low in cost and simple in operation; more importantly, secondary pollution is avoided and zero emission is realized. The obtained fertilizer is good in physical and chemical properties, is not easy to fix in soil, is easily dissolved in water, is not dissociated, and can be well absorbed and utilized by plants.

Description

technical field [0001] The invention relates to the technical field of nitrophosphate fertilizer production, in particular to a method and application for reducing the viscosity of nitrophosphate fertilizer neutralized slurry. Background technique [0002] The production process of nitrophosphate fertilizer by freezing method is to convert phosphate rock into a kind of process through nitric acid decomposition, acid insoluble precipitation and separation, calcium nitrate freezing crystallization, calcium nitrate filtration, mother liquor neutralization process, evaporation, granulation, drying and cooling, etc. The production process of nitric acid-based compound fertilizer. The nutrient structure and performance of this kind of nitrogen and phosphorus fertilizer are in line with the development direction of the world's fertilizer industry, and are widely used in the production of food crops and economic crops. [0003] However, this frozen nitrophosphate fertilizer process...

AI Technical Summary

Problems solved by technology

[0004] Among the many technical difficulties, the most prominent problem is in the neutralization process. During the neutralization process of the mother liquor, a gas-liquid phase chemical reaction involving multiple components will occur, and a variety of solid precipitates will be generated at the same time, making the slurry in The viscosity of the ammonia neutralization process changes significantly, especially when the impurity content in the phosphate rock is high, a large amount of gel-like substances will be generated during the neutralization process, resulting in a sharp increase in the viscosity of the neutralized slurry, which will make the slurry viscosity If it is higher, the neutralization and evaporation cannot be carried out normally. In severe cases, the slurry almost loses fluidity and the system is forced to stop. This will not only bring great economic loss to the factory, but also consume a lot of manpower and material resources for cleaning equipment. It will directly affect the normal production of nitrophosphate fertilizer and the quality positioning of the final product

[0005] At present, most factories use three-stage neutralization process for ammonia neutralization, but this method is costly, complicated to operate, and the process conditions required to be controlled are relatively harsh

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