Production method of novel ureaformaldehyde slow-release nitrogen fertilizer and composite fertilizers of novel ureaformaldehyde slow-release nitrogen fertilizer

Abstract

The invention discloses a production method of a novel ureaformaldehyde slow-release nitrogen fertilizer and composite fertilizers of the novel ureaformaldehyde slow-release nitrogen fertilizer. The production method comprises following steps: urea is dissolved in formaldehyde solutions with common concentrations at a urea / formaldehyde molar ratio of 1.5-2.5:1; under alkaline conditions, an obtained mixture is subjected to hydroxymethylation reaction; and then under acidic conditions, methylenenation of an obtained product is realized quickly. According to the preparation method, technical conditions such as molar ratio of urea to formaldehyde are controlled, so that the pure powdery or granular ureaformaldehyde slow-release nitrogen fertilizer with an activity index (AI value) ranging from 40 to 65 is obtained, and the composite fertilizers of the ureaformaldehyde slow-release nitrogen fertilizer can be obtained via traditional composite fertilizer production methods. The production method comprises following characteristics: technology is simple; reaction time is short; heat energy released by reaction is fully used; energy consumption is low; quality of the obtained products is reliable; slow release performance is excellent; particles are uniform; strength is high; caking is not easily caused; and production cost is low.

Description

technical field [0001] The invention relates to the field of producing urea-formaldehyde slow-release fertilizers, in particular to a production method of a novel urea-formaldehyde slow-release nitrogen fertilizer and a compound fertilizer thereof. Background technique [0002] In 2012, my country's urea output was 65 million tons (equivalent to N100%, the output reached 30.038 million tons), of which about 51 million tons were used for agriculture (equivalent to N100%, the output reached 23.46 million tons). The loss of urea in use accounts for 40% of the consumption, plus other loss methods of nitrogen, the utilization rate of urea nitrogen in my country is between 35% and 40%. Urea is a product with high energy consumption. my country mainly uses coal as raw material to produce urea. With global warming, my country is facing huge pressure to reduce carbon emissions. Therefore, the development of urea value-added technology is an important topic to improve and increase th...

AI Technical Summary

Problems solved by technology

The problem existing in this invention is to prepare starch paste first and then add formaldehyde and urea. It does not mention how to heat to make the reaction happen, and then how to take away the heat released by the reaction to keep the reaction temperature at 60°C-80°C. The second part needs to add an adsorbent, and then the solidified product with a water content of 5%-40% is produced

The problem that it exists is that the solution after the hydroxymethylation reaction in the first step is sprayed on the phosphorus source, the potassium source or the composite substrate, and sprays dilute sulfuric acid at the same time, so that the methyleneation polymerization reaction is carried out on the substrate, because the substrate In this way, it is difficult to control the progress of the methylation reaction, and the quality of the produced fertilizer is not stable enough

The process is relatively complicated, the reaction cycle is long, and the energy consumption is high.