A kind of preparation method of urea-formaldehyde slow-release fertilizer

Abstract

The invention discloses a preparation method of a urea-formaldehyde slow release fertilizer. The preparation method comprises the following steps: mixing urea with formaldehyde in a certain mass ratio, adding sodium hydroxide to adjust the pH value and then heating and stirring for full reaction of urea and formaldehyde; and after reaction for a while, stopping heating and adding monoammonium phosphate to adjust the pH value, mixing and drying the obtained material with a mixture of one or two of an organic fertilizer and humic acid in a certain mass ratio, and then granulating to obtain the urea-formaldehyde slow release fertilizer. According to the preparation method disclosed by the invention, during spin flash drying, the mixture of one or two of the organic fertilizer and humic acid is added into a filter cake of urea-formaldehyde, so that the technical problem that the equipment cannot work normally as the urea-formaldehyde is agglomerated during spin flash drying to lead to accumulation of urea-formaldehyde in the equipment to cause equipment blockage is effectively solved. Meanwhile, the preparation method disclosed by the invention is simple in process and relatively low in production cost.

Description

technical field [0001] The invention relates to the technical field of preparation of slow-release fertilizers, in particular to a preparation method of urea-formaldehyde slow-release fertilizers. Background technique [0002] At present, scientists from all over the world believe that the development of the fertilizer industry in the 21st century should develop in the direction of high efficiency, resurrection, special purpose, multi-function, slow release, and controlled release, and a new type of high-efficiency slow-control fertilizer integrating the above advantages. [0003] Urea-formaldehyde slow-release fertilizer is a high-nitrogen slow-release fertilizer with slow nutrient release, long fertilizer effect period, nitrogen utilization rate of more than 80%, and sustainable fertilizer effect for more than 80 days, up to two years. The wetting rate of urea-potassium aldehyde slow-release fertilizer is very low. Generally, the compound fertilizer of urea and ammonium ni...

AI Technical Summary

Problems solved by technology

[0006] In view of this, the purpose of the present invention is to provide a kind of preparation method of urea-formaldehyde slow-release fertilizer, to solve in the urea-formaldehyde slow-release fertilizer preparation process, when adopting rotary flash dryer to dry urea-formaldehyde slow-release fertilizer, due to Urea-formaldehyde has a certain viscosity, and the moisture content is too high. It is easy to agglomerate when it is rotated and flashed, stirred and crushed, and it is easy to cause equipment blockage, which makes the drying process difficult to carry out.