A kind of preparation method of humic acid coated urea

Abstract

The invention provides a method for preparing humic acid coated urea, which comprises the following steps of: dissolving 20 to 400 parts of urea in 40 to 200 parts of water at the temperature of between 20 and 60 DEG C, reacting with 40 to 200 parts of humic acid feed coal at the temperature of between 40 and 100 DEG C for 5 to 30 minutes, adding 10 to 100 parts of phosphate, continuously stirring for reacting for 30 to 120 minutes, performing solid-liquid separation, and evaporating and concentrating to obtain a humic acid-urea complex concentrated liquor, or drying to obtain a solid humic acid-urea complex; and spraying, infiltrating and drying by using coat drying equipment to obtain the humic acid coated urea. The humic acid feed coal has rich resources, and is cheap and readily available; a process flow is short, equipment is easy and convenient to operate, reaction conditions are mild, and the method is easy for production control; the production process is environment-friendly,pollution emission is avoided, and the method is suitable for large-scale industrial production and promotion and application; and the product has good water solubility and attractive appearance, caneffectively inhibit urease from decomposing the urea and improve the fertilizer efficiency of the urea and the utilization rate of nitrogen.

Description

Technical field [0001] The invention belongs to the technical field of slow-release fertilizers, and particularly relates to a preparation method of slow-release urea for agriculture or humic acid-coated urea used as a slow-release special fertilizer substrate. Background technique [0002] At present, mankind is facing serious challenges such as population growth, reduction of arable land, desertification, environmental pollution and water shortage. In order to meet the ever-increasing demand for human survival, agricultural production must provide adequate, high-quality, pollution-free, green organic food and agricultural by-products, and protect the environment on which mankind depends. This has become a worldwide urgent task. [0003] my country is a developing country with more people and less land. At present, both the total production and consumption of chemical fertilizers rank first in the world. In the past two years, the annual consumption of chemical fertilizers in my ...

AI Technical Summary

Problems solved by technology

There are following defects in the preparation of the above three kinds of humic acid urea products: 1. During the preparation process, weathered coal is only wrapped on the surface of urea by physical methods, or urea is wrapped on the surface of weathered coal or ammonium humate particles, basically no or only a small amount Humic urea formation

Therefore, the urease inhibitory effect of this type of product is bound to be very small, and the effect of improving urea fertilizer efficiency and utilization rate cannot be achieved; 2. The preparation method disclosed in CN 1283600A and CN 200810080040.6 is to directly use weathered coal or peat without extracting humic acid, and the product Low humic acid content in medium, poor water solubility, difficult to be absorbed by crops, and poor use effect; 3. The preparation methods disclosed in CN 1376652A and CN 200810080040.6 all add binders, which increases production costs

[0007] In a word, the above-mentioned disclosed humic acid urea product has high production cost, troublesome operation, slow production speed, and is difficult for large-scale industrial production and popularization and application.