Novel method for preparing humic acid urea slow release fertilizer

Abstract

The invention provides a novel method for preparing a humic acid urea slow release fertilizer. The method comprises the following steps of: dissolving 20-400 parts of urea with 40-200 parts of water at the temperature of between 20 DEG C and 60 DEG C; reacting with 40-200 parts of the humic acid feed coal at the temperature of between 40 DEG C and 100 DEG C for 5-30 minutes; adding 0-100 parts ofphosphate; continually reacting for 30-120 minutes; separating solid from liquid; evaporating and concentrating to obtain a humic acid urea complex compound concentrated solution or drying to obtain a solid humic acid urea complex compound; reacting with a urea solution or melt water; and concentrating, drying and granulating to obtain the humic acid urea slow release fertilizer. In the novel method, the raw material resource is rich, has low cost, and is readily available; the production process flow is short, equipment is easy and convenient to operate, and the slow release fertilizer can be grafted to a mature urea production procedure and is easy for large-scale industrial production; a product has high water solubility and is attractive; and the decomposition speed of the urea in soil can be effectively restrained, and the fertilizer effect of urea and the utilization ratio of nitrogen can be improved.

Description

technical field [0001] The invention belongs to the technical field of slow-release fertilizers, in particular to a new method for preparing slow-release urea for agriculture or humic acid urea slow-release fertilizer used as a special slow-release fertilizer substrate. Background technique [0002] With the rapid development of agricultural production and agricultural science and technology, my country's chemical fertilizer industry is also booming, and its fertilizer production and consumption both rank first in the world. In the past two years, the annual consumption of chemical fertilizers in my country has reached more than 50 million tons (pure conversion), and the consumption per thousand hectares of arable land has reached 366.5 tons, which is 3.5 times the world average level. For urea alone, the national output in 2009 reached 63 million tons (physical volume). Experts estimate that coal is the main raw material for 65% of my country's urea production, and coal is...

AI Technical Summary

Problems solved by technology

CN200610152445.X discloses the preparation method of humic acid urea, in the process of preparing humic acid urea with humic acid or humate and urea, adding alkaline solution and adhesive will inevitably cause the increase of product cost

CN 96108848.6 discloses a method for preparing humic acid urea with weathered coal and urea as raw materials and ammonia water as an activator. The defects in the method are: 1. the temperature is relatively high (90-105° C.) in the implementation process, and the added Ammonia water has a large amount of ammonia volatilization, which leads to waste of raw materials, high production costs, and environmental pollution; ②The solid-liquid separation and settling time is long (24-36 hours), and large-scale continuous production cannot be realized

[0005] In a word, the above-mentioned disclosed method has complex production process, troublesome operation, slow production speed, high production cost, polluting environment, and is difficult to large-scale industrial production and popularization and application