Preparation of controlled release long-acting fertilizer

Abstract

The invention relates to a controllable slow-release fertilizer and a preparation method thereof. Bitumen, urea and flour are selected as raw materials for preparing coating, and the weight ratio of the bitumen, the urea and the flour is 100:50-98:0.5-10. The method comprises the following steps: preparing fertilizer blocks by a block moulding machine or granulating by a rolling granulator; putting the bitumen into a heating container, heating for melting the bitumen, controlling the temperature below the ignition point of the bitumen until the lowest viscosity is achieved; and adding the urea and the flour to the melted bitumen and fully stirring. The preparation method of the controllable slow-release fertilizer has the advantages of simple process, low cost, low coating rate, little residual accessory ingredients, high mechanical strength of the coating and randomly adjustable release rate of the fertilizer, and is applicable to various granular fertilizers and can be widely used for cultivating fruit trees and forest trees.

Description

technical field [0001] The invention relates to a preparation method of a controlled-release long-acting fertilizer. Background technique [0002] Since the 1970s, countries such as the United States, Japan, and Western Europe have successively begun to study slow-release fertilizers to slow down the rate of nutrient release. In the 1980s, research on controlled-release fertilizers began. After several years of research and application, the economic, social and ecological benefits of controlled-release fertilizers have been confirmed, and controlled-release fertilizers have become the main goal in the field of fertilizer research. [0003] At present, controlled-release fertilizers can be divided into two categories: structure-improved controlled-release fertilizers and coated (coated) controlled-release fertilizers. Structure-improved controlled-release fertilizers need to add various controlled-release materials and additives during the fertilizer production process, or ...

AI Technical Summary

Problems solved by technology

Structure-improved controlled-release fertilizers need to add various controlled-release materials and additives during the fertilizer production process, or add substances that can react with fertilizer nutrients, and modify them through chemical reactions in order to achieve controlled-release effects. The production process is extremely complicated and equipment Large investment, difficult to use existing common fertilizer production equipment, high cost, and can only be used for the production of certain fertilizers, the controlled release effect is not obvious, and is gradually being replaced by coated controlled release fertilizers

Existing coated controlled-release fertilizers mainly include resin-coated controlled-release fertilizers represented by 0smocote of Scotts Corporation in the United States and polyethylene-based plastic-coated controlled-release fertilizers developed in Japan and other countries. Although the controlled-release effect of the fertilizer is relatively good, there are two main disadvantages: (1) the coating material is expensive, the equipment investment is large, the fertilizer production process is complicated, and the coating process needs to be processed at a high temperature of 80-170 degrees for a long time, which can The consumption is high; the coating ratio is low, and the ratio of coating quality to fertilizer quality is only 1:10; resulting in high fertilizer production costs, and fertilizer prices are as high as 5 to 14 times that before coating; (2) use toluene, xylene, petroleum ether , turpentine and other petroleum solvents to dissolve coating materials, high cost, high toxicity, unfavorable to the health of production and application personnel, and flammable and explosive in the production process, other solvents such as trichlorethylene and tetrachlorethylene, will cause Destroy the ozone layer and cause air pollution

There are also asphalt-coated controlled-release fertilizers, which are mainly characterized by low cost and small investment, but the controlled-release effect is not good, the controlled-release rate cannot be adjusted, the coating rate is high, and there are many residual by-components, especially in the preparation of asphalt-type fertilizers. When coating, asphalt has high viscosity, is not easy to dry, and has poor mechanical strength and other problems

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