Urea sulfate coated urea slow-release granular fertilizer and preparation method therefor

Abstract

The invention discloses a urea sulfate coated urea slow-release granular fertilizer. The urea sulfate coated urea slow-release granular fertilizer is prepared through the following steps of: adding 100kg of urea granules of which the diameters are 2-4.5mm to a rotary drum type coating machine, preheating the urea granules to 40-45 DEG C, spraying 1-10kg of a binder namely urea sulfate, uniformly mixing the preheated urea granules and the urea sulfate so as to obtain a mixture, spraying 1-20kg of metasilicate powder, cooling the mixture and the metasilicate powder, spraying 1-10kg of mounting addition agents (a mixture of solid paraffin and liquid paraffin) of which the temperature is 50-60 DEG C, cooling the mixture, the metasilicate powder and the mounting addition agents to a room temperature, and repeating the coating operation 2-3 times. The binder namely the urea sulfate is prepared through the steps of slowly adding1-2kg of concentrated sulfuric acid of 90-98wt% to every 1-10kg of urea and performing a reaction in a reaction tank. The urea sulfate coated urea slow-release granular fertilizer disclosed by the invention adopts a urea sulfate metasilicate slow-release film, tests prove that the urea sulfate metasilicate slow release film has a favorable slow-release effect, and in the slow-release process, the slow-release film is not liable to collapse and is easy to degrade. The urea sulfate has subacidity, so that the application range of the urea sulfate is wider than that of sulfur coating urea. The urea sulfate coating film realizes double-film double-control effects, and has the advantages of high efficiency, environmental protection, low cost and the like.

Description

technical field [0001] The invention belongs to agricultural production materials, and in particular relates to a preparation method of urea sulfate-coated urea slow-release granular fertilizer. Background technique [0002] The application of chemical fertilizers has continuously increased global food production, and it is the fastest and most important measure to increase food production in both developed and developing countries, providing food security for the world's population. However, the utilization rate of chemical fertilizers in my country is not high, and the utilization rate of nitrogen fertilizer in the current season is only 35%. According to data from the Food and Agriculture Organization of the United Nations, from 1980 to 2002, China's chemical fertilizer consumption increased by 61%, while grain output only increased by 31%. Due to the low fertilizer utilization rate and the decline of fertilizer efficiency year by year, the amount of fertilizer applied h...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a urea sulfate-coated urea slow-release granular fertilizer to solve the problems of thick sulfur-coated film, low nitrogen content, cracks in the film, expensive resin film and difficult to degrade.

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