Organic matter sustained-release urea and preparation method thereof

Abstract

The invention relates to an organic matter sustained-release urea and a preparation method thereof. A technical scheme adopted in the invention is characterized in that the total nitrogen content by weight is 40-46; the content by weight of lignin by calcium lignosulfonate is 0.3-1.5; the content by weight of methylenediurea by HCHO is below 0.6; the pH value is 5.0-7.0; and the preparation method comprises a step (1) of preparing raw materials comprising solid raw materials and liquid raw materials, and a step (2) of carrying out coating granulation. The adsorption sustained-release property of lignin realizes the good maintenance of the effectiveness of chemical fertilizers and the sustained-release of the chemical fertilizers, so the organic matter sustained-release urea is a good organic composite fertilizer material; and the exploitation researches of the lignin realizes the comprehensive utilization of natural high-molecular resources, the treatment of the environment pollution caused by the papermaking industry, the solving of the loss and pollution problems in the use process of common fertilizers, and the provision of a new product for the reduction of the agricultural production cost.

Description

technical field [0001] The invention relates to a slow-release urea and a preparation method, in particular to an organic slow-release urea and a preparation process. Background technique [0002] The official large-scale application of slow-release fertilizers in the domestic market began with the promotion of sulfur-coated urea (SCU) in 2006. At present, all kinds of coated urea are popular in the domestic market: (1) Thermosetting resins: such as epoxy, phenolic, urea-formaldehyde, etc.; (2) Thermoplastic resins: polyethylene, polyvinyl alcohol, etc.; (3) Water-soluble Sexual polymers; [0003] The advantage of thermosetting resin or thermoplastic resin fertilizer is long release time, but the disadvantages are: [0004] 1) The material is difficult to degrade in the soil, and it generally takes 50 to 60 years. Long-term application will destroy the physical structure of the soil. Even for so-called degradable resins, the degradable time is limited, and it is impos...

AI Technical Summary

Problems solved by technology

[0003] The advantage of thermosetting resin or thermoplastic resin fertilizer is long release time, but the disadvantages are:

[0004] 1) The material is difficult to degrade in the soil, and it generally takes 50 to 60 years. Long-term application will destroy the physical structure of the soil

Even for so-called degradable resins, the degradable time is limited, and it is impossible to achieve complete degradation

[0005] 2) Most of the production equipment adopts the sugar coating machine in the pharmaceutical industry, that is, the so-called bottom spray fluidized bed, which can only be produced in batches. The scale of a single equipment is small and the operation is troublesome

[0006] 3) Resin dissolution requires organic solvents, and organic solvents need to be recycled. There is a certain amount of leakage loss during the recycling process, and these solvents are flammable and explosive chemicals, so extra care must be taken in safe production

[0007] 4) The cost of raw materials is too high to be applied in the field

[0008] However, the technology of water-soluble resin-coated fertilizers has not yet passed the test