Synthesis of Urea-Formaldehyde Fertilizers and Analysis of Factors Affecting These Processes

Abstract

Urea formaldehyde slow-release fertilizers are efficient and environmentally friendly fertilizers. They have good slow-release properties and can significantly improve the utilization rate of fertilizers. However, problems remain regarding the synthesis of urea formaldehyde slow-release fertilizers, their characterization, and aspects of their performance. This study explores the effects of different reaction conditions on the quality of synthesized urea formaldehyde and establishes a response relationship between synthesis factors and sustained-release performance. Optimal conditions for urea formaldehyde synthesis included use of an ammonium chloride catalyst, pH 4 as the final pH condition, and a urea/formaldehyde molar ratio (U/F) of 1.3. Samples prepared in this study were characterized in terms of cold water-insoluble nitrogen, hot water-insoluble nitrogen, and soil-available nitrogen. The samples were also characterized by spectroscopic and instrumental methods to correlate the microscale behaviors of the urea formaldehyde particles with their performance as controlled-release fertilizers. This work is expected to provide a basis for the production of urea formaldehyde and to improve its performance as a slow-release fertilizer.