Sulfur-coated urea controlled-release fertilizer as well as preparation method thereof

The invention relates to a sulfur-coated urea controlled-release fertilizer as well as a preparation method thereof. The preparation method of the sulfur-coated urea controlled-release fertilizer comprises the following step: 1) coating pre-heated base material urea particles with molten liquid sulfur. The preparation method is characterized by further comprising the following steps: 2) coating a sulfur-coated layer prepared in the step 1) with a composition consisting of natural beewax by a pump; and step 3) gradually cooling the natural beewax composition-coated sulfur-coated urea particles processed in the step 2) through a fluidized bed cooler and a solid heat exchanger, wherein the steps of coating sulfur and coating the natural beewax composition on the sulfur layer are implemented in a coating drum and the base material and the coatings comprise the following materials in percentage by weight: 80-90% of urea, 9-17% of sulfur and 1-3% of the natural beewax composition. The natural beewax composition consists of an additive and natural beewax. The product provided by the invention is high in nitrogen content and good in controlled release property. Nutrients of the product can be released according to demands of growth stages of crops. Nitrogen and sulfur nutrients are synergistic and the particles are impact resistant. The natural beewax can be degraded in soil, so that the sulfur-coated urea controlled-release fertilizer is environment-friendly.