淀粉胶生物质炭基氮肥制备及其缓释特性分析

以生物质炭为载体,与自制改性淀粉胶黏剂、尿素进行复合,利用万能力学试验机和自制成型模具制备颗粒缓释肥料,研究水分添加量、成型压力、炭肥比及胶黏剂添加量4个因素对颗粒肥料抗压性能和缓释性能的影响。结果表明:对于纯炭粉成型,当水分含量为10%、成型温度为45℃、成型压力为6k N时,成型颗粒的抗压强度达到最大;尿素与炭粉混合后成型可以增加颗粒强度,当稻壳炭-尿素(即炭肥比)为5:1时,在同样成肥条件下,肥料颗粒的抗压强度最大;改性淀粉胶黏剂可进一步增加肥料颗粒强度,当胶黏剂添加量为5%时,肥料颗粒的抗压强度达到最大。不同配比条件下制备的缓释肥料,其氮素累积释放规律符合"S"型释放模型,添加胶黏剂制备的缓释肥的缓释性能明显优于传统的尿素肥料,以胶黏剂添加量为5%时缓释效果最佳。

Biochar Based Nitrogen Fertilizer Preparation with Starch as Adhesive and Its Release Property Analysis

With biochar as carrier, blending it with modified starch adhesive and nitrogen fertilizer, slow release fertilizer pellets were prepared by universal testing machine and self-made mould, the influences of adding amount of water, pelletizing pressure, ratio of char to fertilizer and adding amount of adhesive on the compression and release properties of slow release fertilizer pellets were studied. The results show: for biochar pelletizing, the pellet shows the largest compression strength at the condition when the water adding amount is 10%, the pelletizing temperature is 45℃ and the pelletizing pressure is 6kN;blending biochar and nitrogen fertilizer may enhance the strength of fertilizer pellet, and the fertilizer pellet has the largest compression strength when the ratio of char to fertilizer is 5:1;the modified starch adhesive may further increase the compression strength of fertilizer pellet that has the largest value when the adding amount of adhesive is 5%. For the slow release fertilizers prepared at different conditions, the cumulative release characteristic of nitrogen conforms to “S”type release model, and the slow release characteristic of fertilizer prepared by adding of adhesive is obviously superior to that of the traditional urea fertilizer, and the fertilizer with adding amount of 5% shows the best effect of slow release.