Industrial production method and device of urea-formaldehyde slow-release compound fertilizer

Abstract

The invention relates to an industrial production method and device of a urea-formaldehyde slow-release compound fertilizer and a device thereof. The industrial production method comprises the steps of adding water and oxidized starch to a reaction still and then pasting, adding urea of which the nitrogen content is 46wt% and formalin, stirring, dissolving and then adjusting the pH value to 8.5-8.8 by an alkaline matter, reacting at constant temperature of 60 DEG C to obtain reaction liquid; adjusting the pH value to 5.4-5.1 by the reaction liquid; reacting for 45 minutes at the constant temperature of 65-68 DEG C, then adjusting the pH value to 6.8-7.2, and terminating reaction to obtain the urea formaldehyde condensation product solution; mixing the urea formaldehyde condensation product solution with nitrogen, phosphorus and potassium materials, pelletizing, drying and cooling to below 35 DEG C, and screening to obtain the urea-formaldehyde slow-release compound fertilizer. The industrial production device of the urea-formaldehyde slow-release compound fertilizer is also provided by the invention. Urea formaldehyde is taken as a skeleton; rapid disintegration phenomenon of fertilizer particles caused by water absorption expansion is effectively prevented; the urea-formaldehyde slow-release compound fertilizer has good nutrient slow-release performance, and is high in pelletizing rate in the production process and strong in granule hardness, and the total nutrient content is improved.

Description

technical field [0001] 本发明涉及一种脲醛缓释复合肥料的工业化生产方法和装置,属于肥料生产的技术领域。 Background technique [0002] 我国是世界上最大的化肥生产和消费国,年消费量约占世界化肥消费总量35%左右,据统计,1996~2008年间,我国化肥使用量增长了36.9%,而粮食总产量却只增长了4.7%,不断增加的化肥投入并没有持续增加粮食产量。出现这一现象的原因是多方面的,肥料利用率降低导致增产效应下降无疑是一个重要的原因。目前发达国家化肥当季利用率平均为50-60%,而我国化肥当季利用率平均仅为30-35%。大量营养元素的流失浪费不仅给社会带来巨大的经济损失,而且还会造成严重的环境污染。提高肥料利用率,减少施肥量,节省施肥劳动力,显得尤为重要,缓 / 控释肥通过对养分释放率的调控而使之与作物养分吸收基本相同步,可以大大提高肥料养分利用率,减少农业面源污染,符合国家可持续发展战略的要求,因此缓控释肥料已成为21世纪肥料产业发展的主要方向之一。 [0003] 目前,国内外有机聚合物包膜控释肥的研究已经发展到了一个较高的高度,工艺技术已日趋成熟,养分控释性能良好,生产成本高的问题得到了初步解决,但距离其在大田作物上普遍应用尚待进一步降低生产成本;硫包膜肥料价格较低,但该工艺会大大降低大量元素的养分含量,使肥料总养分偏低;脲酶抑制剂和硝化抑制剂等稳定性肥料不能满足缓控释性能的要求,而且存在掺混不均匀、施用不方便的问题,因此开发一种施用方便、适合大田作物推广的缓控释肥料具有重要的现实意义。 [0004] 中国专利文献CN1198425A(98109068.0)公开了一种脲醛控释肥料的合成方法,在生产复合肥过程中加入脲醛肥与其它的化肥混合在一起,通过造粒机进行造粒,生产出一种缓释脲醛复合肥,目的是使肥料中的氮施入土壤,能缓慢释放,以满足作物生长的需要,减少氮素流失,提高肥料利用率;脲醛肥是由尿素与甲醛在酸性条件下缩合而成,脲醛肥缓释性能的强弱是决定于缩合物分子链的长短,它取决于甲醛,尿素相互作用的许多条件如尿素与甲醛的摩尔分子比、pH值、温度与反应时间。中国专利文献CN101391905A(200810225221.3)公开了脲醛肥料与脲醛复合肥料及其制备方法,包括如下步骤:1)将淀粉与水混合,糊...

AI Technical Summary

Problems solved by technology

However, most of the above-mentioned Chinese patent documents describe the chemical synthesis method of urea-formaldehyde fertilizers and the physical blending with conventional fertilizers, etc., lacking the systematic combination and optimization of urea-formaldehyde fertilizers and conventional fertilizers in terms of production process equipment

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