微孔陶瓷灌水器的材料学基础与规范化制备方法

Subsurface drip irrigation can supply water directly to crop roots, which has high water use efficiency, obvious water saving and stimulation effects. However, problems such as high system energy consumption, environmental pollution and soil degradation issues caused by the plastic tape and emitter are of difficult degradation and recycling. The above problems are main factors of restricting the large-scale popularization and application of subsurface drip irrigation. Therefore, the project draws on the experience of ancient pottery irrigation, innovatively bring micro porous ceramic materials into the emitter research and development. In this project, emphases is put on the impact of the material formulation and preparation process on the microscopic morphology, open porosity, connectivity and pore size distribution of micro porous ceramic materials. In this way, to establish the quantitative mathematical relationship between material formulation and preparation process and construct the calculation model of the flow rate of micro porous ceramic emitter under different structural parameters combining theoretical analysis, experimental research and numerical simulation, in order to reveal the response between the hydraulic performance of the key parameters (Pore characteristics) and the material properties. Based on the above, with the goal of excellent performance of emitter, low cost and minimum manufacturing deviation, finally put forward the standardized preparation methods of porous ceramic emitters, so as to provide the theoretical and technological evidence for the application of porous ceramic emitter.

地下滴灌可直接向作物根部供水，其水分利用效率较高，具有明显的节水增产效果。但存在系统能耗高、以塑料材质为主的地下滴灌带和灌水器难以回收和降解进而带来环境污染和土壤退化等问题，成为制约其大面积推广应用的主要因素。为此，本项目借鉴古代陶罐灌溉经验，创新性将微孔陶瓷材料引入灌水器研发中，以材料科学为基础，重点分析原料配方和制备工艺对微观形貌、开口孔隙率、连通度和孔径分布等微孔陶瓷材料性能的影响，建立材料性能与原料配方、制备工艺之间的定量数学关系；并通过理论分析、试验研究和数值模拟相结合的方法，构建不同结构参数下微孔陶瓷灌水器出流量计算模型，揭示微孔陶瓷灌水器水力性能对材料性能关键参数（孔隙特征）的响应关系；基于此，以灌水器水力和材料性能优良、造价低廉和制造偏差最小为目标，最终提出微孔陶瓷灌水器的规范化制备方法，为微孔陶瓷灌水器的应用提供理论与技术基础。

地下滴灌可直接向作物根部供水，其水分利用效率较高，具有明显的节水增产效果。但存在系统能耗高、以塑料材质为主的地下滴灌带和灌水器难以回收和降解进而带来环境污染和土壤退化等问题，成为制约其大面积推广应用的主要因素。为此，本项目创新性将微孔陶瓷材料引入灌水器研发中，以材料科学为基础，明确了原料配方和制备工艺对微孔陶瓷灌水器材料性能的影响，初步筛选出制备陶瓷灌水器适宜的原料配方和制备工艺，建议陶瓷灌水器的骨架材料以黏土和石英砂为主，造孔剂以有机造孔剂为宜、含量低于50%，性能改良剂可选择钠长石和硅溶胶，1000℃是黏土基（<1000℃）和石英砂基（>1000℃）陶瓷烧结温度的分界线，同时采用两步烧结法来提高微孔陶瓷强度，控制孔径和微观结构均匀性；在明确了陶瓷材料孔隙特征对水力性能影响的基础上，建立了陶瓷灌水器流量与造孔剂和粘接剂含量、模压压力、烧结温度和结构参数之间的数学关系，并假定陶瓷微孔为一组毛细管，依据Carman-Kozeny理论，结合Hagen-Poisseuille定律，构建了陶瓷灌水器出流模型，实现从原料配方、制备工艺和结构参数上精准控制灌水器流量；分析了搅拌工艺、干燥工艺对陶瓷灌水器材料性能与水力性能的影响，并综合考虑灌水器成本、流量和强度要求，提出了一套微孔陶瓷灌水器规范化制备方法，即：①原材料：应根据情况进行预处理，包括过筛（325目）、去杂、预烧等；②混料：根据原料配方进行称重混合，采用先干料混合，再加入硅溶胶的二次投料顺序，低速搅拌15分钟后取出；③模压制坯：模压压力适宜采用12~14MPa；④坯体干燥：在箱式烘干箱中对坯体进行干燥，干燥时间为9小时，干燥温度为80℃-90℃；⑤坯体烧结：干燥结束完全冷却后，置入隧道炉或箱式炉在设定温度下（黏土基950℃，砂基1200℃）烧结成微孔陶瓷灌水器。