摘要
在黄水的输送过程中,磷基矿物的沉积问题是构建大规模黄水输送系统的主要挑战之一。对此,系统性地评估了黄水中磷基矿物的结晶特性,分析了pH值、n(Ca)/n(Mg)、柠檬酸盐、转速等因素对磷基矿物结晶特性的影响。结果表明pH值和n(Ca)/n(Mg)是影响黄水中磷基矿物结晶特性的主要因素。初始pH值的增加导致结晶产物中鸟粪石的纯度降低,当初始pH值由7.0增加至8.0时,羟基磷灰石(HAP)、磷酸八钙(OCP)、无定形磷酸钙(ACP)及磷酸三钙(TCP)的初始过饱和度指数迅速增大,导致结晶产物中Ca-P化合物的比例迅速增加,Ca-P化合物的存在影响了鸟粪石晶体的生长过程,晶体形态由规则的多面体晶体转变为形状不规则的晶体,并且晶体表面被大量的无定形Ca-P化合物覆盖。在黄水中,相对于钙、镁离子,磷酸盐是“过量”的,Ca-P化合物和Mg-P化合物之间并不存在明显的竞争关系,钙离子主要是参与影响鸟粪石晶体的生长过程,随着初始n(Ca)/n(Mg)的增加,鸟粪石晶体在结晶产物中比例下降的原因主要是因为随着钙离子浓度的增加,黄水中形成了更多的Ca-P化合物。
The deposition of phosphorus-based minerals in urine diversion system has been one of the main challenges to establish large-scale urine diversion system.The crystallization characteristics of phosphorus-based minerals were systematically evaluated in this paper,and the effects of various factors such as pH,calcium-magnesium molar ratio,citrate,and rotational speed on the crystallization characteristics of phosphorus-based minerals were studied.The results indicated that the pH and the calcium-magnesium molar ratio were the main factors affecting the crystallization characteristics of phosphorus-based minerals in urine.The increase in the initial pH resulted in a decrease in the purity of struvite in the crystalline substance.When the initial pH increased from 7.0 to 8.0,the initial supersaturation index of HAP[Ca_(10)(PO_(4))_(6)(OH)_(2)],OCP[Ca_(4)H(PO_(4))_(3)·3H_(2)O(s)],ACP[Ca_(3)(PO_(4))_(2)]and TCP[Ca_(3)(PO_(4))_(2)]increased significantly,resulting in a rapid increase in the proportion of Ca-P compounds in the crystalline substance.The growth process of struvite crystals was influenced by Ca-P compounds,which resulted in the transformation of crystal morphology from regular polyhedral crystals to irregularly shaped crystals.And the crystal surface was covered by a large number of amorphous Ca-P compounds.Compared with calcium and magnesium ions,phosphate is“excessive”in urine.There was no obvious competition relationship between Ca-P compounds and Mg-P compounds.Calcium ions mainly affected the growth process of struvite crystals.With the increase of the initial calcium-magnesium molar ratio,the proportion of struvite crystals in the crystalline substance decreased,which was mainly due to the formation of more Ca-P compounds in the yellow water as the concentration of calcium ions increased.
作者
闫政序
陈静
杨朕
程世昆
李子富
YAN Zhengxu;CHEN Jing;YANG Zhen;CHENG Shikun;LI Zifu(China Urban Construction Design&Research Institute Co.,Ltd.,Beijing 100120,China;Engineering Design and Research Institute,China Architecture Design&Research Group,Beijing 100044,China;School of Chemistry and Materials Science,Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control,Nanjing Normal University,Nanjing 210023,China;School of Energy and Environmental Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《化学工业与工程》
CSCD
北大核心
2024年第6期128-135,共8页
Chemical Industry and Engineering
基金
国家自然科学基金项目(5221101156)
关键词
磷基矿物
黄水输送
自发沉淀
结晶特性
phosphorus-based minerals
urine diversion
spontaneous precipitation
crystallization characteristics
