【作者】 吴育全；

【导师】 魏锡文；

【作者基本信息】 重庆大学 ， 环境工程， 2002， 硕士

【摘要】 氧化铬绿是重要的无机颜料。刚玉晶体结构型氧化铬有高的着色力、高热稳定性及耐化学腐蚀等特点。目前我国颜料级铬绿的生产已具备一定规模，但生产工艺和产品质量距国际先进水平均有不少差距，对于导致这种差距的本质原因的研究也少见报道。民丰农化是氧化铬绿的主要厂家之一，改善我厂氧化铬绿产品质量，尽快提高企业的经济效益和环境效益，关系着企业的发展和前途。因此，本课题的研究具有明显的应用价值和理论意义。氧化铬绿的颜料特征与粒子的结构特别是晶体结构和正负离子配位结构有很大关系，其中起主导作用的是Cr3+及其周围作八面体配位的O2-的影响。考察这一基本单元的构造特征及其电子分布状态，将有利于深入了解氧化铬绿的构效关系，为提高该类产品的颜料性能提供帮助。为此，本文选取德国Bayer公司的标准氧化铬绿样品和民丰农化集团生产的几种有代表性的铬绿样品，采用多种仪器进行了性质状态和结构分析，包括X射线衍射，红外、紫外可见光谱，原子吸收，能谱分析，电子显微分析，热重分析和差热分析，激光粒度分析，色度、色差分析，液相色谱和BEF表面分析等，相互映证，相互配合，全方位多层次获取铬绿颜料的信息。同时用量子化学从头计算方法进行了理论计算，并对有关结果进行了比较研究。结果表明，民丰铬绿颜料与Bayer样品在着色性质上的差别，主要来自二者晶体结构的差异，特别是晶胞在a向线度的微小变化，将使铬离子周围的配体场强弱发生变化，导致Fermi能级附近量子跃迁的明显改变，从而影响铬离子的呈色功能。此外，某些杂质（如六价铬）的存在，以及粒度和表面特征，也会对氧化铬绿的颜料性质产生影响。在工艺方面，本文根据上述分析，对氧化铬绿的生产过程提出了改进意见，如通过控制焙烧温度范围和升温程序、添加整形剂、改进粉碎方法等措施控制和稳定晶型，以及降低有害杂质（如六价铬）的含量，实施合理的后处理方案等。同时重点讨论了铬酐生产车间的固体废料回收利用问题，通过实验，本文提出可以通过碱中和、过滤、水洗、分离除杂、焙烧、粉碎等工序从废弃物中回收氧化铬绿，不仅可以提高铬资源的综合利用水平，而且还能减少环境污染，产生一定的经济效益。更多还原

【Abstract】 Chromium oxide green is a kind of important inorganic pigment. Chromium oxide green with corundum crystal structure has such characteristics as high thermal stability, high painted capacity, chemical corrosion-resisting capacity, etc. At present, in China, the produce of chromium oxide green has reached a certain scale, but there are still some disparities in the producing technology and product quality between home and abroad chromium oxide green. However, the essential factors which result in the disparities are reported scarcely. MinFeng Agricultural and Chemical Factory is one of the main manufacturers producing chromium oxide greens. How to improve the quality of chromium oxide greens and increase economic and environmental benefits as quickly as possible are the keys to our factory’s development and prospect. So the researches have some apparent application values and theoretical significance.The pigmental properties of chromium oxide green have much relationship with its particles’ structures, especially the crystal structures and cation-anion coordination structures, in which trivalent chrome(Cr3+) and the O2- ligands bonded to Cr3+ play main roles. Considering the structural properties of this basic unit and the electron distributing states is helpful to deeply identify the relation between it’s structure and it’s effect, and we can get beneficial information on how to improve the pigments’ properties from it. To get full information about chromium oxide green we analyzed the properties, state and structure of standard chromium oxide green and several representative chromium oxide green samples from MFACF co. ltd. with several apparatus analysis such as X-ray diffraction analysis, IR spectrum analysis, UV-analysis, Atomic Absorption, EDS(energy dispersive spectroscope), Electron Microscope, TG and DTA analysis，laser partial size analysis, chroma and chromatism analysis, Liquid Chromatography and BET analysis, etc. At the same time, we calculated theoretically with ab initio calculation and compared some related results. It shows that the color property difference between the MFACF and Bayer samples mainly comes from the difference of its structures, especially the subtle changes of the parameter a direction , which will change the intensity of ligand field around chromium ion and lead to apparent changes of quantum transition around Fermi energy level consequently affects the hue-showing function of chromic ion. In addition, the impurities(such as Cr6+), granularity and the surface properties will also affect the<WP=6>properties of chromium oxide green .On the basis of previous analysis, some advices are given to improve producing technics about chromium oxide green. For example, the crystal shape can be controlled and stabilized by controlling baked temperature scope and stabilizing heating-up program, adding plastic reagent, improving smashed method etc. We can also reduce the content of some bad impurities (such as Cr6+), adopt some after-processing working procedure, etc. At the same time we discussed the recycling of solid scrap produced by chromic acid anhydride workshop. From our experiments, we put forward a procedure that can reclaim chromium oxide green from the scrap. This procedure includes alkaline neutralization, filtration, water-washing, baking, smashing, etc. The procedure not only can improve the whole application of chrome resource but also can greatly alleviate environment pollutions and bring certain economic benefits.更多还原