氧化铬绿色制备工艺基础与工业应用研究

CORC > 过程工程研究所 > 中国科学院过程工程研究所 > 研究所（批量导入）

题名	氧化铬绿色制备工艺基础与工业应用研究
作者	李平
学位类别	博士
答辩日期	2009-05-31
授予单位	中国科学院过程工程研究所
授予地点	过程工程研究所
导师	张懿
关键词	亚熔盐清洁工艺氢还原铬酸钾铬酸钠氧化铬绿颜料
其他题名	Fundamental and Industrial Research on the Preparation of Chromic Oxide based on a Green Process
学位专业	化学工艺
中文摘要	以清洁工艺为基础的亚熔盐铬盐清洁工艺产品工程，研究铬化合物材料的绿色制备技术，实现铬盐系列产品高值化深加工与环境污染防治的统一，完善铬盐清洁生产的绿色过程工程技术体系。针对氢还原法无法制备氧化铬绿颜料和生产过程铬直收率低的两大突出问题，本文重点研究了钾系和钠系铬盐氢还原法生产氧化铬绿颜料和冶金级氧化铬的绿色制备工艺和过程机理，并进行了工业化扩大试验与工程放大研究。本论文在以下几个方面取得了创新成果: （1）开发了钾系铬盐（K2CrO4）氢还原与活化烧结技术相结合制备氧化铬绿颜料的新工艺，制备出了符合国家标准和工业需求的氧化铬绿颜料。提出了改善中间态活性、强化产物性质的新思路。研究了添加剂、氢还原温度等关键因素对氧化铬绿颜料性能的影响，实现了与铬盐清洁生产工艺的有机衔接。（2）系统研究了氢还原温度、添加剂等因素对氧化铬绿颜料性能的影响规律。发现在氢还原过程中，较低还原温度所得还原产物具有更高活性和更少杂相；在活化烧结过程中，适量的Al和Ba添加导致氧化铬绿颜料分别发生光谱蓝移现象和导致晶格场强度的提高，有利于颜色性能中b值的提高和L值的降低；并确定烧结过程符合蒸发—凝聚机理。（3）进行了K2CrO4制备氧化铬绿颜料的工业化扩大试验。结合现行工业生产条件，控制氢还原温度在500℃左右、产品中Al、Ba和Fe2O3含量分别小于0.2wt%、0.5wt%和0.2wt%、活化烧结温度为890 ~ 920℃，制备出了满足工业需求的氧化铬绿颜料，并提出了工业实施方案。（4）针对工业生产过程中存在的铬直收率低的问题，兼顾铬盐清洁生产中KOH循环的需要，提出高温水热浸出法处理中间产物。以水作为浸出介质，通过控制浸出温度、浸出时间和液固比等因素，将铬直收率由75wt%提高到90wt%以上。（5）在钾系铬盐氢还原工艺基础之上，研究了钠系铬盐（Na2CrO4）氢还原制备氧化铬绿颜料的工艺和影响颜料性能的因素，控制还原温度为400~500℃，烧结温度为950℃，所制备的氧化铬绿颜料颜色性能良好。（6）深入研究并系统优化了Na2CrO4氢还原烧结法氧化铬的绿色制备工艺，提出了低温氢还原—研磨高温水热浸出—保护气氛烧结的工艺路线。控制氢还原产物为NaCrO2，保证Cr(VI)的还原率达到100wt%；采用研磨减小晶粒尺寸，提高产物活性，增大无定形化；通过高温水热浸出处理脱除Na，有效地避免Cr(III)再氧化；在保护性气氛下烧结可得到低S含量的氧化铬，满足工业需求。与现有工艺比较，铬直收率大于99wt%，副产物为NaOH，实现了Cr(VI)污染物的源头污染控制。
英文摘要	The product engineering of chromate cleaner production from process with sub-molten salt media aims to develop green preparation process for chromium compound materials, achieve the unification between the deep high-value processing of chromate series products and environmental pollution prevention, and improve the technical system of green process engineering for chromate cleaner production. In order to improve the poor pigmentary property and low yield of chromic oxide product from the industrial production line through hydrogen reduction technology, the green preparation processes and mechanisms for pigmentary grade and metallurgical grade chromic oxide by hydrogen reduction method were emphatically studied. The industrial-scale test was carried out as well. The following achievements and innovative progresses were exhibited: (1) Research was carried out on the novel process of the chromic oxide green pigment by K2CrO4 with hydrogen reduction and activated sintering method. The chromic oxide green pigment was prepared by improving activities of the intermediates and properties of the samples, which not only prepared the chromic oxide green pigment with excellent performance but also realized cohesion of chromate cleaner production process. Relative factors which influenced the chromic oxide green pigment performance in the new process such as hydrogen temperatures and additives were studied. (2) Mechanism that the chromic oxide green pigment performance was influenced by hydrogen reduction temperature and additives were systematically studied. In the hydrogen reduction step, intermediates obtained by lower hydrogen reduction temperature exhibited higher activities and less impurity phases. In the activated sintering step, suitable Al and Ba addition resulted in blue-shift and crystal field strength improvement of the chromic oxide green pigment, so that benefited to improvement of b* values and decrease of L* values at the color performance. The activated sintering step belonged to evaporation-condensation mechanism. (3) Industrialized test of the chromic oxide green pigment prepared by K2CrO4 was carried out. Controlling hydrogen reduction temperature of 500℃, activated sintering temperature of 890-920℃，Al and Ba contents of less than 0.2wt%and 0.5wt% respectively, and Fe2O3 content of less than 0.2wt% as main impurity, the chromic oxide green pigment which met industry demands was obtained based on the demonstration project of chromate cleaner production process. Besides, according to the production conditions, the engineering amplication problems were investigated. (4) A high pressure leaching method was introduced to resolve low direct chromium recovery in the industrial production and meet the needs of KOH cycling in the chromate cleaner production process. Controlling experiment conditions such as leaching temperature and leaching time, using water as leaching medium, the direct chromium recovery improved from 75wt% to 90wt%. (5) Conditions of the chromic oxide green pigment prepared by Na2CrO4 with hydrogen method and relative factors that influenced the performance of the chromic oxide green pigment were studied. The chromic oxide green pigment with good performance was obtained. Requirement of NaOH cycling in the chromate cleaner production process was realized. (6) A green process to prepare metallurgical chromic oxide by Na2CrO4 with hydrogen method was systematically studied. A new hydrogen-milling and pressure leaching-sintering route was proposed. Cr(VI) recovery rate approaches 100wt% when hydrogen reduction product was NaCrO2 in the hydrogen step. When the NaCrO2 was milled, crystal size decreased, activity and amorphization improved. Na was removed and Cr(III) re-oxidation was prevented when a high pressure leaching method was used to treat the milled NaCrO2. The metallurgical chromic oxide was obtained when the leached product was calcined at inert atmosphere. Compared with the industrial production process, the new process achieves a high trivalent chromium yield of above 99wt%. NaOH is the only byproduct and can be recycled inside the sub-molten salt process, which effectively prevents the circulation of hexavalent chromium and achieves the source control of chromium pollutants.
语种	中文
公开日期	2013-09-13
页码	131
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1262]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	李平. 氧化铬绿色制备工艺基础与工业应用研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009.