【作者】 李华；

【导师】 伍联营；

【作者基本信息】 中国海洋大学 ， 化学工程， 2015， 硕士

【摘要】 随着国家电网、通信网络等行业的迅猛发展,对铁塔的需求日益剧增,铁塔构件进行防腐处理前,常采用稀盐酸清洗以去除其表面的疏松氧化层。该酸洗废水Fe2+、Zn2+含量高,pH值低,有较强腐蚀性,目前尚未有经济合理的处理方案。因此,回收利用酸洗废液生产高附加值产品越来越受到人们的重视。针对某铁塔钢构厂的氯化亚铁废酸液,在分析了其基本成分和性质的基础上,开发了一种氯化亚铁废酸液回收利用的新工艺,该工艺主要包括降温结晶法回收废酸液制备氯化亚铁、氯化亚铁制备氧化铁黄晶种、铁黄晶种的生长三个步骤。该工艺流程具有能量消耗低、生产周期短、产量大、废液资源化利用率高等优点,成功将废酸液“变废为宝”。本文主要研究内容如下：(1)加热浓缩-降温结晶法回收制备氯化亚铁,通过Aspen Plus软件模拟和优化,采用四效蒸发-降温结晶法制备氯化亚铁晶体,设置第一效蒸发器压力5atm、汽化分率0.09；第二效蒸发器压力3 atm、温度143.65℃；第三效蒸发器压力1 atm、温度113.95℃；第四效蒸发器压力0.2 atm、温度76.45℃；并通过结晶器降温至25℃结晶,得到氯化亚铁晶体。根据模拟结果,每蒸出lkg水,四效蒸发比直接加热浓缩-降温结晶法节约能量67.4%,大大提高了降温结晶法回收废酸液的能量利用效率。(2)设计并制作了一种氧化铁黄颜料制备的气液固三相反应器,并利用该反应器开展了氧化铁黄晶种制备、晶种生长的实验研究。首先,考察了温度、压力、初始Fe(OH)2浓度对铁黄晶种生成速率的影响,得到了铁黄晶种生成速率的关系式。结果表明,常温下,在三相反应器内,增加空气流量、液相流量、原料液浓度及反应压力,降低Fe(OH)2胶体颗粒粒径,均有利于氧化铁黄晶种的生成。气液固三相反应器中,晶种制备的最佳工艺条件为：气相流量V=700 L/h、液相流量L=70 L/h、初始pH=7.5、Fe(OH)2胶体颗粒700 nm、初始Fe(OH)2浓度C=0.2～0.6mol/L、反应器压力P=0.1～0.5MPa、反应温度20～30℃。其次,将制得的晶种送入三相反应器内实现晶种的长大,控制反应温度120℃,反应压力3atm,反应15-25min后,经过滤、洗涤、干燥等处理后得到氧化铁黄样品,并通过SEM、 XRD等技术对样品进行了分析和评价,所得氧化铁黄颜料达到了我国化工行业一级标准。(3)设计并组装了氧化铁黄连续化生产的实验装置,考察了Fe(OH)2初始浓度和进料流量对氧化铁黄制备的影响,获得了三塔串联氧化铁黄制备的最佳工艺条件：氢氧化亚铁进料流量20 L/h、进料浓度0.3 mol/L、循环槽操作循环比3-5、晶种制备阶段填料塔温度25℃,压力1 atm、晶种生长阶段温度120℃,压力4 atm。更多还原

【Abstract】 With the rapid development of the electricity and communication networks, the demand for iron tower is increasing. Dilute hydrochloric acid is often used to remove the tower component’s oxide layer on the surface before the anti-corrosive process. The pickling waste water, with high Zn2+, Fe2+ content, low pH value, strong corrosive, can’t be handle economically. Therefore, the recycling pickling waste liquor to produce high value-added products is more and more important. Base on the analysis of the basic composition and properties of the FeCl2 waste acid, provided by a tower steel structure factory, a new process has been developed to recycle FeCl2 waste acid. This process mainly includes three steps:extraction of FeCl2 from waste acid cooling by crystallization, preparation of FeCl2 crystal seed, and iron oxide yellow. The new process consumes less energy, with short production cycle, high yield, resource utilization, etc. This research contains three parts:(1)Concentrated heating-cooling crystallization method was used to FeCl2,By the simulation and optimization the Aspen Plus software, four effect evaporation-cooling crystallization was closed to prepare FeCl2. The first effect evaporator pressure is set up 5atm, vaporization rate is 0.09,and the second effect evaporator pressure is set up 3atm, temperature is 143.65℃, and the third one pressure is 1atm, temperature is 113.95 ℃, the last effect evaporator pressure is set up 0.2atm, temperature is 76.45 ℃. Then, cooling the temperature to 25℃ when those liquid go through the crystallizer, getting high purity FeCl2. This process greatly improves the energy efficiency of cooling crystallization by saving 67.4% energy compared with concentrated heating process, arid realizes the resource utilization of waste pickling liquor.(2)A new method was used to prepare iron oxide yellow. The method uses FeCl2 as raw material,5mol/L NaOH as alkali material, air as oxidant to synthesis α-FeOOH. The influences of temperature, pressure, and the initial concentration of Fe(OH)2 on crystal seed formation rate and the air flow rate, liquid flow rate, feed. concentration and reaction pressure, reducing Fe(OH)2 colloidal particle size, are conducive to the formation of iron oxide crystal seed in the three-phase reactor at room temperature. The optimized parameters of the three-phase reactor is:gas phase flow V=700 L/h, liquid flow rate L=70 L/h, initial pH=7.5, Fe(OH)2 particles 700 nm, the Fe(OH)2 initial concentration C=0.2～0.6mol/L. Control the reactor pressure P =0.1-0.5MPa, reaction temperature 20～30℃, than obtained the relationship between temperature, pressure, initial concentration of Fe(OH)2 and the iron oxide yellow seed generation rate. Controlling reaction temperature 120℃, reaction pressure 3atm, the yellow iron oxide products were characterized after it is pretreatment using the SEM and XRD. The result shows that those products get in line with China’s chemical industry standard level.(3)Designing and assembling a continuous production process for the synthetic of iron oxide yellow. Analyzing and studying the effect of ferrous hydroxide, initial concentration and feed flow rate and other parameters on the preparation of iron oxide yellow and discover that the optimum conditions are:Fe(OH)2 feed flow rate 20L/h, feed concentration 0.3mol/L, cell cycle circulation ratio 3-5, setting up the packed column at a temperature of 25 ℃, the pressure of 1atm during the seed preparation stage, and setting up the packed column at a temperature of 120℃, the pressure of 4atm during the seed growth stage.更多还原