钛白废酸制备α半水石膏及形貌控制

发布时间：2018-04-22 17:51

  本文选题：α半水石膏 + 钛白废酸　； 参考：《郑州大学》2015年硕士论文

【摘要】：目前,钛白粉生产主要有硫酸法、盐酸法以及氯化法。由于硫酸法技术成熟,国内绝大部分钛白粉厂多采用此法。据统计每生产1t钛白粉会产生废酸8~10t。废酸中含有20%左右的硫酸和10%左右硫酸亚铁以及大量钛盐,回收利用难。多采用石粉常温下中和,产物多为二水石膏,由于杂质含量较多,通常被用作堆埋处理,既浪费资源,又污染环境。本文以钛白废酸和石粉(或石灰乳)为原料,利用双加法和常压盐溶液法制备α半水硫酸钙,主要研究了温度、浆料浓度、p H等工艺参数和转晶剂对产物晶体形貌的影响。研究内容主要包括以下几个方面:1)以钛白废酸和石灰乳为原料,利用双加法,通过在母液中加入转晶剂、控制反应温度、进料速度、废酸稀释倍数以及其他工艺参数,从而制备出晶形良好的α半水石膏。但是大量的实验证实,双加法(酸化法的一种)更适合制备长径比大的α半水石膏晶须,不能制备出大的、短柱状的α半水石膏。2)研究了钛白石膏在常压Ca Cl2-Mg Cl2-KCl溶液中的转化过程。讨论了温度、浆料浓度、盐浓度、溶液p H以及转晶剂对产物α-HH(α半水石膏)的影响。结果表明,温度98℃,盐浓度25%,浆料浓度20%,p H=4.5,转晶剂添加量为0.01%时,能制备出粒径相对统一,长径比接近1:1的α-HH,标稠需水量为0.35时,测得绝干抗压强度为32.6Mpa。3)研究了钛白石膏在常压Na Cl溶液中的转化过程。讨论了温度、浆料浓度、盐浓度、溶液p H以及转晶剂对产物α-HH的影响。结果表明,温度在98℃,盐浓度15%,浆料浓度20%,p H=2.5,转晶剂添加量为0.5%时,能制备出长径比约为1:1的短柱状α-HH,标稠需水量为0.33时,测得48h绝干抗压强度为35.2Mpa。
[Abstract]:At present, titanium dioxide production mainly includes sulfuric acid, hydrochloric acid and chlorination. Due to the maturation of sulfuric acid process, most titanium dioxide plants in China adopt this method. According to statistics, each production of 1 ton of titanium dioxide will produce 8 tons of waste acid 10 t. The waste acid contains about 20% sulfuric acid, about 10% ferrous sulfate and a large amount of titanium salt, so it is difficult to recycle. Most of them are neutralized by stone powder at room temperature, and the products are gypsum dihydrate. Because of the high impurity content, it is usually used as a heap disposal, which not only wastes resources, but also pollutes the environment. In this paper, 伪 -hemihydrate calcium sulfate was prepared from titanium dioxide waste acid and stone powder (or lime milk) by double addition method and salt solution under normal pressure. The effects of temperature, slurry concentration, pH and transgranular agent on the crystal morphology of the product were studied. The main contents of the research include the following aspects: (1) using titanium dioxide waste acid and lime milk as raw materials, by adding transgranular agent into mother liquor, controlling reaction temperature, feed rate, dilution ratio of waste acid and other technological parameters. Thus, 伪-hemihydrate gypsum with good crystal shape was prepared. However, a large number of experiments have proved that the double addition method (one of the acidizing methods) is more suitable for the preparation of 伪 -hemihydrate whiskers with large aspect ratio. Short columnar 伪 -hemihydrate gypsum. 2) the conversion process of titanium dioxide gypsum in atmospheric pressure Ca Cl2-Mg Cl2-KCl solution was studied. The effects of temperature, slurry concentration, salt concentration, solution pH and transgranular agent on the product 伪 -HH (伪 -hemihydrate gypsum) were discussed. The results show that when the temperature is 98 鈩，

本文编号：1788287