从制碱白泥中制取纳米碳酸钙的研究

发布时间：2018-02-08 08:23

本文关键词： 制碱白泥碳化纳米碳酸钙白度　出处：《广东工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：我国制碱厂大部分利用氨碱工艺生产纯碱,生产过程中产生了大量的白色沉淀物,即为碱渣,俗称制碱白泥。由于制碱白泥本身难处置的特点,制碱白泥的处理一直得不到很好的解决,因此制碱白泥的处理问题一直限制着氨碱法纯碱企业的发展。纳米碳酸钙的应用广泛,如果将制碱白泥转化为纳米碳酸钙,实现制碱白泥的高值化综合利用,对解决制碱白泥的出路具有现实意义,将取得良好的经济效益和突出的环境效益。本文分析了制碱白泥的化学组分,以制碱白泥和二氧化碳为原料,采用碳化法从制碱白泥中制取纳米碳酸钙,通过控制煅烧温度、反应温度、氢氧化钙浓度等反应条件,研究制取纳米碳酸钙的最佳实验条件。对根据制碱白泥化学成分用无水碳酸钙和相应的还原性化学助剂提高其纯度和白度,通过控制加入无水碳酸钙和化学助剂量的不同,从而使提高纳米碳酸钙纯度和白度达到最好的效果。使制得的纳米碳酸钙的各项技术指标达到工业沉淀碳酸钙的技术指标要求。试验结果表明：水洗实验中加无水碳酸钠使初始白泥中碳酸钙含量55.32%、白度值20.5%提高到碳酸钙含量73.53%、白度值为63.32%,无水碳酸钠大大提高了碳酸钙含量和白度；加入无水碳酸钠量的不同提高的碳酸钙含量和白度也不同,当无水碳酸钠与白泥以1：4的量加入时,提高的碳酸钙含量和白度效果最好,碳酸钙含量为89.63%、白度为75.35%。助剂A可以明显提高纳米碳酸钙的白度值,由原来的平均值70.3%提高到81.58%；纳米碳酸钙的白度随着助剂A加入量的增加而增大,当助剂A与纳米碳酸钙以1：5的量加入时,纳米碳酸钙的增白效果达到最佳,白度可达到83.3%,助剂A可以提高碳酸钙的白度。制取所得的纳米碳酸钙纯度为碳化反应温度和氢氧化钙浓度为碳化反应主要的影响因素,制得的碳酸钙的粒径随着温度的升高粒径慢慢增大,随着氢氧化钙浓度低生成的碳酸钙粒径变小,煅烧温度对纳米碳酸钙粒径影响不大；制碱白泥经过适当的处理是可以制得纳米碳酸钙的。
[Abstract]:Most of the alkali making plants in our country produce soda by ammonia alkali process, and a large amount of white sediment is produced in the production process, that is, alkali slag, commonly known as alkali making white mud. The treatment of alkaline white mud has not been well solved, so the treatment of alkali white mud has been restricting the development of ammonia alkali soda soda enterprises. Nano-calcium carbonate is widely used, if the white mud is converted to nano-calcium carbonate, The realization of high value comprehensive utilization of alkali making white mud is of practical significance to solve the outlet of making alkali white mud, and will obtain good economic benefit and outstanding environmental benefit. The chemical composition of alkali making white mud is analyzed in this paper. Nanometer calcium carbonate was prepared from alkali white mud and carbon dioxide by carbonization. The reaction conditions such as calcination temperature, reaction temperature and concentration of calcium hydroxide were controlled. The optimum experimental conditions for preparing nanometer calcium carbonate were studied. The purity and whiteness of the white mud were improved by using anhydrous calcium carbonate and corresponding reductive chemical auxiliaries, and the quantity of anhydrous calcium carbonate and chemical adjuvant was changed by controlling the addition of anhydrous calcium carbonate and chemical adjuvant. In order to improve the purity and whiteness of nanometer calcium carbonate and achieve the best effect, the technical indexes of the prepared nanometer calcium carbonate can meet the technical requirements of industrial precipitated calcium carbonate. The test results show that there is no addition of calcium carbonate in the washing experiment. Sodium carbonate made the content of calcium carbonate in the initial white mud 55.32, the whiteness value 20.5% increased to the content of calcium carbonate 73.53, the whiteness value was 63.322.The content and whiteness of calcium carbonate were greatly increased by anhydrous sodium carbonate. The content and whiteness of calcium carbonate increased with the addition of anhydrous sodium carbonate was also different. When the amount of anhydrous sodium carbonate and white mud was 1: 4, the increase of calcium carbonate content and whiteness was the best. The content of calcium carbonate was 89.63 and the whiteness of calcium carbonate was 75.35.The whiteness of nano-calcium carbonate increased from the original average of 70.3% to 81.58.The whiteness of nano-calcium carbonate increased with the increase of additive A. When additive A and nano-CaCO3 were added at 1: 5, the whitening effect of nano-CaCO3 was the best. The whiteness of calcium carbonate can reach 83.3, and the whiteness of calcium carbonate can be improved by additive A. the purity of nanometer calcium carbonate obtained is the main influencing factors of carbonation reaction temperature and concentration of calcium hydroxide. The particle size of the prepared calcium carbonate increases slowly with the increase of the temperature, and the particle size of the calcium carbonate with the low concentration of calcium hydroxide becomes smaller. The calcination temperature has little effect on the particle size of the nanometer calcium carbonate. Nanometer calcium carbonate can be prepared by proper treatment of alkali-making white mud.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X781.2;TQ132.32

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