氨法制镁母液蒸发、冷却析盐规律的试验研究

发布时间：2018-01-28 06:27

本文关键词： 苦卤综合利用脱镁母液蒸发冷却析盐规律　出处：《天津科技大学》2010年硕士论文　论文类型：学位论文

【摘要】：海水中几乎含有地球上发现的所有元素,其中含有的矿物质丰富,海水制盐后的苦卤中各种盐类的浓度较高,具有广阔的开发空间。苦卤的组分复杂,因而如何更快地研究和开发苦卤中的各种资源,是苦卤化学资源综合利用中的一个重要问题。各个海盐区的盐化工业是以海水制盐母液(苦卤)综合利用为主体的无机化学工业,水盐体系相平衡与相图是无机盐化工的理论基础。苦卤中提取各盐类的研究通常是建立在水盐体系相图的基础上,通过对卤水体系的分析,结合相图理论确定适宜的工艺参数,进而提出适宜的对卤水资源提取的工艺路线,实现对苦卤的综合利用。本文主要针对卤水-氨法制取氢氧化镁后的母液在蒸发及冷却过程中的析盐规律进行研究。脱镁母液是一个主要含有K+,Na+,NH4+, MG2+,c1-,so42-等离子的复杂多元体系,对于此体系的相平衡数据还未见完整报道。研究脱镁母液的蒸发及冷却析盐规律,这是氨法苦卤综合利用新工艺开发所必需的基础研究,对丰富相图理论及其应用具有一定的指导作用。本研究得出了该体系的蒸发析盐规律,并在此析盐规律的基础上对脱镁母液中氯化钠及硫酸铵的分离分别进行了实验。实验确定了蒸发结晶脱除脱镁母液中氯化钠的工艺条件；并对经蒸发浓缩,分离NaCl晶体后的高温澄清液进行自然冷却实验,得出了其冷却析盐规律,发现该过程的冷却析出物为复合肥的有效成分氯化铵及硫酸铵。根据脱镁母液的蒸发及去除氯化钠后母液的冷却析盐规律,确定了对分离氯化钠后所得母液进行继续蒸发的实验方案,从而进一步得出了脱除氯化钠和硫酸铵混合盐的工艺条件,并使得剩余高温澄清液的最终冷却产物为较纯的氯化铵。对脱镁母液中钠离子的去除进行了探索性实验,采用了向脱镁母液中通入二氧化碳的方法,虽未达到去除钠离子的目的,但是发现其仍有一定的研究空间。本研究是《氨法-苦卤综合利用关键技术的研究》项目的组成部分,这是对苦卤综合利用的一种新的思路及途径。本研究提出的工艺技术在对提高苦卤资源利用率,节能减排,提高企业效益等方而具有明显的作用。
[Abstract]:Almost all the elements found on the earth are found in the sea water, which contains rich minerals. The concentrations of all kinds of salts in the bittern after salt making from sea water are relatively high, and there is a broad space for development. The components of the bittern are complex. Therefore, how to study and develop various resources in bittern more quickly is an important problem in the comprehensive utilization of bittern chemical resources. The salinization industry in each sea salt area is an inorganic chemical industry which takes the comprehensive utilization of salt mother liquor (bittern) as the main body. The phase equilibrium and phase diagram of water-salt system are the theoretical basis of inorganic salt chemical industry. The study of extracting each salt from bittern is usually based on the phase diagram of water-salt system and the analysis of brine system. According to the theory of phase diagram, the suitable technological parameters were determined, and the suitable technological route of extracting brine resources was put forward to realize the comprehensive utilization of bittern. In this paper, the rule of salt evolution of magnesium hydroxide mother liquor prepared by brine ammonia process during evaporation and cooling is studied. The mother liquor of demagnesium is mainly composed of K ~ (2 +) Na ~ (2 +) NH _ (4), MG2. The phase equilibrium data of the complex multicomponent system of c1-so _ 42-plasma have not been reported completely. The evaporation and cooling salt evolution of the mother liquor of demagnesium have been studied. This is the basic research necessary for the comprehensive utilization of the new process of ammonia bitter brine, and has a certain guiding effect on the rich phase diagram theory and its application. In this study, the law of evaporative salt evolution of the system has been obtained. The separation of sodium chloride and ammonium sulfate from magnesium removal mother liquor was carried out on the basis of the law of salt evolution. The process conditions for the removal of sodium chloride from magnesium removal mother liquor by evaporative crystallization were determined. The natural cooling experiment was carried out on the high temperature clarification liquid after evaporating and concentrating and separating NaCl crystal, and the law of cooling and salt evolution was obtained. It is found that the cooling precipitates of this process are ammonium chloride and ammonium sulfate, which are effective components of compound fertilizer. According to the evaporation of demagnesium mother liquor and the law of cooling and salting out the mother liquor after removing sodium chloride, the experimental scheme of continuous evaporation of mother liquor after separating sodium chloride was determined. The technological conditions of removing the mixed salt of sodium chloride and ammonium sulfate were obtained, and the final cooling product of the residual high temperature clarifier was made to be pure ammonium chloride. An exploratory experiment was carried out on the removal of sodium ions from the magnesium removal mother liquor. The method of injecting carbon dioxide into the mother liquor was adopted. Although the purpose of removing sodium ion was not achieved, it was found that there was still some room for study on the removal of sodium ion. This research is a part of the project of "the key technology of ammonia process and bittern comprehensive utilization". This is a new idea and approach to the comprehensive utilization of bittern. The process technology proposed in this study has obvious effects on improving the utilization ratio of bittern resources, saving energy and reducing emissions, and improving the efficiency of enterprises.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TS396.1

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