浓海水鼓泡晒盐及离子筛提锂技术研究

发布时间：2019-04-01 13:34

【摘要】：随着我国海水淡化应用与技术的发展,其副产物浓海水的产量也随之上升,因此浓海水的处理与综合利用是当前海水淡化产业所必须面对、解决的重要问题和挑战。目前,对于浓海水的利用主要集中于浓海水化学资源的提取,主要通过将海盐生产以及苦卤的综合利用相结合,从中制备化工产品。文章根据现有浓海水化学资源综合利用与化工技术,针对海盐生产以及苦卤的综合利用提出了浓海水鼓泡法晒盐以及磁性纳米锂离子筛法提锂,并对上述方法的关键技术进行探索和研究。首先,研究对浓海水鼓泡法晒盐进行探索,为此在舟山六横岛所搭建的120 m2的浓海水鼓泡晒盐池以及1 m2的对比池中进行探索性实验,通过记录液位、温度、波美度、环境温湿度的数据,分析了影响浓海水鼓泡法晒盐的主要影响因素。基于探索实验结果的基础之上,搭建两种实验室级别鼓泡池,在不同的鼓泡口数量与排布方式下,通过调节气量、鼓泡口深度与鼓泡口间距等操作条件,分别考察了两种尺度的气泡群在鼓泡池中运动过程的行为。研究结果表明,浓海水鼓泡法晒盐在固定时间段内鼓泡效果最佳,此外气泡在鼓泡池液面的覆盖率以及破裂后溅射出的小液滴的数量是影响浓海水鼓泡晒盐的主要影响因素。因此,研究提出在气体流量相同的前提下,具有更高表面覆盖度且能迸射出更多的小液滴的小气泡更适合于浓海水鼓泡晒盐过程。随着气流量、鼓泡口深度、间距的增大气泡在液面的覆盖率上升,但达到一定值后覆盖率不再变化。在优化后的操作参数下(单鼓泡口气流量为0.4 L·min-1、鼓泡口深度为8 cm、鼓泡口间距为12 cm),小气泡群的覆盖率可以达到90%,蒸发速率可比传统滩晒过程增加1~1.5倍。其次,研究制定了采用磁性纳米锂离子筛用于浓海水提锂的四步法工艺路线。其中为制备核壳结构的磁性纳米锂离子筛,研究开发出一种新型的高频撞击流反应器(HISR)用于制备前驱体Fe3O4/Mn OOH。实验通过对流量分布、包覆比、压力等操作参数的进行调节,制备了多批磁性纳米锂离子筛前驱体,并结合表征结果对操作参数对产品的影响进行分析。研究结果表明,当包覆比在0.23以下为异相成核,随着包覆比的降低,成核诱导期逐渐延长,更长的分散时间提供给介观与微观混合。另外,随着初始悬浮液流量的增加,反应流道中介观和微观混合过程得到显著强化,而反应器中24条支流道的宏观分布极大地强化宏观混合过程。通过显著强化多尺度混合过程最终获得了包膜致密均匀的产品。
[Abstract]:With the development of the application and technology of seawater desalination in China, the production of concentrated seawater, its by-product, has also increased. Therefore, the treatment and comprehensive utilization of concentrated seawater is an important problem and challenge that must be faced and solved by the desalination industry at present. At present, the utilization of concentrated seawater is mainly focused on the extraction of the chemical resources of concentrated seawater, from which chemical products are prepared by combining the production of sea salt and the comprehensive utilization of bittern. According to the comprehensive utilization of chemical resources of concentrated seawater and chemical technology, this paper puts forward two methods of extracting lithium from sea salt by bubbling method and magnetic nano-lithium ion sieve method, aiming at the production of sea salt and the comprehensive utilization of bittern. And the key technology of the above-mentioned method is explored and studied. First of all, the study of the thick seawater bubbling method to explore the salt, for this purpose in the Zhoushan Liuheng Island 120 m2 of thick sea bubbling salt pool and 1 m2 of contrast pool exploratory experiments, by recording the liquid level, temperature, Baume degree, and so on, through the record of liquid level, temperature, Baume degree, through the record of liquid level, temperature, wave degree, The data of ambient temperature and humidity were analyzed, and the main influencing factors were analyzed. Based on the experimental results, two kinds of laboratory-level bubble cell are built. Under different bubble number and arrangement, the operation conditions such as air volume, bubble depth and bubble spacing are adjusted. The behavior of bubble group moving in bubbling cell at two scales was investigated respectively. The results show that the bubbling effect of concentrated seawater bubbling method is the best in a fixed period of time. In addition, the coverage rate of bubbles on the surface of the bubbling pool and the number of sputter droplets after rupture are the main factors that affect the bubbling salt of concentrated seawater. Therefore, on the premise that the gas flow rate is the same, the small bubble with higher surface coverage and more small droplets can burst out more suitable for the blistering process of concentrated sea water. With the increase of gas flow rate, bubble depth and spacing, the coverage rate of bubbles in the liquid surface increases, but the coverage rate no longer changes when the gas flow rate reaches a certain value. Under the optimized operating parameters (single bulging breath flow is 0.4L 路min-1, bubble mouth depth is 8 cm, bubble spacing is 12 cm), the coverage rate of small bubble group can reach 90%. The evaporation rate can be increased by 1. 5 times compared with the traditional beach process. Secondly, a four-step process for extracting lithium from concentrated seawater with magnetic nano-lithium ion sieve was developed. In order to prepare magnetic nano lithium ion sieve with core-shell structure, a new type of high frequency impinging stream reactor (HISR) was developed for the preparation of precursor Fe3O4/Mn OOH.. By adjusting the operating parameters, such as flow distribution, coating ratio, pressure and so on, several batches of magnetic nano-lithium ion sieve precursors were prepared, and the effect of the operating parameters on the product was analyzed by combining the characterization results. The results show that when the coating ratio is less than 0.23 for heterogeneous nucleation, the induction period is gradually prolonged with the decrease of the coating ratio, and longer dispersion time is provided to the mesoscopic and micro-mixing. In addition, with the increase of initial suspension flow rate, the meso-mixing and micro-mixing processes of the reaction channel are significantly strengthened, while the macro-distribution of the 24 branch channels in the reactor greatly strengthens the macro-mixing process. The dense and uniform coating products were finally obtained by significantly enhancing the multi-scale mixing process.
【学位授予单位】：浙江海洋学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P746

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