【作者】 张宁；

【导师】 朱校斌；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 海洋化学， 2008， 硕士

【摘要】 海水经淡化技术提取淡水后,被浓缩一倍左右的剩余海水被称为高盐度浓海水。日产10万t淡水的海水淡化厂,同时产生10万t以上高盐度浓海水。随着海水淡化规模的迅速扩大,大量浓海水的排放必将对生态环境造成难以估量的威胁。目前,世界各国通常采用浓海水直接排海的方法来处理。这不但威胁了脆弱的生态环境,而且限制了海水淡化事业的发展。同时,海水中大量的化学资源被白白浪费,不符合绿色化学准则与节约资源的要求。研究浓海水资源的综合利用,不但能够缓解浓海水造成的污染,而且能够节约能耗,提高经济效益。本论文研究了冷冻脱盐法处理浓海水的作用机理,探讨了应用冷冻脱盐工艺技术处理浓海水的效果,研究了不同实验条件下冰冻浓海水的脱盐效率,以及多次分步冷冻处理之后,得到的低盐度冰和高盐度盐水的主要离子组成和性质。并利用ICP-MS对其主要离子含量进行测定。实验结果表明:离心机转速变化对冰冻浓海水脱盐、脱除钙镁离子的影响显著。不同离心转速条件下,对脱盐和脱除钙镁离子均有较好效果,脱除率均达到88.5%和87.4%以上。随着离心转速的提高,脱盐率提高,转速4000r/min达到最大,但是其变化幅度减小,进一步提高转速对脱盐率和钙镁离子脱除率的提高影响不大。多步冷冻脱盐的实验表明,一次冷冻离心分离,冰晶的盐度可降低99.0%。与原浓海水相比,钾、钠、钙、镁等主要离子含量降低到原浓海水的3%以下。多步离心分离之后,得到的浓盐水的盐度达到原浓海水的3.3倍。通过对微量金属离子含量的分析表明,冷冻脱盐技术对各种微量离子的脱除率不同,如铜的脱除率为94.3%,钴的脱除率为94.8%,铀的脱除率为60.6%。多步冷冻脱盐后,冰融化成水的总量达到被处理的浓海水总体积的2/3以上。更多还原

【Abstract】 The high concentration seawater which produced after desalination is double concentration compare to ordinary seawater. The size of emission is almost same as the size of yield of freshwater. With the development of desalination industry, it has bought pollution problems and ecological damage of the marine more seriously. The common treatment is to discharge the brine to the sea directly that not only damages the fragile environment, but also becomes a restrictive factor of desalination industry. Meantime countless of chemical resources in seawater were lost without utilization. It is necessary to study the desalinated seawater and solve the pollution issues to make it be positive to the environment and the shortage of resources.Our studies focus on freezing centrifugation to dispose the high concentration seawater besides the various methods of desalination. The mechanism of freezing desalinization technology of high concentration seawater and effect of centrifugal rotational speed on high concentration seawater ice by centrifugal experiments are studied at the laboratory. Under different condition of time or speed of the centrifuge, the freezing high concentration seawater is desalted into two parts that including the freshwater-ice and higher concentration brine.The experimental results show that the effect of rotational speed variance on the desalination and its efficiency are obvious under the same experiment condition. The desalination removal rate value is above 88.5% and the removal of Ca2+ and Mg2+ is above 87.4% under different rotational speed. The desalination removal rate value increases with the raise of rotational speed. When the centrifugal rotational speed is 4000 r/min, the rate of desalination of high concentration seawater ice turns maximum. But rate change is getting small. The impact of raising rotational speed is not obvious towards desalination removal rate and the removal of Ca²⁺ and Mg²⁺. The results of continuous experiment of desalting show that the ice salinity removal rate is 99.0% after first freezing treatment. Compare with the original desalinated seawater, the content of main ion of K⁺Ca²⁺ Na+ Mg²⁺ is only 3% after first freezing treatment. And the salinity of brine is 3.3 times as the original desalinated seawater. The effect of removal of trace elements is different by the freezing desalination technology. The removal rates of Cu、Co、U are 94.3%,98.4% and 60.6%. By every steps of the experiment, the ice of low salinity and low content is left and the amount of ice was 2/3 of the original amount of desalination seawater.更多还原