【作者】 王颖；

【导师】 刘燕；

【作者基本信息】 东北大学 ， 有色金属冶金， 2014， 硕士

【摘要】 氧化铝生产过程中,由于沉降分离操作上的各种失误,常出现沉降槽“跑浑”及“垮槽”等事故,造成极大的经济损失。近些年,高效深锥沉降槽在我国应用广泛,但在处理一水铝石产生的赤泥时存在一些问题。因此,为了强化赤泥的沉降分离,提高赤泥的沉降速度,改善沉降槽溢流质量和底流的浓稠度,并提高设备的生产效率和降低生产成本,本文在深锥沉降槽的基础上,改进并设计了新型沉降槽。主要研究内容如下：(1)根据相似原理设计物理模拟实验装置,本文改进了高效沉降槽,设计了带有圆锥形沉降器的沉降槽和旋液分离沉降槽。(2)对不同结构的四种沉降槽,采用PIV技术测试不同流量下沉降槽内部流体流场及固体沉降流场,得到如下规律：1号和2号沉降槽的固体随着液体在槽内从右向左然后向下沉降,3号和4号沉降槽液体在旋液分离器中从右向左旋转运动,到底部转而向上,流量大时会从旋液分离器顶部产生溢流,固体从右到左呈螺旋状向下沉降运动。3号和4号沉降槽的流场好于1号和2号沉降槽。3号沉降槽在流量为1.0m3/h时固体沉降速度流场比较好。对于4号沉降槽适当增大的流量有利于固体颗粒的沉降,最佳液体流量为2.0m3/h。随着流量的增大,四个沉降槽槽内液体的运动速度及固体的沉降速度均增大。(3)对旋液分离沉降槽进行了速度矢量分布和液相分布的数值模拟,速度矢量分布的数值模拟结果与PIV测试结果基本一致,两种方法得到了较好的相互验证。沉降槽内液相分布数值模拟结果与物理模拟的结果基本一致。采用旋液分离器进行沉降分离时,为保证液体顺利从溢流口排出,进口流量不能过低。(4)对一水铝石溶出的赤泥进行沉降实验研究,结果表明：降低赤泥矿浆的固含可以提高其沉降性能,对赤泥压缩性能没有影响。沉降速度随赤泥矿浆粘度的增大呈明显的下降趋势,增大赤泥矿浆粘度会恶化其压缩性能。赤泥的沉降速度随絮凝剂添加量的增加而先增加后降低,随着絮凝剂加入量的增加,赤泥矿浆的压缩性能先变好后变差。赤泥的沉降速率随温度的升高而增大,温度升高会改善其压缩性能。(5)考察了四种不同结构的沉降槽的沉降功能,结果表明：3个新型沉降槽的沉降效果均好于正常高效沉降槽。低粘度时新型3号、4号沉降槽大于1号沉降槽的沉降速度,沉降速度分别提高了87.3%和100%；高粘度时经改进的3号大于1号和4号沉降槽的沉降速度,且沉降速度提高了43.8%。在旋液沉降槽中,絮凝剂的多点加入好于单点加入。更多还原

【Abstract】 In the process of alumina production, accidents like mudflow and settler collapsing often occurred because of unmerited settling operation, which caused severe losses. During these years, deep cone high rate settler was widely used, but there were some problems in the disposal of red mud produced by diaspore. Therefore, in order to strengthen the separation of red mud, increase the settling velocity, improve the quality of overflow and the consistency of underflow, increase production efficiency and lower costs, a new settling tank was designed and improved based on the deep cone high rate settler. The main contents of the research were as follows.(1) A physical simulation experiment device was established according to the principle of comparability. This paper improved the efficient settling tank and designed the settling tank with cone settler and hydrocylone settler.(2)The fluid flow field and solid settlement flow field of four types of settling tank were measured under different flow rate by using PIV. The results showed that solid in No.1and No.2settling tank followed with the liquid from right to left and then down. The liquid in the hydrocylone settler of No.3and No.4rotated from right to left and then from bottom to top. Overflow occurred in the top of hydrocylone settler under the condition of large flow rate and the solid moved downward from right to left as helical form. The fluid flow field and solid settlement flow field of No.3and No.4settling tank were better than No.1and No.2settling tank. The flow field of solid settling velocity in No.3settling tank was better when the flow rate was1.5m3/h. The flow field of solid settling velocity in No.4was better as flow rate increased suitably. The best liquid flow is2.0m3/h. The flow velocity and solid settling velocity in the four settling tanks increased as flow rate increased.(3) Velocity vector distribution and liquid distribution of the settling tank with bigger hydrocylone separator was studied by numerical simulation. The results of numerical simulation on velocity vector distribution and PIV test were basically the same, which got fine mutual verification. The numerical simulation result of liquid distribution in the settling tank was in accordance with the result of experiments. In order to ensure the liquid discharged from the overflow port of hydrocylone separator, inlet flow rate could not be too low.(4)The experiment about settling property of red mud dissolved from diaspore was performed. The results showed that settling property could be improved by reducing solid content of red mud slurry and solid content had no influence on the compression property of red mud. The settling velocity of red mud decreased significantly and compression property got worse with the increasing of slurry viscosity. The settling velocity of red mud increased firstly and then decreased with the increasing of flocculating agent additive amount. Compression property of red mud got better first and then got worse with the increasing of flocculating agent additive amount. The settling velocity of red mud increased with the increasing of temperature and compression property was improved.(5) Settling capacities of four different structure settling tank were been investigated. Results indicated that, settling capacities of three new settling tanks were all better than normal settling tank. The settling velocity of No.3, No.4in low viscosity was higher than No. I, which had increased by87.3%and100%respectively. Under the condition of high viscosity, settling velocity of No.3was higher than No.1and No.4, and it had increased by43.8%. Several flocculating agent addition points were better than single flocculating agent addition point in hydrocylone settler.更多还原