【作者】 陈禄政；

【导师】 任南琪；

【作者基本信息】 哈尔滨工业大学 ， 环境工程， 2008， 博士

【摘要】 离心分离是回收铁尾矿渣中细粒铁的高效方法,具有快速、成本低、对环境无污染等优点。然而,国内传统间断式离心机应用时故障率很高和处理能力很低,使其不能有效应用于工业生产;国外工业应用离心机如Knelson和Falcon离心机适用于处理微量金属物料,故不能用于处理高铁物料铁尾渣。本文研究连续离心分离回收铁尾矿渣中的铁,对其技术关键连续离心分离设备,提出往复移动水束流冲击卸落富集层实现连续离心分离过程,并进行技术可行性理论分析;在此基础上,研制连续离心分离设备,进行连续离心分离回收铁尾矿渣中铁实验和工业生产应用研究。采用连续离心分离试验设备,对其实现连续分离过程的条件进行实验研究,结果表明:水束流冲击压力和能量同时满足最小门限值要求是实现连续离心分离过程的前提条件;水束流门限冲击压力随转鼓转速提高线性增大,转鼓转速为700 r/min时,冲击压力约0.55 MPa,表明水束流冲击卸落富集层实现连续离心分离要求的冲击压力不高;水束流门限冲击能量随转鼓转速提高和富集产物产量增大而增大;水束流冲击角影响其冲击效率。对磁分离预处理后的铁尾矿渣(铁含量52.42%)进行连续离心分离单因素条件实验,结果表明:最佳操作条件包括给料体积速率约25 L/min,给料固体浓度20%,转鼓转速450 r/min,转鼓半锥角5°和水束流往复速度36 mm/s;此条件下,得到富集产物的产量、铁含量和铁回收率分别为54.69%、62.32%和65.02%;试验设备处理量为0.3525吨铁尾矿渣/小时,电耗为2.57千瓦时/吨铁尾矿渣,水耗为1.30吨水/吨铁尾矿渣,表明铁尾矿渣连续离心分离具有分离效果好和成本低的优点。实验时,水束流往复速度由36 mm/s增加至60 mm/s时,富集产物铁含量由62.32%快速降低至59.16%,铁回收率仅由65.02%降低至64.75%,表明水束流往复速度适宜不会破坏薄流膜分离过程,且有利于提高富集产物质量。为深入了解铁尾矿渣连续离心分离的优越性,进行铁尾矿渣连续与间断离心分离对比实验。与铁尾矿渣渣间断离心分离比较,连续离心分离获得富集产物铁回收率提高,但铁含量有所下降,两者总体分离效能接近;但连续离心分离物料处理量大大提高、设备故障率和能耗明显降低,有利于克服间断离心分离设备故障率高和处理能力小难以推广应用的技术难题,容易与其它分离方法如高梯度磁分离法结合形成工业化生产工艺处理铁尾矿渣。高梯度磁分离处理铁尾矿渣效果好,处理量大,但难以得到铁含量很高的合格富集产物。因此,本研究进行磁分离预处理-连续离心分离法处理铁尾矿渣(铁含量28.76%)实验,获得合格铁精粉产品的产量、铁含量和铁回收率分别为11.05%、62.32%和23.94%,铁回收效果显著。为研究该技术的工业应用可行性,设计筹建连续离心分离工艺工业生产试验回收厂,进行从在排铁尾矿渣中回收铁工业生产性试验。三个月平均工业生产试验指标为:铁尾矿渣铁含量28.12%,获得铁精粉产品的产量、铁含量和铁回收率分别为10.42%、58.48%和21.66%;该技术的工业生产性试验,减少铁尾矿渣排放量10.42%,并实现重要的环境与经济效益。与实验铁回收结果比较,该技术工业生产获得铁精粉产品的铁含量较低,主要原因可能是由于连续离心分离工业设备应用时效能降低造成的。因此,该技术要得到有效工业应用,关键是提高连续离心分离工业应用的效能。上述研究表明,连续离心分离是回收铁尾矿渣中铁的有效方法,可实现重要的环境和经济效益,因此具有重要的工业应用价值。连续离心分离设备可有效用于处理高铁物料铁尾矿渣,可解决目前国内外工业应用离心机适用于处理微量金属物料的技术难题。更多还原

【Abstract】 Centrifugal concentration, which can separate materials quickly at a low cost and in an environment friendly manner, is an effective method for recovering micro iron values from iron tailings residue. However, Chinese traditional intermittent centrifugal concentrator can not be efficiently applied to concentrate iron tailings residue, due to its incapability of working continuously and its very low processing capacity; and centrifugal concentrators available abroad, e.g., Knelson and Falcon concentrators, which are efficient in treating very lean metallic materials, can also not be used to concentrate rich metallic materials such as iron tailings residue. In view of this, continuous centrifugal concentration by reciprocating water sprays to remove the settled bed of heavy particles was theoretically analyzed, and studied for the recovery of iron values from iron tailings residue on the development of continuous centrifugal concentrators. The technology was tested for iron recovery from iron tailings residue both in experimental and in industrial conditions.Discharging experiments were carried out using the pilot continuous centrifugal concentrator developed in the study to treat iron tailings residue. It was found that continuous centrifugal concentration can be achieved only when the water sprays have both a high enough impacting pressure and adequate enough impacting energy. The threshold impacting pressure of water sprays increases with the increase in drum rotation speed proportionally, and it is around 0.55 MPa when the drum roates at the highest speed of 700 r/min; it is therefore concluded that a relatively low impacting pressure of water sprays is needed for achieving continuous concentration of the concentrator. The threshold impacting energy of water sprays increases with the increase in drum roation speed and in concentrate mass; the impacting angle of water sprays has a significant influence on the discharging efficiency of water sprays.The pilot continuous centrifugal concentrator was also used to concentrate iron tailings residue assaying 52.42% Fe from magnetic pretreatment to study the effect of the most important variables on performance of the pilot concentrator. The experimental results show that the optimum values of the variables are feed volume flow rate around 25 L/min, feed % solids 20%, drum rotation speed 450 r/min, drum inclination 5°and reciprocation of water sprays 36 mm/s. When all the variables were kept optimum, an iron concentrate assaying 62.32% Fe with 65.02% recovery at a solid recovery of 54.69% was achieved, with processing capacity, with electric and water consumptions of the concentrator being 0.3525 t/h, 2.57 Kwh and 1.30 t a ton of the residue, respectively; it is therefore concluded that the concentrator is effective and energysaiving in concentrating iron tailings residue. It was found during the experiments that the change in reciprocation of water sprays from 36 mm/s to 60 mm/s causes a drastic deterioration in concentrate grade from 62.32% Fe to 59.16% Fe but a neglectable drop in iron recovery from 65.02% to 64.75%; it is concluded that the impacting of water sprays at an optimum reciprocating velocity do not destroy the thin film flow, besides, it improves concentration performance of the concentrator.Continuous and intermittent centrifugal concentrations of the iron tailings residue were comparatively performed using the pilot concentrator to analyze superiority of the continuous centrifugal concentration over the intermittent one. The results of the comparison indicate that the continuous centrifugal concentration is capable of achieving a higher iron recovery but a lower concentrate grade, with the overall performance near to each other. However, the continuous centrifugal concentrator is much higher in processing capacity and much lower in failure rate and energy consumption in comparison with the intermittent one, which makes it easy to achieve industrialization in treating iron tailings residue combined with other methods such as high gradient magnetic separation.High gradient magnetic separation can be used to concentrate iron tailings residue efficiently at a very high processing capacity, but generally it cannot be used to produce a high grade qualified concentrate. Therefore, a high gradient magnetic pretreamtent-continuous centrifugal concentration method was used to treat iron tailings residue assaying 28.76% Fe; it obtained an efficient recovery of iron values, with a qualified concentrate assaying 62.32 % Fe with 23.94% recovery at a solid recovery of 11.05% achieved.To apply the technology in industry, a full-scale recovering plant by the technology was built and tested for recovering iron values from a currently discarding iron tailings residue. The results of the test of three months show that it can obtain a marketable concentrate assaying 58.48% Fe with 21.66% recovery at a solid recovery of 10.42% from the residue assaying 28.12% Fe; the test reduces 10.42% by weight of the residue and achieves significant environmental and economic benefits. However, the quality of concentrate achieved by the technology in industry is relatively inferior to that achievable in experimental condition; this may be mainly due to the lower efficiency of the full-scale concentrator in industry. It is therefore vitally important for the full-scale concentrator to improve efficiency if the technology is meant to achieve effective applications in industry.In summary, continuous centrifugal concentration is proven effective for recovery of iron values from iron tailings residue and can achieve significant environmental and economical benefits; it has an important industrial application worth. The continuous centrifugal concentrator, which can be used to concentrate iron tailings residue of high iron content, may be an important supplementary for the centrifugal concentrators available domestic and abroad, which are effective in the treatment of very lean metallic materials.更多还原