泡沫浮选分离法的应用及前景

泡沫浮选法是泡沫分离技术中的一种,它是选金生产中应用最广泛的方法之一,现今人们将其应用到分析化学中的分离富集物质且效果甚好,在此我们对此方法进行归纳并展望其发展前景。     

泡沫分离法纯化十二烷基硫酸钠的研究

用泡沫分离法 ,纯化了十二烷基硫酸钠 (SDS) ,并通过红外光谱、熔点测定、表面张力 -表面活性剂浓度的对数 (γ- lgc)曲线的分析 ,确证了 SDS的纯度。     

泡沫浮选分离技术应用进展

综述了泡沫浮选在分离固体粒子、分离溶液中的离子、分子,处理工业废水、油田开发、脱墨、土壤的清洗、回收、浓缩生物活性物质、分离全细胞的应用,并提出将来的发展方向。     

氯气-泡沫分离法处理水合肼生产废水

采用氯气-泡沫分离法处理尿素氧化法水合肼生产废水,考察了pH值、氯气投加量、废水循环处理时间等因素对处理效果的影响。试验结果表明,在pH值为11.0、氯气投加量为400 mg/L、废水循环处理时间为2 h的最佳工艺条件下,废水经氧化、分离处理后,NH3-N、CODCr含量大幅度削减,其去除率分别达到94.35%、96.07%。     

泡沫分离法分离人参皂苷

通过对浓缩倍数和收率的测定,考察了气速、pH值、进料浓度、进料量以及通气类型、操作方式等因素对人参皂苷泡沫分离效果的影响. 结果表明, 泡沫分离是分离浓缩人参皂苷的一种简便有效的方法.     

泡沫分离法处理洗车废水中LAS的试验研究

考察了泡沫分离法去除洗车废水中LAS的效能。单极泡沫分离法对进水LAS小于55 mg/L废水的最高去除率可达94%。在一定气液比下,进水LAS浓度越高,去除率越高,但气液比超过12∶1时,LAS浓度对去除率影响有限。通过对2～5级泡沫分离法处理洗车废水的试验结果进行比较,证明三级泡沫分离法去除效果最佳。当进水LAS为30 mg/L,停留时间25 min,气液比为12∶1时,LAS去除率达到98.4%,出水达到洗车废水回用标准。     

微藻细胞的连续泡沫分离法采收

为考察连续泡沫分离法采收微藻细胞的可行性 ,在一种斜臂泡沫分离装置上 ,以螺旋藻为模型藻种 ,较为详细地研究了载气流率、藻液进料流率、浓度、pH值、离子强度、乙醇浓度、进料位置、泡沫段与液相段高度之比等因素对泡载采收性能的影响。结果表明 :在载气流率、藻液进料流率或藻液浓度较低时采收性能良好 ;当 pH值为 11、离子强度为 1 3× 10 ⁴ μs·cm^-1、乙醇浓度为 3%(体积 )时泡载收率可达 2 5 %～ 45 %;采用泡沫相段进料有利于提高泡载采收性能。提出的连续泡载采收动力学模型与实验值拟合较好 .     

泡沫浮选萃取法分离精氨酸

以精氨酸水溶液为研究体系,采用十二烷基苯磺酸为起泡剂,以二(2-乙基已基)磷酸(P204)为萃取剂,对泡沫浮选萃取法分离提取水溶液中微量精氨酸的工艺进行了研究,考察了溶液中pH、鼓泡气体流量、表面活性剂浓度、萃取剂浓度的影响.结果表明在常温条件下,水相初始pH为7.0,萃取剂P204(稀释剂:正庚烷)体积分数为30%,水相和有机相的相比为17:1,十二烷基苯磺酸浓度为0.15 g/L,气体流量为200 mL/min时,溶液中精氨酸能达到满意的分离效果(富集比16.2,回收率97.2%).     

泡沫浮选在钾盐生产中的应用

按照泡沫浮选的定义,从原理、影响因素及生产工艺方面综述了泡沫浮选分离技术的研究进展,其中对泡膜分离浮选技术的原理、捕收剂及国内工艺改进方面进行了重点阐述,并提出了展望。     

离子交换分离法的发展近况

离子交换分离法是分析领域中一种重要的分离方法,它可用于各种物质的分离与富集,在日常生活和工业生产中有着广泛的应用。因此,离子交换分离法是目前最重要和应用最为广泛的分离方法之一。文章通过介绍离子交换分离法在一些领域的应用,来阐述离子分离法的发展近况。     

Purification of Single-Walled Carbon Nanotubes (SWNTs) by Acid Leaching,NaOH Dissolution,and Froth Flotation

The SWNTs with a carbon content of approximately 3% were synthesized via the disproportionation of CO over a CoMo/SiO₂ catalyst. The three sequential steps, including acid treatment, silica dissolution, and froth flotation, were proposed for the purification of the as-synthesized SWNTs. The pretreatment step for the catalyst removal by acid leaching was optimized at an HCl concentration of 6 M, 50°C, and a sonication time of 3 h, corresponding to the Co and Mo removals of 84% and 44%, respectively. For the silica dissolution, the SWNTs sample after the acid leaching step was treated with a 5 M NaOH solution at 50°C and a sonication time of 3 h, leading to a silica removal of 54%. The froth flotation was employed to separate the SWNTs from the remaining silica using SDBS as an anionic frother. The process performance was maximized at an SDBS concentration of 0.1 × CMC, an air flow rate of 120 cm³/min, and a solution pH of 5, yielding a carbon content of the purified SWNTs of 71%. It was also found that the proposed technique successfully purified the as-synthesized SWNTs sample without damaging its nanostructure.     

基于自适应谷底检测的浮选泡沫形态特征提取

针对矿物浮选泡沫大小形状不一、光照不均等特点,提出一种基于适应度反馈微粒群优化算法自适应优选谷底检测阚值的泡沫形态特征提取方法.将微粒群算法的惯性权重和加速因子设置为全局最优点适应度的函数,优选谷底检测阚值,采用局部灰度极小选择边界检测模板,根据多角度逻辑规则比较,获取气泡边界,分割结果的统计分析表明泡沫形态特征服从g...     

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions II: Continuous Mode of Operation

Abstract

The objective of this study was to investigate the relationship between interfacial tension (IFT) and foam characteristics and the efficiency of diesel oil removal from water in a continuous froth flotation column. The effects of operational parameters, including surfactant concentration, salinity, oil-to-water ratio, foam height, air flow rate, and hydraulic retention time (HRT) on the oil removal were investigated in the continuous mode of a froth flotation operation and compared to batch operation results. Unlike the batch system, for the continuous system used in the present study, having only branched alcohol propoxylate sulfate sodium salt surfactant (C_14–15(PO)₅SO₄Na) and NaCl present in the solution yielded such poor foam characteristics that a stable froth which overflowed the flotation column could not be produced, so the addition of sodium dodecyl sulfate (SDS) as a froth promoter was used to improve the foam stability. Unlike the batch froth flotation system with only C_14–15(PO)₅SO₄Na, the continuous froth flotation with the mixture of C_14–15(PO)₅SO₄Na and SDS, it was not possible to find a SDS and a NaCl concentration at which both ultralow IFT and good foaming were both achieved. Foam formation, stability, and production rate were found to be crucial parameters to the froth flotation efficiency. The continuous froth flotation system offers a high diesel oil removal of 96% in the single stage unit. Demonstration of efficient operation in the continuous mode in this work is important to the practical application of froth flotation in large scale processing.     

Diesel Oil Removal by Froth Flotation Under Low Interfacial Tension Conditions I: Foam Characteristics,and Equilibration Time

Abstract

Froth flotation is a surfactant‐based separation process which is suitable for treating dilute wastewaters. To achieve high performance for the froth flotation operation, the combination of an ultra‐low interfacial tension (IFT) between excess oil and excess water phases, high foam production rates, and high stability of the foam produced, must be attained. To obtain the ultra‐low interfacial tensions, a Winsor Type III or middle phase microemulsion has to be formed. In this study, branched alcohol propoxylate sulfate sodium salt with 14–15 carbon number and 4 PO groups (Alfoterra 145–4PO) was used to form microemulsions with diesel oil. From the results of this work, an increase in surfactant concentration decreased the IFT, and increased foam stability. To obtain the minimum IFT in the region of a Winsor Type III microemulsion, the addition of 5 wt.% NaCl was needed. However, this optimum salinity does not result in effective froth flotation due to poor foam characteristics. The results indicate that both the IFT and the foam characteristics should be optimized to achieve high efficiency of oil removal in a froth flotation operation. Unlike the previously‐studied ethylbenzene system, agitation of the solution before introduction into the flotation column yielded the lowest diesel oil removal efficiency because of the poor foam characteristics compared to either unagitated systems or systems allowed to equilibrate for one month.     

Froth stability and entrainment evaluation of a novel frother for KCl/NaCl flotation

The rate of KCl recovery by froth flotation using low-grade carnallite is 70%–85%. Herein, a novel frother, dipropylene glycol butyl ether (DPNB), was prepared to increase the flotation efficiency of KCl recovery systems. DPNB could be applied at only half the dosage of the conventional frother methyl isobutyl carbinol (MIBC) and achieve a KCl recovery rate of 94.8%–98.6% with a high KCl grade (63.2%–66.5%). To date, these results are the best reported for pneumatic flotation. DPNB had a 10% higher maximum dynamic stability factor compared with MIBC; moreover, the apparent entrainment velocity of DPNB was half that of MIBC. The molecular structure of DPNB had hydroxyl and ether groups, which promoted interactions with water, thereby contributing to its excellent froth stability. DPNB is environment friendly owing to its low volatility and, thus, a promising frother for the green and highly efficient flotation of KCl/NaCl.     

Improvement of the Flotation Selectivity in a Mechanical Flotation Cell by Ultrasound

In this study, the effect of ultrasound on froth and pulp phases has been investigated in the flotation of two different ore samples, namely barite and chalcopyrite. In order to determine the overall flotation rate constants at various froth depths, incremental recoveries obtained from the flotation tests with and without ultrasound were fitted to a first-order rate equation. Thus, the recoveries of froth and pulp phases were calculated.

The use of ultrasound speeded up the bubble coalescence and therefore reduced the froth phase recovery in the ultrasonic flotation of both barite and chalcopyrite. In addition, the results indicate that there is a considerable effect of ultrasound on the pulp phase recovery in the chalcopyrite flotation whereas no significant differences in the separation performance were obtained from the ultrasonic flotation of barite with and without ultrasound. The results also indicate that a pronounced selectivity effect was obtained from the ultrasonic flotation of both barite and chalcopyrite. The use of ultrasound in the froth remarkably improves the quality of the chalcopyrite concentrate, especially at the shallow froths. Therefore, either effective pulp volume can be increased without sacrificing the separation selectivity or the pulp density can be decreased to obtain better product quality at shallow froths in the ultrasonic flotation of chalcopyrite.     

Froth flotation as primary treatment of flowback water: Removal of total organic carbon and prediction of kinetics

Petroleum and exploration industries employ a hydrofracking process where a large volume of water (fracturing fluid) is injected and a fraction (known as flowback water) is returned to the surface. Froth flotation is a typical process employed for the primary treatment of water. In the present work, froth flotation has been used as a pretreatment method for real flowback water sourced from the petroleum and shale gas exploration industry. In the present work, a first-principle based convective mass transfer model has been developed to describe the froth flotation performance. The resultant equation was solved analytically and compared with the numerical solution, and a parametric sensitivity analysis of the process performance was also undertaken. In addition, a correlation to estimate the flotation rate constant was proposed, thereby circumventing the need to obtain a large number of cumbersome parameters experimentally. Overall, this study proposes froth flotation as an efficient primary treatment method towards the separation of dispersed oil droplets from the flowback water and the corresponding prediction of kinetics using a first-principle based transport model.     

沉钒液泡沫的消除

针对酸性铵盐沉钒工艺沉淀酸性铵盐过程中沉钒液内涌起泡沫影响正常操作等问题,考察了钒渣碱比、浸出液pH值、表面张力和沉钒上层液等影响因素,并提出了相应的改进措施.     

浮选技术在煤泥分选中的应用

文章介绍了煤泥浮选技术的原理,概述了浮选药剂和浮选设备的类型和性能,分析了煤泥浮选的工艺条件,并介绍了几种煤泥浮选技术的应用。最后,从浮选药剂的研发、浮选设备的改造、浮选工艺的改进以及浮选技术的创新等方面,对煤泥浮选技术的发展和应用提出了展望。     

Picobubble Enhanced Fine Coal Flotation

Abstract

Froth flotation is widely used in the coal industry to clean ?28 mesh fine coal. A successful recovery of particles by flotation depends on efficient particle‐bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range beyond which the flotation efficiency drops drastically. It is now known that the low flotation recovery of particles in the finest size fractions is mainly due to a low probability of bubble‐particle collision while the main reason for poor coarse particle flotation recovery is the high probability of detachment. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles in a wide range of size by increasing the probability of collision and attachment and reducing the probability of detachment.

A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. They are characterized by a size distribution that is mostly below 1 µm and adhere preferentially to the hydrophobic surfaces. The presence of picobubbles increases the probability of collision and attachment and decreases the probability of detachment, thus enhancing flotation recovery. Experimental results with the Coalberg seam coal in West Virginia, U.S.A. have shown that the use of picobubbles in a 2″ column flotation increased fine coal recovery by 10–30%, depending on the feed rate, collector dosage, and other flotation conditions. Picobubbles also acted as a secondary collector and reduced the collector dosage by one third to one half.