Oil recovery from oil in water emulsions using a flotation column

A flotation column was used to recover oil from oil in water emulsions. The feed oil concentrations investigated were relatively high, in the range of 0.25 to 8 percent by volume. Previous studies using conventional flotation cells dealt with very dilute systems where the oil concentration was less than 0.1 percent by volume. The oil recovery was found to decrease with an increase in the feed oil concentration. The addition of wash water to the froth zone of the column had little effect on the oil recovery. The oil recovery decreased with increasing feed flow rate and surfactant concentration. The effect of increasing the gas flow rate was to initially increase the oil recovery. The oil recovery data were analyzed using a kinetic model. The order of the flotation kinetics was found to be 0.6. The gas hold-up behaviour of the recovery and the froth zones of the flotation column is found to correlate well with the drift-flux model.     

A flotation study of refuse pond coal slurry

The flotation behavior of a refuse pond fine coal slurry sample was studied using mechanical and column flotation techniques. Flotation parameters investigated included type and dosage of frother and collector, agitation speed, scrubbing time, slurry pH, etc. for the mechanical flotation cell, and air flow rate, feed flow rate, and wash water flow rate for the column flotation. Flotation kinetics was also studied in the mechanical flotation cell. The results showed that the coal sample was very difficult to clean by flotation. Low yield (5–15%) and low combustible recovery (6–23%) and high product ash (about 22%) were obtained when methyl-isobutyl-carbinol (MIBC) was used as frother and #2 fuel oil as collector. Adjustment of operating parameters such as agitation intensity showed limited effects. However, flotation yield was significantly improved when MIBC and #2 fuel oil were replaced with frother P948 and collector SPP. Mechanical scrubbing was unable to restore the floatability of the coal sample. ‘Ken-Flote’ column flotation was inferior to mechanical flotation for oxidized coal and possible reasons were given.     

FCMC-3000型旋流微泡浮选柱的应用分析

介绍了浮选柱的结构、特点及其工业应用的效果。分析了浮选柱利用微泡浮选、逆流浮选及旋流离心力场强化分选的机理。分析了入料、操作及环境因素对浮选柱分选系统的影响。工业应用表明,FCMC-3000型旋流微泡浮选柱能在保证精煤质量条件下,提高精煤回收率。     

浮选柱在淮北选煤厂涡北分厂的适用性分析

淮北选煤厂涡北分厂浮选系统存在煤泥量大、设备腐蚀和磨损严重、处理能力不足等问题,通过分析浮选柱在细粒、高灰煤泥分选方面的适用性,提出采用FCMC-4000型微泡浮选柱代替传统的机械搅拌式浮选机的方案,改造后将提高浮选精煤产率,降低电耗。     

应用射流浮选柱分选微细煤泥的试验研究

介绍了细粒煤分选技术的发展现状和射流浮选柱具有的浮选速度快、分选精度高、综合性能显著优于传统机械搅拌式浮选机的特点。试验表明 ,在精煤灰分相近的情况下 ,射流浮选柱浮选微细煤泥的精煤产率明显高于机械搅拌式浮选机 ;在精煤产率相近的情况下 ,前者的精煤灰分比后者的低 2 0 %～ 3 0 %。     

Flow characterization of a flotation column

The flow characteristics of a froth flotation column have been experimentally studied using air and aqueous surfactant solutions without the presence of solids. The hold-up behaviours of the bubbly and the froth zones of the column were linked together using the drift-flux model. The ratio of the gas drift-flux, j_gf, to the bubble terminal velocity, V, for both the bubbly and the froth zones was found to be well correlated by the Richardson–Zaki equation:      

Identification of clay minerals in coal and wastes from main coal washery, Zonguldak, Turkey

Identification of clay minerals present in coal and washery wastes is important in cleaning fine coal by froth flotation and in flocculation and dewatering. Therefore samples of wastes from jigs and the flotation cell at the Zonguldak main coal washery were collected and analyzed petrographically for their mineral matter content and by X-ray diffraction for their clay content. The “loss on ignition” method was carried out to determine their organic carbon and carbonates. The waste samples contain 48–68% clay minerals in addition to silicates, carbonates, sulfides and coal. Three clay minerals were identified, namely illite, kaolinite and chlorite. Illite seemed to be the dominant clay mineral in washery wastes. Loss on ignition indicated high percentages of organic matter in the fine jig tailings (21%) and flotation tailings (33%). 3%–6.5% of carbonates have also been found.     

Cell and surfactant separation by column flotation

The separation of rehydrated Saccharomyces cerevisiae and an alkyl polyglycoside surfactant by column flotation was studied as a function of wash water flow and cation concentration. Separation of cells and surfactant was measured under steady-state conditions. Surfactant recovery in the foam concentrate was in the range of 86–95%. Yeast cells were enriched in the foam concentration by a factor of up to 11, but the recovery only reached 55%. The use of wash water was very effective for removing the cells from the foam, giving a good separation between the cells and the surfactant. Addition of chloride salts of Na, K, Ca, and Mg at concentrations in the range of 0.05-0.1 mol/L increased both the enrichment and the recovery of yeast in the foam. The most effective salt levels for cell flotation, less than 0.1 mol/L, were in the same range of concentration as the minimum electrophoretic mobility of the cells.     

预浮选式浮选柱分选细粒粉煤的实验研究

分析了传统旋流微泡浮选柱的应用现状,阐述了浮选入料性质及条件特别是入料浓度对浮选柱分选效果的影响,提出了采用预浮选式旋流微泡浮选柱分选解决高浓度细粒煤浮选的新方法,并通过试验论证了该方法的可行性,对工业现场的浮选作业具有一定的指导意义。     

Comparative study of the performance of conventional and column flotation when treating coking coal fines

Investigations were carried out on coking coal fines by conventional cell and column flotation techniques. The effects of different operating parameters were evaluated for both conventional and column flotation. The coal fines were collected from Bhojudih washery, India. These coal fines averaged 24.4% ash, 19.8% volatile matter and 53.8% fixed carbon on a dry basis. A commercial grade sodium silicate, light diesel oil and pine oil were used as depressant, collector and frother respectively. The flotation performance was compared with release analysis. The conventional flotation results indicated that a clean coal with 14.4% ash could be obtained at 78.0% yield with 88.4% combustible recovery. The ash of the clean coal could be further reduced to 10.1% at 72.0% yield with 85.6% combustible recovery by using column flotation. The column flotation results were close to those obtained by release analysis.     

充填静态浮选柱在胶磷矿浮选中的应用

考察了在充填式静态浮选柱中浮选低品位胶磷矿时,药剂用量、洗涤水加入位置及用量及各种操作因素对浮选结果的影响,得到了合适的浮选条件,为工业放大提供了依据。     

泉店选煤厂浮选系统改造

通过分析泉店选煤厂原浮选系统工艺流程,提出了选煤厂主要存在浮选尾煤灰分低,浮选药耗高,浮选系统处理能力偏低,浮选床效率低,浮选精矿池泡沫量大等问题。针对选煤厂存在的问题,提出2种改造方案,并最终确定采用新建浮选车间并安装2台浮选机替换原有浮选床的改造方案。改造完成后,泉店选煤厂浮选尾煤灰分、精煤产率和可燃体回收率分别提高了55.61%,43.86%和44.51%,精煤灰分降低了0.29%,药剂用量减少了0.22 kg/t;浮选精矿池泡沫量明显降低,加压过滤机上料情况明显好转,处理量增大,且减少了1台空压机的使用;选煤厂每年增加精煤收益,节省电费和药剂费用总计12770.74万元。     

FCMC型旋流微泡浮选柱在新疆的应用前景

介绍了新疆的煤炭工业现状，阐述了FCMC型旋流微泡浮选柱的工作原理、结构和应用优势，进行了浮选柱与传统浮选机的性能对比，论述了微泡浮选柱在新疆煤炭洗选工业的应用前景。     

分级浓缩浮选工艺探讨

针对选煤厂目前使用的浮选工艺分选精度低、高灰细泥污染严重的问题,提出了分级浓缩浮选工艺;采用分级旋流器组将煤泥分级,粗颗粒用浮选机分选,细颗粒经浓缩后用浮选柱浮选;提高了煤泥的浮选精度和精煤产率,增加了企业经济效益。     

Characterization and column flotation of bottom ashes from Tuncbilek power plant

Bottom ashes from the Tuncbilek power plant have been characterized by size fraction, X-ray diffraction and X-ray Fluorescence. These samples are potentially of class F type and have significant amounts of unburned coal. The unburned coal specimens studied using Fourier Transform Infrared Spectroscopy indicated a significant loss of the aliphatic hydrocarbon groups (C-H) and the carbon bond CC during their stay in the combustion environment. In contrast, they indicated insignificant levels of carbonyl group, CO, possibly due to the loss of CO₂ to air as well as carboxylic ions to disposal water. The effects of various operating variables on the combustible recovery and ash content determined using column flotation were limited due to severely oxidized state of unburned coal. Best set of results was obtained with the bottom ash sample from unit 3, which brought the ash content from 77.6% down to 42.6% at a combustible recovery of 53.8%, and the calorific value was increased from 1270 kcal/kg to 3840 kcal/kg.     

The effect of different flotation operating parameters on the froth properties and their relation to clean coal ash content

Froth properties and their relation to the concentrate grade play an important role in monitoring flotation running conditions and predicting flotation concentrate quality. In this paper, the correlation between the froth properties and clean coal ash content was investigated under complicated conditions where the frother dosage, gas velocity, and froth height were changed together. For the froth properties under study, their degree of correlation with clean coal ash content decreased in the order of homogeneity, water recovery, gray value, and froth velocity. The coefficient of determination (R²) of the fitting relationship between homogeneity and clean coal ash content was as high as 0.9028, because homogeneity has a close correlation with the foam structure and foam destabilization behaviors.     

华恒矿精煤浮选方案设计与实践

华恒矿业公司选煤厂为充分回收煤炭资源,优化选煤工艺,增设了煤泥浮选工艺系统,并根据粒度分析及分步释放浮选试验,确定采用旋流微泡浮选柱进行二次浮选;同时通过有效的改造措施解决了浮选系统运行初期出现的问题,选煤厂精煤产率提高,获得了较好的经济效益。     

Bubble size distribution in a flotation column

The bubbles that were generated in a flotation column were measured. The bubble size distributions were obtained both for air-water and air-water-coal systems. The size distribution pattern was fitted to different equations. It was found that the bubble size distribution in both the flotation and cleaning zones follows the Rosin-Rommler equation used to describe the particle size distribution in crushing. This study indicates that bubbles in the cleaning zone are always larger than those of the flotation zone and finer bubbles are generated when a mixture of frothers is used instead of individual frothers.     

Performance,mixing and kinetics study in the flotation column reactor using coal

ABSTRACT

A flotation column has been designed and characterized with respect to gas velocity, slurry velocity, frother concentration, gas holdup, bubble surface area flux for the study of the mixing property, liquid phase residence time distribution, flotation recovery and rate constant. The study was performed using coal as solid. A strategy of integrating chemical kinetics into the flotation process to test the floatability behaviour of coal and to estimate floatability parameter of coal has been developed. The results indicate that the coal floatability parameter is 3.05 × 10^?4. A relationship between gas holdup and bubble surface area flux was developed.