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1.
The effects of dodecylamine (DDA), kerosene and pH on the recovery of combustible matter and ash content of a lignitic coal from Tuncbilek, Turkey have been studied using a three-variable and two-level (23) factorial experimental design. The coal sample responded favourably to batch flotation with high recoveries in excess of 95% using both kerosene and DDA respectively. The main effects of all three factors on the recovery are positive. Significance of DDA as a collector, is somewhat greater than that of kerosene, but its selectivity for ash reduction is not significant at the 95% confidence level. The pH-dependence of recovery by these collectors is opposite to each other. The DDA-induced flotation recovery is lowest at pH 9.4, an effect which has been related to precipitation of cationic species of this collector. The kerosene-induced recovery and grade of combustible matter increases with pH and this has been attributed to a better dispersion of coal and its associated clays. The two-way interaction effects are all negative at a smaller level. The main and interaction effects have been discussed on the basis of adsorption at most favourable surface sites, different modes of orientation of DDA species, competition with kerosene, and probable collecting properties of the frother used. The simultaneous effects of the two collectors on the recovery of combustible matter have been discussed at each pH value used.  相似文献   

2.
The frothers of alcohol family (MIBC and Alpha-terpineol) were compared with polyglycol ethers (DF-1012) in terms of two phase characterization parameters like foamability, foam stability, surface activity and bubble size distribution. In this research, fundamental two phase frother characterization parameters were linked with three phase coal flotation behavior.  相似文献   

3.
Laboratory batch flotation tests were carried out to determine the effect of grain size on the recovery of four Australian bituminous coals of high and low rank. The flotation concentrates, taken over successive time intervals, and the tailings, were sized and the recovery-size curves plotted. A method was developed for determining the proportions of liberated and composite grains in the various flotation products. Flotation tests were carried out in the presence of methylisobutylcarbinol (MIBC) and MIBC + kerosene. The shapes of the recovery-size curves depended on the rank of the coal and whether or not kerosene was present. The variation of the recovery with size was explained in terms of the joint effect of rank and size on the floatability of composite grains.  相似文献   

4.
微细粒低品位锰矿由于颗粒间的非选择性聚集、浮选药剂用量大、浮选效率低等技术难题而致使其利用困难,造成大量浪费。在品位低于13%的锰矿浮选技术研究中,捕收剂最受关注,前人已研究了多种类型的捕收剂,所得精矿品位在16.9%~18.3%之间,回收率为56%~97%,回收率比较理想,但精矿品位总体不高。本文将新型捕收剂RA-92应用于湖南凤凰-花垣地区低品位碳酸锰矿(锰品位为10.7%)的选矿工艺中,实验研究了磨矿细度、pH值、抑制剂和捕收剂用量对浮选效果的影响,在最佳工艺条件下,精矿品位由原矿的10.7%提升至17.4%,回收率达到80.2%。研究表明RA-92对碳酸锰矿具有良好的捕收性能,浮选工艺相对简单且捕收剂用量少,浮选成本较低,可为此种捕获剂在微细粒低品位碳酸盐锰矿选矿中的应用得到推广。  相似文献   

5.
The Influence of pulp pH, dispersants and auxiliary collectors on reverse flotation of carbonate-containing iron ores were explored. Interactions between iron ores and quartz were theoretically analyzed by flotation solution chemistry and DLVO theory. The results indicated that the iron concentrate grade improved sharply when pH increased from 11.0 to 12.0, but changed unobviously when pH was larger than 12.0, which was related to solution chemistry of siderite and interactions among particles. Sodium tripolyphosphate was an effective dispersant and sodium dodecyl sulfate was an effective auxiliary collector of KS-III. Both recovery and grade enhanced by the action of sodium dodecyl sulfate or sodium tripolyphosphate when pH was 12.0.  相似文献   

6.
Fine hydrophilic particles are known to be entrained with water in flotation of many ores. Flocculation of the hydrophilic particles by polymer depressants could potentially reduce the mechanical entrainment of these particles. This paper reports testwork completed on fine particles of several solids, iron oxide, hydroxyapatite and sphalerite, as well as on a relatively coarse quartz sample (− 75 + 38 μm). Dodecylamine was used as a collector for quartz, and several dispersants and polymer depressants, including sodium silicate, sodium metaphosphate, zinc sulfate, cornstarch, corn dextrin and carboxymethyl celluloses (with molecular weights of both 700,000 and 80,000) were used as flotation modifiers. The major part of the testwork involved flotation tests in a 200 mL flotation column. It was observed that flocculation of the fine hydrophilic particles significantly reduced their mechanical entrainment, while dispersion severely aggravated it. Thus, in the flotation separation of synthetic mixtures of the − 75 + 38 μm quartz and fine (reagent grade) iron oxide or hydroxyapatite, polymer depressants that caused flocculation performed better than those that did not cause flocculation.  相似文献   

7.
Flotation tests of synthetic mixtures of celestite (SrSO4) and calcite (CaCO3) minerals using sodium dodecyl sulfonate as collector were carried out using a factorial experimental design 23. The independent experimental variables included celestite grade in the feed (50% and 90% SrSO4), conditioning pH (6.5 and 9) and sodium silicate depressant concentration (10−5 and 10−3 M). All experiments were performed at a constant collector concentration (10−4 M) and conditioning time of 15 min. The response variables were recovery and grade of SrSO4 in the concentrate.The factors that had the greatest effect on the grade and recovery of celestite were the celestite grade in the feed (L) and the depressant concentration (C); also the combination of these factors significantly affected the response variables. The highest celestite yield (96% recovery, 98% grade) was obtained when a 90% of celestite grade in the feed was used.  相似文献   

8.
Coal flotation studies were carried out in ultrasonically assisted flotation cells. Representative hard coal slime samples from Prosper-Haniel Coal Preparation Plant located in Bottrop, Ruhr Region of Germany were used for this purpose. A Wemco type flotation cell was fitted with transducers and tests were carried out at variable frequency and power. The reagent for coal flotation was Ekofol-440 with variable dosages during conventional and ultrasonic flotation experiments. The results showed that ultrasonic coal flotation yields more combustible recovery and lower ash values in concentrates than conventional flotation by using similar reagent dosages. These results are explained on the basis of efficient surface cleaning of the coal particles.  相似文献   

9.
The effect of humic material on the flotation response of coal has been examined. The results show that while hydrogen ions do not adversely affect the flotation of coal particles, they interact with humic material adsorbed on the surface of the clay particles and render their surfaces oleophilic. This behaviour enables the clay particles to adsorb collector in preference to the coal particles and thus inhibit coal flotation.  相似文献   

10.
In this study, a new flotation approach, a low-alkaline and non-desliming process, was introduced for improving lead and zinc recoveries, lowering production cost and reducing environmental pollution. Lab-scale experiments results show that the new process contributed to the flotation of the complex mixed sulfide-oxide lead and zinc ore regarding two aspects: (1) High alkaline process (pH = 12±) was replaced by low alkaline process (pH = 9±) by using collector WS (a mixture of ethyl thiocarbamate, ammonium dibutyldithiophosphate and dithiophosphate-25) and combined depressant Na2S/ZnSO4/Na2SO3 for lead sulfide flotation; (2) Non-desliming process was successfully achieved by using collector MA (a mixture of ether amine, hydroxyethyl cellulose and polyacrylic acid) and combined depressant SHP/SS (sodium hexametaphosphate/sodium silicate) for zinc oxide flotation. And 43.37% Pb in the Pb concentrate was recovered, the corresponding Pb grade was 52.73%, total 84.42% Zn was recovered by the flotation of zinc sulfide minerals and zinc oxide minerals. Moreover, the two aspects of the new approach were systematically verified from lab-scale to industrial-scale application. The industrial-scale flotation tests show that Pb recovery in Pb concentrate increased by 1.86% compared with that of original system during industrial-scale tests period, and the Pb recovery increased by 4.09% compared with that of original system before industrial-scale tests period, while the Zn operating recovery in zinc oxide concentrate improved by 19.52%. Moreover, the total reagent cost of the whole new process significantly declined by 3.93 yuan per ton of ore.  相似文献   

11.
The effects of Na2SiO3, Na3PO4, Na4P2O7, (NaPO3)6, quebracho, tannic acid and S 808 (sulphonated product of rough phenantrene) on the floatability of the following five pure minerals: scheelite, calcite, fluorite, garnet and quartz, with sodium oleate as collector were investigated in detail as well as the role of pH on these effects. The results obtained indicate that Na4P2O7 and (NaPO3)6 were effective modifiers for the selective flotation of scheelite. The results of the batch flotation tests on mixtures of these minerals showed that the recovery of scheelite from scheelite-silicate mixtures (31% WO3) with (NaPO3)6 or Na4P2O7 increased by 20% as compared with sodium silicate and the WO3 grade of the concentrate by 5%. At room temperature, the scheelite-calcium mineral mixtures could not be separated with sodium silicate. In the separation of these mixtures with the phosphate modifiers, a concentrate grade of 47–60% WO3 was obtained at 70–90% recovery. This showed that the flowsheet of the selective flotation of scheelite with phosphate modifiers may replace the conventional Petrov's process.  相似文献   

12.
Bubble size distributions and flotation rates were determined as a function of air flow rate and frother concentration using a specially designed batch flotation cell. This cell permitted the unambiguous determination of the flotation rate from the slurry to the froth.Flotation rate constants were determined for different size classes of silica and galena. The flotation rate constants increased to a maximum and then decreased as air flow rate was increased. This maximum was predicted by a model which considered the effect of bubble size on both the total bubble surface area and the bubble-particle collision efficiency. This work shows that collision efficiency effects, shown to exist in single-bubble/single-particle systems, are also present in flotation systems where many bubbles and particles interact.A second model for hindered flotation is proposed which assumes that the particle-capturing bubble surface differs from the particle-retaining surface. This model predicts a sharp transition from hindered to free flotation. Experimental results are presented which agree well with those derived from the model.  相似文献   

13.
Long-chain amines, used in potash ore flotation as collectors, are insoluble in NaCl–KCl saturated brine. In commercial applications, these amines are melted at 70–90 °C, dispersed in acidic solution of hydrochloric or acetic acids, and such emulsions are then introduced to the flotation pulp.To model the commercial potash ore flotation process, dodecyl amine, used in this study, was melted at 70 °C, dispersed in hydrochloric acid aqueous solution and was added to a KCl–NaCl saturated brine at room temperature. This results in the precipitation of the amine. The present study summarizes the influence of the conditions on the particle size and morphology of the precipitating amine particles. Methyl isobutyl carbinol (MIBC), common frother in flotation processes, was shown to affect amine dispersion when added into a hot amine emulsion prior to mixing with a saturated brine. This study demonstrates that the precipitating amine particles are selectively abstracted by KCl particles, but not by NaCl particles.  相似文献   

14.
A number of flotation circuits for the recovery of a poorly floating coal were investigated by laboratory batch testing. Analysis of the size and ash distributions of the products and tailings showed that the circuits which would allow an equitable distribution of collector between the coarse and fine size fractions were superior. These circuits were two-stage reagent addition, reflotation of classified tailings and split feed flotation. The reflotation of classified tailings circuit not only gave the best metallurgical performance, it also was the least affected by pulp density variations and imperfect size classification.  相似文献   

15.
本文以油酸钠作为捕收剂,研究了磷酸氢二钠、柠檬酸和硅酸钠等抑制剂对粉石英与红柱石浮选分离效果的影响.结果表明,磷酸氢二钠是红柱石与粉石英浮选分离的一种优良的抑制剂;在其最佳浓度0.47×10-2 mol /L,浮选液pH值为8.5时,粉石英与红柱石浮选回收率差高达47.86％.红外光谱及Zeta电位分析结果表明,油酸钠对红柱石兼有物理和化学吸附作用,对粉石英仅有物理吸附作用,因而对红柱石有更强的捕收能力;磷酸氢二钠对粉石英表面起解吸作用,能有效抑制粉石英起浮,从而实现粉石英与红柱石的分离.  相似文献   

16.
Potato starch and dextrins resulting from thermolysis of potato starch in the absence of reagents and presence of -amino acids are promising depressants for separation of lead and copper minerals present in the Polish industrial copper concentrates. The polysaccharides were used for differential xanthate flotation of the final industrial concentrates produced by flotation with sulfhydryl collectors in the absence of depressants. The polysaccharides depressed galena and provided froth concentrate rich in chalcocite and other copper minerals as well as cell product containing lead minerals. The best results of separation were obtained in the presence of plain dextrin prepared by a thermal degradation of potato starch. The industrial concentrate containing 18.5% Cu and 5.5% Pb was divided into a froth product containing 38.1% Cu with 77% recovery of copper and a cell product assaying 7.3% Pb with 83% recovery of lead. It was accomplished using 2500 g/t of dextrin, 50g/t of potassium ethyl xanthate, and 50 g/t of frother (α-terpineol). The pH of flotation was 8.0–8.2.  相似文献   

17.
Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by mico-flotation tests. The two kinds of quaternary ammonium salts [RN(CH3)3] with different chain lengths, dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075–0.01 mm, 0.045–0.075 mm, 0–0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH when DTAC and CTAC are used as collectors. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075–0.01 mm and 0.045–0.075 mm) are. But the flotation recovery of the finest kaolinite (0–0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unsifted kaolinite (0–0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0–0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the particle size of kaolinite is coarser, the flotation recovery is higher. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (001), (010) and (110) surfaces. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite particles size become, the greater relative surface area of edges is, and the more the number of edges is. It means that fine kaolinite particles have more edges to adsorb less cationic colletors than that of coarse kaolinite particles, which is responsible for the poorer floatability of fine kaolinite.  相似文献   

18.
Single bubble velocity profile (velocity vs. distance) has been measured for a 1.45 mm diameter bubble to try to explain reported differences in gas holdup in two systems: F150 vs. 1-pentanol, and MIBC vs. NaCl. It was found that in F150 the bubble slowed rapidly to reach the terminal velocity stage of the profile while in 1-pentanol the bubble remained in the deceleration stage and was consequently moving faster, at almost twice the speed. The lower rise velocity in F150 means longer bubble residence time and corresponding higher gas holdup than with 1-pentanol, as reported. In the second system, the bubble in MIBC reached terminal velocity more rapidly than in NaCl which agrees with the reported higher gas holdup in MIBC compared to NaCl. An implication for gas holdup evaluation is that the value may depend on the part of the velocity profile over which it is measured. Possible exploitation of this reagent effect on bubble rise velocity in flotation is considered.  相似文献   

19.
针对青海省某金矿采用常规的氰化浸出效果不佳（金浸出率仅为8.19%）和含较高的砷、硫的情况和特点,进行了可选性试验研究。摇床重选虽然可获得品位较高的金精矿,但其回收率太低。浮选试验表明,采用一粗三精三扫的浮选闭路流程,可获得品位为72.72g/t,回收率为88.74%的浮选金精矿,选别指标较为理想。确定的最佳操作条件为...  相似文献   

20.
The effect of operating parameters on the hydrodynamics of three geometrically similar Rushton turbine flotation cells with volumes of 2.25, 10 and 50 dm3 was determined. The operating parameters investigated were superficial gas velocity (Jg), impeller rotational speed (N), and frother (methyl isobutyl carbinol, MIBC) concentration.  相似文献   

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