Interfacial Behavior of Anionic/Cationic Flotation Collectors in Mixed Aqueous Solutions and Their Effect on Flotation Recovery of Quartz

In this study, the effects of anionic/cationic collector mixtures on surface tension (γ) were investigated as a function of pH using the pendant drop method. For the tests, long-chain tallow amine and petroleum sulfonate, which are the most common anionic and cationic flotation collectors, were used individually and as binary mixtures with different mixing ratios. The results show that pH of the solution had crucial effects on surface tension values of the amine whose species distribution varied with pH but not on petroleum sulfonate that is found in the ionized form over the entire pH range. In the case of binary anionic/cationic collector mixtures, the minimum surface tension values were obtained under highly acidic pH conditions with a mixing ratio of 1:3, while the collector mixtures with 3:1 and 1:1 mixing ratios displayed similar surface tension values at all pH values. For all binary-collector mixtures with different mixing ratios, the surface tension values were found to be higher than those of single-collector solutions with equal collector concentrations. In the case of microflotation tests, the flotation recoveries of quartz in the presence of the binary anionic/cationic collector mixtures dropped more than 25% when compared with the results in the presence of single-collector solutions having equal collector concentrations.     

Separation off Silica from Spent Geothermal Fluids by Adsorptive Bubble Techniques

Abstract

A method is described for the separation of amorphous silica from supersaturated high ionic strength geothermal fluids produced by the Hawaii Geothermal Project Well-A. A bench-scale technique which makes use of adsorptive bubble flotation is employed to remove silica after flocculation by the addition of polyvalent metal ions to hot (60–90°C) spent brine discharge. Ferric and aluminum salts are evaluated as flocculants under varying conditions. The anionic surfactant sodium lauryl sulfate and the cationic surfactant lauryl amine hydrochloride (LA) are utilized as the collectors below and above the isoelectric point, respectively. Efficiency of removal of the silica is pH, metal concentration, and surfactant-type dependent. Best results are achieved under slightly alkaline conditions (pH=8), using 3.75 × 10E^?4 M ferric ion present as its sulfate, LA as the collector, and with a gas flow of 15 ± 3 mL/min. Under these conditions, approximately 70 ± 2% of the total silica is separated from the brine discharge; this value, although not quantitative, represents more than 85% removal of the silica present above its amorphous solubility at the operating temperature. After the separation process, fluids contain residual concentrations of silica which are not expected to result in scale deposition and which can then be passed through heat exchangers to extract further energy for secondary uses.     

磷矿浮选药剂对尾矿澄清性能的影响

采用一种简易方法考察了常用磷矿浮选药剂对浮选尾矿澄清性能的影响.结果表明:该试验方法误差较小,可以用于评价浮选药剂对浮选尾矿澄清性能的影响.在海口磷矿浮选药剂中,调整剂水玻璃对浮选尾矿澄清性能影响最大,其次为MW.捕收剂用量对浮选尾矿澄清性能影响较小,但捕收剂的种类则对浮选尾矿的澄清性能影响较大.使用工业捕收剂H969浮选的尾矿澄清性能要远低于使用工业油酸时尾矿的澄清性能.增效剂的使用可提高浮选尾矿的澄清性能.     

Flotation of rutile with anionic and cationic collectors

Results are presented which indicate the effect of pH and flotation-collector type upon the flotation rates of natural rutile particles. Above pH ～2.5, flotation rate decreases with increasing pH for anionic collectors and increases with increasing pH for a cationic collector. These results are in agreement with expectations from the known electrokinetic properties of the mineral. Also, for a fixed pH, the rate of flotation is influenced by the length of the carbon chain associated with the collecting ion, and, for any one collector, by its concentration in solution. Below pH ～2.5, the flotation rate with anionic collectors decreases with fall in pH, whereas with the cationic type a small increase in rate is shown as pH1 is approached.     

广东肇庆某尾矿中赤/褐铁矿反浮选技术研究

广东肇庆某尾矿含铁38.97%,主要赋存于赤铁矿和褐铁矿中.为有效富集回收尾矿中的铁矿物,采用反浮选工艺为原则流程,以自主研发的阳离子捕收剂YA作脉石矿物捕收剂、NaOH作pH值调整剂、改性淀粉作铁矿物抑制剂,经过一粗一精三扫的闭路试验流程,获得了含铁55.47%、铁回收率81.32%的铁精矿.尾矿中铁矿物得到了较好的富集回收.     

Evaluation of a Turkish low quality oil shale by flotation as a clean energy source: Material characterization and determination of flotation behavior

Evaluation possibility of a low quality Turkish oil shale from Beypazarı, Ankara as an alternative clean solid fuel by froth flotation technique was investigated. Oil shale sample was characterized with mineralogical analysis, XRD and FTIR spectrum studies for its mineral content and surface characteristics. The flotation behavior of the sample and extent of cleaning were determined with respect to non-ionizing and ionizing collectors of anionic and cationic types. The effects of collector dosages and pulp pH on the cleaning performance were investigated. XRD analysis showed that the majority of the inorganic matter was constituted by carbonates, montmorillonite, quartz and feldspar while the sample was poor in organic content. In the FTIR spectrum, strong adsorption bands due to oxygen rich carboxyl groups were observed while the characteristic bands of organic groups were in weak forms. The sample was characterized as a fulvic material with low organic content. Ash content and combustible recovery results showed that cleaning of Beypazarı oil shale was a difficult process on accounts of the high inorganic content and fulvic character of the sample. The most effective cleaning was obtained with amine type collectors. With amines, ash could be reduced from 69.88% to 53.10% with 58.64% combustible recovery using 800 g/ton Armoflote 17 at natural pulp pH.     

Flotation of metal hydroxide precipitates. I. Flotation of copper hydroxide

Flotation of copper hydroxide precipitate has been investigated at total initial copper concentration 10^?2M with sodium dodecylbenzenesulphonate (DBSNa) and dodecyldimethylbenzylammonium bromide (DDMBABr), both at initial concentration 10^?4M. In particular, granulometric analysis of the precipitate and measurement of its electrokinetic potential were carried out over a wide range of the acidity of aqueous precipitate suspension in order to establish essential factors governing flotation of the precipitate. Moreover, adsorption of the flotation collectors by the precipitate as well as the rate of precipitate sedimentation were measured. The cationic collector (DDMBABr) neither influenced the electrokinetic potential of copper hydroxide precipitate nor adsorbed on its surface. Consequently, no flotation of copper hydroxide was observed with (DDMBABr). On the other hand, the anionic collector (DBSNa) influenced the electrokinetic potential of copper hydroxide within the same pH range where adsorption of DBSNa on the precipitate was observed and flotation was effective. The rate of flotation varied with the pH of the aqueous suspension. This dependence was irregular and presumably governed by the aggregation of precipitate grains since the rate of flotation increased with the size of the aggregates.     

Effect of calcium ions on scheelite flotation using mixed collectors

The flotation results show that Ca²⁺ significantly reduces the flotation recovery of scheelite using single dodecylamine (DDA) or single sodium oleate (NaOL), whereas Ca²⁺ hardly affects scheelite recovery using mixed collectors DDA/NaOL. Zeta potential measurements and solution chemistry confirm that the zeta potential of scheelite shows a significant positive shift after conditioning of Ca²⁺, which hinders the adsorption of same positively charged DDA on the mineral surface. Simultaneously, the addition of Ca²⁺ consumes single NaOL and generates Ca(OL)₂. As for DDA/NaOL, the predominant components are RNH₃⁺ and RCOO^? at pH 7; they form new highly active complexes through electrostatic attraction, reducing adverse effect of Ca²⁺. Fourier transform infrared spectroscopy measurements and adsorption measurements further confirm that the pre-adsorption of Ca²⁺ does not interfere with the adsorption of mixed collectors.     

从云南某高硫铅锌矿尾矿中综合回收锌的试验研究

云南某高硫铅锌矿尾矿平均含Pb 0.84％、Zn 3.67％,综合回收价值较高,其中含铅矿物主要为方铅矿和白铅矿,含锌矿物主要为闪锌矿和菱锌矿.实验室选矿试验研究表明,采用"硫化矿优先浮选-浮硫尾矿脱泥-氧化锌浮选"工艺可较好地实现尾矿中有价矿物的高效回收,进一步研究发现在氧化锌浮选过程中,粗选和扫选分别采用不同碳链长...     

Enhancing Phosphate Grade Using Oleic Acid–Sodium Dodecyl Sulfate Mixtures

Upgrading of calcareous phosphate ores by reverse flotation in acidic media depends mainly on the chemical reagents used, especially the collectors. Anionic collectors are commonly used in phosphate flotation circuits; however, in the most cases each collector was tested separately. Although using the mixture of the anionic collectors in salt-type minerals flotation is very limited, it has several advantages over using each collector alone. Therefore, in the present paper, the mixture of oleic acid and sodium dodecyl sulfate (SDS) was tested and compared to the usage of each collector individually. A number of experiments were conducted to find out the optimal reverse flotation conditions for each collector in terms of collector dose, pH, and oleic acid to SDS (Ol:SDS) mixing ratio as main variables using factorial design. The design results showed that the Ol:SDS mixture, particularly at 1:1 mixing ratio, improves the phosphate grade with slight decrease in recovery in comparison with using each collector separately. The highest concentrate grade (>33% P₂O₅), with a recovery of 85%, was obtained at pH 6, 1:1 Ol:SDS mixing ratio, and collector dose 3.5 kg/t. In addition, using 1:1 mixing ratio drastically lowers the collector dose from 3.5 to 2 kg/t or even lower depending on the pH to achieve the concentrate grade required by phosphate industry (30% P₂O₅).     

Interaction mechanism of flocculants with coal waste slurry

Coal tailings are the inevitable by-product of coal mining and preparation plants, and often are problematic in terms of dewatering and solid-liquid separation. The interaction of multi-component fine coal tailings with various coagulants and flocculants are important in dewatering processes. Tunçbilek coal preparation plant wastes are composed of 81% inorganic solids with negative surface charges dominating at all pHs. The highest settling rate and turbidity values without flocculant are obtained at natural pH of 8.3 due to the presence of inorganic ions in the suspension particularly Mg²⁺and Ca²⁺that act as natural coagulants. Additon of medium and low charge density anionic flocculants with high molecular weight at natural pH produced higher settling rates at lower dosages than nonionic and cationic flocculants. It shown that the charge density of anionic flocculants has a significant effect on both settling rate and supernatant turbidity, also the settling rate increases with increasing the degree of anionicity. Anionic flocculants having high molecular weight and high anione charge density produced flocs at sufficient size necessary for settling conditions, yet anionic flocculants having low charge density were more effective in the clarification of suspensions containing clay minerals of high stability. The multivalent ions act as a bridge between negatively charged coal, quartz and clay minerals with anionic groups (-CH₂-(CH-CO)-COO groups) of the polymer. Non-ionic flocculants required higher dosages than other flocculants to achieve equivalent settling rates; though excellent turbidity values were obtained in most common pH values. Cationic flocculants of higher charge densities (%70) achieved good settling rates and low supernatant turbidities (9.9 NTU) at natural pH for a dosage of 119.7 g/t-solids flocculant. An interaction mechanism of each polymer type with different components of the tailings is proposed.     

Gemini型阳离子表面活性剂的合成及其对高岭石矿物的浮选性能

制备了3种含有十二碳链的Gemini型阳离子表面活性剂(分别简写为12-2-12、12-4-12和12-6-12)。通过元素分析、红外光谱和质谱等对合成产物进行了表征。研究了3种合成的Gemini阳离子捕收剂对高岭石的浮选行为,并比较了新型捕收剂与传统捕收剂对高岭石浮选回收的差异。在相同实验条件下,Gemini型新药剂对高岭石的捕收能力大于传统药剂,它具有浮选效率高、受pH影响小等特点,是一种高效环保的新型阳离子表面活性剂。     

Flotation Behavior,Collector Adsorption Mechanism of Quartz and Feldspar-Quartz Systems Using PEA as a Novel Green Collector

Silicon - A novel green cationic surfactant Poly (propylene glycol) bis (2-aminopropyl ether) (PEA) with multiple amine groups was utilized as a collector for flotation separation of quartz from...     

Adsorption and column flotation studies on talc using anionic and cationic collectors

Adsorption properties and column flotation were studied to investigate the interaction of the anionic and cationic collectors and flotation recoveries for talc mineral. Adsorption capacity is dependent on pH, adsorption time, temperature, collector concentration, and particle size. Langmuir adsorption model was suitable for describing isotherms. Analyses were carried out using UV spectrometry. In this study, we analyzed some parameters affecting column flotation performance. It was determined that adsorption capacity, especially, had an important role in column flotation enrichment.     

Preparation and characterization of polynaphthyl amine (PNA) as a novel conducting polymer

A series of polynaphthyl amine (PNA) were prepared in acetone/water mixture (v/v) using different concentrations of potassium persulfate as an initiator in presence and in absence of polyvinyl alcohol (PVA) as a surface active agent. Polymers of various physical properties were prepared. The physical properties of PNA using different concentrations of potassium persulfate in presence and in absence of PVA were given. The specific conductance of the prepared polymers was found to be 0.055 ohm cm, 0.145 ohm⁻¹ cm⁻¹ and 0.083 ohm⁻¹ cm⁻¹, at 3, 1.5, and 0.75% of potassium persulfate, respectively. X‐ray diffraction analysis was carried out to the sample having the highest specific conductance. The confirmation of the prepared PNA was carried out using UV and IR spectrophotometry. Finally PNA showed good air stability and excellent solubility in organic solvents differing from that of polyaniline. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 988–992, 2000     

Synthesis and characterization of comb-shaped poly(amido amine)-g-PEO via Michael addition polymerization

Linear pH-sensitive poly(amido amine)s were synthesized via Michael addition polymerization of N-aminoethyl piperazine (AEPZ) or 4-aminomethyl piperidine (AMPD) with 1,12-dodecylene diacrylamide (DDA). Successive Michael addition reaction of acryl-terminated poly(ethylene oxide) (A-PEO) with the secondary amine of linear poly(DDA-AEPZ) that has one secondary amine in every repeating unit afforded PEO-grafted poly(amido amine). Variation of grafting degree could be obtained conveniently via tuning the feed molar ratio of acryl/secondary amine. When this ratio equals to 1.2, all the secondary amines on the backbone of poly(DDA-AEPZ) (or poly(DDA-AMPD)) were consumed and the comb-shaped polymers were formed. The amphiphilic comb-shaped poly(DDA-AEPZ)-g-PEO was molecularly dissolved in water at pH 2.0 (w/v=0.25%), and micelles were formed when pH value of aqueous solution was adjusted to 6.5. ¹H NMR data verify the formation of micelles due to the disappearance of signals attributed to poly(DDA-AEPZ). The formation of micelles can be confirmed further by TEM photos, they show that all the particles are approximately spherical and their number-average diameter is around 95 nm.     

Studies on the selective flotation of pyrochlore

The feasibility and the mechanism of the separation of pyrochlore from associated main silicate gangue minerals such as albite and biotite in an anionic collector system, using oleic acid and sodium dodecyl sulphate as collectors, in absence and presence of Fe(III), Cu(II) and Ca(II) have been investigated. Contrary to published data, the presence or addition of salts of these cations impairs rather than improves the selectivity of both soap and alkyl sulphate flotation of pyrochlore. However, leaching of the minerals investigated by HC1 greatly promotes their selective separation owing to selective teaching of metallic sites, namely Al³⁺, Mg²⁺ and Fe²⁺, from crystalline lattice surfaces of silicate minerals leading to the predominance of the negatively charged silicate sites. This leads to a marked sluggishness of their adsorbability of collector anions and their floatability. In contrast, leaching has almost no effect on the adsorptive capacity and floatability of pyrochlore due to the close chemical similarity of its cationic sites. Sodium dodecyl sulphate is superior to oleic acid because of its low pK_a and the predominance of its collecting anions at pH of 2. These anions possess a great affinity for the positively charged Cb and Ta sites over negatively charged silicate sites, leading to the selective flotation of pyrochlore.     

湖北某磷矿反浮选钾长石试验研究

针对湖北某低品位难选硅钙(镁)质磷矿,主要脉石矿物为钾长石,原矿P2O5品位19.84％,SiO2品位27.78％.在磨矿细度-0.074 mm占比80.16％,预先脱除白云石及细泥的情况下,用醚胺类捕收剂T-609反浮选钾长石,可获得精矿P2O5品位33.65％,回收率达72.83％的良好指标,实现了磷灰石和钾长石的有效分离.捕收剂T-609与钾长石主要以物理吸附为主,T-609和消泡剂TOP的搭配使用,可有效改善阳离子捕收剂反浮选钾长石泡沫性能.     

Reverse flotation studies on iron ore slime by the synergistic effect of cationic collectors

ABSTRACT

Objective of this study is to investigate the synergistic effect of dodecylamine kerosene as a collector in the reverse cationic flotation of iron ore slime. The hematite slime used in the investigation contains 56.32% Fe, 5.3% SiO₂, and 5.79% Al₂O₃. Iron recovery could be enhanced to 64.58% by the mixed dodecylamine-kerosene collector at neutral pH. Iron concentrate with 64.58% Fe, 3.98% SiO₂, and 4.16% Al₂O₃ was obtained using 80:20 of DDA-kerosene. Potential of synergism for slimes processing by emulsified reagent (dodecylamine/amine) using Tergitol TMN-10 as an emulsifier are envisaged based on this study.     

Chelate membrane from poly(vinyl alcohol)/poly(N-salicylidene allyl amine) blend. III. Effect of Mn(II) and Co(II) on oxygen/nitrogen separation

Facilitated transport of oxygen through Co(II) and Mn(II) chelate membranes from poly(vinyl alcohol)/poly(N-salicylidene allyl amine) was investigated. As the membranes became chelated, oxygen diffusivity decreased and the solubility toward oxygen was enhanced. The oxygen permeability of the base poly(vinyl alcohol)/poly(N-salicylidene allyl amine) membrane was 2.6 × 10⁻³ cm³(STP)cm/cm² cm Hg sec (barrer), and the selectivity toward oxygen was 2.2. As Co(II) was introduced into this membrane, oxygen permeability and oxygen selectivity increased to 2.82 × 10⁻² barrer and 8.5, respectively. The permeability and selectivity of Mn(II) chelate membrane were 3.28 × 10⁻² and 5, respectively. A major reason for the increased selectivity was the enhanced solubility of oxygen in chelate membrane upon chelation. The transport behavior of chelate membranes followed a dual-mode transport, and the parameters were estimated and compared between Co(II) and Mn(II) membranes. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 483–490, 1997