Fatty Acid Collectors Research Articles

Mechano-chemical surface modification of calcite by wet-stirred ball milling

In this study, surface modification of calcite was examined using a laboratory stirred ball mill in wet condition. A fatty acid collector, sodium oleate (oleic acid sodium salt), was used as the modifying agent. Surface modification of the ground calcite sample was studied as a function of sodium oleate dosage, time and pH. Modification efficiency was mainly evaluated by floating test, which measures the active ratio. The effect of surface modification was also investigated using thermogravimetric (TG) and fourier transform infrared spectrometry (FT/IR) analyses, and contact angle measurements. Furthermore, mineralogical and microstructural changes were determined with X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. The results indicated that hydrophobicity of the powdered calcite increased with increasing sodium oleate dosage, in which the active ratios of 99.0% and 100.0% were obtained with the dosages of 5.0 and 7.5 kg/ton, respectively. Beyond this point, the active ratio values decreased dramatically down to 33.63% for 15.0 kg/ton. Similarly, hydrophobicity values increased with modification time up to the active ratio of 99.27% for 11.5 min. Different to the modifier dosage, additional time resulted in only a very small decline and the active ratio decreased down to 97.70% for 20 min. The best result of 99.27% was obtained with the natural pH of about 9, and the active ratio values substantially decreased below and above this point down to 38.07% for pH 6 and 47.32% for pH 12. Overall results have shown that natural hydrophilic calcite can easily be made hydrophobic using sodium oleate as the surface modifier.

Enhancement of Efficiency of Low-Hydroxyethylated Alkyl Phenols as Regulators in Selective Flotation of Non-Sulphide Minerals

The research findings on efficiency of hardly soluble low-hydroxyethylated iso-nonylphenols as regulators of selective flotation are presented. The methods for increasing their solubility are developed, which are based on using unsaturated carboxylic acids as wedding agents for alkaline salts. It is shown that addition of such wedding agents to ethoxylated iso-nonylphenols makes it possible to obtain stable aqueous micellar solutions or emulsions under much lower temperatures, as well as ensures permanence of the process and efficiency of regulating agents in selective flotation of phosphorus-bearing ores with fatty acid collector. Efficiency of the developed methods is proved by in practical application of one of them, which improved ore dressing performance, reduced labor content, energy input and time of solution preparation, and provided considerable economic effect.

Effects of structure of fatty acid collectors on the adsorption of fluorapatite (0 0 1) surface: A first-principles calculations

Effects of carbon chain length, carbon chain isomerism, CC double bonds number on fatty acid adsorption on FAP (0 0 1) surface have been investigated based on DFT. The results revealed that fatty acid collector can form stable adsorption configuration at Ca1 (surf) site. Chemical adsorption was formed between O (mole) of fatty acid collector and the Ca1 (surf) of fluorapatite (0 0 1) surface; hydrogen bond adsorption was formed between the H (mole) of fatty acid and the O (surf) of-[PO4]- of FAP (0 0 1) surface. Fatty acid collectors and FAP (0 0 1) surface are bonding by means of the hybridization of O (mole) 2p and Ca (surf) 4d orbitals, H (mole) 1s and O (surf) 2p orbital. The analysis of adsorption energy, DOS, electron density, Mulliken charge population and Mulliken bond population revealed that with the carbon chain growing within certain limits, the absolute value of the adsorption energy and the overlapping area between the DOS curve of O (mole) and Ca (surf) was greater, while that of H (mole) 1s and O (surf) 2p basically remained unchanged. As CC double bonds of fatty acids increased within certain limits, the adsorption energy and the overlapping area between the state density curve of O (mole) and Ca (surf), H (mole) and O (surf) basically remained unchanged. The substituent groups of fatty acid changed, the absolute value of the adsorption energy and the overlapping area between the state density curve had a major change. The influence of fatty acids adsorption on FAP (0 0 1) surface depends mainly on the interaction between O (mole) and Ca (surf).

Effects and Activation Mechanism of Calcium Ion on the Flotation of Quartz with Fatty Acid Collector

Effects and Activation Mechanism of Calcium Ion on the Flotation of Quartz with Fatty Acid Collector

Development of an environmentally friendly flowsheet to produce acid grade fluorite concentrate

Abstract Acid grade fluorite concentrate (AGFC) is the most valuable product of fluorite processing units. In this study, an environmentally friendly flowsheet is developed for the production of AGFC. The ore of the Kamar Mehdi fluorite mine (Tabas, Iran) is considered as a case study with grade of 76.65% fluorite, 21.62% dolomite and 0.32% hematite. The performance of ore flotation by changing operational parameters is evaluated in the presence of common and new fatty acid collectors, sodium oleate (SO) and sodium lauryl sarcosine (SLS), respectively. The best rougher concentrate (CaF2 = 88.49%) was obtained for 100 g/t of SLS and 500 g/t of dextrin at pH = 4. The concentrate is leached by acetic acid for the selective dissolution of dolomite. The acetic acid concentration of 0.31 M, the temperature of 80.33 °C, time of 126.29 min are chosen as optimum operational conditions using central composite design (CCD). It was found out the liquid to solid ratio of 4:1 is suitable for leaching purpose. AGFC containing 98.71% fluorite, 0.19% silica, and 0.05% sulfur is obtained by 91.55% dissolution of dolomite under these conditions. Finally, the calcium and magnesium acetate (CA & MA) is produced as an environmentally friendly by-product through the crystallization of the leaching filtrate.

Effect of calcium minerals reactivity on fatty acids adsorption and flotation

The separation between calcium minerals such as apatite and calcite by flotation relies on the use of long chain fatty acid collectors. Oleic acid, and its salt, is the main fatty acid collector and many studies have reported on the mechanisms of its interaction with calcium at the mineral surface and in solution, and on the oleic acid species present at the mineral surface. Although collector adsorption and mineral flotation depend mainly on solution pH and collector concentration, other factors such as mineral crystallinity and impurity affect mineral dissolution, influence collector adsorption and may explain the different flotation results reported in the literature on the same minerals. In this study the flotation of two calcites, with different degrees of purity, and one apatite was compared and related to the amount and type of collector adsorbed on the mineral surface, and to the reactivity of these minerals (acid-base interaction and dissolution). The results obtained in this study indicate that calcium dioleate (or dilinoléate) is the species present on the minerals surface at pH 9 and its amount increases with collector addition and calcium mineral dissolution, which results in a higher flotation of the calcium minerals. The influence of calcium site density and impurity in the minerals on flotation was also discussed.

The Effect of New Modified Fatty Acid (CY-23) Collector on Chlorite/Hematite Separation

The flotation separation on chlorite and hematite with the new modified fatty acid collector CY-23 was studied. The investigation included both flotation and reagent adsorption tests. And all the characteristics of chlorite surface before and after the adsorption of new collector CY-23 have been studied with X-ray photoelectron spectroscopy (XPS). The flotation results showed that caustic starch (CS) could depress the flotation of hematite and chlorite and CaCl2 could activate chlorite flotation but failed on hematite when using CY-23 as collector. The adsorption rate of CY-23 on the surface of chlorite after being inhibited by CS was relatively smaller, but the amount of CY-23 adsorbed on the inhibited chlorite was greatly increased after adding activator CaCl2. The results of XPS analysis showed that the photoelectron spectroscopy peaks of Mg2p and Al2p moved towards low energy after collector CY-23 was absorbed on chlorite surface, which indicated that chemical bonding through electron cloud transfer occurred between collector CY-23 and Mg, Al ions of chlorite surface. The chemical reaction promoted the adsorption of CY-23 on chlorite surface and eventually improved the ability of CY-23 to float and collect chlorite.

Anisotropic surface physicochemical properties of spodumene and albite crystals: Implications for flotation separation

Aluminosilicate minerals (e.g., spodumene, albite) have complex crystal structures and similar surface chemistries, but they have poor selectivity compared to traditional fatty acid collectors, making flotation separation difficult. Previous research has mainly considered the mineral crystal structure as a whole. In contrast, the surface characteristics at the atomic level and the effects of different crystal interfaces on the flotation behavior have rarely been investigated. This study focuses on investigating the surface anisotropy quantitatively, including the chemical bond characteristics, surface energies, and broken bond densities, using density functional theory and classical theoretical calculations. In addition, the anisotropy of the surface wettability and adsorption characteristics were examined using contact angle, zeta potential, and Fourier-transform infrared measurements. Finally, these surface anisotropies with different flotation behaviors were investigated and interpreted using molecular dynamics simulations, scanning electron microscopy, and X-ray photoelectron spectroscopy. This systematic research offers new ideas concerning the selective grinding and stage flotation of aluminosilicate minerals based on the crystal characteristics.

Selective reverse flotation of apatite from dolomite in collophanite ore using saponified gutter oil fatty acid as a collector

Reverse flotation is an effective method for separating apatite from gangue minerals (such as dolomite) in collophanite ore. However, collophanite ore flotation using traditional fatty acid collectors is uneconomical because of the relatively high cost of the raw materials. In this work, saponified gutter oil fatty acid (GOFA) was used as the collector, and its effect on collophanite ore flotation and the mechanism of adsorption were studied. The results showed that Ca2+ is the active site for reaction with GOFA and initiates apatite flotation. The dissolution of Ca2+ from dolomite was found to be thermodynamically more favorable than that from apatite, and the relative abundance of Ca2+ enhanced the reaction of dolomite with GOFA. XPS analysis revealed that the interaction between GOFA and magnesium on the dolomite surface strengthened chemisorption. As magnesium is a major constituent of dolomite, but not of apatite, GOFA was selectively chemisorbed onto the dolomite surface. Closed-circuit reverse flotation tests using GOFA as the collector resulted in an excellent concentrate with 28.46wt% P2O5 and 0.65wt% MgO, corresponding to a P2O5 recovery of 87.2%. GOFA was demonstrated to exhibit outstanding selectivity for dolomite in the reverse flotation of collophanite ore. The use of GOFA as an environment-friendly, cost-effective, and selective collector is expected to provide new insights into low-cost collophanite ore flotation.

Interaction Forces between Paraffin/Stearic Acid and Fresh/Oxidized Coal Particles Measured by Atomic Force Microscopy

Effective fresh coal flotation can be achieved using conventional hydrocarbon oily collectors while oxidized coal flotation can be enhanced using oxygen-containing fatty acid. Solid-state paraffin and stearic acid were selected to represent a hydrocarbon oil and fatty acid collector in the present study, respectively. The interaction forces between paraffin/stearic acid and fresh/oxidized coal particles were measured directly using atomic force microscopy (AFM) colloidal probe technique. Flotation experiments with hydrocarbon oil (dodecane) and fatty acid (oleic acid) were carried out to validate the AFM results. The results show that a pure attractive force was detected between fresh coal and paraffin while a slightly repulsive force before the jump-into contact was observed between fresh coal and stearic acid. Effective fresh coal flotation can be achieved by using both dodecane and oleic acid, while the recovery with dodecane was always higher than that of oleic acid. In contrast, a significant jump-in...

Effect of depressants in the selective flotation of scheelite and calcite using oxidized paraffin soap as collector

Calcite, in most cases, is the major gangue mineral found in scheelite ores. It is difficult to separate scheelite and calcite due to the similarities in their formation properties. In this study, it was found that scheelite and calcite can be floated using fatty-acid collector oxidized paraffin soap in the pH regions of 8–11 and 6–12, respectively. The effects of sodium hexametaphosphate (SHMP), tanning extract, starch and acidified water glass (AWG) as depressants of calcite have been studied. The AWG was the appropriate depressant without imposing obvious adverse effects on scheelite flotation. In order to prove the validity of the findings, flotation of both mixed mineral (1:1 scheelite:calcite) and real ore were conducted as well as zeta potential measurements.

Effects of surface electrical property and solution chemistry on fine wolframite flotation

Abstract In this paper, the effects of the surface electrical property and solution chemistry on the fine wolframite flotation were investigated by zeta potential measurement and the modified concentration logarithm diagrams. Based on that results, the flotation effects of different monominerals, including wolframite, scheelite, fluorite, calcite and quartz, were studied using different single collector, including sodium oleate, salicylaldoxime, benzohydroxamic acid and fatty-acid collector GYR. However, the wolframite recovery was low, and thus the mixed collectors were used to improve the recovery using benzohydroxamic acid as main collector and other collector as additional collector, including sodium oleate, salicylaldoxime, benzohydroxamic acid, fatty-acid collector GYR and fatty-acid collector TAB-3. The results show that the maximum recovery of wolframite exceeded 86% using GYB and TAB-3 as mixed collectors, which was up 13% compared with single GYB. These results could be explained in terms of the modified concentration logarithm diagrams in conjunction with the IEP values of different monominerals mentioned in this work. The infrared spectrogram indicated that because of different structures and properties of GYB and TAB-3, GYB could be complementary with TAB-3.

Synergistic effect of dodecyl sulfonate on apatite flotation with fatty acid collector

ABSTRACTThe synergistic effects between sodium dodecyl sulfonate (SDS) and a mixed fatty acids collector for apatite flotation were investigated. SDS benefitted the apatite flotation at pH 9.5. The TOC measurements showed that the addition of SDS improved the surfactants adsorption at the apatite surface. The colloidal size measurements suggested that the utilizing of SDS prevented the over-packing of fatty acids in the solution. Additionally, SDS did not adsorb/co-adsorb at the apatite surface as revealed by the FTIR and XPS results, because of the strong electrostatic repulsion between the apatite surface and the SDS ions.

Flotation of rare earth minerals from silicate–hematite ore using tall oil fatty acid collector

The flotation of rare earth (RE) minerals (i.e. xenotime, monazite-(Nd), RE carbonate mineral) from an ore consisting mainly of silicate minerals (i.e. primary silicate minerals and nontronite clay) and hematite was investigated using tall oil fatty acids (Aero 704, Sylfat FA2) as collector. The RE minerals are enriched with Fe. The effects of tall oil fatty acid dosage, pH, temperature, and conventional depressants (sodium lignin sulfonate, sodium metasilicate, sodium fluoride, sodium metasilicate and sodium fluoride, and soluble starch) were determined at grinding size of P80=63μm. At this grinding size, the grain size of the RE minerals ranges from 2 to 40μm, percentage liberation is 9–22%, and percentage association with nontronite and quartz is 30–35%. Results indicated that Sylfat FA2 at 22450g/t concentration was the more efficient tall oil fatty acid collector at natural pH (pH 7) to basic pH (pH 10.0–11.5). Flotation at the room temperature (25°C) gave higher selectivity than 40°C temperature flotation. The results on the effect of depressants showed similar selectivity curves against the gangues SiO2, Al2O3, and Fe2O3 suggesting that the chemical selectivity of the depressants has been limited by the incomplete liberation of the RE minerals in the feed sample. High recoveries at 76–84% (Y+Nd+Ce)2O3 but still low (Y+Nd+Ce)2O3 grade at 2.1% in the froth were obtained at flotation conditions of 63μm, 25°C, pH 10.5, 1,875g/ton sodium metasilicate and 525g/ton sodium fluoride or 250g/ton soluble starch as depressant for the silicates and hematite, and 22,450g/t Sylfat FA2 as collector for the RE minerals (initial (Y+Nd+Ce)2O3 feed grade=0.77%). The recoveries of gangue SiO2, Al2O3, and Fe2O3 in the froth were low at 25–30%, 30–37%, and 30–36%, respectively. The mineralogical analysis of a high grade froth and its corresponding tailing product showed that the RE minerals have been concentrated in the froth while the primary silicate minerals and hematite have been relatively concentrated in the tailing. However, the clay minerals, primary silicate minerals, and hematite still occupy the bulk content of the froth. This suggests that incomplete liberation of the RE minerals led to the poor grade result, supporting likewise the selectivity curve results by the different depressants. This study showed that liberation is important in achieving selective separation.

Rice starch as a depressant in phosphate reverse flotation

Depressants are essential additives, to increase the separation selectivity, in the reverse flotation of phosphate by fatty acid collectors. In the current study, the rice starch is used, as a phosphate depressant, in the reverse flotation of calcareous phosphate by oleic acid. The operating parameters affecting the starch depressing action such as: collector dosage, pH and starch dosage are studied using statistical design of experiments. The design analysis showed that the starch dose has the most significant effect on the concentrate grade. A concentrate containing 30.6% P2O5 with a recovery of 91.6% was achieved at the optimum values of studied parameters, i.e., 4, 4 kg/t, and 4 kg/t for pH, starch dosage, and collector dosage, respectively. The FTIR analysis was used to characterize the interaction between the collector and starch as well as the starch and phosphate ore. It was found that the oleic – ore interaction was chemical, whereas the starch interaction with either phosphate or oleic acid was physical.

Adsorption Selectivity of Fatty Acid Collector by Synthetic Magnetite

Selective adsorption of collectors on mineral surface can directly impact the flotation separation performance. Mineral flotation tests indicated that reverse flotation of synthetic magnetite can only bring a 2 to 4 percent increase in the concentrate grade, tailings grade remains high. The amounts of commonly used fatty acid collector, such as sodium oleate, adsorbed onto mineral surface are measured with indirect measurement to investigate adsorption selectivity of fatty acid collectors by synthetic magnetite. Results showed a higher selectivity in collector adsorption for natural magnetite, with 38.25% difference in the average adsorption rate of sodium oleate between the valuable minerals and gangue, but a less selective adsorption of fatty acid collector onto artificial magnetite, with only 1% difference in the average adsorption rate between its valuable and gangue.

Study on Drainage Oil to Prepare Collectors of Coal Flotation

At present, kerosene is one of the most widely used non-polar hydrocarbon oil collector agent in coal flotation in China, kerosene is difficult to dissolve in water, with good collector, but the dosage is comparatively large in the actual production.The drainage oil is from the dining recycled goods and the waste of animal flesh, can be used for preparation of fatty acid collector, which not only to reduce environmental pollution,but also to reduce the risk of food safety. At the same time, if drainage oil can replace the kerosene in coal collection, it will improve the coal preparation plant efficiency and solve the problem of shortage of national resources. In this study, we use Huangling coal as raw material for flotation experiment, use kerosene, diesel, drainage oil and emulsified drainage oil as collectors. Adding different collectors in the same flotation conditions to research the yield of clean coal, the clean coal ash and the yield of tailings by changing the dosage of collectors. The results show when adding to OP emulsifier and the proportion of water and oil is 6:4, flotation effects is the best, the yield of clean coal is 88.67%, the ash of clean coal is from 9.16% down to 8.63%, the yield of tailings is 11.32% .

Improved Flotation of Oolitic Hematite Ore Based on a Novel Cationic Collector

Oolitic hematite is one of the most refractory iron ores with complicate mineral compositions and abundant reserves in China. The hematite and limonite in the ore integrate closely with fine particles of collophanite, quartz, chamosite, calcite and chalcedony to form concentric ring structure, making the separation of the minerals extremely difficult. Since the tiny hematite crystal can not be liberated during the grinding of the ore the beneficiation can only be accomplished by recovering iron minerals aggregate with hematite as the major component. The previous research results showed that reverse flotation with fatty acid collectors could remove liberated phosphate minerals but not the quartz, chlorite and silicate minerals. This was because the gangue minerals such as quartz were contaminated by iron on the surface and there were high content of iron in some silicate minerals and high content of silicon in iron minerals, causing the floatability difference between the silicon and the iron minerals very small and thus the separation efficiency very low. Experiments were conducted to beneficiate the ore by reverse flotation with different cationic collectors. The results indicated that the flotation separation efficiency with most cationic collectors such as dodecylamine, ether amine, GE601 or GE609 was not satisfactory. However, a novel cationic collector for silicon removal, EM506 was found to be specifically selective to separate the gangue minerals from the iron ore with an increase of TFe grade from 49% to more than 58% and a recovery of TFe greater than 96%, which provided a promising approach for the beneficiation of the refractory oolitic hematite ore.

Detection Study on the Mineral Processing Reagents Preparation from Catering Waste Oil and Application on Ore Flotation

The composition of catering waste oil is similar to that of traditional materials for the preparation of fatty acid collectors, which makes it possible to change catering waste oil into fatty acid collector applied to ore flotation. The collectors which come from catering waste oil are detected by FTIR and GC-MS analyses. The FTIR date shows that collectors contains lively carboxyl functional groups and The GC-MS date reveals that those carboxyl functional groups exist in single unsaturated fatty acid and three unsaturated fatty acid. The collectors can be applied to iron ore reverse flotation, apatite flotation, and fluorite flotation. It has better flotation experiment results than the traditional collector that using in field production.

Design and development of novel flotation reagents for the beneficiation of Mountain Pass rare-earth ore

Bastnaesite, a rare-earth fluocarbonate, was separated from associated calcite and barite gangue minerals in the Mountain Pass, CA rare-earth ore beneficiation plant by froth flotation using fatty acids (tall oil) collector, lignin sulfonate depressant and soda ash modifier after high-temperature (steam) conditioning with reagents. Starting with a feed grade of 7.6% REO, concentrates having a grade of 65% REO can be produced at a recovery of around 80%. A detailed investigation consisting of Hallimond tube microflotation experiments, bench-scale tests with a laboratory Denver flotation cell, and predesigned plant campaigns was made to delineate the underlying surface chemistry involved in this separation and to develop an alternate reagent scheme to enhance the selectivity of separation for this ore. Our results clearly demonstrate the superiority of alkyl hydroxamates to the conventional fatty acid collectors that were being used in the plant. Our study also indicates the possibility of achieving the desired selectivity with alkyl hydroxamates even at room temperature, thus obviating the need for steam conditioning. A critical review of the literature on rare-earth mineral flotation suggests the possibility of designing a more selective reagent combination for the beneficiation of Mountain Pass rare-earth ore, using a methodology based on ab initio molecular modeling computations.