Amount Of Collector Research Articles

Measurement of collector concentrations to make an efficient mixture for flotation of a low grade apatite

It was well documented that a mixture of collectors could have synergistic advantages over the use of an individual collector for apatite flotation. Therefore, it would be an essential procedure to determine an optimum amount of each collector for development of an efficient mixture (collector). In this study, a mixture design (MD) model was used to find an optimum amount of different typical apatite anionic collectors (Atrac, Alke and Dirol) and make an efficient mixture for the direct flotation of a low grade apatite ore. Assessment of responses for apatite flotation tests which their collectors were designed by MD showed that Dirol has the highest selectivity whereas Alke has the highest collectivity for the direct flotation of apatite. According to the experiments, the MD model computed that a mixture collector with Dirol: 364 (g/t), Alke: 295.2 (g/t) and Atrac: 140.8 (g/t) concentrations can provide the most efficient responses through the apatite flotation. Results based on the purposed concentrations for the mixed collector demonstrated that higher apatite flotation responses (grade: 14%, recovery: 76%, and S.E.: 66%) in comparison with the performance of tests with a single collector. These results can be used to design flotation conditions for the apatite flotation-separation in the industrial scale and assessment of collector concentrations for other investigations.

Simultaneous Ash and Sulphur Removal from Bitumen Using Column Flotation Technique: Experiments, RSM Modeling and Optimization

An efficient method was employed for the ash and pyrite sulphur removal from bitumen using column flotation process. The bitumen samples containing 9.6% sulphur (6.81% in the pyrite sulphur form) and 26.4% ash were successfully showed up to 75.20% of pyrite sulphur (e.g.; 51.66% of total sulphur) and 70.81% of ash removal. The Box-Behnken Design (BBD) was employed to design the experiments, to optimize and evaluate the individual and interactive effects of six effective independent factors: the amounts of collector and frother agents, solid weight percentage in the pulp, particle size, wash water rate and feed rate. In order to investigate system a laboratory scale rig was built. In all experiments, pine oil and kerosene were considered as frother and collector agents, respectively. The best result for column flotation process were amount of collector (1.5 kg/tbitumen), amount of frother (0.3 ppm), pulp content (10% of solid), particle size (100 mesh), wash water rate (0.4 L/min), feed rate (1.5 L/min) and flotation time (10 min). The coefficient of determination, R2, showed that the RSM model can specify the variations with the accuracy of 0.924 and 0.938 for the percentage of ash and pyrite sulphur removal from bitumen, respectively.

Flotation study of oxide zinc ore using cationic-anionic mixed collectors

A representative sample of zinc oxide from Dashteh Sefid mine was obtained and then mineral characterization studies were done. The results of mineralogical analysis showed that the main zinc-bearing minerals are smithsonite, hemimorphite and gangue minerals are quartz and dolomite. In the present paper, the effect of important factors including sodium sulfide, collector type (AC and AC/KAX), collector amount, sodium silicate, CMC dosage and frother type (MIBC and pine oil) were investigated. Design of experiment was carried out by the means of Design Expert 7 using Fractional Factorial 26–1. The results indicated that collector type, collector amount, CMC and frother dosage were the most effective factors controlling the zinc flotation recovery. For the zinc grade, it was found that all six parameters play a significant role. The maximum recovery and grade of zinc obtained 97.71% and 10.39% under the following optimum conditions: sodium sulfide, 5935.23 g/t; collector type, AC/KAX; collector amount, 654.09; sodium silicate, 300; CMC dosage, 600; frother type, MIBC. The result of two-stage cleaner flotation showed that zinc grade could be increased up to 16.2% with zinc recovery of 61.39%.

Evaluation and Optimization of Effective Parameters on Zinc Sulfate Flotation by the Taguchi Method

In this research, optimization of effective parameters on zinc flotation of zinc sulfate obtained from the zinc sulfate process is investigated by the Taguchi method. Experiments were evaluated with regard to seven factors in two levels by a Taguchi L8 orthogonal array. The optimum conditions proposed by the model for zinc sulfate flotation tests are as follows: amount of collector and frother 100 g/t, flotation time of 30 min, pH = 9, S/L = 30/70, rotor speed = 1250 rpm and preparation time = 100 min. Under these conditions the zinc grade in the flotation product was 41.5 %, which is little different to the actual amount of 42 % from the flotation tests.

Ultrasound Assisted Ash and Sulphur Removal from Bitumen Using Column Flotation Technique: Experimental, RSM and ANN Methods in Modelling and Optimization of Process

To remove ash and pyritic sulphur from bitumen an experimental study was performed to investigate the use of low frequency ultrasound wave in column flotation. For this purpose, a column flotation rig was equipped with a low frequency 24 kHz ultrasound transducer. The bitumen samples had sulphur content of 9.6 % (6.81 % in the pyritic sulphur form) and 26.4 % ash. All the experiments were carried out under pulp containing 5 % of solid, particle size of 100mesh and aeration rate of 4L/min using pine oil and kerosene as frother and collector agents, respectively. The effects of four parameters including the amounts of collector and frother agents, ultrasound power and ultrasound times were investigated. The optimum conditions for column flotation process with assisted ultrasound were; 1.5 kg/tbitumen of collector, 0.4 ppm of frother, ultrasound power equal to 300 W and ultrasound time of 3 min under flotation time of 5 min. In these conditions, 87.72 % of pyritic sulphur (i.e., 68.03 % of total sulphur) and 83.29 % of ash were removed. Accordingly, the enhancement of column flotation yield with ultrasound mode was approximately 11.9 and 10.3 % more than without ultrasound for ash and pyritic sulphur removal, respectively. The effect of process factors including amounts of collector and frother agents, ultrasound power and ultrasound time on ash and pyritic sulphur removal was investigated by central composite design (CCD) of RSM and multilayer feed forward back propagation neural network with the topology of 4-6-1.

Increasing the Useful Heating Value of Coal Using a Physico-Chemical Process

ABSTRACTCoal is of paramount importance when it comes to producing energy in the industries. In this research, an optimum condition in which coal energy reached its highest level was investigated using a flotation process. A representative coal sample was from the Kerman province mine in Iran. Crushing and screening products were homogenized and prepared to conduct flotation experiments. Based on the statistical design of experiments, solid percent, collector dosage, and frother type were the effective variables that remarkably controlled the flotation results. In this study, efficiency index and the useful heating value (UHV) were two indicators that were considered to determine the coal’s quality. Various kinds of reagents with different amounts were used to find the optimum conditions for experiments. According to the obtained results, the UHV and efficiency index were 6485 (kcal/kg) and 43%, respectively, when the collector amount, frother amount, and solid percent were 5.3 Kg/t, 78 g/t, and 10%, respectively. Three-dimensional graphs were used to visually simplify the interactions between flotation parameters in different values and their effects on the responses. Data showed that in order to increasing the amount of energy that comes from coal, it is necessary to reduce the ash quantity of the coal in a reverse relationship.

Simultaneous ash and sulfur removal from bitumen: Experiments and neural network modeling

Flotation and leaching methods were used to remove ash and sulfur from bitumen by sulfuric acid. The bitumen samples had sulfur content of 9.6% (6.74% in the pyrite sulfur form) and 30% ash. All the experiments were done under aeration rate of 4L/min using pine oil and gasoline as frother and collector agents, respectively. The factors studied were including the amounts of collector and frother agents, pH, solid weight percentage in the pulp, stirrer speed, and particle size. The bitumen samples with dimensions less than 0.5mm were crushed. The flotation experiments were performed in a 3-L Denver laboratory flotation cell to ease the ash and sulfur removal. The optimum condition for plant operation were; foaming (50gr/t), collector (1kg/t), impeller speed of 1200rpm, pH=7, pulp containing 5% of solid, particle size of 100mesh, and flotation time of 3min. In these circumstances, 52.9% of pyrite sulfur (e.g.; 36.45% of total sulfur) and 43% of ash were removed. With the approach of leaching using sulfuric acid, the organic and pyrite sulfur removal were 7% and 13%, respectively. Combination of these two methods (in optimal conditions), removed up to 47% of the total sulfur and 61% of ash through bitumen sample.In the next step of study Artificial Neural Networks (ANN) was employed to model the ash and sulfur removals data obtained by flotation method. A network consisting of two layers of six and nine neurons in the hidden layer were considered. Meanwhile learning algorithm Levenberg–Marquardt (LM) was used. In neural network models “Tansig” and “Purelin”, transfer functions for hidden and output layers were applied, respectively. Very low error in the network estimation confirmed validity of the obtained networks for further analysis and optimization. Moreover, process optimization were carried out by using ANN to predict the best operating conditions, which resulted in the maximum percentage of ash and pyrite sulfur removal from bitumen. The maximum percentage of ash was estimated by ANN to be 42.39% under the following operational conditions; foaming amount of 50.5gr/t, the collector amount of 1.12kg/t, impeller speed of 1200rpm, pH=7.5, pulp equal to 5% of solid, particle size of 110mesh, and flotation time of 3 min. The maximum percentage of pyrite sulfur removal was estimated by ANN to be 52.15% under the following operational conditions; foaming amount of 50gr/t, the collector amount of 1.4kg/t, impeller speed of 1200rpm, pH=7, pulp equal to 5% of solid, particle size of 100mesh, and flotation time of 3 min.

A novel capillary electrophoresis method with pressure assisted field amplified sample injection in determination of thiol collectors in flotation process waters

A new capillary electrophoresis method was developed for the quantification of diisobutyldithiophosphate (DTP), diisobutyldithiophosphinate (DTPI) and ethyl and isobutyl xanthates (EX, IBX) all of which are used as thiol collectors in froth flotation. This method uses pressure assisted field amplified sample injection (PA-FASI) to concentrate the analytes at the capillary inlet. The background electrolyte in electrophoretic separation was 60millimolar (mM) from 3-(cyclohexylamino)propane-1-sulfonic acid (CAPS) in 40mM NaOH solution. The similar CAPS electrolyte solution has earlier been used for screening for diuretics that contained sulphonamide and/or carboxylic groups. In this study, the functional groups are xanthate, phosphate and phosphinate. The method was developed using actual flotation process waters. The results showed that the water delivered from the plant did not contain significant amount of collectors; therefore, method development was accomplished by spiking analytes in these waters. Separation of analytes was achieved in 15min. The range of quantification was 0.27–66.6mg/L (R2 0.9991–0.9999) for all analytes other than ethyl xanthate, for which the range was 0.09–66.6mg/L (R2 0.9999). LOD (S/N=3) and LOQ (S/N=10) values for DTP, DTPI, IBX and EX were 0.05, 0.07, 0.06 and 0.01mg/L and 0.16, 0.25, 0.21 and 0.04mg/L, respectively. No interference from the matrices was observed, when the method was tested at a gold concentrator plant.

Effect of regrinding conditions on pyrite flotation in the presence of copper ions

In this study, the effect of regrinding conditions on copper activation on the pyrite surface and subsequent pyrite flotation in the cleaner stage was investigated. Pyrite was activated by copper ions during primary grinding, and the rougher flotation concentrate was reground in a tumbling mill prior to the cleaner flotation. The regrinding condition was manipulated by two types of grinding media, stainless steel and mild steel. It was found that pyrite flotation in the cleaner stage was depressed especially when mild steel media was used during regrinding. An additional amount of collector improved pyrite flotation especially when stainless steel media was used during regrinding. An additional amount of copper ions further increased pyrite flotation after regrinding with mild steel media but decreased pyrite flotation after regrinding with stainless steel media. XPS (X-ray photoelectron spectroscopy) analyses and EDTA (ethylene diamine tetraacetic acid) extraction revealed that the different response of pyrite flotation in the cleaner stage to stainless steel and mild steel media used during regrinding was associated with the modified property of the Cu-activated pyrite surface carried from the rougher flotation concentrate and the new pyrite surface created during regrinding.

The effect of calcium ions and sodium silicate on the adsorption of a model anionic flotation collector on magnetite studied by ATR-FTIR spectroscopy

Previous studies have shown that agglomeration of the magnetite concentrate after reverse flotation of apatite is negatively affected by the collector species adsorbed on the surface of magnetite. In this work, the effect of ionic strength, calcium ions and sodium silicate on the unwanted adsorption of a model anionic flotation collector on synthetic magnetite was studied in situ using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The amount of collector adsorbed was found to increase with increasing ionic strength at pH 8.5 providing evidence to the contribution of electrostatic forces to the adsorption of the collector. Adding sodium silicate to the system resulted in a threefold decrease in the amount of collector adsorbed compared to when no sodium silicate was added, confirming the depressing activity of sodium silicate on magnetite. Calcium ions were shown to increase the adsorption of both the collector and sodium silicate on magnetite. The depressing effect of sodium silicate on collector adsorption was completely suppressed in the presence of calcium ions under the conditions studied. Furthermore, the amount of collector adsorbed on magnetite from the silicate-collector solution increased 14 times upon addition of calcium ions suggesting that calcium ions in the process water may increase undesired adsorption of the collector on the iron oxide.

Investigation of the effects of various water mediums on desulfurization and deashing of a coal sample by flotation

The aim of this study was to investigate the effects of various water mediums on desulfurization and deashing of a coal sample using flotation. For this purpose, experimental studies were conducted on a coal sample containing high ash and sulfur contents. The effects of pH, solid concentration, collector amount and frother amount on the flotation were investigated separately in Mediterranean Sea water, Cermik thermal spring water, snow water and tap water. Flotation, results indicated that, when comparing the various water mediums, the following order for the ash content was obtained: snow water Cermik thermal spring water > Mediterranean Sea water > tap water. When snow water was used as a flotation medium, it was found that a concentrate containing 3.01% total sulfur and 27.64% ash with a total sulfur reduction of 57.06% was obtained from a feed containing 7.01% total sulfur and 4.1.17% ash.

Recycling of coal combustion wastes

The separation of unburned carbon from coal-fired power plant bottom ashes was conducted in order to increase the possibility of the recycling of coal combustion wastes. A two-stage flotation technique was used for this study. In the rougher flotation experiments the amounts of collector, dispersant and frother, pulp density, pH, particle size distribution, flotation time and flotation temperature were tested as variables. After rougher flotation experiments, at optimum conditions, the carbon content of the concentrate increased from 13.85 to 51.54% at a carbon recovery of 54.54%. Under the same conditions, the carbon content was reduced to 4.54% at a weight yield of over 80% in the tailings fraction. This fraction meets the industrial specifications and can be utilized as a cement additive. After the cleaner flotation experiment the carbon content of the product was enhanced to 64.81% with a 52.16% carbon recovery. This fraction can be blended back into the coal feed to the power plant boilers.

Dynamic froth stability: Particle size, airflow rate and conditioning time effects

The rate of flotation and froth stability affect froth flotation performance and selectivity and strongly depend on various parameters such as the reagent adsorption, particle and bubble size, air flow rate, conditioning time, surface characteristics and elemental composition. Dynamic froth stability measurements are based on the height of froth in a froth column. In this research, the dynamic froth stability tests were performed in a modified Denver flotation cell measuring the height of the froth. The effects of particle size, conditioning time and airflow rates on the dynamic froth stability were determined in terms of maximum froth height. It was observed that there was a very strong relationship between froth stability and particle size. The dynamic froth stability also depends on conditioning time. Increase in conditioning time caused to decrease in the froth stability, solid content of concentrate and water recovery. The performance data show that the values directly depend on the amount of collector adsorbed on the solid particles. When conditioning period increased from 2 min to 6 min, sulphur content in concentrate increased from 2.46% to 3.24%, respectively. It was concluded that the degree of hydrophobicity plays important roles on both dynamic froth stability and performance values.

The Influence of Surfactant on the Surface Characterization of Celestite in Spherical Oil Agglomeration

This study investigates the relationship between the critical surface tension of wetting of celestite and agglomeration recovery as well as the zeta potential in dependence of pH and amount of collector (Na‐Oleate). For this purpose, effects of pH and collector amount on the agglomeration recovery are investigated and zeta potential measurements and Fourier Transform Infrared Spectrophotometer (FTIR) analyses are carried out to determine the adsorption type of Na‐Oleate on celestite surface. The sessile drop technique is used for the measurement of contact angle and determination of the critical surface tension of wetting (YC) of celestite. The maximum agglomeration recovery is obtained at pH 7. The critical surface tension of wetting of celestite is very close to the surface tension of kerosene, which is 25.95 mN/m. Furthermore, at the optimum Na‐Oleate amount of 10 kg/ton, the critical surface tension of wetting of celestite is approximately equal to the surface tension of kerosene.

Enrichment of Elazığ–Keban fluorite by flotation method

In the present study, the upgrading of Elazığ–Keban fluorite was studied using flotation method. For this purpose, experimental studies were conducted on the fluorite sample with a composition of 43·3CaF2–21·3SiO2–32·4CaCO3. The effects of particle size, pH, depressant amount, depressant conditioning time, collector amount, collector conditioning time and water temperature on the fluorite flotation were investigated. As a result, it was found that while a concentrate containing 92·1%CaF2 with 82% recovery was achieved at 30°C, a concentrate containing 87·2%CaF2 with 76·9% recovery was achieved at 16°C.

Performance of classic oils and lubricating oils in froth flotation of Ukraine coal

In this study, the appropriate collector and collector amount for Ukraine coal in froth flotation was determined. For this purpose, the performance of classic oils (kerosene, diesel-oil and fuel-oil) and lubricating oils (spindle oil, bright stock and heavy neutral) was evaluated by combustible recovery, ash rejection and efficiency index. It was found that the combustible recovery and ash rejection changed, depending on the type and concentration of oil. The maximum combustible recovery was obtained by using bright stock. It was determined that bright stock, fuel-oil and kerosene were suitable for the flotation of Ukraine coal. On considering the flotation efficiency index values, the best results were obtained with bright stock and diesel-oil. Consequently, it was shown that bright stock and spindle oil could be used as alternative oils instead of classic oils for cleaning of Ukraine coal by the froth flotation.

Desulfurization and Deashing of Hazro Coal via a Flotation Method

In this study, desulfurization and deashing of Hazro coal via a flotation method were studied. For this purpose, experimental studies were conducted on the coal sample with ash, sulfur, volatile matter, and fixed carbon contents of 24.77%, 6.90%, 35.18%, and 38.06%, respectively, and two groups of flotation experiments were made. The effects of pH, collector amount, and various frothers (MIBC, AF 76, pine oil, DF 250) on the depressing and floating pyrite from Hazro coal were investigated in the first and second group flotation experiments, respectively. Flotation results indicated that, when compared to various frothers, the following order for the depressing of pyrite was obtained: MIBC > pine oil > AF 76 > DF 250. For the floating of pyrite, the following order was obtained: DF 250 > pine oil > AF 76 > MIBC. A concentrate containing 1.12% pyritic sulfur and 13.02% ash with a pyritic sulfur reduction of 66.86% was obtained from a feed that contained 4.95% pyritic sulfur and 24.77% ash. The flotation method removed most of the sulfate sulfur (>90%) and 66.86% of the pyritic sulfur from the coal sample.

A study on the relationship between critical surface tension of wetting and oil agglomeration recovery of calcite

In this study, it was investigated that the relationship between the critical surface tension of wetting of calcite and agglomeration recovery depending on pH and amount of collector (Na oleate). For this purpose, effects of pH and the amount of collector on the agglomeration recovery were investigated and, also, zeta potential measurements and Fourier transform infrared spectrophotometer (FTIR) analyses have been carried out to determine the adsorption type of Na oleate on calcite surface. In this paper, the decisive rules could not put down as evidence of agglomeration success with the critical surface tension of wetting value as in the flotation, because there are different liquids as water and oil (bridging liquid) in the agglomeration system.

Investigation of relationship between critical surface tension of wetting and oil agglomeration recovery of barite

In this study, relationship between the critical surface tension of wetting of barite and agglomeration recovery and also zeta potential depending on pH and amount of collector (Na-oleate) was investigated. For this purpose, effects of pH and the amount of collector on the agglomeration recovery were investigated and also, zeta potential measurements and Fourier transform infrared spectrophotometer (FTIR) analyses have been carried out to determine the adsorption type of Na-oleate on barite surface. At pH 7, the maximum agglomeration recovery was obtained, the critical surface tension of wetting of celestite is very close to the surface tension of kerosene of which is 25.95 mN/m. And also, at the optimum amount of Na-oleate of 3 kg/t, the critical surface tension of wetting of celestite is approximately equal to the surface tension of kerosene. In this paper, the decisive rules could not put down in declare of agglomeration success with the critical surface tension of wetting value as in the flotation, because there are different liquids as water and oil (bridging liquid) in the agglomeration system.

Fundamental study of reactive oily-bubble flotation

A novel concept of reactive oily bubbles (i.e., bubbles covered by a thin layer of oil containing oil-soluble collectors) as a carrier in flotation is proposed. In addition to the role of fine particle agglomeration by oily films, the surface properties of air bubbles coated with a thin oil film can be better controlled for the desired selectivity by adding certain types and concentrations of water insoluble collectors into the oil phase. Oily bubbles attain a much higher contact angle than air bubbles, ensuring a strong collecting power, favorably for floating both coarse and fine particles. The reactive oily bubble flotation can eliminate the addition of collector to the aqueous phase, avoid undesired synergetic interactions among collectors, activators, depressants and dispersants present in slurry, minimize undesired activation of gangue particles and significantly reduce the amount of collectors needed. The electrokinetics of kerosene droplets in aqueous collector solutions was measured as a function of solution pH. The results clearly showed that the surface charge and hence the surface properties of oil droplets can be finely tuned by controlling the type of the collectors to suit the desired flotation needs. The attachment of collector-containing oily bubbles on silica, sphalerite and galena surfaces was investigated with contact angle measurement. The concept of using reactive oily bubble to achieve selective flotation was demonstrated in microflotation tests.