Autor: Irannajad, M. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Investigation of effective parameters for molybdenite recovery from porphyry copper ores in industrial flotation circuit
Autorzy:: Nakhaei, F.
Irannajad, M.
Tematy:: flotation
copper
molybdenum
recovery; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110240.pdf Link otwiera się w nowym oknie
Opis:: The Sarcheshmeh copper mine is a significant copper and molybdenum producer. Sampling of the Sarcheshmeh flotation circuit (in a six-month period) showed that a large share of waste of molybdenite took place in rougher cells. Since the rougher cells tailing is transferred to tailing thickener, the main focus of this paper was on this section. In the current study, the factors which influence the recovery of molybdenite and copper were investigated. Molybdenite recovery in the bulk flotation circuit was consistently lower than that of the copper sulphides as well as being far more variable. This paper describes the methodically use of size by size recovery data, quantitative mineralogy, and liberation degree analysis to identify the factors contributing to molybdenite recovery relative to copper in industrial rougher circuit. The results showed that the size by size recovery for both metals in the ultrafine and coarse fractions recovery was reduced. On the other hand, the highest recovery occurred in the intermediate sizes from 27 μm to 55 μm. Molybdenum recovery in the fine and ultrafine and coarse fractions drops off to a greater extent than the recovery of copper. The investigations of degree liberation showed that the recovery of copper sulphides is more dependent on the liberation state of valuable minerals while for molybdenite some other factor splay a significant role.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Comparison between neural networks and multiple regression methods in metallurgical performance modeling of flotation column
Autorzy:: Nakhaei, F.
Irannajad, M.
Tematy:: metallurgical performance
separation
neural networks
nonlinear regression
prediction
flotation column; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110822.pdf Link otwiera się w nowym oknie
Opis:: Artificial neural networks are relatively new computational tools which their inherent ability to learn and recognize highly non-linear and complex relationships makes them ideally suited in solving a wide range of complex real-world problems. In this research, different techniques (Linear regression, Non-linear regression, Back propagation neural network, Radial Basis Function for the estimation of Cu grade and recovery values in flotation column concentrate are studied. Modeling is performed based on 90 datasets at different operating conditions at Sarcheshmeh pilot plant, a copper concentrator in Iran, which include chemical reagents dosage, froth height, air and wash water flow rates, gas holdup and Cu grade in the rougher feed and flotation column feed, column tail and final concentrate streams. The results of models were also expressed and analyzed by intuitive graphics. The results indicated that a four-layer BP network gave the most accurate metallurgical performance prediction and all of the neural network models outperformed non-linear regression in the estimation process for the same set of data.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Prediction of on-line froth depth measurement errors in industrial flotation columns: a promising tool for automatic control
Autorzy:: Nakhaei, F.
Irannajad, M.
Tematy:: prediction
accuracy
froth height
Kalman filter
error; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110715.pdf Link otwiera się w nowym oknie
Opis:: The pulp-froth interface position is important from a metallurgical point of view because it determines the relative importance of the cleaning and the collection zones. The pulp-froth interface position is measured based on variations of specific gravity, temperature or conductivity between the two zones to locate the pulp froth interface position. In this study, the pressure measurements are used to calculate the values of the froth layer height. These two meters are installed in the upper part of the column at 1.4 m and 2.4 m respectively, from the top of the column. Methods using pressure gauges are commonly used in industrial operations Even though their accuracy is limited (due to assumptions of uniformity of the pulp and froth density), and they always have some error. In the Sarcheshmeh copper industrial plant (Iran), a float was installed near the column with 2.5 m height that was calibrated to 5 cm intervals in order to determine the more exact forth height and compare it with the recorded froth height in control room. In this paper, an algorithm based on Kalman Filter is presented to predict on-line froth height errors using two pressure gauges. This research is based on the industrial real data collection for evaluating the performance of the presented algorithm. The quality of the obtained results was very satisfied. The RMS errors of prediction froth height errors was less than 0.025 m.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Simultaneous optimization of flotation column performance using genetic evolutionary algorithm
Autorzy:: Nakhaei, F.
Irannajad, M.
Yousefikhoshbakht, M.
Tematy:: flotation column
optimization
genetic algorithm
non-linear regression
upgrading curve; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110806.pdf Link otwiera się w nowym oknie
Opis:: Column flotation is a multivariable process. Its optimization guarantees the metallurgical yield of the process, expressed by the grade and recovery of the concentrate. The present work aimed at applying genetic algorithms (GAs) to optimize a pilot column flotation process which is characterized by being difficult to be optimized via conventional methods. A non-linear mathematical model was used to describe the dynamic behavior of the multivariable process. The solution of the optimization problem using conventional algorithms does not always lead to convergence because of the high dimensionality and non-linearity of the model. In order to deal with this process, the use of a genetic evolutionary algorithm is justified. In this way, GA was coupled with the multivariate non-linear regression (MNLR) of the column flotation metallurgical performance as a fitting function in order to optimize the column flotation process. Then, this kind of intelligent approach was verified by using mineral processing approaches such as Halbich’s upgrading curve. The aim of the optimization through GAs was searching for the process inputs that maximize the productivity of copper in the Sarcheshmeh pilot plant. In this case, the simulation optimization problem was defined as finding the best values for the froth height, chemical reagent dosage, wash water, air flow rate, air holdup, and Cu grade in rougher and column feed streams. The results indicated that GA was a robust and powerful search method to find the best values of the flotation column model parameters that lead to more reliable simulation predictions at a reasonable time. Based on the grade–recovery Halbich upgrading curve, the MNLR model coupled with GA can be used for determination of the flotation optimum conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Effect of oxidation roasting on ilmenite flotation
Autorzy:: Mehdilo, A.
Irannajad, M.
Rezai, B.
Tematy:: flotation
ilmenite
oxidation roasting
surface chemistry
zeta potential; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/109387.pdf Link otwiera się w nowym oknie
Opis:: In this study, the oxidation roasting was used to modify the ilmenite chemistry to improve the collector adsorption and ilmenite flotation behavior. The results indicated that the increase of the roasting temperature up to 600 ºC increased the ilmenite flotation recovery. The maximum collector adsorption density occurred on ilmenite roasted at 600 °C which resulted in the increase of ilmenite flotation recovery from 73.5% to 91% at pH 6.3. This improvement was attributed to a greater conversion of Fe2+ to Fe3+ ions and significant decrease in the zeta potential of ilmenite. At the roasting temperatures of 750 °C and 950 °C, ilmenite was converted to rutile and some trivalent iron containing phases such as hematite and pseudobrookite. Under these conditions, the collector adsorption and hence ilmenite flotation improved, however the flotation recovery decreased after the roasting at 950 °C.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Flotation of zinc oxide ore using cationic and cationic-anionic mixed collectors
Autorzy:: Mehdilo, A.
Irannajad, M.
Zarei, H.
Tematy:: flotation
smithsonite
collector
mixed collector
zinc; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110700.pdf Link otwiera się w nowym oknie
Opis:: Flotation of smithsonite coming from a cerussite flotation circuit was investigated using Armac C and Armac T as cationic collectors and their mixtures with potassium amyl xanthate (KAX) as an anionic collector. Under optimum condition using Armac T with sodium hexamethaphosphate as a de-pressant, a smithsonite concentrate with 42% Zn and 89.6% recovery is obtained while in the presence of sodium silicate depressant Armac C produces a concentrate containing 40.8% Zn with 92.5% recovery. However, Armac T acts a little more selectively than Armac C but their mixture with KAX act inversely. The KAX-Armac C mixed collector improves the Zn grade and recovery of the flotation concentrate while KAX-Armac T does not. At the mixture ratio of KAX - Armac C 2:1, the amine collector consump-tion is decreased and an optimal concentrate with 94% recovery and 43% Zn grade is obtained without any gangue depressant reagents.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Adsorption of Zn2+, Cd2+ and Cu2+ on zeolites coated by manganese and iron oxides
Autorzy:: Irannajad, M.
Hhaghighi, H. K.
Soleimanipour, M.
Tematy:: adsorption
wastewater
manganese oxide
iron oxide
zeolite; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110138.pdf Link otwiera się w nowym oknie
Opis:: Adsorption of copper, cadmium and zinc on manganese and iron oxide coated zeolite from aqueous solution was investigated in a batch mode. Experiments were conducted to investigate the effects of the initial concentration of metals, initial pH, contact time and temperature on the adsorption of ions. According to the results, adsorption of ions on manganese and iron oxide coated zeolite increased with the enhancement of initial Cu2+, Zn2+ and Cd2+ concentrations and contact time and also with increase of temperature. The results showed that at the beginning, the adsorption rate of Cu2+ and Cd2+ was more than 90 %. This rate continued to be slower for Zn2+ in both zeolites. Furthermore, the amount of Cu2+, Zn2+, and Cd2+ adsorption on the manganese oxide coated zeolite (qe) was equal to 14 mg/g, 9 mg/g and 16 mg/g and on the iron oxide coated zeolite it was 11 mg/g, 7 mg/g and 13mg/g, respectively. It was shown that at the concentrations below 100 mg/dm3 adsorption was rapid and almost all heavy metals were adsorbed. As a result, the significant factor affecting qe is the proportion of weight to liquid and pH in the solutions. Finally, the results showed that the adsorption of Zn2+, Cu2+ and Cd2+ onto the manganese oxide coated zeolite followed both the Langmuir and Freundlich isotherm models.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Separation of nickel and zinc ions in a synthetic acidic solution by solvent extraction using D2EHPA and Cyanex 272
Autorzy:: Gharabaghi, M.
Irannajad, M.
Azadmehr, A. R.
Tematy:: D2EHPA
Cyanex 272
nickel extraction
zinc extraction; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110275.pdf Link otwiera się w nowym oknie
Opis:: Solvent extraction was used to recover nickel and zinc from synthetic acidic solution. Many leaching solution and waste waters contain both zinc and nickel at the same time. Bis (2,4,4trimethylpentyl) phosphinic acid (Cyanex 272) and Di(2-ethylhexyl) phosphoric acid (D2EHPA) were used to separate nickel and zinc. In the D2EHPA system, at equilibrium pH of 2, zinc extraction was more than 98% whereas nickel extraction was only 0.36%. The extraction of metals was found to increase with an increase of pH of the aqueous phase. At equilibrium pH 3.5, zinc extraction was completed and higher than 99% zinc was extracted using Cyanex 272. The maximum nickel extractions using D2EHPA and Cyanex 272 were achieved at equilibrium pH 4.5 and 7.5, respectively. Both extractants showed the relatively good separation levels between nickel and zinc. D2EHPA and Cyanex 272 isotherms for single metal solutions showed that the extraction order was Zn2+>Ni2+. ΔpH1/2 value showed that the separation of nickel and zinc using Cyanex 272 was simpler than D2EHPA system. The stripping study was performed using sulphuric acid and it was shown that above 98% zinc and nickel could be extracted. These results demonstrated separation of zinc and nickel from sulphate solutions to be favorable.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Estimation of the cost of equity for mining and cement industries by single-index market model
Szacowanie kosztu kapitału własnego dla zakładów górniczych i cementowni w jednowskaźnikowym modelu rynku
Autorzy:: Taheri, M.
Irannajad, M.
Ataee-Pour, M.
Tematy:: kapitał własny
koszt kapitału
jednowskaźnikowy model rynku
model wyceny
aktywa kapitałowe
cost of equity
cost of capital
single-index market model
CAPM
Tehran Stock Exchange; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Powiązania:: https://bibliotekanauki.pl/articles/216531.pdf Link otwiera się w nowym oknie
Opis:: The corporate cost of capital is used by valuators to discount future flows of income from an entity in order to derive a present-day, forward-looking value of that entity. The cost of capital is therefore determined as the weighted cost of the various sources of funding, being typically equity, debt and preference instruments. The tricky and important part is estimating the cost of equity, which usually needs the application of finance models. The study on the texts on mineral valuation or mineral project evaluation demonstrates that the capital asset pricing model (CAPM) is a general model for estimating the cost of equity. However, according to shortfalls and problems relating to it a relatively similar and simpler model i.e. the single-index market model is proposed. The single index market model is an important tool in contemporary research in finance. Much of the importance of the model follows from its 'beta' parameter which, ideally, measures the sensitivity of returns on a security to changes in a market model. To estimate the cost of equity of the mining and cement companies listed in Tehran Stock Exchange (TSE) The single-index market model is selected because of the shortfalls and problems of the CAPM as well as the lack of commercial services for determining the market premium. The regression analysis as well as the statistical analysis is carried out using Excel spreadsheet. The statistic significance of the model is tested using t and F test statistics. The results showed that the independent variable (the rate of return on the market index) has a genuine effect on the dependent variable (the rate of return for the stock) and there is a statistically significant linear relationship between the two variables at significance level of 5%. Finally, the cost of equity formining and cement companies is estimated 25.0% and 31.0% respectively. Knowing the cost of equity, calculating the discount rate will not be very difficult.
Koszt kapitału przedsiębiorstwa jest używany przez taksatorów przy wyznaczaniu przyszłych zdyskontowanych przepływów pieniężnych podmiotów w celu uzyskania przyszłej ich wartości. Koszt kapitału jest zatem określany przez średni ważony koszt różnych źródeł finansowania, którymi są zwykle akcje, papiery dłużne i instrumenty preferencyjne. Szczególnie trudnym i ważnym elementem jest szacowanie kosztów akcji, które zazwyczaj wymaga zastosowania modeli finansowych. Badania materiałów dotyczących wyceny minerałów i oceny ekonomicznej projektów inwestycyjnych związanych z surowcami mineralnymi pokazują, że model wyceny aktywów kapitałowych (CAPM) jest ogólnym modelem używanym dla szacowania kosztu kapitału własnego. Jednakże, w związku z brakami i problemami z nim związanymi, proponuje się zastosowanie stosunkowo podobnego i prostszego modelu, tj. jednowskaźnikowego modelu rynku. Jednowskaźnikowy model rynku stanowi ważne narzędzie współczesnych badań w zakresie finansów. Główną zaletę tego modelu stanowi parametr 'beta', który w najlepszy możliwy sposób mierzy wrażliwości stopy zwrotu z papierów wartościowych na zmiany zachodzące na rynku. W celu oceny kosztu wkładu własnego dla przedsiębiorstw cementowych i górniczych znajdujących się na Teherańskiej giełdzie papierów wartościowych (TSE) wybrano jednowskaźnikowy model rynku, uwzględniając niedostatki i problemy związane z modelem wyceny aktywów kapitałowych, a także niedobór usług określających rynkową premię ryzyka. Analiza regresji, a także analiza statystyczna, zostały przeprowadzone z użyciem arkusza kalkulacyjnego MS Excel. Istotność statystyczna modelu została zbadana przy użyciu testów statystycznych t i F. Wyniki wykazały, że zmienna niezależna (stopa zwrotu z indeksu rynkowego) ma wpływ na zmienną zależną (stopa zwrotu z giełdy), w związku z czym istnieje istotna statystycznie liniowa zależność między dwoma zmiennymi na poziomie istotności 5%. Koszt wkładu własnego dla potrzeb przedsiębiorstw górniczych i cementowych jest szacowany pomiędzy 25,0% i 31,0%. Przy znajomości kosztu wkładu własnego, obliczenie wysokości stopy dyskonta nie powinno stanowić problemu.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Finite element method based simulation of electrical breakage of iron-phosphate ore
Autorzy:: Razavian, S. M.
Rezai, B.
Irannajad, M.
Tematy:: finite element method
numerical simulation
electrical breakage
iron-phosphate ore
COMSOL Multiphysics; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110295.pdf Link otwiera się w nowym oknie
Opis:: In this study, the effect of minerals composition, particle size and shape as well as electrodes distance from iron-phosphate ore samples, was investigated by using a commercial software. Comparison between high voltage pulses and conventional crushing showed that minerals of interest in the electrical comminution product are better liberated than in the conventional comminution. In order to elucidate and confirm the experimental results, numerical simulation of electrical field distributions/intensity were performed. The software uses the finite element method, a numerical technique for calculating approximate solutions of partial differential equations with known boundary conditions. Magnetite, apatite and quartz were the basic minerals of iron-phosphate ore components, and the main material property used in the simulations was electrical permittivity. The results showed that the induced electrical field was strongly dependent on the electrical properties of minerals, the feed particle size and the location of the magnetite mineral (due to higher permittivity) in the ore. The angle of particle contact surface with high voltage electrode was an important factor in the intensity of electrical field. Smaller contact angle resulted in higher intensity of the electrical field. Electrical discharge within the material was converted to electrohydraulic discharge within the surrounding water environment by increasing the distance between the high voltage electrode and the material contact surface.
Dostawca treści:: Biblioteka Nauki

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