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1

The effect of water quality change on copper flotation

Acuña Claudio, Aedo Camila, Leiva Claudio, Flores Víctor

Physicochemical Problems of Mineral Processing

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2023

|

Vol. 59, iss. 5

art. no. 186190

EN

Given the significant consumption and future demand for water resources, this paper intends to find the conditions for using a flotation process with different water quality. One of the alternatives is using water under secondary treatment with industrial water mixtures to partly recycle domestic wastewater and maximize metallurgical benefits. Results show that using wastewater (only with secondary treatment) in flotation is detrimental to copper recovery. However, molybdenum recovery is significantly improved. For mixtures with 50 [%] wastewater, 50 [ppm] frother, 20 [ppm] collector, and pH 10, copper recovery decrease amounts to 0.4 [%], while molybdenum shows a 2.4 [%] recovery increase. In addition, copper concentrate grade decreases by 1.4 [%], while molybdenum grade remains. Therefore, using wastewater is viable, particularly in the case of molybdenum. So, this study proposes using of water mixtures in the copper depression stage to improve molybdenum recovery.

2

Research on New Al-Ag-Mo Alloys Dedicated to Wire Applications in Overhead Power Lines

Grzebinoga Justyna, Mamala Andrzej, Ściężor Wojciech, Kowal Radosław

Journal of Casting & Materials Engineering

|

2023

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Vol. 7, no. 1

9--14

EN

The latest research work in the field of electric power systems focuses on the development of new wire materials which will allow the increase of the transmission capacity of power lines currently in use. The reason for this research was the often limited possibilities of continuous and failure-free transmission of electricity. In this paper, the authors present research on a new aluminium-based alloy dedicated for use as a conductive braid in the HTLS cable group. There are many technical solutions for this group of cables on the market, although they are solutions with a number of disadvantages, ranging from their high price, various operational shortcomings, complicated installation techniques, and ending with the risk of monopolistic practices, which is related to the inability to attract several competitive suppliers. The main aim of the research was to develop a new alloy based on aluminium with the addition of silver and molybdenum dedicated for use in special overhead power cables. Experimental research on new materials focused on obtaining the necessary knowledge to produce an overhead wire from these alloys with higher current carrying capacity in relation to the currently used conventional wire materials based on aluminium.

3

The influence of selected transition elements on cell metabolism

Terpiłowska Sylwia, Rafińska Katarzyna, Gołębiowski Adrian, Kowalkowski Tomasz, Buszewski Bogusław

Ecological Chemistry and Engineering. S

|

2023

|

Vol. 30, nr 4

471--488

EN

The elements are present in the environment. Moreover, they are used in pharmacy and the production of new materials used in medical applications. They are often as environmental pollutants. They can accumulate in organisms and induce toxic effects on the cellular level. HepG2, L929 and Caco-2 cell lines were exposed to known concentrations of chromium chloride, iron chloride, nickel chloride, molybdenum trioxide and cobalt chloride (200 or 1000 μ M used alone and in combinations). Concentrations of chromium, iron, nickel, molybdenum and cobalt in the cell lysate and the culture medium were determined by ICP-MS. Moreover, sodium, potassium, calcium and magnesium concentrations were also measured. What is more, cells were observed under light and scanning electron microscope. The dose-dependent increase in the concentration of chromium, iron, nickel, molybdenum and cobalt in all cell lines after incubation with elements was observed. Potassium concentration decreases while sodium calcium and magnesium increase after incubation of cells with of mentioned elements. The incubation of cells with microelements induces cell morphology changes. The presented study shows the crucial role of tested microelements in the induction of cell death as a result of an imbalance of sodium, potassium, calcium and magnesium concentration inside the cell.

4

Separation of molybdenite from chalcopyrite, using graphene oxide as a novel depressant

Namiranian Afshin, Noaparast Mohammad, Tonkaboni Sied Ziaedin Shafaei

Archives of Mining Sciences

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2023

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Vol. 68, no. 1

71--86

EN

In this research, graphene oxide was introduced as an efficient flotation reagent for the selective separation of molybdenite from chalcopyrite. The performance of graphene oxide and its adsorption mechanism on chalcopyrite were investigated by flotation tests, FTIR spectra, and XPS measurements. First, graphene oxide was synthesised, and then its performance was evaluated by SEM, XRD, and EDX. Flotation tests were carried out in a hallimond flotation cell with a volume of 300 ml. Optimum flotation values were achieved at pH = 9 by adding 250 g/t of PAX (Potassium Amyl Xanthate) as a collector and 50 g/t of A65 (Poly Propylene Glycol) as a frother. The results showed high recovery, around 80% for molybdenite, while chalcopyrite was depressed in high amounts by employing 11 kg/t of graphene oxide as a depressant. Compared to common chalcopyrite depressants such as NaHS, Na2S, and C2H3NaO2S, graphene oxide had a higher potency in depressing, which can be applied as a green-depressant in the separation of molybdenite from chalcopyrite by the flotation process. Also, the validity of the depressing effect on chalcopyrite was verified by XPS and FTIR spectra.

5

Online X-Ray Fluorescence Monitoring of Coarse Ore for Silver at the Process Conveyors at Kazakhmys Corporation LLC

Nigmatulin Aydar, Abdrakhmanova Zaure, Kan Andrey, Efimenko Sergey, Makarov Dmitry

Inżynieria Mineralna

|

2020

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no. 1, vol. 2

145--148

EN

This paper examines the process and methodological aspects of implementing online X-ray fluorescence monitoring of ore in terms of its silver, cadmium, zinc, lead, molybdenum, and iron grade at the process conveyors at Balkhash and Karagaily Concentrators and the main conveyor of the Nurkazgan underground mine operated by Kazakhmys Corporation LLC. The research was complicated by the need to: a) ensure reliable measurement of silver and cadmium in the range of 1+ ppm, molybdenum in the range of 10+ ppm, as well as copper, zinc, lead, and iron in the ore size class –300 mm; b) implement monitoring of the grade of these elements (except molybdenum) at Balkhash Concentrator in the waste slag of Balkhash Copper Smelter, characterized by a very complex elemental matrix. A modification of the ore monitoring station RLP-21T (by Aspap Geo LLC, Alma-Ata) was developed, implemented, and thoroughly tested for online monitoring of low-grade silver ore flows. Energy dispersive X-ray fluorescence method was adopted for ore assays. Instrument spectra were measured every second. Silver, cadmium, and molybdenum grade was calculated based on 40 measurements, copper, zinc, lead, and iron grade – based on 20 measurements.

PL

W artykule przeanalizowano proces i aspekty metodologiczne wdrażania zdalnego monitorowania zawartości srebra, kadmu, cynku, ołowiu, molibdenu i żelaza w zakładach wzbogacania Balkhash i Karagaily oraz na głównym przenośniku w kopalni podziemnej Nurkazgan obsługiwana przez Kazakhmys Corporation LLC. Badania były skomplikowane ze względu na konieczność: a) zapewnienia niezawodnego pomiaru srebra i kadmu w zakresie 1+ ppm, molibdenu w zakresie 10+ ppm, a także miedzi, cynku, ołowiu i żelaza w klasie –300 mm; b) wdrożyć monitorowanie tych pierwiastków (z wyjątkiem molibdenu) w koncentracie Balkhash ,w żużlu odpadowym Huty Miedzi Balkhash, charakteryzującym się bardzo złożoną matrycą elementarną. Opracowano, wdrożono i dokładnie przetestowano modyfikację stacji monitorowania rudy RLP-21T (firmy Aspap Geo LLC, Alma-Ata) do monitorowania online przepływów rudy srebra o niskiej jakości. Do fluorescencji rentgenowskiej zastosowano dyspersyjną metodę rentgenowską. Widma mierzono co sekundę. Zawartość srebra, kadmu i molibdenu obliczono na podstawie 40 pomiarów, a miedzi, cynku, ołowiu i żelaza – na podstawie 20 pomiarów.

6

Otrzymywanie syntetycznych cząstek MoS2 za pomocą metody mokrej

Wojtalik Michał, Przybyt Przybysław, Zubańska Katarzyna, Żuchowska Monika, Bojarska Zuzanna, Arasimowicz-Andres Monika, Rożeń Antonii, Makowski Łukasz

Przemysł Chemiczny

|

2019

|

T. 98, nr 11

1817--1821

PL

Przedstawiono pełną procedurę otrzymywania syntetycznych nanocząstek disiarczku molibdenu za pomocą metody mokrej. W tym celu zastosowano roztwory heptamolibdenianu amonu, siarczku amonu oraz kwasu cytrynowego jako katalizatora reakcji. Proces prowadzono w sposób ciągły, stosując reaktory zderzeniowe. Podano metodę separacji MoS₂ z mieszaniny poreakcyjnej oraz jego krystalizacji. Przeprowadzono również badania nad potencjalnymi zastosowaniami uzyskanego produktu.

EN

(NH₄)₆Mo7O₂₄, (NH₄)₂S and citric acid solns. were introduced into the impinging jet reactor with coaxial and tangential type inlets to obtain MoS₂ nanoparticles. The resulting ppt. was washed with water, dried at 50oC for 24 h and calcined in a furnace under Ar for 1 h. The particle size distribution was detd. by using a laser diffraction particle size analyzer. Sepd. particles smaller than 300 nm were dispersed in engine oil and their effect on rheol. and tribol. properties was examd.

7

Tunable passively Q-switched ytterbium-doped fiber laser using MoWS₂/rGO nanocomposite saturable absorber

Mohanraj J., Velmurugan Venugopal, Sivabalan Sivaraj

Opto-Electronics Review

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2019

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Vol. 27, No. 1

18--24

EN

We demonstrated a tunable Q-switched ytterbium-doped fiber laser (YDFL) using MWS₂/rGO nanocomposite as passive saturable absorber. Further, the Mo₁₋xWxS₂/rGO nanosheets, with x proportion of 0.2, are synthesized using hydrothermal exfoliation technique. The proposed nanocomposite-PVA based thin film is fabricated by mixing the MoWS₂/rGO nanosheets with polyvinyl alcohol (PVA). The fabricated thin film is sandwiched between two fiber ferrules to realize the proposed saturable absorber (SA). Further, the proposed MoWS₂/rGO-PVA based thin film SA exhibits a fast relaxation time and a high damage threshold which are suitable to realize a Q-switched pulsed laser with a tunable wavelength range of 10 nm that extends from 1028 nm to 1038 nm. For the highest pump power of 267.4 mW, the generated Q-switched pulses exhibit a narrow pulse width of 1.22 μs, the pulse repetition rate of 90.4 kHz, the highest pulse energy of 2.13 nJ and its corresponding average power of 0.193 mW. To the best of author’s knowledge, this is the first realization of a tunable Q-switching fiber laser in a 1 μm wavelength using MoWS₂/rGO nanocomposite saturable absorber.

8

Microstructure and Corrosion Behaviour of Co-Mo/TiO2 Nano-Composite Coatings Formed on Disk and Wire Electrodes by Electrodeposition

Krawiec H., Vignal V., Latkiewicz M.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

23--28

EN

The influence of the electrode geometry on the microstructure and corrosion behaviour of Co-Mo nano-crystalline coatings elaborated by electrodeposition is studied. The corrosion behaviour was determined in the Ringer’s solution at 25°C. Electrodeposition mechanisms are also discussed as a function of the electrode geometry. The electrode geometry was found to affect the growth rate and, under certain conditions, the microstructure (existence of channels and pores). It does not have influence on the corrosion behaviour.

9

Influence of Dissolved Oxygen on the Corrosion Behaviour in Ringer's Solution and Artificial Saliva of Co-Mo Nano-Crystalline Coatings Electrodeposited on Co and 316L Substrates

Vignal V., Krawiec H., Latkiewicz M.

Archives of Metallurgy and Materials

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2019

|

Vol. 64, iss. 1

39--43

EN

The influence on the corrosion behaviour of Co-Mo nano-crystalline coatings of dissolved oxygen is studied in the Ringer’s solution and artificial saliva at 25°C. This was done by means of potentiodynamic tests and surface observations. It was shown that dissolved oxygen has no influence on passivity, oxidation of the coating and selective dissolution of cobalt. By contrast, dissolved oxygen affects corrosion. General corrosion was observed in the Ringer’s solution whereas pitting corrosion was found in artificial saliva.

10

Związki boru, kobaltu, manganu i molibdenu w procesie odzyskiwania fosforanów ze ścieków z hodowli zwierząt

Hutnik N., Stanclik A., Piotrowski K.

Przemysł Chemiczny

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2018

|

T. 97, nr 2

294--298

PL

Wydzielano struwit w sposób ciągły z wodnych roztworów fosforanów zawierających także charakterystyczne składniki obecne w gnojowicy: bor, kobalt, mangan i molibden. Wykazano, że bor, kobalt i molibden, w przeciwieństwie do manganu, sprzyjały otrzymywaniu dobrze wykształconych kryształów struwitu. Kobalt i molibden nie zmieniały standardowego pokroju kryształów struwitu (La/Lb ok. 6), ale mangan i bor (obecne w układzie procesowym) zwiększały te proporcje geometryczne odpowiednio do 7,7, a nawet do 9,1. Krystalizacja struwitu przebiegała najlepiej w obecności boru. Liniowa szybkość wzrostu wyniosła ponad 2·10-8 m/s, a szybkość zarodkowania była mniejsza niż 2·108 1/(s·m3). Kobalt i mangan wydzieliły się jako wodorotlenki, a ich zawartość w fazie stałej wynosiła odpowiednio 393 mg/kg i 749 mg/kg.

EN

Struvite was continuously pptd. from aq. solns. of phosphates in presence of B, Co, Mn and Mo salts contained in liq. manure. The B, Co and Mo compds. (in contrast to Mn compds.) favored well-formed struvite crystals. Neither Co nor Mo changed the std. geometrical proportions of struvite crystals, while Mn and B increased the proportions. Struvite crystn. run well in the presence of B. The linear growth rate was more than 2·10-8 m/s, and the nucleation rate was less than 2·108 1/(s·m3). Co and Mn were sepd. as hydroxides and their content in solid phase was 393 mg/kg and 749 mg/kg Mn, resp.

11

Development of Chemosorbent Based on Metallic Waste for Cleaning Mine Water from Molybdenum

Isakov A. E., Matveeva V. A., Chukaeva M. A.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 1

42--47

EN

The article presents the results of hydrochemical studies of water objects, located in the impact zone of one of the largest mining enterprises in the Russian Federation – JSC “Apatite”. According to the monitoring studies, the source of surface water pollution with molybdenum was determined, geochemical assessment of the molybdenum transformation in the system “ore-bearing rocks – mine water – surface water” was performed. In order to reduce the technogenic load on the surface water located in the considered area, the way of large-tonnage mine waters purification from molybdenum was proposed. The method involves using the chemical sorbent based on waste metals. The method of sewage purification will allow solving one of the key environmental problems of the considered enterprise and, in addition, to improve the environmental situation in the considered area as well as the quality of the local population life.

12

Preparatyka materiałów elektrodowych z aktywnymi cząstkami molibdenu w osnowie grafenowej

Ciszewski M.

Rudy i Metale Nieżelazne Recykling

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2017

|

R. 62, nr 10

60

13

Zastosowanie losowej metody pobierania próbek do monitorowania stężeń molibdenu w wodzie przeznaczonej do spożycia na terenach wybranych miast województwa dolnośląskiego

Garboś S., Święcicka D., Kaniowska-Klarzyńska E.

Instal

|

2017

|

nr 12

54--56

PL

Molibden jest biopierwiastkiem, którego niedobór w organizmie człowieka może prowadzić do poważnych schorzeń. Z drugiej strony narażenie na nadmierne ilości tego pierwiastka może powodować szereg negatywnych skutków zdrowotnych. Dane literaturowe dotyczące pobrania molibdenu ze spożywaną wodą w Polsce nie były do tej pory opublikowane. W ramach niniejszej pracy przeprowadzono oznaczenia molibdenu w próbkach wody przeznaczonej do spożycia pobranych z trzech obszarów problemowych województwa dolnośląskiego za pomocą metody losowego pobierania próbek wody – zalecanej w monitorowaniu stężeń metali. Wyznaczone średnie tygodniowe stężenia molibdenu w wodzie przeznaczonej do spożycia dostarczanej na terenach stref zaopatrzenia Wrocławia, Kłodzka i Janowic Wielkich wynosiły odpowiednio 0,868 μg/l, 0,185 μg/l i 1,96 μg/l. Ponieważ obliczone na tej podstawie współczynniki zagrożenia są niskie (HQ<<1), można stwierdzić, że narażenie na ten metal pobierany z wodą jest znikome. Dodatkowo, spożywana woda na terenie ww. miejscowości wnosi niewielki wkład do całkowitego średniego dobowego pobrania tego metalu (0,31-3,3%) oszacowanego na poziomie 120 μg/dobę. Na terenach, na których eksploatowano rudy metali, średnie dobowe pobranie molibdenu wraz z wodą przeznaczoną do spożycia jest nieznacznie wyższe i może dochodzić do 8,7% zalecanego dziennego spożycia w przypadku osób dorosłych.

EN

Molybdenum is a bioelement whose deficiency in the human body can lead to serious illness. On the other hand, exposure to excessive amounts of this element can cause a number of adverse health effects. Literature data on the intake of molybdenum with water intended for human consumption in Poland has not been published so far. In this work molybdenum was determined in samples of drinking water collected from three problem areas of the Lower Silesian Voivodeship using the Random Daytime sampling method – recommended for monitoring of metal concentrations. The average weekly concentrations of molybdenum in drinking water supplied in the supply areas of Wroclaw, Klodzko and Janowice Wielkie were 0.868 μg/l, 0.185 μg/l and 1.96 μg/l, respectively. Because the hazard indexes calculated on this basis are low (HQ<<1), it can be concluded that the exposure to this metal taken from water is negligible. In addition, consumed water in the individual supply zones contributes little to the total daily average metal intake (0.31-3.3%) estimated at the level of 120 μg/day. In areas where metal ores are mined, the average daily intake of molybdenum with drinking water is slightly higher and may reach 8.7% of the Recommended Dietary Allowance for adults.

14

Fitoakumulacja molibdenu i manganu w koniczynie białoróżowej (Trifolium hybridum L.) i babce pospolitej (Plantago major L.)

Stojek M.

Biuletyn Państwowego Instytutu Geologicznego

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2017

|

nr 470

81--87

PL

Badania zawartości molibdenu i manganu w powierzchniowej warstwie gleb i roślinach przeprowadzono w okolicy Jabłonek w Beskidach Wschodnich w rejonie występowania łupków menilitowych i piaskowców z Otrytu. Pracę wykonano w celu zbadania zawartości molibdenu i manganu w roślinach oraz określenia wskaźnika bioakumulacji tych pierwiastków w dwóch gatunkach roślin (Trifolium hybridum L. i Plantago major L.). Oznaczenia Mo wykonano metodą ICP-MS, a Mn analizowano metodą ICP-OES. Stwierdzono wyższe zawartości Mo w Trifolium hybridum L. na terenie występowania łupków menilitowych (w liściach – 14 mg/kg) niż na terenie piaskowców z Otrytu (w liściach – 0,30 mg/kg). Najwięcej Mn gromadzi się w liściach (86–257 mg/kg). Wskaźnik bioakumulacji Mo poszczególnych gatunków roślin jest różny, jego wartości zmieniają się w zakresie 0,13–1,13. Najwyższym wskaźnikiem bioakumulacji molibdenu (1,13) cechuje się Trifolium hybridum L., występująca na terenach łupków menilitowych.

EN

Studies of molybdenum and manganese content in topsoil and plants were carried out in the Eastern Beskids (Carpathians) in area of occurrence of menilite shales and the Otryt sandstones. The aim of the study was to evaluate the content of molybdenum and manganese in plants and the determination of a bioaccumulation of these two chemical elements in two species of plants (Trifolium hybridum L. and Plantago major L.). Mo symbols were performed by means of ICP-MS method, and Mn were analyzed by means of ICP-OES method. Result of studies in the Trifolium hybridum L. have shown higher content of Mo in the area of occurence of menilite shales (in leaves – 14 mg/kg) than in the Otryt sandstones (in leaves – 0.30 mg/kg). Most Mn accumulates in leaves (86–257 mg/kg). The bioaccumulate indicator of Mo in individual plant species is different and ranges from 0.13 to 1.13. The highest rate of bioaccumulation of molybdenum (1.13) can be observed in Trifolium hybridum L., which inhabits areas of menilite shales.

15

The Influence of Mo Content on Phase Transformation in Ti-Mo Alloys

Sochacka P., Miklaszewski A., Jurczyk M.

Archives of Metallurgy and Materials

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2017

|

Vol. 62, iss. 4

2051--2056

EN

Titanium β-type alloys are a class of interesting biomaterials that can exhibit a unique combination of mechanical as well as physicochemical and biological properties. The aim of this study is to develop a titanium-molybdenum alloys (Ti-x at % Mo, x = 15 and 23). These materials were prepared by the combination of mechanical alloying and powder metallurgical process. The details of the processing method were presented. The samples were characterized by X-ray diffraction, scanning electron micros-copy, chemical composition determination as well as density and Vickers microhardness measurements. The corrosion behaviour in Ringer solution was investigated, too. The crystallization of the obtained material upon annealing led to the formation of a near single β type alloys. The molybdenum content in titanium and heat treatment parameters of a nearly amorphous phase allow to synthesize Ti(β)-type alloys. The present study has demonstrated that Ti23Mo alloy can be the next generation of biomaterial for bone tissue engineering.

16

Local resistance of heating molybdenum sheet in a test device

Mitka M., Bastovansky R., Brumercik F., Ignaciuk P.

Advances in Science and Technology. Research Journal

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2017

|

Vol. 11, no 3

87--93

EN

Large demand for bulk of sapphire optical products, which are widely used as illuminators, optical windows in aviation and aeronautics etc., generates the inquiry of effective production of high quality industrial crystals. The technology of crystal growth with the horizontal single crystal sapphire crystallization method is based on putting the crystal seed into the front of the crucible resistant to temperatures up to 2150°C. Without encompassment of the production technology of this special container made from thin molybdenum sheet is not realistic to consider the productive exploitation of horizontal crystallization systems in engineering practice. This paper presents the analysis of the possibility of the local resistance of molybdenum sheet heating by its deep drawing to obtain better drawing properties by increased blank temperature.

17

Odzysk molibdenu ze złomów metodami hydrometalurgicznymi

Kopyto D., Leszczyńska-Sejda K., Benke G., Wroński G.

Rudy i Metale Nieżelazne Recykling

|

2016

|

R. 61, nr 11

476--483

PL

W artykule przedstawiono sposób odzysku molibdenu z materiału złomowego zawierającego: 47,4% Fe; 24,8 %Ni; 19,2% Cr oraz 4% Mo. Zaproponowana metoda, polega w pierwszej kolejności na roztwarzaniu materiału w kwaśnym roztworze chlorku miedzi(II) w temperaturze 50°C, z wysoką, ponad 99,9% wydajnością. Następnie, na selektywnym rozdziale molibdenu od pozostałych składników roztworu, stosując sorpcję jonów molibdenu z zastosowaniem jonitu MP62 i elucję tych jonów 15% roztworem NaOH. Z powstałych po elucji roztworów krystalizuje się Na2MoO4·2H2O o zawartości: 39,8% Mo, 18,7% Na.

EN

The paper presents a method for molybdenum recovery from scrap material containing: 47.4% Fe; 24.8% Ni; 19.2% Cr and 4% Mo. The proposed method is based firstly on material dissolution in copper chloride(II) acidic solution, in the temperature of 50°C, with high efficiency above 99.9%. The next step is a selective separation of molybdenum from other solution elements by sorption on the MP62 ion exchanger and 15% NaOH elution. After elution process of solutions, there is crystallized Na2MoO4·2H2O, containing: 39.8% Mo, 18.7% Na.

18

Wpływ molibdenu na proces krystalizacji, mikrostrukturę i właściwości siluminu 226

Szymczak T., Gumienny G., Pacyniak T.

Prace Instytutu Odlewnictwa

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2016

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Vol. 56, no. 3

193--204

PL

W niniejszym artykule przedstawiono wyniki badań siluminu podeutektycznego z dodatkiem molibdenu przeznaczonego do odlewania ciśnieniowego. Badania obejmowały analizę termiczną i derywacyjną procesu krystalizacji, analizę metalograficzną mikrostruktury odlewów wykonanych w próbniku ATD i ciśnieniowych oraz określenie podstawowych właściwości mechanicznych siluminu. Do badań przeznaczono silumin gatunku 226, który jest typowym siluminem do odlewania pod ciśnieniem. Do tego siluminu wprowadzano zaprawę AlMo8 w ilości pozwalającej na uzyskanie stężenia Mo w stopie po około 0,1; 0,2; 0,3; 0,4 i 0,5%. Badania procesu krystalizacji wykazały analogiczny przebieg krzywych ATD siluminu bez dodatku Mo oraz siluminów zawierających około 0,1; 0,2; 0,3 i 0,4% Mo. Wykazano zmianę w procesie krystalizacji badanego siluminu wywołaną zwiększeniem stężenia Mo do 0,5%. Zmiana ta polegała na wystąpieniu dodatkowego efektu cieplnego na krzywych ATD, który nie występował w siluminie bez dodatku Mo i siluminach o mniejszym jego stężeniu. W mikrostrukturze siluminu odlewanego do próbnika ATD zawierającego 0,3−0,5% Mo wystąpiły fazy, których nie obserwowano w stopach bez badanego dodatku i o mniejszym jego stężeniu. W odlewach ciśnieniowych fazy te wystąpiły we wszystkich badanych siluminach z dodatkiem Mo. Wymiary tych faz zwiększają się wraz ze wzrostem stężenia Mo w siluminie. Przeprowadzone badania podstawowych właściwości mechanicznych siluminów odlewanych pod ciśnieniem wykazały, że największą wartość wytrzymałości na rozciąganie Rm i wydłużenia względnego A uzyskano dla siluminu 226 z dodatkiem 0,4% Mo. Stanowi to wzrost Rm o 7,6% i A o 13,8% w ujęciu względnym w stosunku do siluminu 226 bez dodatku Mo. Największą wartość umownej granicy plastyczności Rp0,2 i twardości HB uzyskano dla siluminu 226 bez dodatku Mo.

EN

The article presents the results of studies of hypoeutectic silumin with a molybdenum addition used for pressure casting. The studies included a thermal-derivative analysis of the crystallization process, a metallographic analysis of the microstructure of casts made in a DTA tester and pressure casts, as well as the determination of the basic mechanical properties of the silumin. For the tests, silumin 226 was selected, which is a typical silumin for pressure casting. The AlMo8 master alloy was introduced into the silumin in an amount allowing the Mo concentration in the alloy to be about 0.1; 0.2; 0.3; 0.4 and 0.5%. The examination of the crystallization process showed an analogous course of the DTA curves of the silumin without the Mo addition and the silumins containing about 0.1; 0.2; 0.3 and 0.4% Mo. A change in the crystallization process of the examined silumin was established, caused by an increase of the Mo concentration to 0.5%. This change consisted in the occurrence of an additional thermal effect on the DTA curves, which did not take place in the silumin without the Mo addition or in the silumins with lower Mo concentrations. The microstructure of the silumin cast into the DTA tester with 0.3−0.5% Mo contained phases which were not observed in the alloys without the examined addition or with its lower concentrations. In the pressure casts, these phases were present in all the examined silumins with the Mo addition. The dimensions of these phases increase with the increase of the Mo concentration in the silumin. The performed studies of the basic mechanical properties of the silumins cast under pressure showed that the highest value of tensile strength Rm and unit elongation A were obtained for silumin 226 with the addition of 0.4% Mo. This constitutes an increase of Rm by 7.6% and of A by 13.8% in relative terms with respect to silumin 226 without the Mo adszczególdition. The highest values of yield strength Rp0.2 and hardness HB were obtained for silumin 226 without the Mo addition.

19

Application of D-optimal design for optimizing copper-molybdenum sulphides flotation

Nakhaei F., Irannajad M., Sam A., Jamalzadeh A.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

252--267

EN

Froth flotation is widely used for concentration of base metal sulphide minerals in complex ores. One of the major challenges faced by flotation of these ores is selection of the type of flotation reagents. In this study, the D-optimal experimental design method was applied to determine the optimum conditions for flotation of copper and molybdenum in the rougher flotation circuit of the Sungun copper concentrator plant. The investigated parameters included types and dosages of collectors and frothers, diesel dosage and feed size distribution. The main effects on copper and molybdenum recoveries and grades were evaluated. Results of optimization showed that the highest possible grade and recovery were obtained for Z11 as a primary collector (20 g/Mg), R407 as a first promoter collector (20 g/Mg), X231 as a second promoter collector (7 g/Mg), A65 (15 g/Mg) and Pine oil as frothers (5 g/Mg), 20 g/Mg of diesel dosage, and d80 of feed size was equal to 80 μm. The analysis of variance showed that the primary promoter collector was the most significant parameter affecting the recovery of Cu, while diesel dosage and d80 were the most significant parameters influencing the Mo recovery.

20

Odporność na utlenianie warstw krzemkowych na molibdenie i stopie TZM

Moskal G., Witala B., Mościcki A., Kałamarz P., Supernak W., Niemiec D., Wrona A., Osadnik M.

Ochrona przed Korozją

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2016

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nr 2

46--52

PL

W artykule przedstawiono wyniki badań charakteryzujące odporność na utlenianie krzemowanego metodą proszkową czystego molibdenu oraz stopu TZM, zawierającego dodatkowo tytan, cyrkon oraz węgiel. Badania odporności na utlenianie przeprowadzono w powietrzu w temperaturze 1200°C w warunkach quasi izotermicznych. Próbki do badań pobierano po 25, 50 i 100 godzinach testu. Wykazano, że o trwałości powłoki krzemkowej na molibdenie i jego stopach decyduje jej jakość, a szczególnie obecność pęknięć i ich zdolność do samozaleczania. W powłokach typu MoSi2 obecność pęknięć penetrujących do materiału podłoża gwałtownie przyspiesza proces niszczenia stopu podłoża, a efekt samozaleczania nie jest obserwowany. W obszarach powłoki wolnych od pęknięć jej trwałość w warunkach utleniania była bardzo dobra.

EN

Results of investigations characterizing oxidation resistance of pure Mo and TZM alloy (with addition of Ti and Zr) after siliconizing process in activated pack were showed in this article. The oxidation test was made in laboratory air at temperaturę 1200°C in quasi isothermal conditions. The specimens to microstructural investigations were taken after 25, 50 and 100 hours of exposure. The durability of silicide’s coatings on Mo and TZM alloy is related strongly to their quality and especially to: presents of microracks as well as ability to self-healing process. In the case of MoSi2 type of coatings the presents of deeply penetrating microcracks suddenly increased the failure process of substrate materials, and the self-healing effect was not observed. In the areas of coatings free from discontinuities the durability of silicide layer was very good in oxidation test condition.