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1

Role of ammonium phosphate in improving the physical characteristics of malachite sulfidation flotation

Ibrahim Ayman M., Jia Xiaodong, Cai Jinpeng, Su Chao, Yu Xingcai, Zheng Qifang, Peng Rong, Shen Peilun, Liu Dianwen

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 1

art. no. 161510

EN

In this study, ammonium phosphate ((NH4)3PO4) was employed to realize improvement by modifying the physical characteristics of the malachite surface, ensuring sustainable flotation throughout the flotation operations, and enhancing the flotation process to be more stable. Furthermore, various techniques, including X-ray photoelectron spectroscopy, were intensely used to investigate the configuration and physico-chemical surface characteristics through micro-flotation experiments, contact angle and zeta potential measurements, and XRD, ToF-SIMS, EPMA, and FTIR spectrum analyses. The FTIR findings showed that new characteristic peaks of -C(=S)-N.H. groups formed and adsorbed on the surfaces of malachite at 1636 cm-1. The -CH2 groups throughout the flotation process, further promoted the attachment of the CH3 ligand to the Cu2+ ion, and the XPS analysis confirmed this. Consequently, it can be concluded that (NH4)3PO4 played a substantial part in the improved recovery rate, as demonstrated and confirmed by the methods carried out in this study. Thus, it was used to modify the physical properties surface before adding Na2S to efficiently enhance malachite floatability and reduce the loss rate of malachite. Regarding the alterations in the physical characteristics which occurred to the malachite surface, and as a consequence of increasing the recovery results of flotation, the malachite sample treated initially with (NH4)3PO4 exhibited micro flotation results with a considerably greater flotation recovery than malachite treated initially with only Na2S ions.

2

Insight into the effect of galvanic interactions between sulfide minerals on the floatability and surface characteristics of pyrite

Yang Bo, Tong Xiong, Xie Xian, Huang Lingyun

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 2

24--33

EN

Complex sulfide ores are usually found as a mixture of various sulfide and gangue minerals, and froth flotation is the predominant method for the selective separation of sulfide minerals. Adherence and contact between sulfide minerals are inevitable during froth flotation, and galvanic interactions between sulfide minerals will occur because of differences in rest potentials. However, the effect of these galvanic interactions on the selective flotation of sulfide minerals have been rarely studied. In this work, the effect of the galvanic interaction between pyrite and sphalerite on the flotation behavior and surface characteristics of pyrite was investigated by micro-flotation tests, collector adsorption tests, electrochemical techniques and XPS (X-ray photoelectron spectroscopy) surface analysis. The micro-flotation tests indicated that the floatability of pyrite decreased in the pH range of 4.0 to 9.5 and increased under strongly alkaline pH conditions (pH > 10) due to the galvanic interaction. The collector adsorption results demonstrated that the adsorption capacity of the collector on the pyrite surface was significantly reduced because of the galvanic interaction between pyrite and sphalerite. The electrochemical measurements revealed that the decrease in the oxidation current of xanthates to dixanthogen was responsible for the decreasing adsorption capacity of the collector on the pyrite surface. The XPS results indicated that the formation of the S"O$ "% oxidation product on the pyrite surface decreased at a strongly alkaline pH due to the galvanic interaction. Therefore, pyrite floatability improved at an alkaline pH. These results consistently showed that the galvanic interaction between pyrite and sphalerite had an important influence on the floatability and surface characteristics of pyrite.

3

Understanding the difficult selective separation characteristics of high-ash fine coal

Yang Zili, Liu Min, Chang Guohui, Xia Yangchao, Li Ming, Xing Yaowen, Gui Xiahui

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 5

874--883

EN

As the supply of high-quality coals decreases and mechanical coal mining becomes more widespread, the high selective recovery of high-ash fine coal has become a prominent problem in the flotation process. Herein, we discuss the main reasons why the selective separation of high-ash fine coal is difficult. The analysis of high-ash fine coal properties shows that coarse particles (0.25-0.5 mm) account for 22.53% of the total size fraction and that 57.90% of the coal is moderate- or high-density (+1.4 g/cm3) intergrowth. Grinding experiments show that the traditional rod mill has little impact on the liberation of the intergrowth. Instead, its main function is to adjust the particle size composition to ensure that the particle sizes of high-ash fine coal are within the particle size range suitable for flotation. The flotation results show that a clean coal yield of 30.42%, with a 12.46% ash content, is obtained with the optimal flotation parameters through the roughing and cleaning flotation process. However, the flotation results also show that in the separation of high-ash fine coal, it is difficult to obtain clean coal with a high yield and low ash content at the same time. This is mainly due to the similar floatability of moderate-density and low-density coal particles, which allows a large number of moderate-density coal particles to be recovered, and a significant slime coating of clay on the coal’s surface that is generated during the flotation process. The results of this work provide valuable guidance for high-ash fine coal industrial flotation applications.

4

Influence of High-Voltage Electromagnetic Pulses on Technological Properties of Diamond Crystals and Kimberlite Rock-Forming Minerals

Anashkina N. E., Bunin Igor Zh., Khachatryan G. K.

Inżynieria Mineralna

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2019

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R. 21, nr 1/2

133--138

EN

For optimization of diamond processing technology the influence of nanosecond high voltage pulses on mechanical and technological properties of diamond crystals and kimberlite rock-forming minerals (calcite, olivine, serpentine) was investigated. Using methods of Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), microscopy and mikrohardness measurement the changes of structural, physic-chemical surface properties, and microhardness of minerals as the result of impacts, was studied. Non-thermal impacts caused a decrease of kimberlite rock-forming minerals microhardness in general to 40–66% as the result of surface microstructure destruction which is caused by formation of micro cracks, traces of surface breakdown and other defects. At the same time, the pulse energy impact on natural diamonds led to formation of B2 type crystal lattice microsift defects, elevated concentration of which increases the hardness properties of crystals. The obtained result indicates possibility of applying pulsed energy effects to improve the softening efficiency of diamond-bearing kimberlites rock-forming minerals without damaging the diamond crystals and ensuring their preservation by the subsequent grinding of ores. The effect of increasing the natural diamonds flotation activity by 14% (from 47% to 61%) was experimentally established as a result of processing diamond crystals with nanosecond pulses (~ 10–50 sec), which indicates the principal possibility of using pulsed energy impacts to intensify the diamond flotation during processing diamond-bearing kimberlites.

PL

W celu optymalizacji technologii przeróbki diamentów zbadano wpływ impulsów wysokiego napięcia nanosekundowego na właściwości mechaniczne i technologiczne kryształów diamentu i minerałów tworzących skały kimberlitowe (kalcyt, oliwin, serpentynit). Przy pomocy metod spektroskopii w podczerwieni z transformacją Fouriera (FTIR), rentgenowskiej spektroskopii fotoelektronowej (XPS), mikroskopii i pomiaru mikrotwardości badano zmiany strukturalnych, fizykochemicznych właściwości powierzchni oraz mikrotwardości minerałów w wyniku uderzeń. Uderzenia nietermiczne spowodowały zmniejszenie mikrotwardości minerałów tworzących skały kimberlitowe ogólnie do 40–66% w wyniku zniszczenia mikrostruktury powierzchni, spowodowanego powstawaniem mikropęknięć, śladów rozpadu powierzchni i innych wad. Jednocześnie wpływ energii impulsu na naturalne diamenty doprowadził do powstania defektów mikroprzesunięcia sieci krystalicznej typu B2, których podwyższone stężenie zwiększa właściwości twardości kryształów. Uzyskany wynik wskazuje na możliwość zastosowania efektów pulsacji energii w celu poprawy wydajności zmiękczania zawierających diamenty minerałów tworzących skały jak kimberlity, bez uszkadzania kryształów diamentu i zapewnienia ich zachowania w czasie późniejszego mielenia rudy. Efekt zwiększenia naturalnej aktywności flotacyjnej diamentów o 14% (z 47 do 61%) ustalono eksperymentalnie w wyniku przetwarzania kryształów diamentu za pomocą impulsów nanosekundowych (~ 10–50 sekund), co wskazuje na główną możliwość wykorzystania energii pulsacyjnej. Impulsy wpływają na intensyfikację flotacji diamentów podczas przetwarzania kimberlitów zawierających diamenty.

5

Effect of surface oxidation in air and water on hydrophobicity and floatability of a bituminous coal

Wen Baofeng, Xia Wencheng, Sokolovic Jovica M.

Archives of Mining Sciences

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2019

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Vol. 64, no. 1

223--233

EN

Fresh bituminous coal was stored in air-/water-oxidation conditions after 20 and 80 days, respectively. FTIR results show that the Hydrophilicity Index (HI) value of air-oxidized coal is higher than that of water--oxidized coal. SEM results show that the surface roughness of water-oxidized coal is higher than that of air-oxidized coal and water-oxidized coal surface has more holes and chips than air-oxidized coal surface. Flotation results show that the floatability of water-oxidized coal is worse than that of air-oxidized coal. The flotation performance of both air-/water-oxidized coals can be improved at larger collector dosages. The air-oxidation processes changed the HI value of coal greater than the water-oxidation processes while the water-oxidation processes changed the surface morphology of coal greater than the air-oxidation processes. Both the changes in HI value and surface roughness of coal determine the flotation behavior of oxidized coal. The changes in the surface morphology of coal particles after oxidation processes may be the primary factor determining the floatability of coal particles while the changes in the HI value of coal particles may be the inferior factor.

PL

Świeży węgiel bitumiczny przechowywano w warunkach sprzyjających procesom utleniania, w obec-ności wody i powietrza, odpowiednio przez 20 i 80 dni. Badania metodą spektroskopii w podczerwieni z transformatą Fouriera (FTIR) wykazały że wskaźnik hydrofilności (HI) węgla podlegającego utlenianiu w obecności powietrza jest wyższy niż w przypadku węgla poddanego oddziaływaniu wody. Wyniki badań z użyciem mikroskopu elektronowego wykazują, że powierzchnia węgla który uległ utlenieniu pod wpływem powietrza i wody wykazuje większą ilość nierówności i szczelin niż powierzchnia węgla poddanego oddziaływaniu powietrza. Badania procesu flotacji wskazały, że flotacyjność węgla podle-gającego utlenianiu pod wpływem wody jest wyższa niż w przypadku węgla poddanego oddziaływaniu powietrza. W przypadku obydwu węgli poddawanych oddziaływaniu powietrza i wody, ich flotacyjność można poprawić poprzez zwiększenie dozowania w dużych kolektorach. Procesy utleniania w obecności powietrza prowadzą do zmiany wskaźnika HI węgla w większym stopniu niż ma to miejsce w przypadku węgla poddanego działaniu wody; z kolei utlenianie w obecności wody w znacznie większym stopniu wpływa na strukturę powierzchni węgla. Zarówno zmiany wartości wskaźnika HI jak i nierówności po-wierzchni w dużej mierze określają zachowanie węgla w trakcie procesu flotacji. Zmiany w strukturze powierzchni cząstek węgla po procesie utleniania mogą okazać się być głównym czynnikiem decydującym o zachowaniu węgla w trakcie procesu flotacji; z kolei wydaje sięże zmiany wartości wskaźnika HI dla cząsteczek węgla mają znaczenie drugorzędne.

6

Flotation behavior of nickel sulfide ore in a cyclonic flotation column

Deng L., Li G., Cao Y., Ma Z.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

770--780

EN

This study aimed to show the flotation behavior of a nickel sulfide ore in a cyclonic flotation column. The flotation experiments were carried out using a sample of nickel sulfide ore obtained from a mineral processing plant of China. Representative samples collected from the feed, concentrate, tailing, and circulation middling were sieved using a cyclonic particle analyzer to collect different size fractions for analysis. The function of the column cyclonic zone of was evaluated by comparing the quality of tailing and circulation middling. The flotation results showed that the concentrate with Ni grade of 1.78% and recovery of 65.56% was obtained under given test conditions. The content of main sulfide minerals and coarse particles in the circulation middling was higher than that in the tailing. The results indicated that, unlike conventional cyclone classification, separation achieved in the cyclonic zone of the column was not dependent on the particle size and density. Sulfide minerals with good floatability were easily captured by bubbles and moved toward the center of the column, even if these particles were coarser and heavier.

7

Charakterystyki hydromechaniczne decydujące o zachowaniu się uszkodzonego statku powietrznego na powierzchni wody

Boyke J.

Prace Naukowe Politechniki Warszawskiej. Transport

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2013

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z. 92

5--20

PL

Wypadki lotnicze związane z lądowaniem awaryjnym skłoniły autora do przeanalizowania czy lądowanie awaryjne na akwenie wodnym jest lepszym rozwiązaniem z punktu widzenia bezpieczeństwa ludzi, mienia i środowiska naturalnego, niż lądowanie na płycie lotniska. Jeśli przyjmiemy, że miarą bezpieczeństwa jest ryzyko wypadku. Biorąc pod uwagę fakt, że autor zajmuje się problematyką bezpieczeństwa obiektów oceanotechnicznych w stanie uszkodzonym, zdecydowano się na przedstawienie w artykule podstawowych elementów modelu zachowania się statku powietrznego w ostatniej fazie podchodzenia do lądowania awaryjnego na akwenie wodnym i zachowaniu się na swobodnej powierzchni wody. Podano warunki równowagi oraz opisano pływalność i stateczność statku powietrznego po wykonaniu manewru awaryjnego lądowania na wodzie. Przedstawiono problemy związane z modelowaniem zachowania się statku powietrznego na swobodnej powierzchni wody w tym problemy związane z stateczności i pływalności zarówno w stanie uszkodzonym, jak i nieuszkodzonym. Opisano też problemy związane z określeniem czasu ewakuacji i czasu ewentualnego zatapiania statku powietrznego na skutek utraty integralności kadłuba.

EN

The accidents connected with an emergency landing of the air craft have been the reason to analyze if the emergency landing on the free surface of water is a better form the safety of human, property and environment point of view than landing in the airport. Assuming that the measure of safety is the risk. Taking into account that the author work is connected with the safety of ocean engineering objects in damaged conditions a decision has been made to present in the paper the major elements of the model for analyzing the motions of a air craft in close proximity to the water surface. The buoyancy conditions have been given and the floatability and stability conditions have been described for the conditions after the air craft landing on the free surface of water. The problems regarding the time for evacuations and the so-called time for flooding after the loss of air craft hull integrity is described.

8

Improving floatability of taixi anthracite coal of mild oxidation by grinding

Xia W., Yang J., Zhao Y., Zhu B., Wang Y.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 2

393-401

EN

Grinding is widely used in ore size reduction. In this investigation, grinding is proved to be advantageous in improving the floatability of anthracite coal of mild oxidation. FTIR was used to explain changes in the main functional chemical groups of anthracite coal of mild oxidation upon grinding. Improvements of the floatability of four size fractions, namely, +0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and -0.074 mm, were discussed respectively. The results show that the floatability of anthracite coal of mild oxidation can be improved by 30 minutes grinding. The anthracite coal of mild oxidation can obtain many fresh hydrophobic surfaces by scuffing. Besides, the anthracite coal of mild oxidation can be crushed and/or ground to form fines which also contain many fresh hydrophobic surfaces. Combustible matter recovery of anthracite coal of mild oxidation, ground by 30 minutes, can reach 72.14% with ash content of 8.63%, while combustible matter recovery of original coal is 56.65% with ash content of 9.90%.

9

Activation of oxidized surface of anthracite waste coal by attrition

Sokolovic J. M., Stanojlovic R. D., Markovic Z. S.

Physicochemical Problems of Mineral Processing

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2012

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Vol. 48, iss. 1

5-18

EN

In this paper the activation of oxidized surface of anthracite waste coal was investigated. Coal weathering leads to physical and chemical changes on the coal surfaces and a reduction of its hydrophobicity and floatability. The changes and the presence of oxygen functional groups in the structure and surfaces coal was confirmed by the FTIR study on the raw and waste coal. The groups have remarkable impacts on surface charge and thus flotation kinetics. The floatability of oxidized coal may be improved by the creation of fresh, unoxidized surfaces on coal by attrition at high solid concentration prior to introducing coal to the froth flotation process. This paper presents the results of the effects of attrition on the floatability of the oxidized surface of waste coal, coal pyrite and alumino-silicate minerals through electrokinetics and microflotation experiments. The results show that the attrition, in the viscous pulp with the solid content of 50%, lead to the mechanical cleaning of oxidized surface and activation of the surface of coal particles, which agrees with the change of zeta potential and increasing floatability of coal by 10%. Obviously that the mechanical scrubbing may be able to restore the natural floatability of superficially oxidized coal by removing the thin oxidation layer from the coal surface. The results show that attrition time is an important parameter from the point of view of activating the oxidized coal surface, and positive changes in zeta potential and floatability. The change of zeta potential, as a measure surface charge state of coal particles, from -15 mV to about 0 mV, after attrition for 30 minutes, confirms positive application of attrition. Zeta potential approaching 0 mV resulted in increasing floatability down to the real possibilities of the attrition process prior the coal flotation.

10

Floatability and stability of floating dock-docked ship system

Stasiak J.

Polish Maritime Research

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2005

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S 1

39-45

EN

An analysis of floatability and stability of the floating dock- docked ship system is the subject of this paper. These properties are considered for a cubicoid box dock whose dimensions are close ( almost identical) to those of SINE 212 CD dock designed by SINUS design office. The analysis is first of all aimed at determination of the above mentioned hydromechanical properties in the light of the relevant requirements of PRS dealing with minimum freeboard of the dock and its initial metacentric height. It has been concluded that the analyzed dock reveals the designed docking capability which is not constrained by the PRS requirements though the dock in question is fitted with the roofing unfavourable for dock stability. It has been shown that assessing the tranverse stability of the dock as well as of docked ship ( floating object) by means of a stability factor instead of metacentric height, is reasonable. The work was performed within the frame of EUREKA – E! 2968 ECOLOGICAL DOCK research project.