scholarly journals Active carbons for selective flotation of primary gold-copper-porphyry ore

2020 ◽  
Vol 192 ◽  
pp. 02004
Author(s):  
Margarita Gurman ◽  
Abdakim Ashimbayev
Keyword(s):  
Sulfide Minerals ◽  
Active Carbons ◽  
Carbon Coatings ◽  
Selective Flotation ◽  
Copper Porphyry ◽  
Coal Deposits ◽  
Coal Particles ◽  
Quartz Grains ◽  
Primary Gold

The results of a study on the flotation of gold-copper-porphyry ore are presented. The quality of the obtained concentrates is confirmed by the efficiency of using activated carbon to reduce the excess of reagents accumulating in the collective concentrates. Detailed studies of concentrates of copper selection using scanning electron microscopy revealed the presence of carbon in their composition. On the surface of gold and chalcopyrite particles, thin coal deposits and coatings were observed. Flotation of particles of gold and sulfide minerals can probably be improved by naturally hydrophobic or hydrophobized coal particles. “Carbon” coatings are selective with respect to the surface of sulfide minerals. No coal coatings were found on the surface of quartz grains and crystals.

scholarly journals Stability Assessment of Mining Excavations: the Impact of Large Depths

2018 ◽  
Vol 40 (3) ◽  
pp. 180-187
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Łukasz Bednarek
Keyword(s):  
Rock Mass ◽  
In Situ Monitoring ◽  
Stability Assessment ◽  
Underground Excavations ◽  
Deformation Prediction ◽  
Large Depth ◽  
Coal Deposits ◽  
The Impact

AbstractBack in the early 1980s, coal deposits occurring at depths of ~700 m below surface were already regarded as large-depth deposits. Meanwhile, today the borderline depth of large-depth mining has extended to >1,000 m. Design, excavation and maintenance of mining roadways at the depth of >1,000 m have, therefore, become crucial issues in a practical perspective in recent years. Hence, it is now extremely important to intensify research studies on the influence of large depths on the behaviour of rock mass and deformation of support in underground excavations. The paper presents the results of the study carried out in five mining excavations at depths ranging from 950 to 1,290 m, where monitoring stations with measurement equipment were built. The analysis of data from laboratory and coal mine tests, as well as in situ monitoring, helped to formulate a set of criteria for stability assessment of underground excavations situated at large depths. The proposed methodology of load and deformation prediction in support systems of the excavations unaffected by exploitation is based on the criteria referring to the depth of excavation and the quality of rock mass. The depth parameter is determined by checking whether the analysed excavation lies below the critical depth, whereas the rock mass quality is determined on the basis of the roof lithology index (WL) and the crack intensity factor (n)

Factors Influencing the Quality of Carbon Coatings on LiFePO[sub 4]

2007 ◽  
Vol 154 (5) ◽  
pp. A389 ◽  
Author(s):  
James D. Wilcox ◽  
Marca M. Doeff ◽  
Marek Marcinek ◽  
Robert Kostecki
Keyword(s):  
Carbon Coatings ◽  
Factors Influencing

scholarly journals Работа выхода электрона углеродных нанокомпозитных пленок по данным вакуумной и атмосферной фотоэмиссии

2020 ◽  
Vol 90 (6) ◽  
pp. 982
Author(s):  
Д.А. Бокизода ◽  
А.Ф. Зацепин ◽  
Е.А. Бунтов ◽  
А.И. Слесарев
Keyword(s):  
Fermi Level ◽  
Work Function ◽  
Ambient Pressure ◽  
Contact Potential Difference ◽  
Electron Work Function ◽  
Silicon Substrates ◽  
Contact Potential ◽  
Carbon Coatings ◽  
Energy Characteristics

The energy characteristics of carbyne-containing films on copper and silicon substrates have been studied using the methods of optically stimulated electron emission (OSEE) and ambient pressure photoemission spectroscopy (APS). The average contact potential difference and the work function were determined, and the positions of the Fermi level for carbonaceous films of various thicknesses were calculated. It was found that the electron work function and the position of the Fermi level of the studied film samples are independent of the film thickness and the type of substrate. The information capabilities of the OSEE and APS methods for assessing the quality of carbon coatings on various substrates are shown.

scholarly journals Tribological Performance of Si-Doped Hydrogenated Diamond-Like Carbon Coatings in Different Biodiesel

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Annett Dorner-Reisel ◽  
Zeynep Burcu Kavaklioglu ◽  
Stefan Svoboda ◽  
Jürgen Engemann
Keyword(s):  
Methyl Ester ◽  
Biodiesel Production ◽  
Diamond Like Carbon ◽  
Tribological Behaviour ◽  
Carbon Coatings ◽  
Wear Rates ◽  
Si Doped ◽  
Silicon Doped ◽  
Polar Functional Groups

In this paper, two kinds of different biodiesel were tested in terms of their impact on wear resistance of Si-DLC coated 100Cr6 flat worn by an oscillating 100Cr6 ball. The knowledge about the tribological behaviour of different types of biodiesel is rare. Rape and soybean are two of the most common natural sources for biodiesel production. Also, if the quality of biodiesel seems to be similar and, according to the demands, biodiesel from different natural origin could affect changes in the tribological behaviour. Although, soybean methyl ester (SME) gives the best results at room temperature wear tests, 150°C SME reaches wear rates of Si-DLC flat against 100Cr6 ball almost double as high as rapeseed methyl ester (RME). It is evident that, with increasing fraction of oxidation stabilizer C23H32O2, the wear rate increases. For silicon doped hydrogenated diamond-like carbon is especially suitable, for use in biodiesels, where certain fraction of humidity, dissociated water, or polar functional groups may present.

New influence factor inducing difficulty in selective flotation separation of Cu-Zn mixed sulfide minerals

2015 ◽  
Vol 22 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Jiu-shuai Deng ◽  
Ying-bo Mao ◽  
Shu-ming Wen ◽  
Jian Liu ◽  
Yong-jun Xian ◽  
...  
Keyword(s):  
Influence Factor ◽  
Sulfide Minerals ◽  
Selective Flotation ◽  
Mixed Sulfide

scholarly journals Beneficiation and Physiochemical Characterization of Coal Deposits in Achibo-Sombo Area, South-Western Ethiopia

2021 ◽  
Author(s):  
Temam Usman ◽  
Samuel Abicho ◽  
Daniel Meshesha ◽  
Getachew Adam Workneh
Keyword(s):  
Coal Sample ◽  
Calorific Value ◽  
Volatile Matter ◽  
Crystal Structure Analysis ◽  
Fixed Carbon ◽  
Coal Deposits ◽  
Treated Sample ◽  
Coal Particles ◽  
Coal Grade ◽  
Froth Floatation

Abstract This study was conducted to upgrade the quality of Achibo-Sombo coal deposits by physiochemical beneficiation methods particularly by using froth floatation technique to minimize the ash and sulfur content from coal particles. During the floatation test, proximate, ultimate, calorific value, functional groups, surface morphology and crystal structure analysis of Achibo-Sombo coal was carried out through different methods. The moisture content of a raw sample and treated sample is found in the range of 11.81 to 20.27% and 8.12 to 14.02 % respectively. The volatile matter is ranging from 22.74 to 34.85 % for raw coal and 21.92 to 30.64 % for treated coal samples. The ash content of the raw coal sample is ranging from 22.47 to 36.58 % which became in the range 7.49 to 13.62 % after treatment. The fixed carbon is also changed from 23.85–38.31% of raw sample to 44.47–55.87 % for treated coal samples. The calorific value of a raw sample is found in the ranges of 5838.46 Btu/lb. to 9531.29 Btu/lb. whereas for treated coal samples it is found in the ranges of 9438.12 Btu/lb. to 11756.63 Btu/lb. The sulfur and nitrogen contents of the raw coal sample which were ranged from 0.57 to 1.9 % − 1.22 to 1.44 % are reduced to 0.25 to 0.41% -0.52 to 0.92% respectively after treatment. Generally, the Achibo-Sombo raw coal is falling under the coal grade of lignite B to sub-bituminous B whereas the treated coal sample is grouped under sub-bituminous C to high volatile bituminous C. Accordingly, the results obtained indicate that the Achibo coal streams are upgraded relatively with better calorific value and fixed carbon and with lowest ash contents as compared to samples collected from other sites.

scholarly journals The role of digital simulation in assessing and reassessing the potential of complex coal deposits

2020 ◽  
Vol 192 ◽  
pp. 03014
Author(s):  
Vladimir Gavrilov ◽  
Evgenii Khoiutanov ◽  
Natal’ya Nemova ◽  
Dmitrij Son
Keyword(s):  
Rock Mass ◽  
Mineral Content ◽  
Digital Simulation ◽  
Raw Material ◽  
Material Base ◽  
Coal Deposits ◽  
Selective Mining ◽  
External Conditions

The article addresses the increasing complexity of mined or prospective coal deposits. The paper analyses the role of digital simulation in operation assessment and reassessment of the potential of complex in structure coal deposits for more accurate understanding their investment attractiveness, reliability of knowledge on quantity and quality of the reserves. The article stresses the objective need to take into account the realities of the VUKA-world, when companies have to react rapidly to changing of external conditions by adapting organizational and technological measures as much as possible to the constantly overestimated potential of the raw material base. It is of note that reserves should be assessed in accordance with international requirements in the light of the increasing number of parameters for management. The complexity of the structure, the geomechanical heterogeneity of the rock mass, the mineral content of the impurities in the coal, its caking capacity, oxidation and enrichment are taken into account in the estimation. The paper presents the measures to increase the level of utilization of geological potential through the application of selective mining and the control of different quality coal streams in preparation for enrichment and during primary processing.

scholarly journals Valorization of coal mining waste dumps from he mines of Katowicki Holding Węglowy

2017 ◽  
Vol 33 (1) ◽  
pp. 35-50
Author(s):  
Krystian Probierz ◽  
Łukasz Gawor ◽  
Iwona Jonczy ◽  
Marek Marcisz
Keyword(s):  
Coal Mining ◽  
Mining Waste ◽  
Waste Material ◽  
Hard Coal ◽  
Recovery Processes ◽  
Waste Dumps ◽  
Upper Silesian Coal Basin ◽  
Coal Particles ◽  
Hard Coal Mining

Abstract The cataloging of over 220 coal mining dumping grounds after hard coal mining was carried out on the area of the Upper Silesian Coal Basin (USCB). Considering the significant content of coal particles in the waste, these object may be perceived as perspective anthropogenic deposits. In order to define the possibilities of recovery, an attempt of linking the quality of coal in the deposit and the in waste material was performed. Another step is the reclamation and use of dumping grounds after completing effective recovery processes. The purpose of the research was the cataloging, mapping and valorization of coal mining waste dumps from Katowicki Holding Węglowy coal mines, for the needs of reclamation and management of examined objects and defining the potential recovery of coal from the dumps. The valorization of the post-mining waste dumps was done with the use of original methodology, considering the problems of: reclamation, management, accessibility of the dumps as well as environmental hazards. T he directions of the technical reclamation (e.g. landscape objects, tabular dumps) and biological reclamation (e.g. forest direction, mixed reclamation (grass and tree reclamation), grass cultivation, lack of reclamation) were defined. Accessibility with regard to open access/closing of the dump area and the roads leading towards the object were evaluated. T he connection of coal quality in the deposits of KHW S.A. and in waste material enabled the definition and evaluation of the potential possibilities of recovery of coal from the post mining dumping grounds.

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