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Wyświetlanie 1-12 z 12
Tytuł:
Influence of lead nitrate on cyanide leaching of gold and silver from turkish gold ores
Autorzy:
Sayiner, B.
Powiązania:
https://bibliotekanauki.pl/articles/109335.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
lead nitrate
gold
silver
cyanide leaching
Opis:
Effect of lead nitrate addition on cyanidation of Havran, Ovacık, Mastra LCu (low copper) and Mastra HCu (high copper) gold ores was investigated by laboratory tests at the Ovacik Gold Mine Metallurgy Laboratory. Leach tests were performed at optimum NaCN additions and pH values while different lead nitrate additions were applied. Ovacik cyanidation plant leaching time, 24 hours for the constant 100 Mg/h ore feed rate was applied as optimal for all lead nitrate tests. Results showed the increase in gold and silver recoveries between 0.4-1.2% for gold and 3.9-11.6% for silver at the end of 24 hours leaching by the addition of lead nitrate as 0.1-0.5 kg/Mg. NaCN consumption decreased or did not change except for the Ovacik ore. In the case of the Ovacik ore it slightly increased.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 507-514
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of the carbon in pulp (cip) process in gold cyanide leaching plants using the plant data
Autorzy:
Sayiner, B.
Powiązania:
https://bibliotekanauki.pl/articles/110084.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
modeling
cyanide leaching
activated carbon
adsorption
gold
Opis:
An improved method to model CIP plants by plant data is presented. The Turkish gold cyanide leaching CIP plants, Bergama Ovacik, Gumushane Mastra and Eskisehir Kaymaz were modeled by using gold concentrations of monthly carbon, solution and solids spot samples of adsorption tanks without a need of laboratory work. Five carbon adsorption models were used namely k-n, Nicol-Fleming, Dixon, Film Diffusion with Langmuir isotherm and Film Diffusion with Freundlich isotherm (Johns model). Several monthly obtained plant data were collected and modeled separately and model parameters as well as regression coefficient R2 values were found by non-linear regression. By comparing R2 values, the best fit model for the three CIP plants was determined as Film Diffusion with Langmuir Isotherm that R2 values were above 0.95. Thus, by using the best fit model, the Kaymaz plant was optimized for existing 49 Mg per hour ore feed tonnage and plant parameters were predicted according to planned feed tonnage increase to 120 Mg per hour.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 2; 841-852
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of pre-aeration on cyanide leaching of a non-refractory sulphide gold and silver ore
Autorzy:
Aydin, B.
Basturkcu, H.
Gul, A.
Powiązania:
https://bibliotekanauki.pl/articles/951867.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
nonrefractory sulphide gold–silver
cyanidation
lead nitrate
hydrogen peroxide
aeration
Opis:
The leaching behaviour of a sulphide gold-silver ore was investigated in terms of a relationship between gold and silver extractions and cyanide consumption. Ninity five Au % and 88.0% Ag extractions were obtained under the determined conditions of 24 h leaching duration, -74 μm particle size, 40% solids ratio, 4 g/dm3 NaCN concentration, and 450 rpm stirring speed with NaCN consumption of 3.35 g/dm3. Since the NaCN consumption was higher than in industrial applications, Pb(NO3)2 and H2O2 additions and aeration using an air pump were tested during leaching in order to decrease the consumption. While Pb(NO3)2 addition with aeration caused a decrease in the metal extractions, the individual or combined additions of H2O2 and aeration could not provide a reduction in the cyanide consumption. Therefore, the effect of the pre-aeration followed by cyanidation was tested. Eventually, applying 4 h of pre-aeration before a shorter leaching duration of 12 h provided 92.0% Au and 90.5% Ag extractions with a reduced NaCN consumption of 2.44 g/dm3.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 647-660
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of hydrogen peroxide and lead(II) nitrate on gold cyanide leaching of Malaysian mesothermal deposit gold ore
Autorzy:
Baharun, Norlia
Ling, Ong Pek
Ardani, Mohammad Rezaei
Ariffin, Kamar Shah
Powiązania:
https://bibliotekanauki.pl/articles/1845218.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold cyanidation
mesothermal lode gold
statistical analysis
design of experiment
Van’t Hoff differential method
Opis:
The gold extraction from Malaysian mesothermal lode gold ore through the cyanidation method was performed. The effect of hydrogen peroxide (H2O2) and lead nitrate Pb(NO3)2 were investigated on the percentage of gold recovery. The statistical analysis method using a response surface design-central composite design was applied to find the optimum condition for gold extraction. The studied parameters were NaCN concentration (300-500 ppm), H2O2 concentration (205-410 ppm), and Pb(NO3)2 concentration (50-150 ppm). It was found that increasing the amount of NaCN and H2O2 as well as decreasing the amount of Pb(NO3)2 in the studied range, increased the gold recovery. The analysis of variance suggested the linear model for the gold extraction with the optimum condition at 467.3 ppm NaCN, 94.96 ppm Pb(NO3)2, and 340 ppm H2O2. The gold extracted from the ore at the optimum condition was 88.97% as compared to 62.02% from conventional cyanidation. The characterization study of the gold ore indicated that the finely gold particles interlocked in the aluminosilicate phase (grain size of ~10.0 μm). The Van’t Hoff differential method justified that the cyanidation was of second order with a specific reaction rate of 0.0501/hour.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 905-918
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chloride–hypochlorite oxidation and leaching of refractory sulfide gold concentrate
Autorzy:
Hasab, M. G.
Rashchi, F.
Raygan, S.
Powiązania:
https://bibliotekanauki.pl/articles/110795.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
refractory gold ore
oxidative pre–treatment
non–cyanide leaching
Opis:
In this research, oxidation of sulfide minerals and leaching of gold from a gold–bearing sulfide concentrate using chloride–hypochlorite solution was investigated. The effects of calcium hypochlorite concentration, sodium chloride concentration and initial pH of leachant on changes of the slurry pH and Eh were examined. Then, considering the stability range of the gold complex (Eh ~ 1000 mV) and for-mation of chlorine gas (pH < 3.5), the optimum leaching parameters were determined. The optimum conditions were obtained at 200 g/dm3 calcium hypochlorite, 200 g/dm3 sodium chloride and initial pH 11 (with 200 g/dm3 concentrate, stirring speed 600 rpm and temperature 25C) at which about 82% gold was extracted in 2 h.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 1; 61-70
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of silver, nickel and copper cyanides on gold adsorption on activated carbon in cyanide leach solutions
Autorzy:
Sayiner, B.
Acarkan, N.
Powiązania:
https://bibliotekanauki.pl/articles/109675.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold
silver
nickel
copper
cyanide leaching
activated carbon adsorption
Opis:
The effect of Ag, Ni and Cu cyanides on gold adsorption on activated coconut carbon in cyanide leach solutions was investigated by synthetic cyanide leach solutions containing gold and other metal cyanides. According to the adsorption tests Ag remarkably reduces the gold adsorption on activated carbon by competing with gold to adsorption sites. When the Ag concentration in solution increases up to 200 ppm the carbon adsorption method for gold recovery becomes inapplicable. Ni has an effect on gold adsorption on activated carbon, however even at as high concentrations of Ni as 250 ppm residual Au in solution is still below 1 ppm. Cu addition up to 300 ppm does not affect the gold loading significantly. According to the adsorption test studies, it is concluded that the metal-cyanides diminish the gold adsorption on activated carbon by adsorbing themselves and competing with gold. When the metals are present in the leach solution all together with gold, they also prevent adsorption of themselves as well as gold. Thus, when Au, Ag, Ni and Cu are present in solution simultaneously, the adsorption of all these metals decreases. The adsorption results were modeled by Fleming k,n adsorption kinetic model.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 277-287
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of lead nitrate and pre-aeration on the deportment of base/precious metals in cyanide leaching of a pyritic refractory gold concentrate
Autorzy:
Hacı, Deveci
Ersin, Yener Yazıcı
Oktay, Celep
Murat, Mercimek
Cumhur, Demirel
Serkan, Çakmak
Melih, Baki Cingöz
Ömer, Hami Kavlu
Hüseyin, Kömürcü
Powiązania:
https://bibliotekanauki.pl/articles/24085578.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold
cyanide leaching
pyrite
copper
refractory ore
lead nitrate
Opis:
This study was undertaken to improve gold and silver extraction from a pyritic gold flotation concentrate, which assayed 11 g/t Au, 42 g/t Ag, 0.21% Cu, 3.57% Zn, and 31% Fe. Direct cyanide leaching of the concentrate at 1.5 g/L NaCN yielded a low gold extraction (37%), confirming its refractory nature. Effects of lead nitrate (200-500 g/t Pb(NO3)2) and pre-aeration (24 h) before cyanide leaching at 1.5-3.5 g/L NaCN were investigated. Earlier studies have focused on the impact of these parameters on gold leaching. Besides gold, this study demonstrated the behaviour of silver and base metals (copper and zinc) from the pyritic gold concentrate. Adding lead nitrate had a negligible effect on gold extraction whilst improving silver extraction. Dissolution of copper was substantially suppressed by adding lead nitrate, i.e., from 23% (no Pb(NO3)2) to 4% (500 g/t Pb(NO3)2) over 24 h. Zinc dissolution was negligible (≤0.01%). Pre-aeration of the concentrate improved the gold and silver extractions by 4-14% and 23-44% at the subsequent cyanide leaching (1.5-3.5 g/L NaCN). However, it did not affect the leaching of copper. Only negligible leaching of zinc (≤0.6%) occurred during cyanide leaching. Pre-aeration also reduced cyanide consumption in subsequent cyanide leaching (1.5 g/L NaCN), i.e., from 2.83 kg/t to 2.03 kg/t NaCN per solids. These results suggested that lead nitrate can improve silver extraction while suppressing copper dissolution, which would be advantageous in the leaching-adsorption circuit (CIP), mitigating the dissolved copper-associated problems. Pre-aeration can also be suitable for improved gold/silver extractions and reduced reagent consumption.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 166259
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gold deposits of the Czech Republic from a mineral policy perspective
Złoża złota w Republice Czeskiej z punktu widzenia polityki surowców mineralnych
Autorzy:
Janíková, P.
Starý, J.
Klika, R.
Kavina, P.
Jirásek, J.
Sivek, M.
Powiązania:
https://bibliotekanauki.pl/articles/216368.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
gold deposit
Bohemian Massif
mineral policy
cyanide leaching
złoże złota
czeski masyw
polityka surowcowa
ługowanie cyjankiem
Opis:
Gold production in the region that currently makes up the Czech Republic has a thousand-year-old tradition with peaks around the third century BC, 14th century AD and 20th century AD. In general, approximately 100 metric tonnes were produced by the end of mining in 1994, of which nearly 9 tonnes were produced in the 20th century and approximately 3 tonnes were produced after World War II. Significant gold deposits were discovered during the last extensive exploration conducted in the 1970s to 1995, motivated by the sharp rise in the price of gold at the beginning of the 1970s and in the 1980s. Fifteen deposits with 239 tonnes of geological resources of gold were registered. Another 112 tonnesare recorded as prognosticated resources. None of these deposits are mined, due to unresolved issues involving environmental protection. The exploitation of these deposits is restricted primarily due to concerns regarding the environmental impacts of the mining and processing of extracted minerals. A key aspect of these restrictions is likely the existing ban on the use of cyanide mining technologies. A new and yet-to-be-approved proposal for an updated mineral policy in the Czech Republic is attempting to gradually change this stance. Yet another problem lies in the unfinished surveys of mineral deposits, which would specify the total amount of gold and upgrade the resources to higher categories concerning the level of exploration. Without these, it is impossible to prepare the necessary economic assessments of potential production and of the deposits to the fullest extent of activities involving exploration, mineral extraction and processing, including subsequent reclamation of affected areas, elimination of mining impacts and regeneration of post-mining landscapes. The future of gold deposits in the Czech Republic also greatly depends on future trends in the price of gold and accompanying (by-product) minerals occurring together with gold in mined ores.
Produkcja złota w Czechach ma ponad tysiącletnią tradycję sięgającą trzeciego wieku przed naszą erą. Ogółem do końca 1994 roku wyprodukowano około 100 ton złota, z czego prawie 9 ton zostało wyprodukowanych w XX wieku i około 3 tony − po II wojnie światowej. Znaczne złoża złota odkryto podczas ostatnich rozległych badań, przeprowadzonych w latach 1970−1995, które determinowane były gwałtownym wzrostem cen złota w latach 1970−1980. Odkryto 15 złóż złota o zasobach geologicznych wynoszących 239 ton. Kolejnych 112 ton złota oszacowano w zasobach prognostycznych. Żadne z tych złóż nie jest eksploatowane z powodu nierozwiązanych problemów dotyczących ochrony środowiska. Eksploatacja tych złóż jest ograniczana przede wszystkim ze względu na obawy dotyczące wpływu na środowisko procesów wydobywczych i przetwórstwa wydobywanych kopalin. Kluczowym aspektem tych ograniczeń jest istniejący zakaz stosowania technologii wydobywczych z wykorzystaniem cyjanku. Nowy, jeszcze nie zatwierdzony, wniosek o zaktualizowanej polityce surowców mineralnych w Czechach, stopniowo stara się zmienić tę postawę. Jeszcze innym problemem są niedokończone badania złóż kopalin, które określą całkowitą ilość złota i spowodują przeszacowanie zasobów do wyższych kategorii. Bez nich niemożliwe jest przygotowanie niezbędnych analiz ekonomicznych, potencjalnej produkcji, rekultywacji obszarów dotkniętych działalnością górniczą. Przyszłość złóż złota w Republice Czeskiej zależy również od przyszłych trendów cen tego surowca i towarzyszących mu (produkt uboczny) minerałów.
Źródło:
Gospodarka Surowcami Mineralnymi; 2015, 31, 4; 35-49
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomic scale study of silver sulfide leaching with cyanide and thiourea
Autorzy:
Bernaola-Flores, Roxana
Silva-Quiñones, Dhamelyz
Balbuena, Perla B.
Rodríguez-Reyes, Juan Carlos F.
Tarazona-Vasquez, Francisco
Powiązania:
https://bibliotekanauki.pl/articles/109763.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
leaching
cyanidation
thioureation
DFT
cluster models
Ag2S
Opis:
Understanding of atomic scale interactions of molecular species with mineral surfaces is needed to bring about mineral processing innovation. In this regard, Density Functional Theory (DFT) methods are well suited. In this work, the outcome of leaching synthetic acanthite –a surrogate for a silver-containing sulfide ore- with both cyanide ion and thiourea are studied with DFT considering solvent effects. The results are correlated to the experimental percentage of silver extracted with each of the leaching agents under similar conditions of molar concentration, temperature and percentage of solids. Our calculations show both leaching reactions to be exergonic and of the same order of magnitude in Gibbs energy of reaction than values determined from thermodynamic tables. Also, less favorable Gibbs reaction energies are obtained for cyanidation in absence of oxygen and thioureation in absence of Fe(II) highlighting the impact of oxidants on the exergonicity of the respective global leaching reactions. Finally, analyzing the percentage of silver extracted from acanthite and the absolute value of Gibbs energies of the respective reaction, we conclude that the more exergonic a leaching reaction, the higher percentage of silver is extracted from acanthite, provided that there is no kinetic control of each of the leaching reactions.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 4; 969-980
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dissolution of gold with cyanide replacingreagents
Autorzy:
Aromaa, J.
Rintala, L.
Kahari, M.
Forsen, O.
Powiązania:
https://bibliotekanauki.pl/articles/109410.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold leaching
ammonium thiosulfate
chloride
thiourea
thiocyanate
Opis:
Cyanide is used in the leaching phase of hydrometallurgical recovery of gold. The toxicity and environmental risks have created a need for safer alternatives. There is a vast amount of information about gold extraction and a selection has been collected and formalized to be used in a decision support tool. The tool Auric Advisor uses case-based reasoning (CBR) to provide process alternatives for the user queries. The aim of this paper is to study leaching of gold with cyanide replacing alternatives such as ammonium thiosulfate, chloride-hypochlorite, thiourea and thiocyanate to provide new cases for the tool. The behaviour of gold was examined with electrochemical tests and weight loss measurements a using quartz crystal microbalance (QCM) were used to determine the dissolution rate. Based on literature, the dissolution rate determined for cyanide solution was 2.5 mgcm-2h-1. Based on polarisation experiments and potential measurements, the ammonium thiosulfate system with cupric ion as oxidant was estimated to dissolve gold slower than cyanide. In the QCM tests the chloride-hypochlorite alternative showed highest dissolution rate of 8.6 mgcm-2h-1 at the redox potential of 900 mV vs. SHE. The thiocyanate system with ferric ion dissolved gold at a rate of 3.4 mgcm-2h-1 at the redox potential of 620 mV vs. SHE. Thiourea system with ferric ion showed the dissolution rate of 1.65 mg cm-2 h-1 at the redox potential of 450 mV vs. SHE. The results of the rapid tests were comparable with literature and were included in the case base of the Auric Advisor decision-support tool.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 269-279
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of leaching kinetics modelling to a gold cyanide leach plant by using real plant data
Autorzy:
Sayiner, B.
Powiązania:
https://bibliotekanauki.pl/articles/109738.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
gold
cyanide
leach
kinetics
model
Opis:
Gold cyanide leach kinetics modeling was applied to the Bergama Ovacik gold cyanide leach plant in Turkey by processing the real plant data without need of any laboratory work. For this aim, solid ore samples were taken from each leaching tanks and analysed for gold contents as Au ppm while plant variables such as solid % concentrations in each tank, feed rate of plant as megagrams per hour (Mg/h), slurry flow rate as m3/h and the slurry residence times in each tank calculated and noted for modelling study. Five sampling work performed at plant at different times. Each sampling data were modelled seperately by the Anglo-American Research Laboratories (AARL) leach kinetics model to obtain five seperate model parameters and regression coefficient (R2) values. Then, total five sampling data were all together modelled to obtain just one model equation and R2 value to represent the plant generally. All R2 values were above 0.90 indicating that the AARL gold leaching kinetics model fits well on real plant leaching conditions. By using the model parameters, the residual gold contents in each tank were predicted for different possible ore feed rate tonnages such as 80, 90, 100, 110 and 120 megagrams per hour. Thus, leaching recoveries for any ore feed rate would be estimated for possible tonnage increases in the future.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 1; 109-114
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prospects for thiourea as a leaching agent in Colombian gold small-scale mining: a comprehensive review
Autorzy:
Borda, Johana
Torres, Robinson
Powiązania:
https://bibliotekanauki.pl/articles/2201416.pdf
Data publikacji:
2022
Wydawca:
Główny Instytut Górnictwa
Tematy:
górnictwo
złoto
cyjanek
tiomocznik
mining
gold
cyanide
thiourea
Opis:
Thiourea, as an alternative medium, is one of the most promising leaching agents for gold recovery by its commercial benefits and research challenges associated with performance and environmental impacts. This review article describes the operational conditions for the use of Thiourea vs cyanide, its chemistry, limitations, toxicity factors, environment, and recovery processes. Although thiourea gold extraction processes have not been applied on a large scale due to the instability of the reagent, its potential to overcome the limitations of cyanide is attractive to the process; with pH, potential, oxidant dosage, and temperature control, solubilized gold thiourea species are achieved. These can be recovered from the pregnant leach solution through methods such as activated carbon absorption and adsorption, polyurethane foams, ion exchange, and electrodeposition.
Źródło:
Journal of Sustainable Mining; 2022, 21, 4; 298--308
2300-1364
2300-3960
Pojawia się w:
Journal of Sustainable Mining
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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