INTENSIFICATION OF DISPERSED AND FINE-GRAINED SILVER EXTRACTION IN CYANIDE HEAP LEACHING OF GOLD

2020 ◽  
Vol 26 (8) ◽  
pp. 40-48
Author(s):  
Yu. Rubtsov ◽  
◽  
А. Trubachev ◽  
E. Voronov ◽  
A. Lavrov ◽  
...  
Keyword(s):  
Noble Metals ◽  
Ph Value ◽  
Chemical Activation ◽  
Precious Metals ◽  
Federal District ◽  
Heap Leaching ◽  
Sodium Cyanide ◽  
Cycle Duration ◽  
Mining Equipment ◽  
Gold Bearing

Since the cost of gold has increased by an order of magnitude over the past 20 years, gold mining began to be carried out from ores that are not previously acceptable for heap leaching (HL) technology – these are refractory ores with thin and ultrafine inclusions of precious metals, ore with an increased silver content. In the Russian Federation, classical representations in the field of gold and silver HL prevail in design solutions. At the same time, the problem of silver leaching is considered in terms of the associated extraction of the main component. This approach is determined by a limited set of technological measures that have become an integral part of the classic technological regulation: ore crushing to the class –200–40 mm, sodium cyanide consumption at the level of 0,5 kg/t; pH value – 10,5; cycle duration 65 days or more; gold concentration in production solutions – fractions, mg/l; using activated carbon for sorption of noble metals. Processing ores with silver contents of 30 g/t and a more classical approach to gold HL does not allow to increase the degree of extraction. There is a need to modernize the circuit or change the parameters of the technological regulations. The object of the study was a sample of poor quartz ore provided by the customer developing one of the gold and silver deposits of the Far Eastern Federal District, the object was to increase the degree of leaching of silver from poor gold-bearing ores without changing the technological scheme and without attracting additional mining equipment. Critical analysis of literary data was carried out and the main directions of gold production from poor gold-bearing ores were identified. Chemical and mineralogical compositions of silver-containing minerals and ore rocks were investigated. Forms of association of silver with ore minerals and rocks have been established. The option of physical and chemical activation of increase of reactivity of cyanide solutions during heap leaching of silver from poor gold-bearing ores is chosen. In laboratory conditions, it was found that an increase in the concentration of sodium cyanide by 6 times or more contributes to a satisfactory extraction of gold both in agitation and percolation leaching of silver. However, in the latter case, the positive result was obtained only with the use of solutions with increased reactivity

Studies on Hydrometallurgical Treatment of Oxydized Gold-Bearing Copper Ore

2020 ◽  
Vol 989 ◽  
pp. 519-524
Author(s):  
Almaz Kozhonov ◽  
Kulgamal A. Nogaeva ◽  
Aleksei V. Kritskii
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Precious Metals ◽  
Sodium Cyanide ◽  
Cyanide Leaching ◽  
Sulfuric Acid Leaching ◽  
Copper Ore ◽  
Hydrometallurgical Treatment ◽  
Copper Ores ◽  
Gold Bearing

Inherent problems of oxidized gold-bearing copper ores processing and a comparison of hydrometallurgical methods, applied for such materials, are discussed in this article. Studies on sulfuric acid and cyanide leaching have been carried out, using the following sample of oxidized ore from one of the copper deposits (Kyrgyzstan), %: 15 Mg O, 45.6 SiO2, 0.1 S, 20 Ca O, 12.1 Fe2O3, 0.86 Cu, 1.78 Au, 9.61 Ag. Studies have been carried out. Agitation sulfuric acid leaching able to extract up to 29.9% of copper. At the same time, column sulfuric acid leaching able to extract up to 78.5% of total copper and 85.23% of copper presented by acid-soluble compounds. In case of precious metals, the agitation cyanide leaching is able to extract up to 97.6% of gold in 24 h. Increasing the grinding fineness up to 90% - 74 μm reduces cyanidation duration down to 12 h. The consumption of sodium cyanide is 4.8 kg/t of ore. At the same time, column cyanide allows to extract 73.5% Au and 81.9% Ag during 111 days, whereas 52.4% of gold is recovered in the first 10 days. Consumption of sodium cyanide is 5.45 kg/t. The most efficient ways for processing of such materials are proposed.

STALE GOLD-BEARING TAILINGS OF THE BALEIZOLOTO PLANT AND THE PROBLEM OF THEIR DISPOSAL

2021 ◽  
Vol 27 (4) ◽  
pp. 45-54
Author(s):  
G. Yurgenson ◽  
◽  
L. Shumilova ◽  
А. Khatkova ◽  
◽  
...  
Keyword(s):  
Negative Impact ◽  
Chemical Elements ◽  
Raw Materials ◽  
Precious Metals ◽  
Gold Content ◽  
Residential Areas ◽  
Extraction Technology ◽  
Useful Components ◽  
Technogenic Raw Materials ◽  
Gold Bearing

The relevance of the research is the need to recultivate the waste from the enrichment of gold-bearing ores that lie in the immediate vicinity of the residential areas of Baley city, which have a negative impact on the environmental situation in it, as well as to develop a technological approach to the extraction of gold and silver. The purpose of the study is to study the material composition and develop a technology for extracting precious metals. The object of the study is the stale tailings of the ZIF-1 plant “Baleizoloto”. The subject of the study is mineral composition of stale tailings, content of useful components and their extraction technology, the method and methodology presented by mineralogical and chemical analyses of enrichment tailings. Results. The analysis of the tailings dumps’ state of the gold recovery factories of the Baleizoloto plant was carried out. The contents of gold and other chemical elements, among which arsenic, zinc, copper, antimony, and lead predominate, were determined. The gold content prevails in the stale tailings of the ZIF-1 factory, which processed the ores of the Baley deposit, and is in the range of 1.09-1.37 g / t, on average – 1.17 g/t. This determines the prospects for their primary processing. The gold in the clay-sand fraction of the stale tailings is mainly found in thin accretions with quartz, carbonates, pyrite, arsenopyrite, sulfosols, and tellurides. The field of application is processing of technogenic raw materials. Conclusions. It was determined that the sizes of gold inclusions are in the range of 0.7-0.03 mm, the gold penetration varies from 63 to 91.15, and on average is 82.13; the main impurity in gold is silver with a content of 8.85-37%; the average silver content in the tailings of the ZIF-1 factory is 1.85 g/t; the recommended technological scheme for processing stale tailings of ZIF-1 of the Baleizoloto plant has been developed, including the following operations: photoelectron-activation preparation, pelletizing with active solution, heap leaching, two-stage sorption with bubbling with ozone

scholarly journals A Phenomenological Study on the Synergistic Role of Precious Metals in the Steam Reforming of Logistic Fuels on Trimetal-Supported Catalysts

2010 ◽  
Vol 2010 ◽  
pp. 1-12 ◽  
Author(s):  
Abdul-Majeed Azad ◽  
Desikan Sundararajan
Keyword(s):  
Steam Reforming ◽  
Precious Metal ◽  
Noble Metals ◽  
Phenomenological Study ◽  
Supported Catalysts ◽  
Precious Metals ◽  
Jet Fuels ◽  
Metal Loading

Fuel processors are required to convert sulfur-laden logistic fuels (jet fuels, diesel, and coal) into fuel cell quality hydrogen-rich reformate with little or no sulfur for extended periods. Sulfur poisons and deactivates the reforming catalyst, therefore, sulfur-tolerant catalysts ought to be developed. In this paper, the development, characterization, and evaluation of a series of nanoscale ceria-supported reforming catalysts containing three noble metals in low concentration (1 wt% ≤ total metal loading ≤ 1.33 wt%) for the steam-reforming of kerosene (a JP-8 surrogate) are reported. Their performance is quantified in terms of H2yield, tolerance towards sulfur in the fuel, and the on-stream stability and compared with that of monometal and bimetal analogs under identical conditions. Due to the inherent cooperative synergy, a trimetal catalyst was found far superior to its mono- and bimetallic analog containing same amount of the precious metal loading in terms of quality of the reformate (measured by H2level in steady-state) as well as the catalyst longevity on-stream prior to deactivation. At the same time a mechanistic correlation between the distinct role of a given precious metal and the extent of its loading in each of the formulations and quality of the corresponding desulfurized H2-rich reformate was discovered.

scholarly journals Phenol adsorption on high microporous activated carbons prepared from oily sludge: equilibrium, kinetic and thermodynamic studies

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
N. Mojoudi ◽  
N. Mirghaffari ◽  
M. Soleimani ◽  
H. Shariatmadari ◽  
C. Belver ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Pore Volume ◽  
Activated Carbons ◽  
Ph Value ◽  
Chemical Activation ◽  
Bet Surface Area ◽  
Polluted Water ◽  
Oily Sludge ◽  
Maximum Adsorption Capacity ◽  
Adsorption Desorption

AbstractThe purpose of this study was the preparation, characterization and application of high-performance activated carbons (ACs) derived from oily sludge through chemical activation by KOH. The produced ACs were characterized using iodine number, N2 adsorption-desorption, Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The activated carbon prepared under optimum conditions showed a predominantly microporous structure with a BET surface area of 2263 m2 g−1, a total pore volume of 1.37 cm3 g−1 and a micro pore volume of 1.004 cm3 g−1. The kinetics and equilibrium adsorption data of phenol fitted well to the pseudo second order model (R2 = 0.99) and Freundlich isotherm (R2 = 0.99), respectively. The maximum adsorption capacity based on the Langmuir model (434 mg g−1) with a relatively fast adsorption rate (equilibrium time of 30 min) was achieved under an optimum pH value of 6.0. Thermodynamic parameters were negative and showed that adsorption of phenol onto the activated carbon was feasible, spontaneous and exothermic. Desorption of phenol from the adsorbent using 0.1 M NaOH was about 87.8% in the first adsorption/desorption cycle and did not decrease significantly after three cycles. Overall, the synthesized activated carbon from oily sludge could be a promising adsorbent for the removal of phenol from polluted water.

Archaean precious-metal hydrothermal systems, Dome Mine, Abitibi Greenstone Belt. I. Patterns of alteration and metal distribution

1979 ◽  
Vol 16 (3) ◽  
pp. 421-439 ◽  
Author(s):  
B. J. Fryer ◽  
R. Kerrich ◽  
R. W. Hutchinson ◽  
M. G. Peirce ◽  
D. S. Rogers
Keyword(s):  
Greenstone Belt ◽  
Precious Metals ◽  
Hydrothermal Systems ◽  
Tectonic Deformation ◽  
Hydrothermal Quartz ◽  
Abitibi Greenstone Belt ◽  
Two Stages ◽  
Host Rocks ◽  
Chemical Sediments ◽  
Gold Bearing

The Porcupine District, Abitibi Greenstone Belt is one of the most extensive areas of Archaean auriferous mineralization. At least two stages of lode gold emplacement may be recognized. The first involves gold-bearing ferroan dolomite layers with subordinate chert, sulphides, and graphite deposited as laterally extensive chemical sediments at interflow horizons within the mafic volcanic sequence. The second stage is represented by major gold-bearing hydrothermal quartz–albite–dravite veins which transect diverse host rocks including the carbonate chemical sediments. Differences between gold-bearing chemical sediment and auriferous hydrothermal veins, in terms of texture, mineralogy, and nature of inclusions, together with considerations of chemistry are not compatible with local derivation of veins from enveloping chemical sediments or adjacent host rocks. The chemical sediments display slump structures and predate all tectonic deformation. In general, auriferous hydrothermal quartz veins transect bedding and/or schistosity, and are at a low state of internal strain. They appear to have been emplaced late during the second regional fold episode.Au, Ag, and Pd average 10, 2, and 0.1 ppm respectively in ore types at the Dome mine; representing concentration factors of 10 000,40, and 10 times background values in unmineralized metabasalt, and primary igneous rocks worldwide. Au and Ag are inhomogeneously distributed.Mineralized metabasic rocks adjacent to vein stockworks have Ti/Zr and Ti/Al2O3 ratios comparable to tholeiitic basalts, but display variable enrichment or depletion of silica, systematic depletion in Na2O, and where intensely altered significant extraction of calcium. The low Ni and Cr contents of the carbonate layers, together with low Ti/Zr ratios (43–78) of the carbonates and their enveloping mafic schists, are not consistent with the hypothesis that these auriferous rocks are carbonated ultramafics. Massive banded quartz–fuchsite–dravite veins have Cr and Ni abundances averaging 350 ppm, implying hydrothermal transport of these elements. Ti/Zr ratios of 120, together with high Mg, Cr, and Ni abundances in magnesite–dolomite–quartz– chlorite schists which host the banded veins are compatible with a primary komatiitic composition. Mineralized metabasic rocks are reduced (Fe2+/ΣFe = 0.9) relative to rocks with primary background abundances of precious metals (Fe2+/ΣFe = 0.7). This change of oxidation state implies that large volumes of reducing hydrothermal solutions were involved in vein mineralization.

Slow and Fast Transport in Heap Leaching of Precious Metals

2012 ◽  
Vol 94 (3) ◽  
pp. 707-727 ◽  
Author(s):  
Suresh A. Kartha ◽  
Rajesh Srivastava
Keyword(s):  
Precious Metals ◽  
Heap Leaching ◽  
Fast Transport

Determination of Pb2+ in Wastewater by Lead(II)-dithizone-xylenol Orange Tenary Complex Spectrophotometry

2014 ◽  
Vol 1030-1032 ◽  
pp. 301-304 ◽  
Author(s):  
Jian Qi Sun
Keyword(s):  
Standard Deviation ◽  
Ph Value ◽  
Xylenol Orange ◽  
Direct Determination ◽  
Sodium Cyanide ◽  
Relative Standard ◽  
Efficient Recovery ◽  
Wastewater Samples ◽  
Orthogonal Tests

An novel Lead (II)-dithizone-xylenol orange tenary complex spectrophotometry was developed for the determination of Pb2+ in wastewater. For this purpose, the parameters of spectrophotometry such as the detection wavelength, pH value, the dosage of dithizone-xylenol orange and reaction time were studied and optimized through orthogonal tests. The method was linear in the ranges from 2.1×10-3 to 6.0 μg·mL-1 for Pb2+ with R2≥ 0.999. The procedure allowed efficient recovery of the investigated Pb2+ ranging between 95 % and 103 % with a relative standard deviation (RSD) ≤ 2.1 for actual wastewater samples spiked with 1.00, 2.00 and 3.00 μg·mL-1 of standard Pb2+, respectively. These results show the method can be applied to the direct determination of Pb2+ in wastewater, avoiding the use of toxic extrant (chloroform) and masking reagent (sodium cyanide) in the traditional methods and time-consuming procedures, moreover, the investigated method is simple, accurate, reliable, and inexpensive, which implies the potential of this technique for Pb2+ monitoring in wastewater samples.

scholarly journals A Phenomenological Study on the Synergistic Role of Precious Metals in the Steam Reforming of Logistic Fuels on Bimetal-Supported Catalysts

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Abdul-Majeed Azad ◽  
Desikan Sundararajan
Keyword(s):  
Steam Reforming ◽  
Noble Metals ◽  
Phenomenological Study ◽  
Hydrogen Generation ◽  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Precious Metals ◽  
Weight Percent ◽  
Sulfur Tolerance

Fuel processors are required to convert sulfur-laden logistic fuels into hydrogen-rich reformate and deliver to the fuel cell stack with little or no sulfur. Since sulfur poisons and deactivates the reforming catalyst, robust sulfur-tolerant catalysts ought to be developed. In this paper, the development, characterization and evaluation of a series of reforming catalysts containing two noble metals (with total metal loading not exceeding 1 weight percent) supported on nanoscale ceria for the steam-reforming of kerosene is reported. Due to inherent synergy, a bimetallic catalyst is superior to its monometallic analog, for the same level of loading. The choice of noble metal combination in the bimetallic formulations plays a vital and meaningful role in their performance. Presence of ruthenium and/or rhodium in formulations containing palladium showed improved sulfur tolerance and significant enhancement in their catalytic activity and stability. Rhodium was responsible for higher hydrogen yields in the logistic fuel reformate. Duration of steady hydrogen production was higher in the case of RhPd (75 h) than for RuPd (68 h); hydrogen generation was stable over the longest period (88 h) with RuRh containing no Pd. A mechanistic correlation between the characteristic role of precious metals in the presence of each other is discussed.

scholarly journals OBTAINING SOME THERMOD AINING SOME THERMODYNAMIC PARAMETERS CONTAINING ME AINING METACRYLATE AND ALL TE AND ALLYL GROUPS CON YL GROUPS CONTAINING IN COMPOSITION

2019 ◽  
Vol 2019 (1) ◽  
pp. 69-75
Author(s):  
Kh Akhmedov ◽  
Zh Bekpulatov ◽  
G Solijonova ◽  
N Sharifova
Keyword(s):  
Sulfuric Acid ◽  
Acid Treatment ◽  
Noble Metals ◽  
Material Composition ◽  
Rational Analysis ◽  
Sulfuric Acid Treatment ◽  
Chemical Assay ◽  
Sulfide Ore ◽  
Content Of Gold ◽  
Gold Bearing

The article discusses the results of studying the material composition and the development of technology for processing gold-bearing sulfide ore samples. The material composition of the ore samples was studied by spectral, chemical, assay and rational analysis of gold and silver. Based on a study of the material composition of the ore samples, the following conclusions were made: gold and silver are the industry's most valuable components. It is shown that the use of sulfuric acid treatment of a cinder of graviofloraf concentrate can allow to improve the technological performance of the process. As a result of the mixture of gravio-flotation concentrate after sulfuric acid treatment drying, grinding to a size of 95% CL. -0,074+0 mm and subjected to sorption cyanidation. In the initial cake, the content of gold -77.83 u. e. and silver-16.3 u. e., the concentration of sodium cyanide 0.15%, the ratio W:t=2:1; resin AM-2B-5% of the pulp volume, the duration of cyanidation 36 hours.the Content in the tailings of cyanidation of gold - 6.5 u. e., and silver - 4.8 u. e. the Extraction of noble metals in solution and on the resin was 91.65 and 70.55%, respectively. Through extraction of 87.63% gold and 55.6% silver from ore.

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