scholarly journals Synthesis and flotation activity of reagent-collectors based on dithiocarbonyl and phosphoryl derivatives of amino alcohols

2017 ◽  
pp. 32-41
Author(s):  
Nazgul Akimbaeva ◽  
Indira Anuarbekova ◽  
Zhanibek Asylkhanov ◽  
Svetlana Vizer ◽  
Kazbek Yerzhanov ◽  
...  
Keyword(s):  
Gold Recovery ◽  
Synthesis Methods ◽  
Gold Extraction ◽  
Butyl Ether ◽  
Flotation Reagents ◽  
Catalytic Systems ◽  
Selective Enrichment ◽  
Flotation Activity ◽  
Derivatives Of ◽  
Gold Bearing

Research has been carried out to study flotation activity of new surface active substances among dithiocarbonyl and phosphoryl derivatives of monoethanolamine and diethanolamine on the gold-bearing sulphide ore of the Bestobinskoye deposit of Kazakhstan. Among the synthesized compounds, effective collectors for selective enrichment of sulfide polymetallic gold ores were found. Sodium N-octyl-N-2-hydroxyethyldithiocarbamate (AA-41) and sodium O-2-(dimethoxyphosphoryl- 2-hydroxyethylamino)ethylxanthate (GF-2) were proposed as new flotation reagents. They were tested in flotation of gold-bearing polymetallic ore as additional collectors contributing to an increase in percentage of gold extraction in the collective concentrate in comparison with the factory basic regime in which a mixture of butyl xanthate (BX) and ditiophosphate butyl ether or butyl airoflot (BAF) was used. The results of flotation tests indicate that collective ability of GF-2 in combination with BAF provides a higher gold recovery to the concentrate – 90.8%, than gold recovery with BX and BAF is (87.7%). It should be specially emphasized that consumption of GF-2 in comparison with BX is lower on 33%. Synthesis methods of the AA-41 and GF-2 flotation agents were developed, and evidence of their structure was given by IRS and NMR 1Н, 13С. The principal technological scheme of GF-2 obtaining was developed. In synthesis of collector AA-41, one of the principles of “green” chemistry “catalytic systems and processes (as selective as possible) are in all cases better than stoichiometric ones” was used. The use of tetrabutylammonium iodide as catalyst in synthesis allows shorten the reaction time, reduce reaction temperature and increase the selectivity.

scholarly journals Introduction of Mercury-Free Gold Extraction to Small-Scale Miners in the Cabo Delgado Province in Mozambique

2018 ◽  
Vol 8 (19) ◽  
Author(s):  
Birgitte Stoffersen ◽  
Peter WU Appel ◽  
Leoncio D Na-Oy ◽  
Asta Selloane Sekamane ◽  
Ivan Zahinos Ruiz ◽  
...  
Keyword(s):  
Urban Areas ◽  
Extraction Method ◽  
Extraction Methods ◽  
Gold Recovery ◽  
Small Scale ◽  
Gold Extraction ◽  
Governmental Organization ◽  
Free Gold ◽  
Financial Interests ◽  
Gold Bearing

Background. The majority of small-scale gold miners worldwide, including those in Mozambique, use mercury to extract gold. Over the last fifty years, gold production from small-scale mining has been accelerating and consequently the amount of mercury released to the environment has increased dramatically, causing major global health problems. In 2018, a team from the Danish non-governmental organization Diálogos introduced the mercury-free gold extraction method in the Cabo Delgado province in Mozambique in the villages of Waqueia and Nanlia. Objectives. The objective of this project was to teach local miners this method to reduce mercury pollution. An additional objective was to compare the local gold extraction method and the mercury-free gold extraction method in terms of gold recovery. The hypothesis was that the level of gold recovery would be higher with the mercury-free method compared to the locally used amalgamation method. Materials and Methods. An experimental study comparing the two gold extraction methods was carried out where local miners processed gold-bearing ore using their standard procedures with the amalgamation method and the Diálogos team processed an equivalent amount of gold-bearing ore with the mercury-free gold extraction method. The tests were carried out once at each mining site. Results. Under even circumstances in a controlled setting, the mercury-free method yielded up to 78% more gold than the amalgamation method normally used by the miners. Conclusions. The strengths of the mercury-free gold extraction method include low costs, higher gold yield, benign environmental impact, legality and needed chemicals are more readily available compared with the amalgamation method. However, the mercury-free method may be more time consuming than the amalgamation method, especially for beginners. Borax is typically available in developed urban areas, as it is commonly used in the welding industry and by jewelers, but can be hard to find in more remote villages. Competing Interests. The authors declare no competing financial interests.

scholarly journals Performance-Based Selection of the Cathode Material for the Electrodeposition-Redox Replacement Process of Gold Recovery from Chloride Solutions

2021 ◽  
Author(s):  
Ivan Korolev ◽  
Kirsi Yliniemi ◽  
Mari Lindgren ◽  
Leena Carpén ◽  
Mari Lundström
Keyword(s):  
Material Selection ◽  
Recovery Process ◽  
Multiple Attribute Decision Making ◽  
Gold Recovery ◽  
Process Efficiency ◽  
Gold Extraction ◽  
Corrosion Properties ◽  
Multiple Attribute ◽  
Replacement Process ◽  
Cathode Substrate

AbstractRecently, an emerging electrodeposition-redox replacement (EDRR) method was demonstrated to provide exceptionally efficient gold recovery from cyanide-free hydrometallurgical solutions. However, the effect of electrode material and its corrosion resistance in this process was overlooked, even though the EDRR process is carried out in extremely corrosive, acidic chloride solution that also contains significant amounts of strong oxidants, i.e., cupric ions. In the current study, nickel alloy C-2000, stainless steels 316L and 654SMO, and grade 2 titanium were for the first time critically evaluated as potential cathode materials for EDRR. The particular emphasis was placed on better understanding of the effect of cathode substrate on the overall efficiency of the gold recovery process. The use of a multiple attribute decision-making method of material selection allowed reaching of a well-founded compromise between the corrosion properties of the electrodes and process efficiency of gold extraction. The 654SMO steel demonstrated outstanding performance among the examined materials, as it enabled gold recovery of 28.1 pct after 3000 EDRR cycles, while its corrosion rate (CR) was only 0.02 mm/year.

Gravity-flotation gold-bearing ore concentration

2021 ◽  
Vol 1 (1) ◽  
pp. 4-15
Author(s):  
P. K. Fedotov ◽  
A. E. Senchenko ◽  
K. V. Fedotov ◽  
A. E. Burdonov
Keyword(s):  
High Performance ◽  
Gold Recovery ◽  
Gold Content ◽  
Flotation Concentrate ◽  
Stage Scheme ◽  
Study Results ◽  
Ore Minerals ◽  
Concentrate Yield ◽  
Flotation Concentration ◽  
Gold Bearing

The paper focuses on the study of the gold-bearing ore dressability. According to technological research, the average gold content is 11.88 g/t. The silver content is insignificant – 2.43 g/t. Main ore minerals in the sample are pyrite and pyrrhotite. According to mineralogical and X-ray structural analysis, the average content of these minerals in the ore is about 6 % (in total). Main rock-forming minerals of the original ore are: quartz (60.1 %), quartz-chlorite-mica aggregates (3.8 %), carbonates (7.1 %). According to the study results, it was found that the gold recovery in the GRG test was 72.75 % with a total concentrate yield of 1.34 % and a content of 664.78 g/t. At the same time, the gold content in tailings was 3.29 g/t. A stage test showed that it is advisable to use a two-stage scheme for ore processing by gravity technology only. The first stage is in the grinding cycle with the 60–70 % ore size, and the second stage is with the final classifier overflow size of 90 % –0.071 mm. Centrifugal separation has high performance as a free gold recovery operation in the grinding cycle. A concentrate with a gold content of 2426 g/t was obtained with a yield of 0.31 % and a recovery of 63.74 %. The beneficiation of first stage tailings ground to 90 % –0.071 mm at the KC-CVD concentrator (modeling) made it possible to extract gold into a total gravity concentrate (KC-MD + KC-CVD) of 87.25 % with a concentrate yield of 22.63 %. The gold content in tailings was 1.97 g/t. The results of gravity and flotation concentration of the original ore indicate the feasibility of using a combined gravity-flotation technological scheme. In a closed experiment of the initial ore beneficiation according to the gravity-flotation scheme at a natural pH of the pulp (without adding acid), the following products were obtained: gravity concentrate with a gold content of 2426 g/t at a yield of 0.31 % and recovery of 64.06 %; flotation concentrate (after the II cleaning) with a gold content of 122 g/t at a yield of 2.90 % and recovery of 33.01 %; the total gold recovery in the gravity-flotation concentrate was 94.07 % with a yield of 3.21 % and an Au content of 345.87 g/t, the gold content in the flotation tailings was 0.72 g/t.

scholarly journals Possibility of implementation of dry technology of gold-bearing ores roughing: case study of “Gurbey” deposit

2018 ◽  
Vol 56 ◽  
pp. 03012
Author(s):  
Andrey Matveev ◽  
Ivan Lebedev ◽  
Evgeniy Lvov ◽  
Diulustan Osipov ◽  
Dmitry Gavriliev ◽  
...  
Keyword(s):  
Gold Extraction ◽  
Centrifugal Mill ◽  
Free Gold ◽  
Heavy Medium ◽  
Irkutsk Region ◽  
Pneumatic Separation ◽  
Shock Impact ◽  
Ore Treatment ◽  
Gold Bearing ◽  
Air Separator

The aim of the research is to identify the ability/feasibility of dry roughing of ore taking as the example “Gurbey” deposit in Irkutsk Region and to develop a rational scheme for processing ores containing free gold. Studies of the dry processing technology of gold-bearing ore at “Gurbey” deposit with the initial weight of 1,123.8 kg were carried out by semi-industrial plants: the DKD-300 combined shock impact crusher, the CMVU-800 centrifugal mill and the POS-2000 air separator developed by CNMI SD RAS. The sample was subjected to two cycles of crushing and four cycles of grinding followed by pneumatic separation. The circulating load is class +12 mm after the DKD-300 crusher, and for the mill, all screening products are +3 mm, as well as the products of classification -3 + 1 mm of the POS-2000 concentrate. As a result of treatment of the concentration products, 23.93 grams of free gold was recovered (concentration on tables: control, recleaning, concentration of the Mosely minerals by analyzer, magnetic separation, heavy medium separation on bromoform). At the same time, it was established that gold from the ore with initial size of 150 mm can be completely stripped and recovered with the POS-2000 air separator with a particle size of up to 100 microns. At the same time gold extraction into the primary concentrate is up to 60%. Based on the results of the research, a basic scheme for dry roughing of “Gurbey” ore containing “free” native gold was developed using the ore treatment devices: RD-MDV-900, DKD-300 crushers, CMVU-800 centrifugal mill and POS-2000 air separator. The technological scheme is fundamental for gold-bearing ores containing "free" gold of fineness over 100 microns.

scholarly journals Valorization of Biomass Derived Terpene Compounds by Catalytic Amination

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 365 ◽  
Author(s):  
Irina L. Simakova ◽  
Andrey V. Simakov ◽  
Dmitry Yu. Murzin
Keyword(s):  
Transition Metal ◽  
Nucleophilic Substitution ◽  
Transition Metal Complexes ◽  
Production Costs ◽  
Solid Materials ◽  
Catalytic Systems ◽  
Solid Catalysts ◽  
Catalytic Amination ◽  
Derivatives Of

This review fills an apparent gap existing in the literature by providing an overview of the readily available terpenes and existing catalytic protocols for preparation of terpene-derived amines. To address the role of solid catalysts in amination of terpenes the same reactions with homogeneous counterparts are also discussed. Such catalysts can be considered as a benchmark, which solid catalysts should match. Although catalytic systems based on transition metal complexes have been developed for synthesis of amines to a larger extent, there is an apparent need to reduce the production costs. Subsequently, homogenous systems based on cheaper metals operating by nucleophilic substitution (e.g., Ni, Co, Cu, Fe) with a possibility of easy recycling, as well as metal nanoparticles (e.g., Pd, Au) supported on amphoteric oxides should be developed. These catalysts will allow synthesis of amine derivatives of terpenes which have a broad range of applications as specialty chemicals (e.g., pesticides, surfactants, etc.) and pharmaceuticals. The review will be useful in selection and design of appropriate solid materials with tailored properties as efficient catalysts for amination of terpenes.

scholarly journals Bio-Oxidation of a Double Refractory Gold Ore and Investigation of Preg-Robbing of Gold from Thiourea Solution

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1216
Author(s):  
Rui Xu ◽  
Qian Li ◽  
Feiyu Meng ◽  
Yongbin Yang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Active Sites ◽  
Gold Recovery ◽  
Ftir Analysis ◽  
Gold Extraction ◽  
Gold Ores ◽  
Gold Ore ◽  
Thiourea Solution ◽  
Refractory Gold ◽  
Pure Cultures

Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing A. ferrooxidans and L. ferrooxidans was investigated. The results showed that direct thiourea leaching of the as-received DRGO yielded only 28.7% gold extraction, which was due to the encapsulation of sulfides on gold and the gold adsorption of CM. After bio-oxidation, thiourea leaching of the DRGO resulted in gold extraction of over 75–80%. Moreover, bio-oxidation can effectively reduce the adsorption of carbon to gold. XRD, SEM-EDS and FTIR analysis showed that many oxygen-containing groups were introduced on the surface of DRGO during bio-oxidation, while the C=C bond was cleaved and the O–C–O and C–N bonds were degraded, causing a decrease in active sites for gold adsorption. Moreover, passivation materials such as jarosite were formed on the surface of DRGO, which might reduce the affinity of CM for gold in solutions. In addition, the cleavage of the S–S band indicated that sulfides were oxidized by bacteria. This work allows us to explain the applicability of pre-bio-oxidation for degrading both sulfides and CM and increasing gold recovery from DRGO in the thiourea system.

scholarly journals Metodología geometalúrgica para mejorar el proceso de extracción de oro en pequeña escala de la mina Gualconda en Nariño – Colombia

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Gabriel Kamilo Pantoja-Barrios ◽  
Eliana Katherine Molina-Ramírez ◽  
Silvia Natalia Fuentes-Torres ◽  
Fabian Andrés Ramírez ◽  
Jaime Mojica ◽  
...  
Keyword(s):  
Particle Size ◽  
Low Cost ◽  
Size Reduction ◽  
Gold Recovery ◽  
Small Scale ◽  
Operational Parameters ◽  
Particle Size Reduction ◽  
Mineralogical Characterization ◽  
Analytical Technique ◽  
Gold Bearing

In the gold beneficiation processes, the degree of particle size reduction is strongly influenced by the size and shape of the mineral species associated with the economically important metals. The capacity, energy consumption, and costs of the gold-bearing ore processing depend mainly on the operational parameters of the equipment of comminution and gravimetric concentration; therefore, it is essential to characterize the liberation degree of the minerals of interest as function of particle size. The small-scale mining beneficiation plants usually do not consider the liberation of sulfide particles as a requirement to define the grinding size reduction ratio, this is determined empirically, evaluating in which size a higherpercentage of gold recovery is obtained. The methodology proposed in this paper constitutes a low cost analytical technique, using the free software IMAGE-J, to determine the appropriate liberation size for sulfide particles and associated gold particles,as well as the size distribution of gold ore particles. Additionally, the Molycop-Tools software was used to simulate the best grinding strategy based on the liberation results obtained.Through the methodology of automatic image analysis to determine the liberation degree of sulfides, the mineralogical characterization, and the recommendation of a metallurgical processing strategy for the gold-bearing ore based on steady-state simulations, it was possible to establish the appropriate parameters of ball mill grinding and gravimetric concentration of the Gualconda mine in the Department of Nariño, in order to improve the gold recovery and increase the plant capacity.

scholarly journals BEHAVIOUR OF SULFUR, ARSENIC AND ORGANIC CARBON IN A GRAVITY CONCENTRATION OF GOLD FROM REFRACTORY ORE

2020 ◽  
Vol 5 (443) ◽  
pp. 116-125
Author(s):  
Surimbayev Bauyrzhan Nurzhanovich, ◽  
◽  
Kanaly Yernazar Serikuly, ◽  
Bolotova Lyudmila Sergeevna, ◽  
Shalgymbayev Serikbol Tleulesovich, ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sulfide Ores ◽  
Sulfide Sulfur ◽  
Gravity Concentration ◽  
Gold Extraction ◽  
Gold Ore ◽  
Primary Zone ◽  
Degree Of Oxidation ◽  
Concentrate Yield ◽  
Gold Bearing

The results of assay-gravimetric, chemical, mineralogical analyzes of gold ore are presented. According to the content of sulfide sulfur and the degree of oxidation of sulfur gold-bearing ore is assigned to the poor sulfide type of ore in the primary zone. Gold ore refers to refractory carbonaceous arsenic-containing sulfide ores. The gravity concentration of ore was assessed using a laboratory 3-inch Knelson KC-MD3 centrifugal concentrator. According to the results of the GRG test, the total gold extraction was 39.58% with the total concentrate yield of 3.96%. The extraction of gold in the first stage is lower than in the subsequent stages. This indicates the absence of large gold in the ore. The behavior of sulfur and arsenic during gravity concentration is similar to the behavior of gold. These data confirm that the main amount of gold is associated with arsenopyrite (arsenic pyrite) and pyrite. The behavior of organic carbon during gravity is significantly different. Only 3.39% of organic carbon passes into the gravity concentrate from ore, which reduces the persistence of the concentrate. Most of the organic carbon (96.61%) remains in the tails of gravity. The content of components in the total gravity concentrate was: Au 21.63 g/t, S 6.40%, As 0.82%, C(organic) 0.58%. The extraction of the components in the total concentrate is as follows, %: Au 39.58; S 34.52; As 27.27; C(organic) 3.39.

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