Wyniki wyszukiwania - BazTech

1

Ocena wzbogacalności flotacyjnej rudy złota

Krawczykowska A.

Inżynieria Mineralna

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2017

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R. 18, nr 1

221--226

PL

W artykule przedstawiono wyniki wzbogacania rudy złota. Do badań wykorzystano dwie próbki rudy, znacznie różniące się zawartością tego pierwiastka. Zostały one poddane operacjom przygotowawczym, polegającym głównie na głębokim rozdrobnieniu i klasyfikacji. Porównano wyniki wzbogacania flotacyjnego próbek w dwóch różnych układach wzbogacania: bezpośrednio po rozdrobnieniu oraz po wstępnym wzbogaceniu na stole koncentracyjnym. Flotacja okazała się efektywną metodą wzbogacania badanej rudy, uzyskane koncentraty cechują się wysokimi zawartościami złota, natomiast w odpadach pozostały śladowe jego ilości. Ponadto analiza wyników wykazała, że wprowadzenie wzbogacania grawitacyjnego przed procesem flotacji wpłynęło pozytywnie na jakość flotowanych koncentratów.

EN

The article presents the results of gold ore beneficiation process. Two samples of ore, significantly differed in terms of gold content, were utilized for investigations. Samples were subjected the preparatory operations, consisting of fine comminution and classification. There were compared the results of flotational beneficiation obtained in two different processing circuits: directly after grinding and after pre-concentration operation with using the shaking table. The flotation operation has proven to be an effective method of concentration for this type of ore, the obtained concentrates were of a high gold grade, while the gold contents in tails were very low. In addition, the analysis of the results showed that application of gravity concentration prior to flotation process positively influenced the quality of flotation concentrates.

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Applicability of published experimental works as a knowledge source in recommendation of gold ore processing workflows

Rintala L., Aromaa J., Forsen O.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

707--717

EN

The experimental work is the most time consuming and expensive part of the process design. A case-based reasoning (CBR) methodology can be used to assist in the process design. Auric Adviser is a CBR system under development for recommendation of gold ore processing workflows. In Auric Adviser the knowledge in gold ore processing is represented in two models. The first model holds the knowledge needed to recommend process chains already used in industry. The second knowledge model is intended to recommend the most efficient unit processes based on research results. The objective of this study was to analyse the information richness of journal articles and other publications concerning single process steps of gold extraction. The aim was to study the applicability of these publications as a source for the second Auric Adviser knowledge model. In this study, 25 publications concerning leaching of gold were analysed and information was extracted in a case base. The case base was taken as either a process or experimental description with clearly defined differences to other descriptions. In total, 218 cases that described results of gold leaching were extracted from the sources. The analysis of descriptions showed that the knowledge necessary for design the second Auric Adviser model can be elicited from journal articles and other publications concerning single process steps. The trends in the case description were that the gold content and process outcome were usually well described. Nevertheless, the information richness varied in descriptions of raw materials, experimental arrangements but the results were often missing details. The incompleteness of information causes challenges in the process comparison although it does not prevent the CBR system to work.

3

Mineralogical study of the Drazhnje Prospect (Kosovo) - preliminary report

Kołodziejczyk J., Asllani B., Prsek J.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 1

91--92

EN

The mining activities took place in Kosovo since ancient times. The object of interest at these times was gold and silver ores. One of such old mining areas is located in north-east Kosovo, close to the Batlava Lake. Contemporary works include exploration activities and the goal of this research is to determine the features of mineralisation in that deposit. The name Drazhnje is used interchangeably with Cuka e Batllaves. In the close vicinity, there are known also several other base-metal ore bodies that may be of economic interest. During last years, an exploration gallery was built in Drazhnje, which gave an opportunity to collect mineralogical samples of ore from the upper part of the deposit. The Drazhnje prospect is located in area built of Paleozoic metamorphic complex, Jurassic sediments, ophiolite and Cretaceous flysch sediments. The volcanogenic-sedimentary complex of the Tertiary covers all the older rocks. The mineralisation in Drazhnje prospect is located within marbles, serpentinites and volcanic rocks. Mineralogical study is focused on the sulphide composition of the ore. Minimum two stages of mineralization can be distinguished. During the first one, pyrite, pyrrhotite, sphalerite and galena were formed. The younger stage comprises marcasite, chalcopyrite, arsenopyrite, stannite and Pb-Sb sulphosalts, mainly boulangerite. The gangue minerals are quartz and carbonates. Carbonates of different compositions belong to the youngest minerals in both stages. In the polished sections we have observed that stannite replaces sphalerite, and bournonite replaces galena. Galena is also being replaced by boulangerite. Evidence for boulangerite presence was confirmed by XRD method. Smithsonite was recognized as a main secondary mineral. It occurs as a greenish-to pinkish collomorphic coating on the surface of other minerals or it fills cavities in the ores. The Drazhnje deposit exhibits similarities to other Pb-Zn deposits in the area. The mineralization of stockwork character is hosted mainly by carbonates and its genesis is related to the volcanic activity. Preliminary data on ore chemistry indicate that the content of zinc is higher than content of lead, and is estimated at about 4% and 2%, respectively. In the other deposits of Kosovo, these values are reversed. High content of sulphosalts in the studied deposit, like bournonite and boulangerite, indicates that these minerals could be one of important bearers of lead in the Drazhnje deposit. Content of antimony reaches 0.3 wt. %, which could be correlated with relatively low content of lead (around 2 wt. %). During the field studies, we have confirmed that boulangerite is the most common lead mineral in the upper (reachable) part of deposit, whereas galena is not so common. It is worth to add that some amounts of galena have been replaced by bournonite. In comparison to samples from the other Kosovo deposits, we have noticed unusually high content of stannite, which was found in nearly all of the studied polished sections. Further exploration and start of extraction of the deeper parts of the deposit will allow collecting more samples that are necessery for future mineralogical and geochemical studies.

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Pressure oxidation of pyrite-arsenopyrite refractory gold concentrate

Rusanen L., Aromaa J., Forsen O.

Physicochemical Problems of Mineral Processing

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2013

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Vol. 49, iss. 1

101--109

EN

Refractory gold ores have poor gold recoveries with direct cyanide leaching. Typically the refractoriness is due to encapsulation of the gold particles inside the host mineral. To liberate gold for leaching the host mineral must be broken by mechanical or chemical means. The aim of this study was to study the effect of temperature, oxygen partial pressure and slurry density on pressure oxidation of pyrite-arsenopyrite gold concentrate. Batch oxidation tests in an autoclave were done using a factorial design. Different responses were measured and analysed to study effect of the three factors and oxidation kinet-ics. Generally, high slurry density required high temperature and oxygen partial pressure to reach com-plete oxidation. Oxidation kinetics at 225°C temperature, with 1050 kPa oxygen partial pressure and 15% slurry density was found to be fastest resulting in complete conversion of sulfides in 30 minutes. At 195°C, 700 kPa oxygen partial pressure and 10% slurry density, the oxidation kinetics for complete sul-fide conversion was about 60 minutes. Slurry densities above 10% had an adverse effect on the oxidation rate, when the temperature was below 225°C and oxygen partial pressure below 1050 kPa.