SPECIATION FEATURES OF GOLD IN ORES AND MINERALS OF THE NATALKINSKOE DEPOSIT (NORTH-EAST RUSSIA)

IF 0.8 Q4 GEOCHEMISTRY & GEOPHYSICS

Geodynamics & Tectonophysics Pub Date : 2022-02-10 DOI:10.5800/gt-2022-13-2s-0595

R. Kravtsova, A. S. Makshakov, V. L. Tauso, O. Belozerova, V. Tatarinov

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引用次数: 0

Abstract

The distribution and speciation features of gold in ores and minerals of the Natalkinskoe gold deposit (North-East Russia) are studied using light microscopy (LM), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX), X-ray electron probe microanalysis (EPMA), "phase" chemical analysis with atomic absorption spectrometry (PCA-AAS) and atomic absorption spectrometry with analytical data selections for single crystals (AAS-ADSSC). The vein and streaky-vein ores are high-grade ores, whereas veinlet-disseminated ores are less rich and disseminated ores are poor in gold. Up to 85 % of the gold in the ores is in a free native state, associated with quartz and sulfide minerals. LM, SEM-EDX and EPMA reveal that the predominant gold grains are 0.01 to 2.00 mm in size and at a fineness of 720 to 900 ‰. The finely dispersed and submicron elemental gold particles (Au0) amounted to 20 % and are mainly enclosed into arsenopyrite and pyrite. According to PCA-AAS data, the highest Au concentrations (up to 1383 ppm) are recorded in arsenopyrite; lower contents are typical of pyrite (up to 158.2 ppm). In these sulfides, two non-mineral species of "invisible" Au are the structurally bound and surface-bound species recognized by AAS-ADSSC. The structural Au is included in the mineral structure. The surface-bounded Au prevails and is confined to nano-sized, non-autonomous phases (NAPs) on the sulfide surface. In common with "invisible" Au, the micro-sized particles of native gold are often observed on the surface and within the surface layers of sulfide crystals. This is consistent with the model of post-growth transformations of nano-sized NAPs, resulting in the formation of nano and micro-sized Au0 particles. It is expected that the major part of gold contained in arsenopyrite and pyrite as finely dispersed and submicron particles, as well as the surface-bound gold in NAPs, can be won with modified current schemes of gold concentration, which enhances the value of the gold ore mining.

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俄罗斯东北部纳塔金斯克矿床矿石及矿物中金的形态特征

采用光学显微镜(LM)、扫描电子显微镜(SEM-EDX)、x射线电子探针显微分析(EPMA)、原子吸收光谱“相”化学分析(ca - aas)和原子吸收光谱法(AAS-ADSSC)研究了俄罗斯东北部Natalkinskoe金矿床矿石和矿物中金的分布和形态特征。脉状和条纹脉状矿石为高品位矿石，细脉浸染型矿石含金量较低，浸染型矿石含金量较低。矿石中高达85%的金处于游离天然状态，与石英和硫化物矿物伴生。LM、SEM-EDX和EPMA分析表明，金晶粒尺寸为0.01 ~ 2.00 mm，细度为720 ~ 900‰。细小分散的亚微米单质金(Au0)占20%，主要包裹在毒砂和黄铁矿中。根据PCA-AAS数据，毒砂中记录的金浓度最高(高达1383 ppm);硫铁矿的典型含量较低(高达158.2 ppm)。在这些硫化物中，AAS-ADSSC识别的两种“看不见”的非矿物金是结构结合的和表面结合的。构造金包含在矿物结构中。表面结合的Au普遍存在，并且局限于硫化物表面的纳米级非自治相(nap)。与“看不见的”金一样，天然金的微小颗粒经常在硫化物晶体的表面和表层内被观察到。这与纳米尺寸的nap生长后转化的模型一致，导致纳米和微尺寸的Au0颗粒的形成。通过对现有选金方案的改进，可以获得砷黄铁矿和黄铁矿中含金的大部分以细分散亚微米颗粒形式存在的金，以及纳米颗粒中的表面结合金，从而提高该金矿的开采价值。

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来源期刊

Geodynamics & Tectonophysics GEOCHEMISTRY & GEOPHYSICS-

CiteScore

1.20

自引率

14.30%

发文量

审稿时长

24 weeks

期刊介绍： The purpose of the journal is facilitating awareness of the international scientific community of new data on geodynamics of continental lithosphere in a wide range of geolchronological data, as well as tectonophysics as an integral part of geodynamics, in which physico-mathematical and structural-geological concepts are applied to deal with topical problems of the evolution of structures and processes taking place simultaneously in the lithosphere. Complex geological and geophysical studies of the Earth tectonosphere have been significantly enhanced in the current decade across the world. As a result, a large number of publications are developed based on thorough analyses of paleo- and modern geodynamic processes with reference to results of properly substantiated physical experiments, field data and tectonophysical calculations. Comprehensive research of that type, followed by consolidation and generalization of research results and conclusions, conforms to the start-of-the-art of the Earth’s sciences.