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The Occurrence Mechanism of Gold in Pyrite from the Qiucun Gold Deposit in Fujian Province, China
Author(s) -
ZHANG He,
CAI Yuanfeng,
NI Pei,
ZHANG Yang
Publication year - 2017
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13186
Subject(s) - pyrite , china , mechanism (biology) , geology , geochemistry , mining engineering , geography , archaeology , philosophy , epistemology
Precipitation and enrichment of gold is an important subject in the study of gold deposits. As the most common sulphide in gold deposits, pyrite is not only a good indicator of the evolution of mineralizing fluids, but also the important gold-bearing mineral. In this paper, we have focused on the occurrence form of invisible gold in pyrite, which has a great significance in understanding mineralogy and geochemical behavior of gold and choosing the technology to extract gold ores. Scientists hold different views in the enrichment and the occurence form of gold in pyrite. Palenik et al. (2004) considered gold nanoparticles form by exsolution from pyrite as the temperature decreases. Reich et al. (2005) indicated that the relationship of gold and arsenic in pyrite (CAu=0.02CAs+4×10) puts an upper limit on the solubility of gold in pyrite; above the limit, gold nanoparticles would occur, while gold would form the solid solution in pyrite below the limit. The above two views are closely related to gold solubility in pyrite. Fougerouse et al. (2016) considered that the occurrence of gold nanoparticles may result from the combined effect of crystal growth rate and gold ion diffusion; the slow growth favors ion diffusion on the surface and formation of nanoparticles. Prokhorov and Lu (1971) considered that arsenic can change semiconducting properties of pyrite and promote the adsorption of gold on the surface of pyrite (Prokhorov and Lu, 1971; Mironov et al.,1981;Maddox et al., 1998; Mikhlin et al. 2007). The substitutions of Au for Fe and As for S will inevitably result into changes of the lattice because gold and arsenic own larger effective ion radii than iron and sulfur. Moreover, the faster the crystal grows, the denser the defects are. Invisible gold is probably accommodated