Gold, Silver and Iron in Iron Oxy-hydroxide Precipitate Formed in Process of Acid Mine Drainage
Oxidation of sulfide-containing ores is the main cause of Acid Mine Drainage (AMD), which is an environmental problem associated with both the abandoned and active mines. Iron-bearing sulfide minerals can be oxidized and form mine waters with high sulfate content, low pH, high electrical conductivity, high redox potential, and high concentrations of iron, aluminum, and other heavy metals. In the process of AMD, precipitation of poorly crystalized oxy-hydroxides of iron with a large active surface can occur. On the surface of iron oxy-hydroxide, the precipitated particulate matter, anions, and cations (metals) could be adsorbed. Mine waters can contain a certain amount of precious metals that can also be adsorbed onto an iron particulate matter surface, which is investigated in this research work. In this work, the samples of iron oxy-hydroxide particulate matter at abandoned gold mine waste in Bakovići (Central Bosnia and Herzegovina) are used. Several parameters including pH, water content, particle size distribution, sulfate content, electrical conductivity, redox potential, and amounts of gold, silver, and iron are measured on the selected mine waste samples. The results obtained indicate that significant amounts of gold (average: 6.8 mg/kg) and silver (average: 7.13 mg/kg) are present in the iron precipitate. Adsorption of precious metals onto the iron oxy-hydroxide surface is strongly pH-dependent. At a very low pH value, desorption of precious metals is favorite. Thus, precious metals are only partially adsorbed onto the iron oxy-hydroxide surface.
The oxidation of iron sulfides in mine wastes is the main cause of acidic, sulfate, and trace element-rich acid mine drainage (AMD). However, the suite of reactions that transform iron from one species to another is quite complex. A reasonable strategy for controlling AMD production is to identify and further slow the slowest, rate-determining step (RDS) in the overall process. This paper provi...متن کامل
The Richmond Mine at Iron Mountain, Shasta County, California, USA provides an excellent opportunity to study the chemical and biological controls on acid mine drainage ~AMD! generation in situ, and to identify key factors controlling solution chemistry. Here we integrate four years of field-based geochemical data with 16S rRNA gene clone libraries and rRNA probe-based studies of microbial popu...متن کامل
P r e v i o u s s t u d i e s of t h e o x i d a t i o n of i r o n p y r i t e and t h e subsequent r e l e a s e of a c i d i t y i n t o mine d r a i n a g e w a t e r s have provided no c o n c l u s i v e r e su l t s i n a s c e r t a i n i n g which of t h e s t e p s i n t h e o v e r a l l r e a c t i o n i s r a t e d e t e r m i n i n g . Although microorganisms have f r e q u e n t ...متن کامل
Bio-Remediation of Acid Mine Drainage in the Sarcheshmeh Porphyry Copper Mine by Fungi: Batch and Fixed Bed Process
Acid mine drainage (AMD) containing high concentrations of iron and sulphate, low pH and variableconcentrations of heavy metals leads to many environmental problems. The concentrations of Cu and Mnare high in the AMD of the Sarcheshmeh porphyry copper mine, Kerman province, south of Iran. In thisstudy, the bio-remediation of Cu and Mn ions from acid mine drainage was investigated using two nati...متن کامل
This study demonstrates substantial removal of iron (Fe) from acid mine drainage (pH ≈3) in a passive vertical flow reactor (VFR) with an equivalent footprint of 154 m(2) per L/s mine water and residence times of >23 h. Average Fe removal rate was 67% with a high of 85% over the 10-month trial. The fraction of Fe passing a 0.22 µm filter (referred to here as Fe-filt) was seen to be removed in t...متن کامل
gol-e-gohar iron ore mine of sirjan in southern part of iran is a large open pit that operates below the groundwater table and during mining operation, dewatering is required to prevent operation processes from flooding. current operation is going on by digging wells in or out of the pit and pumping to prevent flooding. as a result of the former dewatering operation a vast deep cone of depressi...
دوره 11 شماره 2
صفحات 335- 346
تاریخ انتشار 2020-04-01
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