scholarly journals A comparison of the acid mine drainage (AMD) neutralization potential of low grade nickel laterite and other alkaline-generating materials

2020 ◽  
Vol 778 ◽  
pp. 012142 ◽  
Author(s):  
C. Turingan ◽  
G. Singson ◽  
B. Melchor ◽  
R. Alorro ◽  
A. Beltran ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Low Grade ◽  
Nickel Laterite ◽  
Neutralization Potential ◽  
Acid Mine

Uranium Bioleaching from Low Grade Ore

2020 ◽  
Vol 989 ◽  
pp. 559-563
Author(s):  
Ashimkhan T. Kanayev ◽  
Khussain Valiyev ◽  
Aleksandr Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leach Solution ◽  
Low Grade ◽  
Bacterial Cells ◽  
Acid Mine

The goal of the present work was to perform bioleaching of uranium from low grade ore from Vostok deposit (Republic of Kazakhstan), which was previously subjected to long-term acid leaching. The ore initially contained from 0.15 to 0.20% of uranium in the form of uraninite, but ore samples used in the study contained about 0.05% of uranium, as it was exhausted during acid leaching, and uranium was partially leached. Representative samples of ore were processed in 1 m columns, leach solutions containing 5, 10, 20 g/L of sulfuric acid and bacterial cells (about 104) were percolated through the ore. Leaching was performed at ambient temperature for 70 days. In one of the percolators, the leaching was performed with leaching solution containing 10 g/L of H2SO4, cells of A. ferrooxidans, and 0.5 g/L of formaldehyde. Leaching with the solution containing 5, 10, and 20 g/L of sulfuric acid made it possible to extract 50, 53, and 58% of uranium. Addition of formaldehyde in leach solution led to the decrease in uranium extraction extent down to 37%. Thus, the results of the present work demonstrated that uranium ore exhausted during long-term acid leaching may be successfully subjected to bioleaching, that allows extracting residual quantities of uranium. Leaching rate of uranium from exhausted ore depended on both sulfuric acid concentration and microbial activity of bacteria isolated from acid mine drainage, formed on uranium deposit. In the same time, acid mine drainage may be used as a source of inoculate, to start bioleaching process.

Preliminary Study of Neutralization and Inhibition of Chemolitotrophic Bacteria in an Acid Mine Drainage from Rio Tinto Site

2009 ◽  
Vol 71-73 ◽  
pp. 677-680 ◽  
Author(s):  
D. Carnicero ◽  
E. Díaz ◽  
O. Escolano ◽  
D. Rubinos ◽  
O. Ballesteros ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Red Mud ◽  
Mine Drainage ◽  
Initial Conditions ◽  
Microbial Populations ◽  
Low Grade ◽  
Neutralization Capacity ◽  
Acid Mine ◽  
Rio Tinto ◽  
Río Tinto

Limestone is commonly used for neutralization of acid mine drainage (AMD). Its main advantages are its lower price, sustained generation of alkalinity and production of low sludge volumes. Nevertheless, armouring of limestone by ferric hydroxides is a problem in oxic limestone drains and in active limestone treatment systems, reducing the efficiency of the process. Due to these disadvantages, there is a permanent search for cheaper and more effective neutralization agents. Many alkaline industrial wastes are gaining importance in the treatment of AMD. The possibilities to use two different industrial by-products, red mud from a bauxite exploitation and low grade magnesium hydroxide from a magnesite mine, as neutralizing and bacterial inhibiting agents, and the comparison with conventional limestone treatment has been studied in this paper. An AMD from Rio Tinto mine site with an initial pH of 2.4 and a ferric concentration of 1 g/L was used. Comparative test were done percolating the AMD in a continuous form with a peristaltic pump through three different columns filled with limestone, red mud and low grade magnesite, during one month and in same conditions of flow rate and amount of each compound used to fill the columns. The evolution of pH, iron and heavy metals, sulphates and microbial populations in the percolate were monitored at different times. The results showed that the best neutralization capacity was obtained with low grade magnesite during the month treatment. By contraire limestone and red mud loosed their neutralization capacity after 10 and 13 days respectively. The control of microbial populations showed that there is an inhibition of chemolithotropic bacteria as long as the materials maintain their neutralization capacity, reverting to the initial conditions when this capacity was loosed.

Comparing the performance of low‐grade nickel ore and limestone for treatment of synthetic acid mine drainage

2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Casey Oliver A. Turingan ◽  
Divina Joyce A. Fabella ◽  
Kim Ahmed N. Sadol ◽  
Arnel B. Beltran ◽  
Richard D. Alorro ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Low Grade ◽  
Acid Mine ◽  
Synthetic Acid

Bacterial Oxidation of Ferrous Iron and RISCs at Low Temperatures: Their Effect on Acid Mine Drainage and Bioleaching of Sulphide Minerals

2009 ◽  
Vol 71-73 ◽  
pp. 433-436 ◽  
Author(s):  
B. Escobar ◽  
S. Buccicardi ◽  
G. Morales ◽  
J.V. Wiertz
Keyword(s):  
Acid Mine Drainage ◽  
Low Temperatures ◽  
Mine Drainage ◽  
Basal Medium ◽  
Copper Production ◽  
High Price ◽  
Low Grade ◽  
Isolated Cells ◽  
Sulphide Minerals ◽  
Acid Mine

Chilean copper production has been growing in the last 20 years reaching an annual production of 5,557,000 tons of Cu in 2007. For each ton of copper produced, about 200 tons of sterile and low grade ore and 100 tons of tailings are discharged in the environment. Most of these wastes contain significant amounts of sulphide minerals, mainly pyrite, and once submitted to weathering, may produce acid mine drainage. On the other hand, the high price of copper raised the interest for processing by leaching the low grade ore deposited in large dumps. An important part of these mining wastes and low grade ores is located in the Andes, where the mean temperature is usually ~5°C or less. The rate at which bioleaching reactions occur is directly related to the temperature at which the microorganisms (bacteria and archaea) develop. A temperature decrease causes both a decrease of the rate of the involved chemical reactions and a decrease or inhibition of microbial growth. In this work we present the results of the isolation of microorganisms from an old tailing deposit, exposed at low temperatures (5oC) during most of the winter. The isolated microorganisms initially showed a low capacity to oxidize 3g/L Fe(II) sulfate at pH 1.6, and tetrathionate 0.01 M, with an initial pH 4 both at 5oC. However, after successive cultures, microorganisms showed a slow capacity to oxidize both substrates, as well as the sulphide contained in the tailings samples. The terminal Restriction Fragment Length Polymorphism (tRFLP) of the isolated cells grown in basal medium containing Fe(II) showed a nearly pure culture of Acidithiobacillus ferrooxidans. The present study indicates that, even at very low temperatures, microorganisms play an important role in the generation of acid mine drainage and in the oxidation and leaching of sulphide ores.

scholarly journals Evaluation of Efficiencies of Locally Available Neutralizing Agents for Passive Treatment of Acid Mine Drainage

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 845
Author(s):  
Casey Oliver A. Turingan ◽  
Giulio B. Singson ◽  
Bernadette T. Melchor ◽  
Richard D. Alorro ◽  
Arnel B. Beltran ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Passive Treatment ◽  
Concrete Aggregate ◽  
Low Grade ◽  
Ph Change ◽  
Acid Mine

Acid mine drainage (AMD) generated from the mining industry elevates environmental concerns due to the pollution and contamination it causes to bodies of water. Over the years, passive treatment of AMD using alkalinity-generating materials have been widely studied with pH neutralization as its commonly observed mechanism. During the treatment process, heavy metal removal is also promoted by precipitation due to pH change or through adsorption facilitated by the mineral component of the materials. In this study, four materials were used and investigated: (1) a low grade ore (LGO) made up of goethite, calcium oxide, and manganese aluminum oxide (2–3) limestone and concrete aggregates (CA) composed of calcite, and (4) fly ash consisting of quartz, hematite, and magnetite. The performance of each alkalinity-generating agent at varying AMD/media ratios was based on the change in pH, total dissolved solids (TDS), oxidation reduction potential (EH); and heavy metals (Fe, Ni, and Al) removal and sulfate concentration reduction. Concrete aggregate displayed the most significant effect in treating AMD after raising the pH to 12.42 and removing 99% Fe, 99% Ni, 96% Al, and 57% sulfates. Afterwards, the efficiency of CA at various particle sizes were evaluated over 1 h. The smallest range at 2.00–3.35mm was observed to be most effective after 60 min, raising the pH to 6.78 and reducing 94% Fe, 78% Ni, and 92% Al, but only 28% sulfates. Larger particles of CA were able to remove higher amounts of sulfate up to 57%, similar to the jar test. Overall, CA is an effective treatment media for neutralization; however, its performance can be complemented by a second media for heavy metal and sulfate removal.

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