Complete sulphate removal from neutralised acidic mine drainage with barium carbonate

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
H. Swanepoel ◽  
M. de Beer ◽  
L. Liebenberg
Keyword(s):  
Mine Drainage ◽  
Barium Carbonate ◽  
Industrial Process ◽  
Positive Influence ◽  
Molar Ratio ◽  
Acidic Mine Drainage ◽  
Dissolved Metals ◽  
Sulphate Concentration ◽  
Sulphate Removal ◽  
Low Solubility

The most widespread method used for the treatment of acidic mine drainage (AMD) is neutralisation through the addition of lime to the effluent in order to raise the pH. As a result, dissolved metals precipitate as metal hydroxides while partial sulphate removal is achieved. However, further treatment is required in order to reduce the sulphate concentration to below 500 mg/ℓ, which is the required concentration for discharge into waterways. The CSIR developed and patented the ABC (alkali-barium-calcium) Desalination process which uses barium salts to further reduce the sulphate concentration to acceptable levels with the added advantage that sulphate removal can be controlled due to the low solubility of BaSO4. This paper reports on the results of an investigation to demonstrate the performance of this sulphate removal reaction. Laboratory results that draw attention to the conditions required for BaSO4 precipitation are presented. A number of parameters, including temperature, initial sulphate concentration, barium-to-sulphate molar ratio and different BaCO3 sources were considered. The results were also tested and verified on industrial process water. The results clearly demonstrate that the reactor temperature, initial sulphate concentration, and molar ratio of barium to sulphate have a positive influence on sulphate removal.

scholarly journals Sulphate removal technologies for the treatment of mine-impacted water

2021 ◽  
Vol 121 (10) ◽  
pp. 1-7
Author(s):  
M. van Rooyen ◽  
P.J. van Staden ◽  
K.A. du Preez
Keyword(s):  
Mine Drainage ◽  
Barium Carbonate ◽  
Operating Costs ◽  
Dissolved Metals ◽  
Cost Component ◽  
Sulphate Removal ◽  
Removal Technologies ◽  
High Level ◽  
Mine Impacted Water ◽  
Lime Addition

Mine-impacted water, including acid mine drainage (AMD), is a global problem. While precipitation of dissolved metals and neutralization of acidity from mine-impacted water is accomplished relatively easily with lime addition, removal of sulphate to permissible discharge limits is challenging. This paper presents a high-level comparison of four sulphate removal technologies, namely reverse osmosis, ettringite precipitation, barium carbonate addition, and biological sulphate reduction. Primarily operating costs, based on reagent and utility consumptions, are compared. Each process is shown to be subject to a unique set of constraints which might favour one over another for a specific combination of location and AMD composition. Access to and cost of reagents would be a key cost component to any of the processes studied. The total cost calculated for each process also depends on the type of effluents that are allowed to be discharged.

Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage

2012 ◽  
Vol 65 (2) ◽  
pp. 324-331 ◽  
Author(s):  
J. Mulopo ◽  
J. N. Zvimba ◽  
H. Swanepoel ◽  
L. T. Bologo ◽  
J. Maree
Keyword(s):  
Acid Mine Drainage ◽  
Flow Rate ◽  
Mine Drainage ◽  
Barium Carbonate ◽  
Pilot Scale ◽  
Carbonation Reaction ◽  
Column Reactor ◽  
Acid Mine ◽  
Sulphate Removal ◽  
Co2 Flow

Batch regeneration of barium carbonate (BaCO3) from barium sulphide (BaS) slurries by passing CO2 gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO3 recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO2 flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO3 were investigated. It was observed that the carbonation reaction rate for BaCO3 regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO2) flow rate whereas the BaS slurry content within the range 5–10% slurry content did not significantly affect the carbonation rate. The CO2 flow rate also had an impact on the BaCO3 morphology. The BaCO3 recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO3.

scholarly journals Covellite (CuS) Production from a Real Acid Mine Drainage Treated with Biogenic H2S

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 206 ◽  
Author(s):  
Patricia Magalhães Pereira Silva ◽  
Adriano Reis Lucheta ◽  
José Augusto Pires Bitencourt ◽  
Andre Luiz Vilaça do Carmo ◽  
Ivan Patricio Ñancucheo Cuevas ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Raw Materials ◽  
Industrial Applications ◽  
Molar Ratio ◽  
High Concentration ◽  
Dissolved Metals ◽  
X Ray ◽  
Synthesis Conditions ◽  
Acid Mine

Acid Mine Drainage (AMD) is an environmental problem associated with mining activities, which resulted from the exposure of sulfur bearing materials to oxygen and water. AMD is a pollution source due to its extreme acidity, high concentration of sulfate, and soluble metals. Biological AMD treatment is one alternative to couple environmental amelioration for valuable dissolved metals recovery, as a new source of raw materials. Covellite (CuS) particles were synthetized from an AMD sample collected in a Brazilian copper mine, after 48 and 96 h of exposure to hydrogen sulfide (H2S) produced in a bioreactor containing acidophilic sulfate reducing bacteria (SRB). The time of exposure affected the morphology, nucleation, and size of CuS crystals. CuS crystals synthetized after 96 h of H2S exposure showed better ordination as indicated by sharp and intense diffractograms obtained by X-ray diffraction (XRD), and the predominance of placoid sheets with hexagonal habit structure as observed by scanning electrons microscopy (SEM). Energy dispersive X-ray fluorescence (EDXRF) spectrometry indicated a Cu:S molar ratio in agreement with CuS. Granulometric analysis demonstrated that 90% of CuS particles were less than 22 µm size. AMD biological treatment is a potential economical CuS recovery option for metallurgical process chain incorporation, or new industrial applications, since the alteration of synthesis conditions can produce different crystal forms with specific characteristics.

A Review of Technologies Used in Handling The Acid Mine Drainage Challenge: Perspectives on Using Green Liquor Dregs As a Sustainable Option For Treatment of Acid Mine Drainage

2021 ◽  
Vol 47 (1) ◽  
pp. 1-18
Author(s):  
Keolebogile R. Sebogodi ◽  
Jonas K. Johakimu ◽  
B. Bruce Sithole
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Current Trend ◽  
Dissolved Metals ◽  
Green Liquor ◽  
Acid Mine ◽  
Treatment And Prevention ◽  
Green Liquor Dregs ◽  
High Concentrations ◽  
By Products

Acid mine drainage (AMD) is one of the repercussions that result from earth-moving activities around the sulfide-bearing mineral hosts. The detrimental effects associated with this AMD are driven by its characteristics, which include low pH and high concentrations of sulfate and toxic dissolved metals. Traditionally, the prevention and treatment of AMD are achieved by using technologies that use, amongst other, naturally occurring soils and carbonates. However, the continual use of these materials may eventually lead to their depletion. On the other hand, industrial by-products have been proven to occupying land that could have otherwise been used for profitable businesses. Additionally, the handling and maintenance of landfills are costly. In this current trend of a circular economy that is driven by industrial symbiosis, scientists are concerned with valorizing industrial by-products. One such by-product is the green liquor dregs (GLD) from Kraft mills. The neutralizing and geotechnical properties of these wastes have prompted the research pioneers to seek their potential use in handling the challenges associated with AMD. In this review, the formation AMD, trends in technologies for treatment and prevention of AMD are critically analyzed. This includes the feasibility of using GLD as an alternative, promising sustainable material.

scholarly journals Removal of Metals by Sulphide Precipitation Using Na2S and HS−-Solution

2020 ◽  
Vol 4 (3) ◽  
pp. 51
Author(s):  
Hanna Prokkola ◽  
Emma-Tuulia Nurmesniemi ◽  
Ulla Lassi
Keyword(s):  
Mine Water ◽  
Mine Drainage ◽  
Anaerobic Treatment ◽  
Reduction Reaction ◽  
Sulphate Reduction ◽  
Acidic Mine Drainage ◽  
Acid Mine Water ◽  
Metal Hydroxides ◽  
Sulphide Precipitation ◽  
Ph Dependent

Precipitation of metals as metal sulphides is a practical way to recover metals from mine water. Sulphide precipitation is useful since many metals are very sparingly soluble as sulphides. Precipitation is also pH dependent. This article investigates the precipitation of metals individually as sulphides and assesses which metals are precipitated as metal hydroxides by adjustment of the pH. The precipitation of different metals as sulphides was studied to determine the conditions under which the HS− solution from the sulphate reduction reaction could be used for precipitation. H2S gas and ionic HS− produced during anaerobic treatment could be recycled from the process to precipitate metals in acidic mine drainage (AMD) prior to anaerobic treatment (Biological sulphate reduction), thereby recovering several metals. Precipitation of metals with HS− was fast and produced fine precipitates. The pH of acid mine water is about 2–4, and it can be adjusted to pH 5.5 before sulphide precipitation, while the precipitation, on the other hand, requires a sulphide solution with pH at 8 and the sulphide in HS− form. This prevents H2S formation and mitigates the risk posed from the evaporation of toxic hydrogen sulphur gas. This is a lower increase than is required for hydroxide precipitation, in which pH is typically raised to approximately nine. After precipitation, metal concentrations ranged from 1 to 30 μg/L.

Migration of acidic pore waters at the Waite Amulet tailings site near Rouyn–Noranda, Quebec, Canada

1992 ◽  
Vol 29 (3) ◽  
pp. 466-476 ◽  
Author(s):  
Ernest K. Yanful ◽  
Luc C. St-Arnaud
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Water ◽  
Mine Drainage ◽  
Geotechnical Properties ◽  
Horizontal Flow ◽  
Sulphide Mineral ◽  
Saturated Zone ◽  
Pore Waters ◽  
Dissolved Metals ◽  
Water Contents

Pore waters found in the unsaturated zone of the Waite Amulet tailings have been modified by sulphide mineral oxidation, resulting in acidic pH (near 4) and high concentrations of dissolved iron and sulphate at about 5 and 12 g/L, respectively. These pore waters have been displaced down into the shallow saturated zone of the tailings by infiltrating water. Most metals are removed from the pore water as a result of pH buffering before they reach the deeper saturated zone. However, some dissolved metals still remain in solution and are transported with the pore water through the tailings. Numerical flow modelling shows that an anisotropy in hydraulic conductivity (ratio of Kx/Ky is estimated to be 100) exists in the tailings, most likely due to the presence of horizontal fine-grained "slime" layers. The estimated horizontal pore-water velocity is almost 20 times higher than the vertical velocity. Anisotropy in hydraulic conductivity has the effect of promoting horizontal flow over vertical flow in the model. The geometry of the tailings impoundment and the assumed impermeability of the varved clay soil underlying the tailings also contribute to increased horizontal flow. To verify that a preferred horizontal flow exists and that the clay subsoil is indeed impermeable, the geotechnical properties and hydrogeochemistry of the clay are also evaluated. The results indicate that clay located beneath the tailings is slightly overconsolidated in the shallow zone but normally consolidated at greater depth by the weight of the tailings. Overconsolidation ratios reach a maximum value of 2.0. In the clay–tailings interface zone, the soil is characterized by lower in situ water contents and slightly higher undrained shear strengths Cu than the deeper clay. The water contents of the near-interface clay average about 40% and the Cu values 80 kPa, compared with an average water content of 55% and a Cu value of only 20 kPa for the clay at greater depths. These geotechnical properties confirm the presence of a desiccated oxidized upper zone identified in previous studies. It is hypothesized that fractures that could have appeared in the oxidized zone before the tailings deposition would have been closed due to consolidation by the tailings mass. Above-background sulphate concentrations observed in the clay layer at a depth of 1 m are believed to be controlled by diffusion and advection. The presence of fractures in the oxidized zone and excess pore-water pressures generated during consolidation of the clay by the tailings mass could have also influenced chemical transport. Key words : acid generation, acid mine drainage, diffusion, geotechnical, hydrogeochemistry, tailings.

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