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.

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.

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.

A computational analysis on energy consumption of a Ryerson building

2021 ◽  
Author(s):  
Mohammad Adnan Naeem.
Keyword(s):  
Energy Consumption ◽  
Energy Management ◽  
Computational Analysis ◽  
Operating Costs ◽  
Indoor Temperature ◽  
Energy Assessment ◽  
Repair Costs ◽  
Building Load ◽  
High Level ◽  
Storey Building

This project analyses the energy consumption of 44 Gerrard St. East. This site is primarily used as the Ryerson University Theatre School and it consists of four classrooms, seventeen offices, six studios, and two theatre auditoriums. Since it is a three-storey building, plus a basement, thus, the energy level for this building is supposed to be moderate. However, because it is an old structure, constructed back in the early 1940s, this building seemingly has considerable energy consumption. The main objective of this energy assessment is to reduce the building load. This goal can be achieved by simplifying and controlling certain parameters that directly and indirectly involve energy consumption. For example, indoor temperature and relative humidity can be maintained at low level in winter and at high level in summer. In addition, monitoring heat loss, heat gain, infiltrations through the building surrounds, and the level of illumination for various types of lights helps to reduce overall energy consumption. Several other factors such as operating costs, maintenance costs, and repair costs influence the energy management of the site. With the help of energy management software, eQUEST, the structure, outlook of all the walls, windows, roof and the type of HVAC system can be developed for analysis. Through eQUEST, various tasks such as heat transfer involvement, energy consumption load calculations and load balancing in comparison with energy saving guidelines will be discussed in detail.

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.

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.

Selective Recovery of Dissolved Metals from Mine Drainage Using Electrochemical Reactions

2015 ◽  
Vol 181 ◽  
pp. 248-254 ◽  
Author(s):  
Sang-Min Park ◽  
Su-Yeon Shin ◽  
Jung-Seok Yang ◽  
Sang-Woo Ji ◽  
Kitae Baek
Keyword(s):  
Mine Drainage ◽  
Electrochemical Reactions ◽  
Dissolved Metals ◽  
Selective Recovery

scholarly journals A computational analysis on energy consumption of a Ryerson building

2021 ◽  
Author(s):  
Mohammad Adnan Naeem
Keyword(s):  
Energy Consumption ◽  
Energy Management ◽  
Computational Analysis ◽  
Operating Costs ◽  
Indoor Temperature ◽  
Energy Assessment ◽  
Repair Costs ◽  
Building Load ◽  
High Level ◽  
Storey Building

This project analyses the energy consumption of 44 Gerrard St. East. This site is primarily used as the Ryerson University Theatre School and it consists of four classrooms, seventeen offices, six studios, and two theatre auditoriums. Since it is a three-storey building, plus a basement, thus, the energy level for this building is supposed to be moderate. However, because it is an old structure, constructed back in the early 1940s, this building seemingly has considerable energy consumption. The main objective of this energy assessment is to reduce the building load. This goal can be achieved by simplifying and controlling certain parameters that directly and indirectly involve energy consumption. For example, indoor temperature and relative humidity can be maintained at low level in winter and at high level in summer. In addition, monitoring heat loss, heat gain, infiltrations through the building surrounds, and the level of illumination for various types of lights helps to reduce overall energy consumption. Several other factors such as operating costs, maintenance costs, and repair costs influence the energy management of the site. With the help of energy management software, eQUEST, the structure, outlook of all the walls, windows, roof and the type of HVAC system can be developed for analysis. Through eQUEST, various tasks such as heat transfer involvement, energy consumption load calculations and load balancing in comparison with energy saving guidelines will be discussed in detail.

scholarly journals Assessment of three solar-assisted heat pump typologies in Canada: parallel, series, and ice storage

2021 ◽  
Vol 246 ◽  
pp. 06006
Author(s):  
Benjamin Beauchamp ◽  
Sébastien Brideau ◽  
Cynthia Cruickshank
Keyword(s):  
Heat Pump ◽  
Energy Savings ◽  
Operating Costs ◽  
Future Research ◽  
Ice Storage ◽  
Energy Modelling ◽  
Detached House ◽  
High Level ◽  
Series Systems ◽  
Level Analysis

This paper discusses the energy savings, operating costs, and net present values of three typologies of solar assisted heat pump in Canada: parallel systems, series systems, and ice storage systems. Typologies are evaluated for three detached house archetypes of varying energy performances, and across a variety of Canadian climates. Hourly energy modelling is accomplished with a custom spreadsheet tool. The models developed are approximate and meant for high level analysis. This work is meant as a first step in a process of verifying the potential for each of the typologies. In most cases, the parallel system performs best in terms of annual energy savings. The paper goes over the models, assumptions, and some results. Recommendations are discussed for future research focusing on system payback times. The next step will consist of using a detailed sub-hourly simulation tool for the typology that has been found to be the most promising.

scholarly journals Treatment of LF slag to prevent powdering during cooling

2017 ◽  
Vol 53 (2) ◽  
pp. 123-130 ◽  
Author(s):  
S. Ghorai ◽  
G.K. Mandal ◽  
S. Roy ◽  
R.K. Minj ◽  
A. Agarwal ◽  
...  
Keyword(s):  
Polymorphic Transformation ◽  
Induction Furnace ◽  
Barium Carbonate ◽  
Ladle Furnace ◽  
Toxicity Characteristic Leaching Procedure ◽  
Silica Source ◽  
Treated Steel ◽  
High Level ◽  
Furnace Slag ◽  
Leaching Procedure

The polymorphic transformation of the monoclinic ?-polymorph to the orthorhombic ?-polymorph of di-calcium silicate at around 500?C during cooling results in disintegration of slag. The slag generated, during the production of thermo mechanically treated steel in ladle furnace at M/s Tata Steel Limited, Jamshedpur, India, behaves in similar manner. An attempt has been made to prevent the crumbling of ladle furnace slag. The experiments were conducted in 10 kg air induction furnace. Various types of silica source were used to prevent the disintegration of ladle furnace slag by reducing the basicity and optimizing the additives amount. Apart from silica sources, other additives like borax and barium carbonate were also used to stabilize the ? phase. Present investigation reveals that disintegration of ladle furnace slag can be prevented either by addition of 0.2% boarx or 2% barium carbonate. Dust formation can also be prevented by decreasing the ladle furnace slag basicity to about 1.7. Toxicity Characteristic Leaching Procedure test, of the borax and barium carbonate treated slag samples, indicates that barium carbonate treated slag cannot be used for the dusting prevention as it contains high level of barium.

Recovery of Copper from Acid Mine Drainage by an Integrated Sulphate Reducing Process

2009 ◽  
Vol 71-73 ◽  
pp. 557-560 ◽  
Author(s):  
Bo Wei Chen ◽  
Jian Kang Wen ◽  
Xing Yu Liu
Keyword(s):  
Acid Mine Drainage ◽  
Hydraulic Retention Time ◽  
Mine Drainage ◽  
Removal Rate ◽  
Uasb Reactor ◽  
Sulfate Reducing ◽  
Acid Mine ◽  
Sulphate Removal ◽  
High Concentrations ◽  
Treat Acid Mine Drainage

An integrated sulfate reducing process was used to treat Acid Mine Drainage with high concentrations of Cu2+, Fe and SO42-. The water treatment system integrated a sulfidogenic UASB bioreactor with a precipitation reactor which was used to recover copper. Sodium lactate was used as energy source. The effective volume of the UASB reactor was 2 L and the hydraulic retention time was 12.57h. In the sulphate removal reactor, sulphate was removed from 21160 to 195 mg/L with a rate of 4427.8 mg/L/d. Cu2+ and Fe was removed by biologically generated S2- and OH- from 360 and 6520 to 0.049 mg/L and less than 10 mg/L respectively. The average COD, copper and iron removal rate was 2523.2, 15.21 and 274.98 mg/L/d separately. The effluent pH reached 6.0-7.0. The results showed potential usage of this bioreactor in treating Acid Mine Drainage.

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