Effectiveness of Fly Ash and Red Mud as Strategies for Sustainable Acid Mine Drainage Management

Keller, Viktoria; Stopić, Srečko; Xakalashe, Buhle; Ma, Yiqian; Ndlovu, Sehliselo; Mwewa, Brian; Simate, Geoffrey S.; Friedrich, Bernd

doi:10.3390/min10080707

Cited by 19 publications

(12 citation statements)

References 27 publications

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“…Researchers have focused on various metals present in major and minor quantities in red mud and of which significant amounts could be removed using various processes, such as sintering and carbothermal smelting processes using metallurgical routes [ 25 , 26 , 46 , 47 , 48 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ]. Additional methods, such as the chemical process of leaching, are also investigated as one of the beneficiary ways to extract various categories of elements from red mud [ 9 , 22 , 36 , 81 , 90 , 94 , 99 , 100 , 101 , 102 ]. The economic cost of red mud handling and use is one of the important issues associated with the bauxite industry.…”

Section: Discussionmentioning

confidence: 99%

“…Coating technology opens the door for applications in pigment areas using Ti as pigment ion. Red mud could be used as a coating by thermal plasma spray technologies for wear resistance coating or corrosive resistance coating layers that could stand as a barrier against environmental conditions [ 81 , 82 , 83 ]. Coatings based on red mud offer an important erosion wear resistance, which can further be improved.…”

Section: Fields Of Application Of Red Mudmentioning

confidence: 99%

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Utilization of Red Mud as a Source for Metal Ions—A Review

Samal

2021

Materials

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An overview is presented on the prospective use of red mud as a resource in this review. Various scopes are suggested for the utilization of red mud to maintain a sustainable environment. The potential use of red mud covers the valuable metal recovery that could emphasize the use of red mud as a resource. Red mud could act as reduced slag in the metallurgical field for the extraction of minerals and metals for upscale application. Although many studies have revealed the potential utilization of red mud, most of them are only limited to a lab-scale basis. Therefore, a large-scale investigation on recycling of red mud for the extraction in the area of the metal recovery section will draw attention to the extensive use of red mud. Metal ions of major elements Fe (44 wt.%), Al (18.2 wt.%), Si (14.3 wt.%), Ti (9.3 wt.%), Na (6.2 wt.%), Ca (4.4 wt.%) as major elements and of Mg, V, Mn, Cr, K as minor elements and rare earth elements such as Ce (102 mg/kg), La (56 mg/kg), Sc (47 mg/kg), Nd (45 mg/kg), Sm (9 mg/kg). Moreover, an appropriate in-house metal recovery facility with the alumina industry will come out as a cost–benefit analysis.

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Section: Discussionmentioning

confidence: 99%

Section: Fields Of Application Of Red Mudmentioning

confidence: 99%

Utilization of Red Mud as a Source for Metal Ions—A Review

Samal

2021

Materials

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“…AMD and BR are frequently available in the metallurgical and mining industry. The AMD sample was collected from Mpumalanga, South Africa [96] containing the initial concentration of cerium of 5.51 mg/L and yttrium of 2.05 mg/L. Treating AMD solutions requires the generation of enough alkalinity to neutralize the acidity excess.…”

Section: Recovery Of Yttrium Oxide From Waste Materialsmentioning

confidence: 99%

“…Transforming CFA to zeolites can increase the adsorption of dissolved metals [106]. Flying ash can be used for the neutralization of AMD [96] and carbonation process [107].…”

Section: Recovery Of Ree From Phosphogypsum (Pg) and Coal Flying Ash (Cfa)mentioning

confidence: 99%

Advances in Understanding of the Application of Unit Operations in Metallurgy of Rare Earth Elements

Stopić

Friedrich

2021

Metals

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Unit operations (UO) are mostly used in non-ferrous extractive metallurgy (NFEM) and usually separated into three categories: (1) hydrometallurgy (leaching under atmospheric and high pressure conditions, mixing of solution with gas and mechanical parts, neutralization of solution, precipitation and cementation of metals from solution aiming purification, and compound productions during crystallization), (2) pyrometallurgy (roasting, smelting, refining), and (3) electrometallurgy (aqueous electrolysis and molten salt electrolysis). The high demand for critical metals, such as rare earth elements (REE), indium, scandium, and gallium raises the need for an advance in understanding of the UO in NFEM. The aimed metal is first transferred from ores and concentrates to a solution using a selective dissolution (leaching or dry digestion) under an atmospheric pressure below 1 bar at 100 °C in an agitating glass reactor and under a high pressure (40–50 bar) at high temperatures (below 270 °C) in an autoclave and tubular reactor. The purification of the obtained solution was performed using neutralization agents such as sodium hydroxide and calcium carbonate or more selective precipitation agents such as sodium carbonate and oxalic acid. The separation of metals is possible using liquid (water solution)/liquid (organic phase) extraction (solvent extraction (SX) in mixer-settler) and solid-liquid filtration in chamber filter-press under pressure until 5 bar. Crystallization is the process by which a metallic compound is converted from a liquid into a crystalline state via a supersaturated solution. The final step is metal production using different methods (aqueous electrolysis for basic metals such as copper, zinc, silver, and molten salt electrolysis for REE and aluminum). Advanced processes, such as ultrasonic spray pyrolysis, microwave assisted leaching, and can be combined with reduction processes in order to produce metallic powders. Some preparation for the leaching process is performed via a roasting process in a rotary furnace, where the sulfidic ore was first oxidized in an oxidic form which is a suitable for the metal transfer to water solution. UO in extractive metallurgy of REE can be successfully used not only for the metal wining from primary materials, but also for its recovery from secondary materials.

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“…In order to avoid any water pollution, essential methods should be adopted to remove these ions. To solve the acid mine drainage problem, Portland cement with different slurry viscosity is used to neutralize the acid mine water [23,24]. The long term effectiveness is satisfactory and the total cost is better than lime neutralization.…”

Section: Introductionmentioning

confidence: 99%

Combined Treatments of Underground Coal Slurry: Laboratory Testing and Field Application

Zhang

Dong

Zhao

et al. 2021

Water

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During the coal mining process, underground water is generated from the longwall face. In the meantime, the coal cutting process would produce coal particles. Coal slurry is generated in the underground working site, especially for water abundant coal mines. The generated coal slurry is treated to prevent water pollution. Due to the extensively existing of the suspended solid, the traditional process method would often introduce new problems. In this study, laboratory testing was conducted to investigate the characteristics, including the particle size distribution of the coal sludge, coal slurry compositions, slurry viscosity and coal mine water quality. In order to improve the coal slurry treatment efficiency, based on the laboratory results, a novel combined treatment of underground coal slurry is proposed. First, the coarse grained coal slurry is process by a vibrating screening machine. Then, the coal slurry containing fine coal powders is processed through a settling pond. The sedimentation results of the coal solid materials are analyzed. The polymer flocculant is also added into the coal slurry to improve the sedimentation. These combined treats of the coal slurry significantly remove the suspended solid and improve the quality of the coal mine water. Based on the laboratory testing, the specific details of the field applications are designed. The key novelty of this paper is the underground background. All of these treatments are based on the underground environment and are capable of being applied in underground workings. From field applications and observations, these novel combined treatments of coal slurry in the underground site are effective. This study provides a novel method to treat the coal slurry, which has innovations from engineering aspect. These procedures are useful for the underground coal slurry treatment, especially for water-abundant coal mines. The normal coal production is guaranteed and less affected by the coal slurry discharge process. Meanwhile, the water pollution problem is much addressed and the damage of coal slurry to the environment is reduced.

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Effectiveness of Fly Ash and Red Mud as Strategies for Sustainable Acid Mine Drainage Management

Cited by 19 publications

References 27 publications

Utilization of Red Mud as a Source for Metal Ions—A Review

Utilization of Red Mud as a Source for Metal Ions—A Review

Advances in Understanding of the Application of Unit Operations in Metallurgy of Rare Earth Elements

Combined Treatments of Underground Coal Slurry: Laboratory Testing and Field Application

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