Using static, kinetic and metal mobility procedures to evaluate possibilities of coal waste land disposal at Moatize Mine, Mozambique

Weiler, Jéssica; Silva, Aline Capoani da; Firpo, Beatriz Alícia; Fernandes, Eunírio Zanetti; Schneider, Ivo

doi:10.1590/0370-44672019730112

Cited by 2 publications

(1 citation statement)

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“…By predicting mine-waste drainage quality before the inception of mining, planning for mineral-resource development and mine-waste management can be made to minimize adverse environmental impacts throughout the lifetime of the working mine, and after mine closure [21,23,24]. The most widely used tests to quantify acid drainage potential are static tests and kinetic tests.…”

Section: Acid Drainage Static Tests Proceduresmentioning

confidence: 99%

Static tests to assess acid mine drainage potential of copper sulfide flotation tailings

Silva¹,

Couto²,

Tavares³

et al. 2023

Tecnol. Metal. Mater. Min.

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Most copper flotation tailings contain a significant amount of sulfide minerals that can generate effluent resulting from the oxidation of sulfides when they are exposed to oxygen and water. This study aimed to characterize and evaluate the acid drainage potential of five different copper flotation tailings, named samples I, II, III, IV, and V. Sample I was taken from an industrial operation, while Samples II, III, IV, and V were produced in pilot plant tests. All samples were characterized and submitted to static acid drainage tests, such as paste pH, Net Acid Generation (NAG) pH, and Modified Acid-Base Accounting (MABA). The sulfur as sulfide/total sulfur mass ratios varies from 0.40 up to 0.89 showing the presence of a high amount of minerals rich in pyrite and alunite, being higher than 13 wt% of pyrite in samples IV and V and around 19 wt% of alunite in sample III. Samples I and II presented a high number of alkaline elements, totalizing more than 8 wt% of K 2 O+CaO+MgO, while samples III, IV, and V show the lowest amount of these elements (<4 wt%). Only samples III, IV, and V show Paste pH results lower than 5.0, indicating superficial oxidation on their surfaces and/or the presence of water-soluble acidity minerals. Due to the high pyrite content in samples III and IV, it was not possible to measure their NAG pH due to the high heat released with the addition of hydrogen peroxide. The low NAG pH obtained with sample III (5.30) was due to its high pyrite content (0.30 wt%) in comparison with the results obtained with sample I (NAG pH of 8.15 and 0.10 wt% of pyrite), and sample II (NAG pH of 8.18 and 0.10 wt% of pyrite). The MABA results show that samples III, IV and V presented acid drainage potential due to the neutralization potential (NP)/acidity potential (AP) ratio being lower than 1. On the other hand, samples I and II presented NP/AP ratio higher than 4, not showing potential to generate acid drainage. Due to these results, it is recommended to carry out acid drainage kinetic tests with samples III, IV, and V to determine the long-term weathering rates, evaluate lag time to acid generation and provide reaction rates for geochemical modeling.

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Section: Acid Drainage Static Tests Proceduresmentioning

confidence: 99%