Enhancing the sedimentation of clay-based tailings in seawater by magnesium removal treatment
| Autor: | Pedro Robles, Matías Jeldres, Steven Nieto, Gonzalo R. Quezada, Ricardo I. Jeldres, Eder C. Piceros, Norman Toro |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Flocculation Materials science Magnesium chemistry.chemical_element Filtration and Separation 02 engineering and technology Polymer engineering.material 021001 nanoscience & nanotechnology Pulp and paper industry Tailings Analytical Chemistry 020401 chemical engineering chemistry Settling engineering Seawater 0204 chemical engineering Turbidity 0210 nano-technology Lime |
| Zdroj: | Separation and Purification Technology. 242:116762 |
| ISSN: | 1383-5866 |
| Popis: | The pH of the seawater was raised with lime before it was used into the process, generating solid precipitates of magnesium that were removed by vacuum filtration. Then this treated seawater was applied to improve the flocculation of clay-based tailings in a highly alkaline environment (pH 11). Tailings settling assays were conducted by using a PTFE 30 mm turbine type stirrer with an in-situ floc size characterisation utilising the Focused Beam Reflectance Measurement (FBRM) and Particle Vision Measurement (PVM) techniques. After mixing the pulp with the flocculant, the sample was settled, registering the evolution of the mudline and turbidity of the supernatant liquid. When operating with direct seawater at pH 11, magnesium complexes arise that impairs the flocculant performance. The polymer loses selectivity for the particles, causing weak aggregation and low settling rates. However, by diminishing the magnesium content before the seawater is incorporated into the process, the flocculant was able to bridge the particles and achieve a promising flocculation response. Microscopic characterisation of aggregates showed that these were larger and denser, improving the sedimentation rates considerably. The proposed research provides a new strategy to advance in tailings management issues for the mining industry, focusing on plants that use seawater in their operations. |
| Databáze: | OpenAIRE |
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