TY - JOUR
T1 - Enhancing the sedimentation of clay-based tailings in seawater by magnesium removal treatment
AU - Jeldres, Matías
AU - Piceros, Eder C.
AU - Toro, Norman
AU - ROBLES VASQUEZ, PEDRO ADRIAN
AU - Nieto, Steven
AU - Quezada, Gonzalo R.
AU - Jeldres, Ricardo I.
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - 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.
AB - 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.
KW - Clays
KW - Magnesium removal
KW - Tailings flocculation
KW - Thickening
KW - Treated seawater
UR - http://www.scopus.com/inward/record.url?scp=85081013539&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2020.116762
DO - 10.1016/j.seppur.2020.116762
M3 - Article
AN - SCOPUS:85081013539
VL - 242
JO - Separation and Purification Technology
JF - Separation and Purification Technology
SN - 1383-5866
M1 - 116762
ER -