TY - JOUR
T1 - Lime/sodium carbonate treated seawater to improve flocculation and sedimentation of clay-based tailings
AU - Pulgar, Francisco
AU - Ayala, Luis
AU - Jeldres, Matías
AU - Robles, Pedro
AU - Toledo, Pedro G.
AU - Salazar, Iván
AU - Jeldres, Ricardo I.
N1 - Funding Information:
Funding: Please add: This research was funded by ANID Fondecyt 1211606 and Centro CRHIAM Project Anid/Fondap/15130015.
Funding Information:
Acknowledgments: Ricardo I. Jeldres is grateful for the support of ANID FONDECYT 1211606. Francisco Pulgar, Ricardo I. Jeldres and Pedro G. Toledo are grateful for the financial support of Centro CRHIAM Project Anid/Fondap/15130015. Pedro Robles thanks the Pontificia Universidad Católica de Valparaíso for the support provided. Matías Jeldres acknowledges the infrastructure and support of the Programa de Doctorado en Ingeniería de Procesos de Minerales of the Universidad de Antofagasta.
Funding Information:
Please add: This research was funded by ANID Fondecyt 1211606 and Centro CRHIAM Project Anid/Fondap/15130015.Acknowledgments: Ricardo I. Jeldres is grateful for the support of ANID FONDECYT 1211606. Francisco Pulgar, Ricardo I. Jeldres and Pedro G. Toledo are grateful for the financial support of Centro CRHIAM Project Anid/Fondap/15130015. Pedro Robles thanks the Pontificia Universidad Cat?lica de Valpara?so for the support provided. Mat?as Jeldres acknowledges the infrastructure and support of the Programa de Doctorado en Ingenier?a de Procesos de Minerales of the Universidad de Antofagasta.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Seawater treated with lime and sodium carbonate in different proportions to reduce magnesium and calcium contents is used in flocculation and sedimentation tests of artificial quartz and kaolin tailings. Solid complexes were separated from water by vacuum filtration, and factors such as lime/sodium carbonate ratio, kaolin content, flocculation time, and flocculant dose are evaluated. The growth of the aggregates was captured in situ by a focused beam reflectance measurement (FBRM) probe. Solid magnesium and calcium complexes are formed in raw seawater at pH 11, impairing the performance of flocculant polymers based on polyacrylamides. The results show that the settling rate improved when the treatment’s lime/sodium carbonate ratio increased. That is, when a greater removal of magnesium is prioritized over calcium. The amount of magnesium required to be removed depends on the mineralogy of the system: more clay will require more significant removal of magnesium. These results respond to the structural changes of the flocs, achieving that the more magnesium is removed, the greater the size and density of the aggregates. In contrast, calcium removal does not significantly influence flocculant performance. The study suggests the necessary conditions for each type of tailing to maximize water recovery, contributing to the effective closure of the water cycle in processes that use seawater with magnesium control.
AB - Seawater treated with lime and sodium carbonate in different proportions to reduce magnesium and calcium contents is used in flocculation and sedimentation tests of artificial quartz and kaolin tailings. Solid complexes were separated from water by vacuum filtration, and factors such as lime/sodium carbonate ratio, kaolin content, flocculation time, and flocculant dose are evaluated. The growth of the aggregates was captured in situ by a focused beam reflectance measurement (FBRM) probe. Solid magnesium and calcium complexes are formed in raw seawater at pH 11, impairing the performance of flocculant polymers based on polyacrylamides. The results show that the settling rate improved when the treatment’s lime/sodium carbonate ratio increased. That is, when a greater removal of magnesium is prioritized over calcium. The amount of magnesium required to be removed depends on the mineralogy of the system: more clay will require more significant removal of magnesium. These results respond to the structural changes of the flocs, achieving that the more magnesium is removed, the greater the size and density of the aggregates. In contrast, calcium removal does not significantly influence flocculant performance. The study suggests the necessary conditions for each type of tailing to maximize water recovery, contributing to the effective closure of the water cycle in processes that use seawater with magnesium control.
KW - Calcium and magnesium removal
KW - Lime
KW - Seawater
KW - Sodium carbonate
KW - Tailings flocculation
UR - http://www.scopus.com/inward/record.url?scp=85119991299&partnerID=8YFLogxK
U2 - 10.3390/polym13234108
DO - 10.3390/polym13234108
M3 - Article
AN - SCOPUS:85119991299
VL - 13
JO - Polymers
JF - Polymers
SN - 2073-4360
IS - 23
M1 - 4108
ER -