|
Título:
|
Silica removal in industrial effluents with high silica content and low hardness
|
|
Autores:
|
Latour, Isabel ;
Miranda, Rubén ;
Blanco, Ángeles
|
|
Tipo de documento:
|
texto impreso
|
|
Editorial:
|
Springer, 2014
|
|
Dimensiones:
|
application/pdf
|
|
Nota general:
|
info:eu-repo/semantics/openAccess
|
|
Idiomas:
|
|
|
Palabras clave:
|
Estado = Publicado
,
Materia = Ciencias: Química: Industria del papel
,
Materia = Ciencias: Química: Ingeniería química
,
Materia = Ciencias: Química: Residuos
,
Tipo = Artículo
|
|
Resumen:
|
High silica content of paper mill effluents is limiting their regeneration and reuse after membrane treatments such as reverse osmosis (RO). Silica removal during softening processes is a common treatment; however, the effluent from the paper mill studied has a low hardness content which makes necessary the addition of magnesium compounds to increase silica removal. Two soluble magnesium compounds (MgCl2?6H2O and MgSO4?7H2O) were tested at five dosages (250-1500 mg/L) and different initial pHs. High removal rates (80-90%) were obtained with both products at the highest pH tested (11.5). With these removal efficiencies, it is possible to work at high RO recoveries (75-85%) without silica scaling. Although pH regulation significantly increased the conductivity of the waters (at pH 11.5 from 2.1 mS/cm to 3.7-4.0 mS/cm), this could be partially solved by using Ca(OH)2 instead of NaOH as pH regulator (final conductivity around 3.0 mS/cm). Maximum chemical oxygen demand (COD) removal obtained with caustic soda was lower than with lime (15% vs. 30%). Additionally, the combined use of a polyaluminum coagulant during the softening process was studied; the coagulant, however, did not significantly improve silica removal, obtaining a maximum increase of only 10%.
|
|
En línea:
|
https://eprints.ucm.es/id/eprint/29263/1/Silica%20removal%20in%20industrial%20effluents%20with%20high%20silica%20content%20and%20low%20hardness_Latour_ESPR_2014.pdf
|
