Comparison of ultra-flocculation reactors applied to fine quartz slurries. (15th March 2020)

• Record Type: Journal Article
• Authors: Betancourt, Fernando; Celi, Diana; Cornejo, Pablo; del Río, Marco; Macera, Luciana; Pereira, Alonso; Rulyov, Nicolaj
• Is Part Of: Minerals engineering. Volume 148(2020)
• Publication Date: 2020-03-15
• Subjects: Ultra-flocculation -- Fine particles -- Shear rate gradient -- Flocculation; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2019.106074
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: Flocculation studies were carried in six different ultra-flocculation reactors at high shear rates. The six ultra-flocculation reactors allow flocculation in times below of 10 s. Results showed an average improvement in settling velocity and turbidity below 100 NTU compared with flocculation in cylindrical columns at low shear rate. Abstract: Ultraflocculation can be defined as: flocculation performed in a highly non-uniform hydrodynamic field ( ε > 1 [J/kg · s ], G > 10 3 [ s - 1 ]) in a short period of time ( t < 10 [s]), which is used mainly to aggregate fine particles in dispersed, and diluted systems. In this study, four hydraulic ultra-flocculation reactors were tested, UF1, UF2, UF3 and UF4 with tangential inlets/outlets and a cylindrical body, the inside of which varies by reactor. Model flocculated fine quartz slurries were employed as material. Based on a comparison of the three flocculation process indicators – initial settling velocity, supernatant turbidity, and sludge volume – in general the reactors present better performance than that in the base case. There was an average improvement in settling velocity of 300[%], turbidity remains below 100 [NTU], and sludge volume values indicated a higher possibility of water recirculation. Additionally, it was observed that the ultra-flocculation process could be used in relatively concentrated suspensions ( φ > 10 - 2 ) with treatment times below to 5 [s].