Title

GAS DISPERSION MEASUREMENTS AS A DIAGNOSTIC TOOL FOR THE PERFORMANCE OF INDUSTRIAL FLOTATION CELLS AT MINAS-RIO

GAS DISPERSION MEASUREMENTS AS A DIAGNOSTIC TOOL FOR THE PERFORMANCE OF INDUSTRIAL FLOTATION CELLS AT MINAS-RIO

Authorship

Malinga, Thokozani Lehae Hanes

Malinga, Thokozani Lehae Hanes

I am this author

DOI

10.5151/2594-357X-31847

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Abstract

Anglo American‘s Minas-Rio complex began operations in August 2014. The processing plant, produced approximately 15 million tonnes of dry concentrate in 2017. Concentration of the ore to obtain a pellet feed concentrate is achieved using reverse froth flotation, where silica is separated from hematite by floating the silica. Maximizing the recovery of the hematite in the flotation cells is of extreme importance. Hydrodynamic properties, i.e. bubble size (d32) and superficial gas velocity (Jg) have been proven industrially to define gas dispersion and therefore flotation cell performance. The Minas-Rio Hydrodynamics Program was initiated in order to understand flotation cell hydrodynamics. Superficial gas velocity and bubble size measurements were carried out using the Anglo Platinum Bubble Sizer (APBS). The measurements were carried out on roughers, cleaners and scavengers in order to map the cells and understand how gas is dispersed in the cells. From the measurements it was discovered that some of the cells were not dispersing gas evenly; i.e. higher Jg and d32 values measured closest to the impeller, whist low Jg and d32 values were measured furthest from the impeller. Subsequently, a flotation impeller change program was undertaken in order improve gas dispersion in the cells and thus flotation cell recoveries. Furthermore, from the bubble images captured with the APBS camera, it was discovered that some cells had bubbles which were larger than expected and that can be associated with a lack of the frothing reagent.

Anglo American‘s Minas-Rio complex began operations in August 2014. The processing plant, produced approximately 15 million tonnes of dry concentrate in 2017. Concentration of the ore to obtain a pellet feed concentrate is achieved using reverse froth flotation, where silica is separated from hematite by floating the silica. Maximizing the recovery of the hematite in the flotation cells is of extreme importance. Hydrodynamic properties, i.e. bubble size (d32) and superficial gas velocity (Jg) have been proven industrially to define gas dispersion and therefore flotation cell performance. The Minas-Rio Hydrodynamics Program was initiated in order to understand flotation cell hydrodynamics. Superficial gas velocity and bubble size measurements were carried out using the Anglo Platinum Bubble Sizer (APBS). The measurements were carried out on roughers, cleaners and scavengers in order to map the cells and understand how gas is dispersed in the cells. From the measurements it was discovered that some of the cells were not dispersing gas evenly; i.e. higher Jg and d32 values measured closest to the impeller, whist low Jg and d32 values were measured furthest from the impeller. Subsequently, a flotation impeller change program was undertaken in order improve gas dispersion in the cells and thus flotation cell recoveries. Furthermore, from the bubble images captured with the APBS camera, it was discovered that some cells had bubbles which were larger than expected and that can be associated with a lack of the frothing reagent.

Keywords

Flotation; Hydrodynamics; Dispersion; Bubble size

Flotation; Hydrodynamics; Dispersion; Bubble size