The interactive effect of depressant type and dosage with frother dosage in the flotation of a PGE ore
type: CreativeWork
description: The valuable components of the platinum group element (PGE) bearing ores of the Bushveld complex in South Africa constitute between 1 % and as little as 0.1 % of the total mass. In the processing of these ores by flotation, the naturally hydrophobic talc minerals cause over stable froths. The drainage of liquid and entrained particles is reduced thus the recovery of other gangue minerals by entrainment increases and grade decreases. In the rougher float depressants are added to produce a manageable froth and improve the grade by reducing the overall amount of the naturally floating gangue in the concentrates. Depending on dosage, depressants may also affect the recovery of the valuable minerals in the ore positively by slime cleaning or negatively by depression. Depression of stabilising gangue minerals such as talc decreases the froth stability and may also affect the recovery of valuables. Frothers are added to flotation systems to create stable froths. They increase the water layer around bubbles and the carrying capacity of the froth and thus recovery by entrainment. The drainage of entrained particles from the froth may be further increased by increasing the froth depth. This study investigated the interactive effects of depressant dosage and type, frother dosage and froth depth on the recovery and grade of copper and nickel sulphides, recovery of water, floatable and entrained gangue in the flotation of a Merensky ore. Since it is known that water recovery is closely related to froth stability it was used to infer froth stability in this study. Two types of depressants carboxymethyl cellulose (CMC) and guar gums which are usually used in the flotation of PGE bearing ores were used. The frother was Dow 250. Results showed that increasing either guar or CMC dosages from 50 to 100 g/t enhanced the recovery of copper and nickel sulphides. This was attributed to the slime cleaning action of the depressants and their stabilising effects. A further increase of dosage…
abstract: The valuable components of the platinum group element (PGE) bearing ores of the Bushveld complex in South Africa constitute between 1 % and as little as 0.1 % of the total mass. In the processing of these ores by flotation, the naturally hydrophobic talc minerals cause over stable froths. The drainage of liquid and entrained particles is reduced thus the recovery of other gangue minerals by entrainment increases and grade decreases. In the rougher float depressants are added to produce a manageable froth and improve the grade by reducing the overall amount of the naturally floating gangue in the concentrates. Depending on dosage, depressants may also affect the recovery of the valuable minerals in the ore positively by slime cleaning or negatively by depression. Depression of stabilising gangue minerals such as talc decreases the froth stability and may also affect the recovery of valuables. Frothers are added to flotation systems to create stable froths. They increase the water layer around bubbles and the carrying capacity of the froth and thus recovery by entrainment. The drainage of entrained particles from the froth may be further increased by increasing the froth depth. This study investigated the interactive effects of depressant dosage and type, frother dosage and froth depth on the recovery and grade of copper and nickel sulphides, recovery of water, floatable and entrained gangue in the flotation of a Merensky ore. Since it is known that water recovery is closely related to froth stability it was used to infer froth stability in this study. Two types of depressants carboxymethyl cellulose (CMC) and guar gums which are usually used in the flotation of PGE bearing ores were used. The frother was Dow 250. Results showed that increasing either guar or CMC dosages from 50 to 100 g/t enhanced the recovery of copper and nickel sulphides. This was attributed to the slime cleaning action of the depressants and their stabilising effects. A further increase of dosage…
author: Dhliwayo, Evelyn Chengetanai
language: eng
date published: 2005
date modified: 2026-07-24T01:34:19Z
provider: University of Cape Town
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Department of Chemical Engineering

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11427/6732