The Behaviour of Mixtures of Sodium Iso-Butyl Xanthate and Sodium Di-Ethyl Dithiophosphate during the Flotation of a Cu-Ni-Pt Ore in Degrading Water Quality

Abstract

The use of mixtures of thiol collectors is reportedly beneficial in sulfide flotation. This is becoming standard practice for many concentrators, but process water recirculation and re-use in flotation circuits may compromise the behaviour of such mixtures owing to changes in physicochemical interactions occurring in the pulp phase as a result of water quality variations. It is expected that changes in the pulp chemistry would in turn affect both the pulp and froth phase phenomena, thereby affecting flotation performance. Thus, this study considers mixtures of thiol collectors, sodium iso-butyl xanthate (SIBX), and sodium di-ethyl dithiophosphate (SEDTP) in degrading water quality. Bench-scale flotation tests were conducted on various molar ratios of the selected thiol collectors under different ionic strengths (0.0242 mol·dm−3 and 0.1212 mol·dm−3) of synthetic plant water. Increasing the ionic strength of synthetic plant water and SEDTP molar ratio resulted in an increase in water, solids, Cu, and Ni recoveries. Cu-Ni grades decreased in increasing SEDTP molar ratios. The highest Cu-Ni grades were obtained in degrading water quality. The increase in water and solids recoveries in increasing SEDTP and ionic strength of plant water is attributed to an increase in froth stability. It can be concluded that the increase in the ionic strength of plant water increased water recoveries and therefore froth stability in parallel with SEDTP’s froth stabilizing effect, thus suggesting an additive interaction on the froth stabilisation effect seen.

Specific Ion Effects on the Behavior of Mixtures of Sodium Iso-Butyl Xanthate and Sodium Diethyl Dithiophosphate during the Flotation of a Cu-Ni-PGM Ore: Effects of CaCl2 and NaCl

“…A 1 kg amount of a Merensky ore sample was milled at 66% solids in single-salt solutions in order to obtain a grind of 60%, passing 75 µm for 13.5 min, as determined by the milling curve shown in [4], for each experimental test. The milled sample was transferred into a 3 L Barker flotation cell.…”

“…This was attributed to better surface coverage with mixed thiol collectors and, therefore, better hydrophobization. Thiol collectors such as dithiophosphates (DTP) and xanthates are said to have the ability to increase hydrophobicity and are also classified as good froth stabilizing agents [1][2][3][4]. These attributes of most thiol collectors result in recoveries of heterogeneous minerals such as base metal sulfides and may also result in high solids recoveries of both fine and coarse interlocked particles owing to a possible increase in froth stability [2,4].…”

“…Thiol collectors such as dithiophosphates (DTP) and xanthates are said to have the ability to increase hydrophobicity and are also classified as good froth stabilizing agents [1][2][3][4]. These attributes of most thiol collectors result in recoveries of heterogeneous minerals such as base metal sulfides and may also result in high solids recoveries of both fine and coarse interlocked particles owing to a possible increase in froth stability [2,4]. Roy et al [5] concluded that the xanthates are able to adsorb selectively on fine particles, with co-collectors such as dithiophosphates and hydroxamate playing an important role in adsorbing onto coarse particles.…”

The Influence of Specific Ions and Oxyhydroxo Species in Plant Water on the Bubble–Particle Attachment of Pyrrhotite

“…This study by Manono et al maintained the ionic strength of various single salt solutions constant at 0.0213 M. This ionic strength could possibly be very low to see the effect of specific ions on mineral recoveries as the ionic strength of plant water used on a concentrator was shown to be closer to 0.0723 and 0.1205 M . Following Manono et al, oxyhydroxo species were considered on a similar sulfidic copper and nickel ore in a different study; it was shown that operating at pH 11 resulted in a decrease in copper and nickel recoveries, suggesting that the floatabilities of copper (chalcopyrite) and nickel (pentlandite) were impeded.…”

“…As this study specifically considers the bubble–particle attachment of pyrrhotite in specific inorganic electrolytes found in process water, building on the work of Manono et al, , it was speculated that pyrrhotite would be of interesting consideration owing to its rather peculiar surface chemistry. A number of studies on the behavior and floatability of pyrrhotite against different pulp chemistry have been conducted. − It is important to note that pyrrhotite is an iron sulfide mineral with the formula Fe (1 – x ) S, where 0 < x ≤ 0.125; this results in many pyrrhotite superstructures.…”