A Novel Method to Limit the Adverse Effect of Fine Serpentine on the Flotation of Pyrite

Abstract

A novel method to limit the adverse effect of fine serpentine on the flotation of pyrite was investigated in this paper. The flotation results showed that coarser serpentine possessed a weaker depression effect on the pyrite flotation process, and the use of KAl(SO 4 ) 2 ·12H 2 O could efficiently limit the detrimental effect of fine serpentine on pyrite with a maximum increase of pyrite recovery from 14% to 86% at pH 9.0. The results of particle size measurements and rheological measurements exhibited that the addition of KAl(SO 4 ) 2 ·12H 2 O increased the particle size of serpentine buta hrdly affected the particle size of pyrite, then limited the formation of serpentine-pyrite aggregates. Adsorption test results showed that the adsorption density of potassium butyl xanthate (PBX) onto pyrite regained with the addition of KAl(SO 4 ) 2 ·12H 2 O, thereby achieving good flotation improvement. It can be concluded that KAl(SO 4 ) 2 ·12H 2 O is likely to be an effective pyrite flotation reagent, especially in the presence of fine serpentine.Aluminum potassium sulfate dodecahydrate (KAl(SO 4 ) 2 ·12H 2 O), which is commonly known as potassium alum, has been most commonly used as an inorganic coagulant for decades due to its characteristics of nontoxicity, cheapness, and wide sources [15,16]. KAl(SO 4 ) 2 ·12H 2 O hydrolyzes to form an amorphous floc of Al(OH) 3 (s) to coagulate small particles into large flocs by its high adsorption affinity in aqueous solution [17,18]. However, the utilization of KAl(SO 4 ) 2 ·12H 2 O to remove the depressant of fine serpentine on the flotation of sulphide minerals has not been studied previously, and thus it was chosen as a potential coagulant in removing slime coatings of fine serpentine from sulphide minerals in this study. Pyrite is the most widespread and abundant of naturally occurring metal sulphides, and is always associated with magnesium silicate minerals [19,20]. Therefore, it was chosen as the valuable mineral in this paper. The effect of KAl(SO 4 ) 2 ·12H 2 O on the flotation process was evaluated through single mineral flotation, particle size measurements, rheology measurements, and adsorption measurements. Materials and Methods Samples and ReagentsThe serpentine and pyrite minerals used for all the experiments were obtained from Donghai, Jiangsu Province, and Yunfu, Guangdong Province of China, respectively. Serpentine and pyrite samples were crushed to −1 mm in a laboratory roll crusher and grounded using an agate mortar and pestle to the designed fraction. Here, −150 + 74 µm, −74 + 38 µm, and −10 µm serpentine and −150 + 74 µm pyrite particles were used for the flotation tests; the −10 µm serpentine and −150 + 74 µm pyrite particles were used for particle size measurements and rheology measurements; and the −10 µm serpentine and −38 µm pyrite particles were used for the adsorption measurements. According to the results of X-ray diffraction (XRD), shown in Figure 1, the serpentine sample constituted 98% serpentine and 2% chlorite, and the purity of pyrite was higher...

X-ray Photoelectron Spectroscopy in Mineral Processing Studies

“…In particular, it was demonstrated that smaller sulfide mineral particles are more oxidized and attract more ferric hydroxides after the comminution in steel mills than coarser ones [192]. The grinding of sulfide ores was found to produce ultrafines in quantities comparable with, or exceeding the amounts of flotation reagents [193,194], particularly serpentine gangues [194][195][196] which bear positive charge and adhere to negatively-charged sulfide minerals, suppressing their flotation. Thus, correct procedures of sampling and handling of mineral dispersions for XPS exploration still need to be elaborated.…”