Managing clay minerals in froth flotation—A critical review

Abstract

Clay minerals are widely present in various ore deposits as gangue minerals. The processing of high-claycontent ores is becoming a significant challenge for the mining industry owing to the poor flotation performance caused by the presence of clay minerals. Different types of clay minerals are typically present in ore bodies, and they cause several detrimental effects to flotation that require different treatments. In this article, a comprehensive review of the studies on understanding and mitigating the negative effects of clay minerals in flotation is presented. It starts with a review of the classification and structures of clay minerals commonly occurring in ore deposits and their properties that determine the behavior of clay minerals in flotation. It is followed by a critical review of two main negative effects of clay minerals on flotation, the recent research findings mainly from The University of Queensland group. The first negative effect is the coating of clay minerals on the surface of valuable minerals that decreases the floatability of valuable minerals. The second negative effect is the formation of network structures in the slurry. Depending on the type and strength of the network structure, it can cause either high pulp viscosity or increased gangue entrainment, which reduces the flotation recovery and flotation product grade, respectively. In this section, the mechanisms and key factors behind each negative effect are presented and critically discussed. Then, the approaches and techniques developed to mitigate the different negative effects of clay minerals are reviewed. To conclude, future directions for a more complete understanding of mechanisms and problem solving are recommended.

The Effect of Sodium Alginate on Chlorite and Serpentine in Chalcopyrite Flotation

“…The calibration standard was obtained by fitting the total organic carbon with the concentration (0, 5, 10, 20, 30, 40, 50, 60, 80, 120, 200) of pure NaAl solution at pH 9. For each adsorption test, 2 g of −10 μm mineral (single mineral) was added into an 80-mL beaker together with 40 mL of NaAl solution, which was prepared at the desired concentration (5,10,20,30,40,50,60,80, 120 mg/L) at pH 9. The suspension was stirred for 40 min using a magnetic stirrer and then centrifuged.…”

“…At present, flotation is the most commonly-used method to separate the valuable copper sulfide mineral from these two phyllosilicates. Nevertheless, due to the unique properties of chlorite and serpentine, the phyllosilicates impair the flotation of copper sulfide ore. A high content of these phyllosilicates in slurry increases the pulp viscosity [8,9], which can result in a significant reduction in flotation recovery [10]. These phyllosilicates also adhere to valuable minerals to form a hydrophilic coating, which prevents the adsorption of collectors on sulfide minerals and reduces their floatability [11].…”

“…Polysaccharides, such as carboxymethyl cellulose (CMC) [21], chitosan [22], guar gum [23], dextrin [24], and lignosulfonate [25], have been applied to eliminate the harmful effects of phyllosilicates. The most reported polymeric depressant is carboxymethyl cellulose (CMC), which has been widely used for depressing MgO-type gangue minerals in nickel sulfide flotation [10]. Although many works on the polysaccharide depressants of chlorite and serpentine have been presented, they have generally focused on the condition that one kind of magnesium silicate-bearing gangue mineral is present in the ores.…”

Effects of Ultrasound on Desliming Prior to Feldspar Flotation

“…The negative effects of slimes during froth flotation for feldspar ores were also revealed by many researchers [4,15,[26][27][28]. It was stated that fine particle minerals not only effect as slime coating but also affect pulp rheology and the subsequent mineral flotation.…”

Effect of ultrafine kaolinite particles on the flotation behavior of coking coal

“…and theoretical calculation of liquid film drainage rate Figure 7 illustrates that the content of ultrafine kaolinite particles in the low-concentration NaCl solution has little effect on the apparent viscosity of the suspension. Owing to different compositions, structures, and charge properties, clay minerals and nonclay minerals affect pulp rheology quite differently (Chen and Peng 2018). In the literature, the change in pulp rheology can also significantly affect froth stability as reviewed by Farrokhpay (2011).…”