Effectiveness of sodium silicate as gangue depressants in iron ore slimes flotation

Abstract

The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO 2 and Al 2 O 3 levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO 2 , and 5.28wt% Al 2 O 3 with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO 2 , and 6.80wt% Al 2 O 3 , when Na 2 SiO 3 with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.

The Challenge of Tungsten Skarn Processing by Froth Flotation: A Review

“…Moreover, it is known to adsorb with a high affinity on the gangue mineral surfaces, mostly silicates, and therefore, it constitutes a strong depressant in the froth flotation process. Over the past decades, Na 2 SiO 3 has been successfully used in the flotation separation of rare earth minerals (Filippov et al, 2016), zinc minerals (Ejtemaei et al, 2012), iron minerals (Rao et al, 2011), scheelite (CaWO 4 ) (Kupka and Rudolph, 2018a;Yang, 2018;Foucaud et al, 2019c), fluorite (Song et al, 2006;Zhou et al, 2013), apatite (Qi et al, 1993;Sis and Chander, 2003), and many other minerals. The behavior of Na 2 SiO 3 in aqueous solutions have been intensively investigated: depending on the pH of the solution and the total silica concentration, the silica tetrahedral (SiO 4 ) can be under SiO 4− 4 , SiO 3 (OH) 3− , SiO 2 (OH) 2− 2 , SiO(OH) − 3 , and Si(OH) 4 forms (Engelhardt et al, 1975;Marinakis, 1980;Marinakis and Shergold, 1985;Bass and Turner, 1997;Halasz et al, 2007;Jansson et al, 2015).…”

Synergistic adsorptions of Na2CO3and Na2SiO3on calcium minerals revealed by spectroscopic andab initiomolecular dynamics studies

“…depressed. Therefore, Na 2 SiO 3 is commonly used in the otation separation of rare earth minerals, 11 zinc minerals, 12 iron minerals, 13 scheelite (CaWO 4 ), [14][15][16][17] uorite (CaF 2 ), 18,19 apatite [Ca 5 (PO 4 ) 3 (OH,F)], 20,21 and many other minerals.…”

Beneficiation and Purification of Tungsten and Cassiterite Minerals Using Pb–BHA Complexes Flotation and Centrifugal Separation

“…The inhibition effect of the depressant on upgrading is a common issue in flotation. As is well known, floatability of the minerals greatly depends on the surface properties of the minerals, such as the crystal anisotropy, which can be greatly influenced by the depressant [24][25][26][27]. Take scheelite as an example; the wettability of the (001) plane of scheelite decreased slightly, whilst increasing the dosage of Al-SiO3, while the wettability of the (112) plane decreased significantly.…”

“…XRD results show that quartz, chlorite, muscovite, feldspar, and amphibole also exist in the rougher concentrate, which could be due to the entrainment of super fine particles in the foam. The existence of those minerals made it easier for the grinding process to get muddy because of their lower hardness [27][28][29], posing great challenges for the separation of them from the valuable minerals by flotation. As shown in Figure 6, D 50 of the rougher concentrate was 0.021 mm, which falls into the fine particle size range, causing problems for further improvement of the concentrate quality.…”