New reagent formulations for selective flotation of scheelite from a skarn ore with complex calcium minerals gangue

Filippov, L.O.; Foucaud, Yann; Filippova, I.V.; Badawi, Michaël

doi:10.1016/j.mineng.2018.05.001

Cited by 63 publications

(31 citation statements)

References 49 publications

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“…In such collector's mixtures, the classical above-described fatty acids are also associated with rosin acids, large-sized hydrophobic terpenederived compounds among which abietic, pimaric, and palustric acids are dominant (Logan, 1979). Albeit authors suggested that rosin acids do not adsorb onto mineral surfaces (Pearse, 2005), recent studies highlighted their negative impact on the flotation of sparingly soluble minerals: they increase the recoveries of all the minerals therefore inducing a considerable decrease in selectivity (Filippov et al, 2018).…”

Section: Carboxylatesmentioning

confidence: 99%

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

et al. 2020

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Recently, tungsten has drawn worldwide attention considering its high supply risk and economic importance in the modern society. Skarns represent one of the most important types of tungsten deposits in terms of reserves. They contain fine-grained scheelite (CaWO 4) associated with complex gangue minerals, i.e., minerals that display similar properties, particularly surface properties, compared to scheelite. Consistently, the froth flotation of scheelite still remains, in the twenty first century, a strong scientific, industrial, and technical challenge. Various reagents suitable for scheelite flotation (collectors and depressants, mostly) are reviewed in the present work, with a strong focus on the separation of scheelite from calcium salts, namely, fluorite, apatite, and calcite, which generally represent significant amounts in tungsten skarns. Albeit some reagents allow increasing significantly the selectivity regarding a mineral, most reagents fail in providing a good global selectivity in favor of scheelite. Overall, the greenest, most efficient, and cheapest method for scheelite flotation is to use fatty acids as collectors with sodium silicate as depressant, although this solution suffers from a crucial lack of selectivity regarding the above-mentioned calcium salts. Therefore, the use of reagent combinations, commonly displaying synergistic effects, is highly recommended to achieve a selective flotation of scheelite from the calcium salts as well as from calcium silicates.

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Section: Carboxylatesmentioning

confidence: 99%

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

et al. 2020

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“…Overall, for the best tests in terms of gangue minerals elimination, 89% of the apatite, 89% of the fluorite, and 93% of the silicates (light + dense) are rejected from the concentrate. This crucial result indicates that apatite and fluorite, which are highly problematic in fatty-acid flotation [12,16], can be eliminated by a Falcon pre-concentrating stage prior to flotation.…”

Section: Discussion On Experimental Resultsmentioning

confidence: 96%

“…However, due to the small liberation size (<150 µm), the classical gravity separation methods are usually inefficient and froth flotation is often preferred to process W skarn ores [7,10,11]. Fatty acids, particularly sodium oleate, are widely used as collectors for scheelite flotation considering their low cost, environmental friendliness, and high efficiency [7,12,13]. However, separation of calcium-bearing minerals by flotation with fatty acids is very difficult due to the tendency of these collectors to chemisorb onto the surface calcium atoms [14][15][16].…”

Section: Challenges In Tungsten Ore Processingmentioning

confidence: 99%

“…Therefore, it is crucial to eliminate these minerals during mineral processing. Though new fatty acids formulations allowed to enhance significantly the separation contrast [12], an acceptable flotation selectivity cannot be attained without either a high energy consumption-e.g., using the Petrov's process that consists in heating the pulp to 80 • C [18]-or using ecotoxic reagents as lead-benzohydroxamic acid (Pb-BHA) complexes [19,20]. Thus, finding efficient, low cost, and environment friendly processes to beneficiate W-skarn ores is a real challenge for the next decades.…”

Section: Challenges In Tungsten Ore Processingmentioning

confidence: 99%

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Application of Falcon Centrifuge as a Cleaner Alternative for Complex Tungsten Ore Processing

et al. 2019

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Scheelite (CaWO4) is one of the main raw material for the production of tungsten. It is usually encountered in skarn deposits where it is commonly associated with other calcium minerals as fluorite, apatite, and calcium silicates. Worldwide, scheelite is upgraded to the chemical grades by direct flotation, but the separation efficiency remains limited due to similar flotation behaviors of scheelite and gangue minerals with fatty acid. The only solutions used to overcome this issue involve high energy consumption or ecotoxic reagents. In the present study, a novel method based on the use of a centrifugal Falcon concentrator was investigated to perform an efficient elimination of gangue minerals and fine particles as well as an acceptable scheelite recovery enabling a decrease of the flotation reagents consumption. The performances of the two types of laboratory Falcon bowls, Falcon UltraFine (UF) and Falcon Semi-Batch (SB), were modeled using the design of experiments (DoE) methodology, which allowed to determine the best operating parameters for each bowl. The separation performances were mainly affected by the rotary speed and the pulp density for the Falcon UF and by the rotary speed and the fluidization pressure for the Falcon SB. Due to the fluidization pressure, the Falcon SB exhibited higher gangue minerals rejection with slightly lower recoveries than the Falcon UF. Overall, the optimized Falcon SB test allowed to reach 71.6%, 22.6%, 17.2%, and 12.6% for scheelite, calcium salts, dense calcium silicates, and light non-calcic silicates respectively while the desliming efficiency reached 98.8%. For comparison purposes, a classical hydrocyclone allowed to attain 89.1%, 89.3%, 79.5%, and 76.5% for scheelite, calcium salts, dense calcium silicates, and light non-calcic silicates respectively while the desliming efficiency reached 52.0%. Theses results can be used reliably to assess the separation performances of an industrial Falcon C which can be regarded, along with Falcon SB, as a sustainable and efficient gangue rejection method for complex W skarn ore, which allows the use of environmentally friendly reagents during downstream flotation stages.

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“…Similarly, scheelite and calcite have similar chemical compositions and chemical interactions with corresponding flotation reagents, which makes the separation of scheelite and calcium-containing minerals different [14]. Therefore, the flotation of scheelite is also facing enormous challenges in the process of utilization of tungsten resources [15]. Flotation reagents are the key to improving flotation indicators.…”

Section: Introductionmentioning

confidence: 99%

Use of Sodium Hexametaphosphate and Citric Acid Mixture as Depressant in the Flotation Separation of Scheelite from Calcite

et al. 2019

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The floatability of scheelite and calcite in the presence of single depressant (SHMP or H 3 Cit) and mixed depressant (SHMP/H 3 Cit) was studied by microflotation experiments and artificial mixed mineral experiments. Solution chemical calculation, zeta potential tests, thermodynamic analysis and XPS analysis were used to explain the relevant depressive mechanism. Mixed depressant (SHMP/H 3 Cit) exhibited excellent selective depressive effect on calcite. The optimal molar ratio of SHMP to H 3 Cit was 1:4. The depressant SHMP and H 3 Cit can be chemically bonded with Ca 2+ to form CaHPO 4 and Ca 3 (Cit) 2 at pH 8. The CaHPO 4 was more easily formed than Ca 3 (Cit) 2 on the mineral surface, which indicated that the depressive effect of SHMP was stronger than H 3 Cit. The SHMP and H 3 Cit of the mixed depressant were co-adsorbed on the calcite surface, while the H 3 Cit of the mixed depressant was weakly adsorbed on the scheelite surface. The mixed depressant can significantly improve the separation efficiency of scheelite from calcite. Sodium silicate (water glass) has been widely used as a depressant in flotation of scheelite from calcite [23]. However, sodium silicate also has some disadvantages as a depressant, such as frequent acidification, narrow optimum pH range, and weak selectivity. Single phosphates are also used for calcite depressants, but they are often limited by their weak selectivity, so mixed reagents are often required [24]. Organic macromolecular depressants have also received attention. Zhang et al. studied the role of sodium polyacrylate in flotation separation of scheelite and calcite [25]. However, sodium polyacrylate also has an unfavorable inhibitory effect on scheelite over a wide range of pH conditions, with poor flotation selectivity. Carboxymethyl cellulose has also been studied as a depressant in the flotation separation of scheelite from calcite [26], but it is difficult to dissolve carboxymethyl cellulose at room temperature, which is not conducive to flotation. In view of the shortcomings of the above single depressants, such as poor collecting ability, weak selectivity, and large dosage, it is often necessary to use mixed depressant to achieve flotation separation between scheelite and gangue minerals.Sodium hexametaphosphate (SHMP) is a clean, non-toxic phosphate that is widely used in the food industry and the chemical industry [27,28]. It can be used as a chelating reagent for metal ions, an adhesive, and a swelling reagent [29,30]. It is also widely used in the mineral processing industry, especially in the floatation. SHMP is used as a dispersant and depressant of minerals in flotation [31][32][33][34][35]. In addition, SHMP can be used to depress calcite [24], but it also has a strong depressive effect on scheelite. Citric acid (H 3 Cit) is also a clean, non-toxic organic acid and is a tricarboxylic acid compound. It is mainly used in the food industry, chemical industry, textile industry, cosmetics and pharmaceutical industries [36][37][38]. Citric acid can be used as depress...

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New reagent formulations for selective flotation of scheelite from a skarn ore with complex calcium minerals gangue

Cited by 63 publications

References 49 publications

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

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

Application of Falcon Centrifuge as a Cleaner Alternative for Complex Tungsten Ore Processing

Use of Sodium Hexametaphosphate and Citric Acid Mixture as Depressant in the Flotation Separation of Scheelite from Calcite

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