Separation of rutile and garnet flotation and mechanism of action of regulator

I. Introduction

Rutile is the nature of most minerals containing titanium, a titanium metal extracted, the main raw material for manufacturing titanium dioxide, and titanium dioxide having photocatalytic material properties ^[1]. Among the eclogite-type primary rutile ore, garnet is the main associated gangue mineral and has become an important limiting factor for rutile ore dressing purification. For many years, the work on the separation of rutile and garnet has been valued at home and abroad ^{[2 , 3]} .

Reselection method garnet rutile separation can not be achieved, because the two have similar densities (respectively 4.16g / cm ³ and 4.03g / cm ^3); there is magnetic separation more difficult, since the magnetic rutile although with weak The garnet is moderately magnetic, but the presence of iron in the rutile crystal lattice and the iron contamination on the surface of the granule cause the magnetic enhancement to be close to the garnet. Therefore, it is necessary and crucial to study the separation of the two by flotation.

Previous studies on flotation separation of rutile and garnet have shown that oxidized circulating oil, oleate and benzyl phthalic acid are the collectors, and sodium fluorosilicate is used as a regulator for flotation, which can realize rutile and garnet. Separation ^[3] . However, both benzyl decanoic acid and sodium fluorosilicate are highly toxic agents, so considering environmental factors, this technique is difficult to promote in practice.

In this paper, non-toxic alkyl methyl amine phosphate bis (ATF1024, structure having P = O and P-O bond) as collector, sodium hexametaphosphate [(NaPO _{3) 6]} was isolated as a flotation adjusting agent The technology of rutile and garnet, and the mechanism of action of (NaPO ₃ ) ₆ inhibiting garnet was tested and analyzed.

Second, experimental research methods

Flotation separation technology was studied by rutile and garnet single mineral flotation and simulated mixed ore flotation. The flotation was carried out on an XFGC-80 flotation machine (volume 50 ml), each time using a sample lg, a flotation temperature of 25 ° C, and a flotation time of 2.5 min. The test ATF1024 and (NaPO ₃ ) ₆ are chemically pure reagents, and the water is distilled water.

Test garnet and rutile single mineral (iron aluminum garnet) were extracted from the actual ore (a Hubei rutile ore) in a non-flotation process. The single mineral is ground by a ceramic ball mill and sieved in distilled water to obtain a product of 0.1 mm to 0.045 mm for use in a flotation test. The rutile and garnet single minerals have been identified and their purity is above 95%, which meets the test requirements.

Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) were used to study the interaction properties of (NaPO ₃ ) ₆ with rutile and garnet, and the inhibition mechanism of (NaPO ₃ ) ₆ on garnet was analyzed accordingly. . Infrared spectroscopy (IR) was measured by a Fourier infrared spectrometer manufactured by Bruker, Germany, and X-ray photoelectron spectroscopy (XPS) was measured using a KRATOS-XSAM800 multi-function surface analyzer manufactured in the United Kingdom.

Third, flotation test and results analysis

Flotation behavior of rutile and garnet single minerals

The effect of ATF1024 dosage and system pH on flotation behavior of rutile and garnet single minerals under ATF1024 as collectors is shown in Figure 1 and Figure 2, respectively. The results showed that ATF1024 had a strong effect on the collection of rutile, and it also had a certain collection effect on garnet. At pH=6, the ATF1024 dosage was 40mg/Ll, the rutile and garnet floatation rates reached saturation values ​​of 93.44% and 72.47, respectively. %.

Figure 1 Effect of ATF1024 dosage on mineral flotation

Figure 2 Effect of pH on mineral flotation

The flotation results also show that although there is a certain difference in floatability between rutile and garnet, this difference is not sufficient to achieve the separation of the two minerals. Effective separation must also rely on suitable inhibitors.

(2) (NaPO ₃ ) ₆ flotation of rutile and garnet

In the ATF1024 flotation system, the effect of adding different amounts (NaPO ₃ ) ₆ on the flotation efficiency of the two minerals is shown in Figure 3.

Figure 3 Effect of addition (NaPO) on flotation of rutile and garnet

It can be seen from Fig. 3 that (NaPO ₃ ) ₆ has a strong inhibitory effect on garnet and a weak effect on rutile. Obviously, (NaPO ₃ ) ₆ can be used as a regulator for the separation of rutile and garnet flotation, and the separation of the two minerals is achieved under the condition of ATF1024 as a collector.

(3) Flotation separation of artificial mixed ore

The experiment used artificially mixed ore samples of 1 g, which contained 0.5 g of rutile and garnet single minerals. Calculated according to the purity of rutile, the ore contains TiO ₂ 48.32%. The artificial mixed ore was floated according to the test conditions and dosages determined by a single mineral. The flow and results are shown in Table 1 and Figure 4, respectively.

Table 1 Results of artificial mixed ore flotation test

Figure 4 rutile and garnet mixed ore flotation process

It can be seen from Table 1 that with ATF1024 as the collector and (NaPO3)6 as the inhibitor, the rutile concentrate containing TiO286.52% can be separated from the ore containing TiO248.32%, the recovery rate is 77.48%, flotation The separation of rutile and garnet has obvious effects.

Mechanism of action of sodium hexametaphosphate

(a) Adsorption behavior and properties of (NaPO ₃ ) ₆ on rutile surface

The effect of rutile with (NaPO ₃ ) ₆ and its associated infrared spectrum is shown in Figure 5. Contrast can be considered, rutile (NaPO ₃₎ infrared spectrum (FIG. 5c) after ₆ acts 1023cm ^{- 1} new absorption peak position it is clear that (NaPO _{3) 6} absorption of P-O-P (FIG. 5b, 1015cm ^{- 1} ), which indicates that (NaPO) has been adsorbed on the rutile surface.

Figure 5 (NaPO ₃ ) ₆ and rutile infrared spectrum

The surface XPS detection results before and after the interaction of rutile with (NaPO ₃ ) ₆ (Fig. 6) also confirmed the adsorption of (NaPO ₃ ) ₆ (the P2P peak of the phosphorus atom appeared at the 133.30 eV spectrum after the action). In addition, it can be seen from Fig. 6 that the binding energy displacement of Ti _2P3/2 on the rutile surface is 0.15 eV before and after the action of (NaPO ₃ ) ₆ , and the displacement value is small (instrument error ± 0.4 eV), which indicates the chemical environment of Ti. There was no change before and after the action of (NaPO3) ₆ , and it is apparent that the adsorption of (NaPO ₃ ) ₆ is a physical adsorption.

Fig. 6 XPS before and after rutile and (NaPO ₃ ) ₆

Since (NaPO ₃ ) ₆ exhibits weak binding characteristics on the surface of rutile, that is, (NaPO ₃ ) ₆ adheres to the surface of rutile with a very weak effect, so when there is a collector with stronger binding to the surface of rutile in the flotation system When competing with it, (NaPO ₃ ) _{6 is} often difficult to hinder the action of the latter, even if the site of adsorbed (NaPO ₃ ) ₆ still gives way to the collector and the collector is firmly adsorbed. This therefore becomes the intrinsic mechanism by which rutile is not inhibited by (NaPO ₃ ) ₆ .

(2) The action properties and inhibition mechanism of (NaPO ₃ ) ₆ and garnet

1. The interaction property of (NaPO ₃ ) ₆ with garnet surface The molecular formula of garnet can be expressed as X ₃ Y ₂ (SiO ₄ ) ₃ , where X,

Y represents a divalent and trivalent cation, respectively. In the iron-aluminum garnet discussed in this paper, X is mainly Fe ^{2 +}

And Ca ^{2 +} , Y is mainly Al ^{3 +} . There are two kinds of chemical bonds in the garnet crystal, which are the chemical bond between the metal ion and the oxygen between the Si-O bond and the tetrahedron inside the [SiO ₄ ] tetrahedron, and the latter is easy to break when the mineral is broken ^[4] . Therefore, the cationic active sites exposed on the garnet fracture surface are mainly Al ^{3 +} , Fe ^{2 +} and Ca ^{2 +} .

Figure 7 is a surface XPS spectrum of the garnet before and after the action of (NaPO ₃ ) ₆ . Comparing Fig. 7a and Fig. 7b, it is seen that the garnet after the action of (NaPO ₃ ) ₆ exhibits a P _2P peak of a phosphorus atom at an XPS spectrum of 132 eV to 140 eV, and a garnet which is not affected by (NaPO ₃ ) ₆ . The XPS spectrum did not appear at the same position, indicating that (NaPO ₃ ) ₆ has been adsorbed on the surface of the garnet. After (NaPO ₃ ) ₆ action, the Ca2P3/2 binding energy of the garnet surface is shifted by 0.leV than the forward low energy direction of the action, and the Al _2P binding energy is shifted by 0.leV compared with the forward high energy direction. The displacement values ​​are less than the instrument error value. Obviously, the chemical environment of Ca and Al did not change before and after the action of (NaPO ₃ ) ₆ . The binding energy of Fe _2P3/2 was shifted from 710.20eV to 710.65eV before the action, and increased by 0.45eV, indicating that the chemical environment of Fe changed, that is, (NaPO ₃ ) ₆ and Fe ^{2 +} were chemically bonded.

Fig. 7 XPS spectrum before and after garnet and (NaPO ₃ ) ₆

2. (NaPO ₃ ) ₆ dissolution of metal ions on the surface of garnet

(NaPO _{3) 6} is a chelating agent, of a suitable metal ions (such as Ca ^{2 +,} etc.) as well as with a strong chelation of mineral ions eluted from the surface ^{[5, 6],} which may result in surface mass concentration of metal ions And change the surface properties including flotation characteristics.

The surface atomic concentration of garnet before and after interaction with (NaPO ₃ ) _{6 was} determined by XPS peak intensity integration method, and the atomic mass concentration ratio was calculated according to this. The ratio of the ratio of Si to the mass concentration of Al, Fe and Ca on the mineral surface will directly reflect the changes of these metal ions. It can be seen from Table 2 that the Si/Al value and the Si/Fe value of the garnet surface are 1.659 and 3.782, respectively, after the action of (NaPO ₃ ) ₆ , which is not much different from the 1.695 and 3.525 before the action, but Si/Ca. The value increases from 13.202 before the action to 16.130, which is a big change. This indicates that, by garnet (NaPO ₃₎ the effect of ₆ mass ratio of the concentration of Ca front active surface significantly reduced, apparently (NaPO _{3) 6} selectively dissolves the surface of the garnet Ca ^{+ 2.}

Table 2 (NaPO ₃ ) ₆ ratio of atomic concentration of garnet surface before and after action (based on XPS method)

Since the Ca ^{2 +} is the main active agent particles acting ATF1024 garnet and the collector surface, thus, elution with Ca ^{2 +} concentrations reduced will greatly diminish the role of adsorbed surface ATF1024 garnet, garnet is not conducive Flotation.

3, (NaPO ₃ ) ₆ inhibition mechanism of garnet flotation

Through the above research, the intrinsic mechanism of inhibition of garnet during the flotation process (NaPO ₃ ) ₆ can be obtained: First, (NaPO ₃ ) ₆ is firmly adsorbed on the surface of garnet by chemical bonding with Fe ^{2 +} on the surface of garnet. this leads to the surface strongly hydrophilic, reducing activity and impede the flotation collector effect thereto; second, (NaPO _{3) 6} ⁺ surface by chelating Ca garnet cause a ² Ca ^{2 +} selective dissolution. The dissolution and concentration reduction of Ca ^{2 +} in turn weakens the action of the collector on the garnet surface.

V. Conclusion

Alkylamine bismethylphosphoric acid (ATF1024) is a good collector for rutile, and sodium hexametaphosphate [(NaPO ₃ ) ₆ ] strongly inhibits the flotation of garnet. Flotation separation of rutile and garnet can be achieved by using ATF1024 as a collector and (NaPO ₃ ) ₆ as a regulator. The results of flotation of artificial mixed ore are basically consistent with the single mineral experiment.

(NaPO ₃ ) ₆ produces only a small amount of physical adsorption on the surface of rutile that does not interfere with the action of the collector, and has no inhibitory effect on rutile; (NaPO ₃ ) ₆ chemically bonds with Fe ^{2 + on the} surface of garnet, resulting in its strong adsorption. Hydrophilic. (NaPO _{3) 6} further selectively dissolves the surface of garnet Ca ^{2 +,} thereby reducing the surface of the mineral collector cation-active action particles. As a result of the double action, the garnet is strongly inhibited by (NaPO ₃ ) ₆ .

references:

[1] Sun Wei, Yan Yuchun, Ma Peihua. Preparation and Photocatalytic Activity of Supported Ca-Doped TiO2 Materials[J]. Journal of Liaoning Technical University, 2006, 25(2): 261-263

[2] C. Clericu. Recovery of rutile from eclogite [J]. Foreign metal ore dressing, 1980, (3): 31-38

[3] Cui Lin, Liu Junqi. Study on flotation separation of rutile and garnet[J]. Chemical Mining Technology, 1986, (5): 32-35

[4] Ma Hongwen. Industrial Minerals and Rocks [M]. Beijing: Geological Publishing House, 2002

[5] Li Changgen, Lu Yongxin. The mechanism of the interaction between phosphate modifiers and minerals [J]. International Journal of Mineral Processing, 1983 (l0): 219-235.

[6] Hao Ding, Hai lin, Yanxi Deng. Depressing effect of sodium hexametaphosphate on apatite in flotation of Rutile [J], Journal of University of Science and Technology Beijing, 2007, 14(3): 200-203.

Author unit

School of Materials Science and Engineering, China University of Geosciences (Ding Hao, Deng Yanxi, Du Gaoxiang)

School of Resources and Environmental Engineering, Liaoning Technical University (Ren Ruichen)

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