Study on flotation of strontium ore
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Research fersmite flotation
H · Ren  Wait
Abstract The effect of different collectors synthetic fersmite flotation. These collectors include benzyl phthalic acid, a-styrene phosphonic acid, bisphosphonic acid, cycloalkyl hydroxamic acid, and alkyl hydroxamic acid. The test results show that bisphosphonic acid is an effective selective collector for flotation of strontium calcium ore. Under the conditions of bisphosphonic acid concentration of 20mg/L and pH 2.5~5.0, the flotation recovery of barium calcium ore was 83.27%~85.10%. The interaction between bisphosphonic acid and barium calcium ore was analyzed by infrared absorption spectroscopy (IAS) and X-ray photoelectron spectroscopy (XPS). X-ray photoelectron spectroscopy results show that the P 2p binding energy of the bismuth phosphate-treated barium calcium ore is shifted by 3.85 eV, and it is known that the bisphosphonic acid is chemically adsorbed on the surface of the barium calcium ore.
Keywords adsorption bisphosphonate strontium calcium ore flotation IAS XPS
Introduction
There are more than 130 kinds of antimony minerals on earth, but only a few antimony minerals can be used by industry. One of them is calcite ore, and its chemical formula is (Ca, Ce, Na) (Nb, Ta, Ti) 2 (O, OH, F) 6 . Niobium is an important component of the alloy, is also widely used in chemical manufacturing. The most industrially valuable plutonium resource is Brazil's plutonite deposit, which is the world's most famous antimony resource. The reserves of antimony resources in the Baiyun Obo deposits in northern China, including rare earths, strontium, iron and fluorite , rank second in the world.
Flotation is an effective economic mineral processing method and is widely used for sorting strontium-containing minerals. Other methods, such as re-election and magnetic separation, are also used to sort the strontium ore from continuous gangue minerals. However, the recovery and concentrate grades obtained by these methods are unsatisfactory.
A large amount of research work has recently been done on highly selective collectors containing antimony minerals. The flotation characteristics of several new collectors are introduced. The organophosphorus compounds of bisphosphonic acid derivatives are recommended as flotation collectors for cassiterite , fluorite and phosphocalcium. Tests have shown that they are highly selective in separating these minerals from complex mineral combinations. A range of chelating collectors, such as hydroxamic acid, have been widely used for the flotation of rare earth ore. Styrene phosphate is an effective collector in the selective flotation of fine-grained cassiterite complexes.
In this study, various collectors were used to conduct flotation tests on the synthesized barium calcium ore, and the test results were compared. The flotation mechanism of barium calcium ore was studied by infrared absorption spectroscopy (IAS) and X-ray photoelectron spectroscopy (XPS). The chemical adsorption mechanism of bisphosphonic acid on barium calcium ore was determined from the experimental data of IAS and XPS.
1, test
1.1 Preparation of strontium ore
It is difficult to obtain the high-purity barium calcium ore required for the test from nature. High-purity barium calcium ore can be produced by high-temperature synthesis and oxidative roasting. The synthesized barium calcium ore is a colorless transparent crystal or a white powder. The X-ray diffraction spectrum (XRD) of the crystal powder and the correlation data of the diffraction intensity (I) and the crystal plane distance (d) are shown in Fig. 1 and Table 1, respectively.
Figure 1 X-ray diffraction spectrum of the synthesized strontium ore
Table 1 X-ray diffraction data of synthesized strontium ore
Serial number
Measurement data
Standard data
d r (A)
I/I 0
d r (A)
I/I 0
1
7.506
twenty one
7.470
40
2
5.381
8
5.340
20
3
3.770
27
3.950
60
4
3.440
11
3.428
20
5
3.060
100
3.049
100
6
2.879
10
2.863
30
7
2.688
6
2.681
10
8
2.612
9
2.606
20
9
2.574
6
2.564
10
10
2.520
8
2.510
30
11
2.498
12
2.498
30
12
2.316
3
2.306
10
13
2.250
6
2.242
20
14
2.091
5
2.090
20
15
1.768
7
1.768
50
XRD results indicated that all diffraction peaks were generated by CaNb 2 O 6 . No impurities were detected in the sample. Chemical analysis showed that the content of Nb 2 O 5 in the synthesized barium calcium ore was 82.15%. Since the theoretical value of Nb 2 O 5 content in the barium calcium ore is 82.58%, the purity of the synthesized sample is 99.48%.
1.2 Preparation of gangue minerals
Limonite, nepheline and dolomite are the main gangue minerals that coexist with barium calcium deposits. The preparation of these gangue minerals is necessary to study the flotation of the strontium ore in the presence of gangue. The purification process of different minerals and their main physical properties are shown in Table 2.
Table 2 Method for purifying gangue minerals coexisting with barium calcium ore and their density and purity
Mineral name
Place of origin
Purification method
Density / g · cm -3
purity/%
Limonite
China Anhui copper officer mountain
Mincing, hand picking and porcelain ball milling and screening
4.034
95.8
Nepheline
Baiyun Obo, Inner Mongolia, China
Crushed ore, hand-selected, porcelain ball mill grinding and screening
3.552
95.0
dolomite
Laiyang, Hunan, China
Shaker re-election, wet magnetic separation and screening
2.843
98.2
1.3 pharmacists
Tannin, phosphonic acid and alkyl hydroxamic acid are considered to be special collectors for barium calcium ore. Benzyl decanoic acid, a-styrenephosphonic acid, bisphosphonic acid, cycloalkyl hydroxamic acid, and alkyl hydroxamic acid were used as collectors in this study.
1.4 flotation test
This experiment used a 70mL XFGC-80 flotation cell for flotation test; the slurry temperature was controlled between 25 ° C and 30 ° C; the impeller rotation speed was fixed at 2000 r / min. The type of collector, the pH value of the slurry and the dosage of the agent are the key parameters of the mineral flotation test. Their effects on the flotation of barium calcium ore were studied in the test.
1.5 IAS and XPS analysis
Infrared absorption spectroscopy was performed using a JEOL JIR 5500 Fourier transform infrared spectrometer with an MCT ( mercury cadmium telluride ) detector. Differential infrared spectra were taken from the bismuth-acid-treated barium calcium ore samples in the fluorite infrared sample chamber in the range of 400 to 4000 cm -1 .
X-ray photoelectron spectroscopy studies were performed using a Vacuum Generator Escalab MK II spectrometer with an AIK a1.2 source as the excitation source (hr = 1486.6 eV). The electronic analyzer operates in a fixed 2.0 eV pass energy transfer mode. All test tests were performed at an analytical chamber vacuum of less than 10.10 -8 Pa.
The test samples for IAS and XPS analysis were two granular barium calcium ore that had been treated with and without bisphosphonate. The untreated test sample was ground to 2 Km with stirring, and then 1.0 g of the sample was subjected to analysis. The preparation process of the treated barium calcium ore sample is as follows:
1) The barium calcium ore was ground to 2 μm with a stirring mill to increase its specific surface area so that more bisphosphonic acid was adsorbed on the surface of the barium calcium ore.
2) Prepare 150 mL of 1% bisphosphonic acid in a 200 mL beaker at a pH of 5.0.
3) Add 2.0 g of ground barium calcium ore to the beaker, and then stir the slurry at about 25 ° C, pH 5.0 for 2 h.
4) The slurry is subjected to solid-liquid separation using a centrifugal filter.
5) The separated solid was washed with deionized water at pH 5.0 and repeated 5 times in order to reduce the concentration of the dissolved drug in the liquid.
6) The solid sample was dried at 30 ° C and kept dry for analysis. [next]
2 results and discussion
2.1 flotation test
The selectivity and capture capacity of various collectors for the flotation of barium calcium ore were studied using a single mineral flotation test. The recovery rates of the four mineral flotations of the five different collectors at different pH values ​​are shown in Figure 2. Obviously, the floatability of these minerals is relatively poor when using benzyl phthalic acid as a collector. The maximum recovery of strontium ore is about 50% at a concentration of 216 mg/L benzyl citrate, which is suitable for flotation pH. The value range is very narrow. It can be seen from Fig. 2 that cycloalkyl hydroxamic acid has a strong trapping ability for four minerals under a wide pH condition, but the selectivity is poor. Alkyl hydroxamic acid (C 7-9 ) and cycloalkyl hydroxamic acid have similar capture effects under weakly acidic, neutral and weakly alkaline conditions. A-styrenephosphonic acid has better selectivity under acidic conditions, but the amount of the agent is large. The use of these collectors does not effectively separate the barium calcium ore and gangue minerals. Bisphosphonic acids have good selectivity for these minerals. Using bisphosphonic acid as a collector, the strontium ore has a good selectivity at pH 2.5~5.0. When the pH is higher than 5.0 or less than 2.5, its floatability drops rapidly. When the pH is between 2.0 and 11.0, nepheline is difficult to float. The floatability of dolomite reaches a maximum at pH 6.0, and its floatability is very low at pH values ​​below 5.0. When bisphosphonic acid is used as a collector, the floatability of barium calcium ore and limonite is very different under the condition of pH 2.0~4.0. It is apparent that the selectivity of the different collectors is sequentially decreased in the following order: bisphosphonic acid > benzyl decanoic acid > a-styrene phosphonic acid > alkyl hydroxamic acid (C 7-9 ) > cycloalkyl hydroxamic acid. These results are very consistent with the results of Zheng et al. Ren et al. observed that bisphosphonic acid exhibited a good trapping effect on black rutile ((Ti, Nb, Fe) 3 O 6 ) at a bisphosphonic acid concentration of 75 mg/L. The recovery rate of black rutile at pH 2.0~4.0 was 90.87%~91.70%. Chen et al. found that bisphosphonic acid is an effective collector for coltan ((Fe, Mn) Nb 2 O 6 ) under acidic conditions. The recovery of coltan was 84.24%~91.17% when the concentration of bisphosphonic acid was 140 mg/L and the pH was low at 5.0. These results indicate that bisphosphonic acid and its derivatives are effective collectors for strontium-containing minerals. The effect of different collector dosages on the recovery of barium calcium ore at the optimum pH is shown in Figure 3. From this, it can be seen that the order of the collecting ability of the different collectors is: cycloalkyl hydroxamic acid > alkyl hydroxamic acid (C 7-9 ) > bisphosphonic acid > a styrene phosphonic acid > benzyl citric acid.
Fig. 2 Relationship between recovery rate of different minerals and pH value during flotation of different collectors
(A) benzyl decanoic acid (216 mg/L); (B) cycloalkyl hydroxamic acid (8 mg/L);
(C) alkyl hydroxamic acid (10 mg/L) (D) a-styrene phosphonic acid (184 mg/1)
(E) bisphosphonic acid (20 mg/L)
â—†-é“Œ calcium ore; â– - limonite; â–²- nepheline; â—-dolomite
Figure 3 The amount of collector at their optimum pH
Impact on the recovery rate of barium ore flotation
Oral-cycloalkanoic acid (pH 7.0); â—‹-C 7~9 alkyl hydroxamic acid (pH 6.0);
△-bisphosphonic acid (pH 5.0); Δ-a-styrenephosphonic acid (pH 5.0);
+-benzyl decanoic acid (pH 5.0)
2.2 Theoretical research
In order to better understand the basic principle of flotation of strontium ore with bisphosphonate, the characteristics of the strontium ore sample treated with 1% bisphosphonic acid solution for 2 h were analyzed by IAS and XPS.
2.2.1 IAS analysis
The adsorption characteristics of the agent and the bonding atoms of the functional group can be identified by IAS. The IAS spectra of bisphosphonate, barium calcium ore and bisphosphonate treated barium calcium ore are shown in Figure 4. The infrared differential spectroscopy of the strontium calcium ore which has been treated with and without bisphosphonic acid is shown in FIG. It can be clearly seen from Fig. 4 that the bisphosphonate-treated barium calcium ore has four characteristic absorption peaks, which are related to the vibration of the methyl group and the methylene group at wave numbers of 1465, 2854, 2925 and 2957 cm -1 , respectively. related. In the differential spectrum of Fig. 5, the absorption peaks at the wave numbers associated with the -P-O- and -P=O-functional group vibrations at 1178, 1142, 1087, and 934 cm -1 were not significant. Since the -P-O- characteristic peak of the bisphosphonic acid is at the wave number of 1062 cm- 1 , the peak position is significantly shifted to 1087 cm -1 , indicating that the bisphosphonic acid is adsorbed on the surface of the barium calcium ore. Chen et al. reported that when bisphosphonate was used as a collector to float coltan, the -P-O- characteristic peak shifted from 1062 cm -1 to 1049 cm -1 . Their data indicate that bisphosphonic acid is adsorbed on the surface of the coltan, but the peak position shift is not as pronounced as that of the strontium ore. [next]
Figure 4 Bisphosphonic acid (top), barium calcium ore (middle) and treated with bisphosphonic acid
IAS spectrum of strontium ore (bottom)
Figure 5 Differential infrared spectroscopy of barium calcium ore with and without bisphosphonate treatment
2.2.2 XPS analysis
The sample was illuminated with a single soft X-ray and the electrons were ejected for XPS analysis. The relative concentration of electrons is determined by the photoelectric intensity. Different chemical states can be identified by the strength of XPS, which is useful for studying the growth process of adsorbed components, oxidized/corroded products, and films.
Bisphosphonic acids are composed of phosphorus, carbon, hydrogen and oxygen. Either neither oxygen nor carbon can be used as evidence of the presence of bisphosphonic acid due to the possible presence of carbon contamination on the mineral surface and the mineral itself containing oxygen. XPS does not detect hydrogen because hydrogen has no inner electrons. Therefore, phosphorus is the best indicator of bisphosphonic acid.
Figure 6 shows the overall XPS spectrum of barium calcium ore that has been treated with and without bisphosphonate. In the untreated barium calcium spectrum, there are peaks of strontium, oxygen and calcium of the mineral itself, as well as extraneous carbon peaks. The spectrum of the bisphosphonate-treated barium calcium ore is characterized by the appearance of a P 2P peak, and the C 1s peak is enhanced, while the other peaks are slightly reduced. The relative atomic concentrations of the surface of the strontium ore that has not been treated with bisphosphonate are shown in Table 3. The P/Nb concentration of the bisphosphonate-treated barium calcium ore increased from 0.01 to 0.96, and the C/Nb concentration increased from 3.06 to 12.30. These results indicate that the concentration of phosphorus and carbon on the surface of the barium calcium ore after treatment with bisphosphonic acid is significantly increased.
Figure 6 without (top) and by (bottom) bisphosphonic acid treatment
The entire XPS spectrum of barium calcium ore
Table 3 Relative atomic concentration of the surface of the strontium ore
Sample
Ca/Nb
P/Nb
C/Nb
O/Nb
Untreated barium ore
0.47
0.01
3.06
3.57
Treated barium ore
0.68
0.96
12.30
6.02
The effect of drug adsorption on the P 2p peak is shown in Figure 7. Bisphosphonic acid P 2p peak is located at 132.95eV, and P 2p peak by bisphosphonic acid treated fersmite located at 136.80eV, a difference of 3.85eV. Similar results were obtained for other minerals treated with bisphosphonic acid. Ren et al. and Chen et al. reported that the binding energy change of the P 2p peak of black rutile after bisphosphonate treatment was 0.45 eV, and the binding energy of P 2p peak of coltan was 2.85 eV. It can be seen from Fig. 7 that after the bisphosphonic acid treatment, the P 2P peak position of the strontium calcium ore is changed, and a chemical replacement reaction of phosphorus occurs. From this, it can be concluded that the bisphosphonic acid is chemisorbed on the surface of the strontium calcium ore and the concentration of phosphorus atoms is increased.
Figure 7 P 2P peak of bisphosphonic acid (top) and bisphosphonate-treated barium calcium ore (bottom)
3. Conclusions
Based on the above results and discussion, the following conclusions can be drawn:
1) Cycloalkyl hydroxamic acid has a higher flotation recovery rate for strontium calcium ore. The order of flotation recovery of different collectors for barium calcium ore is: cycloalkyl hydroxamic acid > alkyl hydroxamic acid (C 7-9 ) > bisphosphonic acid > a-styrene phosphonic acid > benzyl citric acid.
2) Bisphosphonic acid is the best selective collector for barium calcium ore. The selective sequence of different collectors for flotation of barium calcium ore is: bisphosphonic acid > benzyl decanoic acid > a-styrene phosphonic acid > alkyl hydroxamic acid (C 7-9 ) > cycloalkyl oxindole acid.
3) When the concentration of bisphosphonate is 20 mg/L and the pH is 2.5~5.0, the flotation recovery of barium calcium ore is 83.27%~85.10%.
4) The results of IAS analysis showed that the wave numbers corresponding to the -P=O and -P-O- characteristic peaks adsorbed by bisphosphonic acid on the surface of the strontium calcium ore were 1178, 1142, 1087 and 934 cm -1 .
5) From the results of XPS analysis, it can be concluded that the bisphosphonic acid is chemisorbed on the surface of the barium calcium ore, and the binding energy of P 2p of the bisphosphonic acid is shifted by 3.85 eV.