Most of the foreign rutile beach placer resources, its coarse particle size, high degree of dissociation, generally does not require grinding and flotation, and therefore less foreign studies on rutile flotation process. The rutile resources in China are characterized by a small proportion of sand mines and a fine grain size. The key to development and utilization is to solve the problem of fine rutile flotation. At present, the domestic rutile ore dressing , according to the nature of the ore , often uses re-election (shaker, spiral beneficiation, etc.) tailing, re-election of fine ore selection and other processes. Some ores are still magnetically selected before re-election, some are for pickling of coarse concentrates, and some are for electrification after flotation. Pickling effect is washed rutile edge quality iron minerals and gangue minerals, with students rutile dissociation, so that different physical properties and gangue minerals rutile fully displayed; electric separation can be further improved flotation concentrate grade . Rutile flotation existing problems and promote the theory and practice of people rutile flotation, but because of similar crystal structure of rutile and gangue silicate minerals, resulting rutile flotation technology, but currently off, have yet to find an effective rutile catch Collecting agent .
Oleic acid, alkyl sulfate, alkyl sulfonate, swollen acid, phosphonic acid, etc. can be used as collectors for flotation rutile, but these agents generally cannot achieve effective separation of rutile and gangue minerals, achieving effective separation. A suitable conditioner must be used. According to the calculation method of selecting the complex collector proposed by Marabili et al. in Italy, the bonding atoms of the polar group are mostly O, N, etc., and the organic agent with a benzene ring in the non-polar group can be used for rutile. Has a good harvesting effect. In response to this feature, TPRO, salicyl hydroxamic acid, N-benzoylphenylhydroxylamine, hydrazine reagent, 1-nitroso-2-naphthol ( cobalt reagent) and catechol-3 were selected in the experimental study. A series of agents such as sodium 5-disulfonate (tested titanium ) were used to conduct a preliminary test of rutile single mineral flotation. In this study, TPRO and salicyl hydroxamic acid, which have the best effect, were selected for detailed sapphire and quartz single mineral flotation and mixed ore flotation experiments, and UV and IR spectra were detected to study its mechanism. The experimental results show that TPRO has a very high recovery rate in the flotation of rutile single minerals, and the flotation of rutile and quartz mixed minerals also has good selectivity, which provides a basis for the application of TPRO in the actual ore flotation of rutile.
1. Mineral samples and test methods
(1) Test materials and reagents
The pure minerals used were rutile and quartz, with rutile being re-elected concentrate ore (+0.100 mm) from Australia. Chemical analysis and X-ray analysis indicated that the samples met pure mineral conditions. The pure minerals were crushed, dried by ceramic ball milling and sieved. The chemical analysis showed that the purity was above 98%. The particle size of all pure minerals used in the flotation test was -0.074+0.037mm. The analysis results of rutile pure mineral elements are shown in Table 1.
Table 1 Elemental analysis results of rutile pure minerals (mass fraction) /%
Ti0 2 | V | Zr | Fe | Nb | Mn | W | Mo | Sn | Light element |
94.70 | 1.30 | 0.62 | 0.50 | 0.38 | 0.07 | 0.04 | 0.01 | 0.02 | 2.34 |
The collector used in the test was salicyl hydroxamic acid and the new agent TPRO. Salicyl hydroxamic acid is a typical chelating collector. TPRO is a phenolic derivative containing two hydroxyl groups in the molecule and can be bonded through oxygen atoms on two phenolic hydroxyl groups. It was first used as a collector for titanium minerals in this test. The pH adjusters used were NaOH and HCl, the flotation frothing agent was MIBC, and all tests were carried out at room temperature. Table 2 shows the purity levels of the chemical reagents used in the test and the manufacturer.
Table 2 Main reagents used in the test
Reagent | purity | factory |
Methyl isobutylmethanol (MIBC) | 99% | Shanghai Jingchun Reagent |
TPRO | CR | Shanghai Jingchun Reagent |
Salicylic acid | ≥98% | 衢州 future reagent |
Pb(N0 3 ) 2 | AR | Tianjin Damao Reagent |
NaOH | AR | Tianjin Damao Reagent |
HCl | AR | Tianjin Damao Reagent |
(2) Test instruments and methods
1. Pure mineral flotation test
The XFD-76 40mL hanging tank flotation machine is used. The impeller diameter is 25mm and the rotation speed is 1700r/min. The mineral content of each test is 2g for minerals and 4g for mixed minerals. During the test, 40 mL of slurry was first stirred for 2 min, and then added as needed in the following order: pH adjuster, activator, collector MIBC. The stirring time of the collector was 3 min, MIBC 30s, others were 2 min, single mineral flotation was scraped for 3 min, and mixed ore flotation was performed for 1.5 min. The foam and the products in the tank were separately filtered, dried, and weighed to calculate the mineral recovery rate. The mixed ore flotation concentrate was analyzed by X-ray fluorescence for its chemical composition.
2, UV spectrometry
The amount of adsorption of the collector TPRO by rutile minerals was determined by subtractive subtraction. 2g rutile single mineral case was added to XFD-76 type trough flotation machine according to the operation of flotation test. After stirring for 2 minutes, pH adjuster and collector were added, but no foaming agent was added, flotation was carried out for 2 min, and adjustment was added. The stirring time after the agent and the collector was the same as the flotation test. The slurry after flotation was centrifuged for 15 min, and the supernatant was taken to determine the absorbance. It is known from the literature that the maximum adsorption wavelength of TPRO is 279 nm. The UV spectrometer used in the test was a Beijing Puyang TU-1810 UV-Vis spectrophotometer.
3. Infrared spectroscopy
The single mineral sample is ground to -5 μm with an agate mortar. Under a room temperature condition, a certain amount of minerals and chemicals are added to the distilled aqueous solution of a certain pH value, and the mixture is fully stirred to fully act on the mineral and the agent, and is naturally dried after solid-liquid separation. . The infrared spectrum of the agent before and after the action of the rutile mineral was measured by a diffuse reflection method using a mineral sample, a mineral sample after the mineral action, a single mineral sample of -5 μm, and a powder sample. The infrared spectrometer used in the test was a Nicolet 670 type FT-IR spectrometer.
Second, the test results and discussion
(1) Test of TPRO flotation minerals and mixed minerals
Figure 1 is a plot of the recovery of a single mineral versus pH for a TPRO of 2 x 10 -4 mol/L. It can be seen from Fig. 1 that the recovery rate of rutile in the range of pH=6.5-9.5 is more than 91%, and gradually increases to 94.5%; quartz does not substantially float in the whole pH range.
Figure 2 is a plot of the recovery of a single mineral versus the amount of TPRO at pH = 8. It can be seen from Fig. 2 that the recovery rate of both minerals increases with the increase of TPRO dosage at pH = 8. When the amount of TPRO is less than 1×10 -4 mol/L, the recovery rate of rutile has reached 60%, and quartz is basically not flotation; when the amount of TPRO is 1.2×10 -3 mol/L, the recovery rate of rutile reaches 97.5%, while the recovery rate of quartz is only 40%. This indicates that there is a significant difference in the floatability of rutile and quartz when TPRO is used as a collector in a wide range of weakly acidic, neutral and weakly alkaline at pH=5-10. It can be speculated that under the condition of weak alkaline conditions of pH=8 and suitable TPRO dosage, it is completely possible to achieve effective separation of rutile and quartz.
Figure 3 is a plot of the flotation of rutile and quartz flotation versus pH for a TPRO dosage of 4 x 10 -4 mol/L. It can be seen from Fig. 3 that in the mixed ore flotation concentrate at pH=5.5 and pH=8-9.5, the grade of rutile is more than 80%, the recovery rate is greater than 92%; in the larger range of pH==5-9.5, floating The recovery rate of rutile in the concentrate is gradually increased with the increase of pH value and is always greater than 92%. At pH=6-9.5, the recovery rate of rutile in the concentrate is even greater than 97%. This proves that when TPRO is used as a collector, the effective separation of the two minerals can be achieved by using the significant difference in floatability of the two minerals.
(II) Test of flotation of single minerals by salicyl hydroxamic acid (SHA)
Figure 4 is a plot of the recovery of sapphire and quartz single mineral flotation versus pH for a SHA concentration of 5 × 10 -4 mol/L. Figure 5 is a plot of rutile single mineral flotation recovery versus SHA concentration at pH = 5. It can be seen from Fig. 4 and Fig. 5 that SHA has poor ability to capture both minerals, and there is basically no difference in floatability. It can be speculated that the use of SHA alone as a collector makes it difficult to achieve effective separation of rutile and gangue.
(III) SHA-mixed ore flotation test under Pb 2+ activation
Figure 6 is a graph showing the relationship between the recovery rate of rutile and the relationship between pH and pH in SHA flotation mixed concentrate when the amount of Pb(NO 3 ) 2 is 1×10 -4 mol/L and the amount of SHA is 5×10 -4 mol/L. curve. It can be seen from Fig. 6 that in the range of pH=5-8, the grade of rutile in the mixed ore flotation concentrate reaches 80%, and reaches 88% at pH=7; while in the range of pH=6-8, it is tight. When the recovery rate of rutile in the mine is close to 80%, it is close to 90% at pH ≈6.5.
(4) Comparison of TRO and SHA's ability to collect rutile
Figure 7 and Figure 8 show the different pH conditions when the amount of TPRO is 4×10 -4 mol/L, the amount of SHA is 5×10 -4 mol/L, and the amount of Pb(N0 3 ) 2 is 1×10 -4 mol/L. The effect of TPRO and SHA on the flotation effect of rutile single mineral and mixed ore. It can be seen from Fig. 7 and Fig. 8 that when the amount of TPRO is 2×10 -4 mol/L, the recovery rate of rutile in the range of pH=6.5-9.5 is more than 91% and gradually increases to 94.5%; no Pb 2+ activation The recovery rate of SHA flotation rutile single mineral is less than 40% in the whole pH range. Even under the activation condition of 1×10 -4 mol/L Pb 2+ , the SHA flotation rutile single mineral is only at pH ≈6.5. The recovery rate in the extremely narrow range is only 90%.
For the flotation of mixed ore, when the amount of TPRO is 4×10 -4 mol/L, the recovery rate of rutile in the flotation concentrate gradually increases with the increase of pH in the range of pH=5-9.5. Increased, and always greater than 92%, the concentrate grade has been close to 80%; at pH = 5 ~ 9.5, the recovery rate of rutile in the concentrate is even greater than 97%. When the amount of SHA is 5×10 -4 mol/L and the amount of activator Pb 2+ is 1×10 -4 mol/L, the recovery rate of rutile in concentrate is only in the small range of pH=6-8. It is close to 80% and is only close to 90% at pH ≈6.5.
Compared with SHA, when TPRO is used as a collector, the significant difference in floatability of rutile and quartz can be achieved, and their effective separation can be achieved without any activator.
(5) Determination of adsorption amount
Figure 9 shows the adsorption amount of TPRO adsorbed by rutile minerals with pH value when the amount of TPRO is 2 × 10 -4 mol/L. It can be seen from Fig. 9 that in the range of pH=4-9, the percentage of adsorption of TPRO is more than 20%; in the range of pH=6-8, the percentage of adsorption of the collector is more than 30%; when it is close to neutral, adsorption The amount is the largest.
It can be seen from Fig. 1 and Fig. 2 that when the amount of TPRO is 2×10 -4 mol/L, rutile has good floatability in the range of pH=6.5-9.5, and the recovery rate is more than 91%, and quartz is almost impossible. Flotation. This indicates that TPRO is due to the obvious adsorption on the surface of rutile minerals, and thus the effect of rutile on the capture performance. The flotation test phenomenon is basically consistent with the measurement results of adsorption. In order to determine the adsorption characteristics of TPRO on the surface of rutile minerals and the structure of the adsorbed products, infrared detection was further carried out.
(6) Determination of the properties of mineral-aqueous solution interface reactants
Figure 10 is an infrared spectrum of TPRO, rutile pure minerals, and rutile and TPRO. The main adsorption peak of TPRO is 3349 cm -1 , which should be the stretching vibration of the hydroxyl group (-OH) on the benzene ring or the vibration of intramolecular hydrogen bond association; 1213, 1189 cm -1 are all hydroxyl (-OH) stretching vibration; 1343 1367 cm -1 is a bending vibration of a hydroxyl group (-OH). TPRO infrared spectrum after rutile effect, the absorption peak at 3349cm -1 moved to 3279cm -1, and the hydroxyl (-OH) at the absorption peak 1213,1189,1343,1367cm -1, etc. are disappeared, it can be inferred The surface of the rutile mineral is chemically bonded to the hydroxyl group on the TPRO benzene ring.
Paula et al. and Ivana et al. believe that the bonding atoms of the hydroxyl group -0- have a strong effect on Ti(IV), and Ti(IV) can replace the protons on the hydroxyl group (-OH) to form an internal complex compound. The possible product of TPRO and Ti(IV) on the rutile mineral surface is shown in Figure 11. Two adjacent hydroxyl groups (-OH) can form a stable five-membered ring chelate with Ti(IV) on the surface by chelation (see Figure 11(a)), or with Ti(IV) on the surface. ) forms a bridge structure (Fig. 11(b)). According to the structural characteristics of the chelating ring, the structure of the five-membered ring is more stable and more likely to be a surface action product than the bridged seven-membered ring product. In the flotation pulp, the bare Ti(IV) on the rutile surface should form a five-membered ring-like complex similar to that in Figure 11(a), with the -O-atom of the two hydroxyl groups in the TPRO molecule. Has a strong selective harvesting effect.
Third, the conclusion
(1) Under the optimal flotation conditions, the flotation recovery rate of rutile single mineral can reach 97.5%. When pH=8～9.5, TPRO dosage is 4×10 -4 mol/L, the grade of rutile in mixed ore flotation concentrate is more than 80%, the recovery rate is more than 92%; at pH=6～10, concentrate The recovery rate of the medium gold is greater than 97%. When SHA is used as a collector, the grade and recovery of rutile in the mixed ore are less than 90% even under the optimum dosage and optimum Pb(N0 3 ) 2 activation conditions. Compared to SHA, TPRO is a highly efficient, highly selective new rutile collector that requires no activation and is likely to be used in practice.
(2) The measurement results of adsorption amount are basically consistent with the flotation results. With the increase of TPRO adsorption amount, the flotation recovery rate of rutile is gradually increased.
(III) Infrared studies show that TPRO has a trapping property for rutile because TPRO and chevron surface Ti(IV) are chemisorbed. Further analysis can be speculated that TPRO passes through two hydroxyl groups with a relatively high electronegativity. Ti(IV) forms a chelate, the possible product of which is a stable five-membered ring chelate.
Dissolved Air Flotation,Fully Automatic Dissolved,Automatic Dissolved Air,Fully Dissolved Air
Wuxi Feiyiya Environmental Protection Technology Co., Ltd. , https://www.feiyya.com