Beneficiation method for improving flotation separation efficiency of micro-fine particle ilmenite

Abstract

The invention relates to the technical field of beneficiation, in particular to a beneficiation method for improving the flotation separation efficiency of micro-fine-particle ilmenite. The method comprises the following steps: sequentially adding a sodium silicate and citric acid composite dispersing agent, a sodium alginate flocculating agent and a combined collecting agent consisting of sodium oleate (NaOL) and (2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester (HEHEHP) into the desulfurization tailings, and stirring; then, a Fenton-like reagent composed of soluble ferrite and peroxysulfate is added for targeted activation; and finally, the titanium concentrate is obtained through one-time roughing, four-time concentration and one-time scavenging. According to the method, the traditional dosing mode of'first activation and second collection 'is subverted, the problems that micro-fine-particle ilmenite is prone to agglomeration and poor in separation selectivity are effectively solved through the effects of collecting agent pilot adsorption, Fenton-like reagent post-strengthening, synergistic dispersion and selective flocculation, and high-grade and high-recovery-rate efficient separation is achieved in the weak acid environment.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and specifically to a mineral processing method for improving the flotation separation efficiency of fine-grained ilmenite. Background Technology

[0002] my country possesses abundant ilmenite resources, but their composition is complex, with fine-grained ilmenite (smaller than 0.045 mm) accounting for over 60% of the reserves. The Panxi region is my country's main ilmenite producing area, where -0.045 mm particles account for as much as 75%, and TiO2 distribution exceeds 80%. However, due to their large specific surface area and high surface energy, these fine-grained ilmenite particles are prone to agglomeration, resulting in low recovery efficiency during flotation and severely restricting the efficient development and utilization of my country's titanium resources. Furthermore, fine-grained ilmenite is often closely associated with gangue minerals such as pyroxene, olivine, and feldspar, making precise separation during flotation difficult and leading to a decrease in concentrate grade. Therefore, improving the flotation separation efficiency of fine-grained ilmenite is crucial for the sustainable development of mines and the comprehensive utilization of resources.

[0003] In recent years, various methods have been developed to improve the recovery of fine-grained ilmenite, mainly including gravity separation, magnetic separation, electrostatic separation, and flotation. Among these, flotation is the most important method for processing fine-grained ilmenite. The order of reagent addition in flotation is generally as follows: first, add a modifier (activator or depressant), then add a collector. That is, first, add a modifier to the pulp to change the surface physicochemical properties between the valuable mineral and the gangue mineral, and then add a collector to adsorb onto the surface of the target mineral, increasing the hydrophobicity of the mineral surface to achieve the purpose of separation.

[0004] Fenton oxidation, as an advanced green oxidation technology, has been widely used in mineral processing. Depending on the oxidant used, it is divided into the Fenton process and Fenton-like processes. In the traditional Fenton oxidation process, Fe... 2+ Catalyzing the reaction of H₂O₂ under acidic conditions generates hydroxyl radicals (•OH) with a high redox potential of 2.8 eV, which can effectively remove Fe from the surface of ilmenite. 2+ Oxidized to Fe 3+ However, traditional Fenton technology has many limitations, such as a narrow acidic pH range and the formation of large amounts of iron-containing sludge. Therefore, Fenton-like processes are receiving increasing attention, which utilize oxidants (such as PMS and PDS) to oxidize Fe... 2+ With the assistance of [unclear], the stability and decomposition efficiency of Fenton-like reagents are improved, effectively generating sulfate free radicals (SO42-). •- ), hydroxyl radicals (•OH) and superoxide radicals (O2) •- This improves the efficiency of oxidation on the surface of ilmenite.

[0005] Current technologies still have some shortcomings, with a large amount of fine-grained ilmenite being lost in tailings, resulting in resource waste. Therefore, developing new and efficient flotation reagents to improve the separation efficiency of fine-grained ilmenite is of great significance for the sustainable development of mines and the comprehensive utilization of resources. Summary of the Invention

[0006] The purpose of this invention is to provide a mineral processing method that improves the flotation separation efficiency of fine-grained ilmenite. By first adding a combination of collectors and then introducing a Fenton-like reagent, and through synergistic dispersion and selective flocculation, a highly efficient and selective separation of fine-grained ilmenite is achieved under weakly acidic conditions, which significantly improves the concentrate grade and recovery rate.

[0007] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0008] A mineral processing method for improving the flotation separation efficiency of fine-grained ilmenite includes the following steps:

[0009] The pH of the fine-grained ilmenite slurry was adjusted to 5.0-6.0 using a pH adjuster, and xanthate collectors and frothers were added for flotation desulfurization to obtain sulfur concentrate and desulfurized tailings.

[0010] The pH of the desulfurized tailings was adjusted to 5.0-6.0 using a pH adjuster, then a dispersant was added and stirred to react, followed by the addition of a flocculant and stirring to react.

[0011] A combination of collectors is added sequentially to the slurry and stirred to react. Then, a Fenton-like reagent is added and stirred to react. The Fenton-like reagent is composed of soluble ferrous salt and persulfate.

[0012] The slurry is subjected to one roughing, multiple cleaning, and one scavenging process to obtain titanium concentrate and final tailings.

[0013] Furthermore, the dispersant is a mixture of water glass and citric acid, the flocculant is sodium alginate, the combined collector is a mixture of sodium oleate (NaOL) and (2-ethylhexyl) phosphate mono-2-ethylhexyl ester (HEHEHP), and the persulfate is permonosulfate or perdisulfate.

[0014] Furthermore, the mass ratio of water glass to citric acid is (2-8):1; the mass ratio of sodium oleate to (2-ethylhexyl)phosphate mono-2-ethylhexyl ester is (1-9):1; and the mass ratio of soluble ferrous salt to persulfate is (1-6):1.

[0015] Furthermore, in the fine-grained ilmenite, the proportion of particles with a diameter less than 0.038 mm is greater than 90%, and the TiO2 grade is 11% to 20%.

[0016] Furthermore, the xanthate collector is butyl xanthate, and its dosage is 50-300 g / t of raw ore; the frother is No. 2 oil, and its dosage is 10-30 g / t of raw ore; the flotation desulfurization step is carried out at a stirring speed of 1900-2100 r / min.

[0017] Furthermore, the amount of water glass used is 200-1000 g / t of desulfurization tailings, the amount of citric acid used is 50-250 g / t of desulfurization tailings, and the stirring reaction time after addition is 3-6 min; the amount of sodium alginate used is 50-500 g / t of desulfurization tailings, and the stirring reaction time after addition is 2-5 min.

[0018] Furthermore, the amount of sodium oleate used is 300-3000 g / t of desulfurized tailings, the amount of (2-ethylhexyl)phosphate mono-2-ethylhexyl ester used is 100-2000 g / t of desulfurized tailings, and the stirring reaction time after addition is 3-6 min.

[0019] Furthermore, with Fe 2+ The dosage of the soluble ferrous salt is 50-500 g / t of desulfurization tailings, the dosage of the persulfate is 50-500 g / t of desulfurization tailings, and the stirring reaction time after addition is 5-15 min.

[0020] Furthermore, the flotation time for the coarse selection is 3 to 8 minutes, the number of fine selections is four times and the flotation time for each selection is 2 to 6 minutes, and the flotation time for the sweep selection is 3 to 8 minutes.

[0021] The beneficial effects of this invention are:

[0022] This invention achieves enhanced selectivity by adding a Fenton-like reagent after the collector, thereby altering the reaction pathway and adsorption layer formation mechanism on the mineral surface. In traditional activation-follow-collection processes, oxidative free radicals act non-selectively on the entire mineral surface, resulting in poor selectivity for subsequent collector adsorption. This invention enables the combined collector to competitively adsorb based on the differences in the intrinsic properties of the mineral surface. The subsequently added ferrous salt reacts with peroxysulfate to generate active free radicals such as SO42-. •-Instead of indiscriminate oxidation of the mineral surface, the reaction preferentially occurs with the Fe(II) active sites in the collector already adsorbed on the ilmenite surface. This process promotes the transformation of the collector from a physically adsorbed or coordinate adsorbed state into a more stable hydrophobic metal salt chemical deposition layer, substantially enhancing the hydrophobicity of the useful mineral. Simultaneously, residual free radicals degrade the free collector in the slurry and slightly oxidize the gangue surface, inhibiting its floatability. As shown in Examples 1-4 and Comparative Examples 1-4, this change in the order of reagent addition is the direct cause of the simultaneous and significant improvement in concentrate grade and recovery.

[0023] This invention presents a reagent system consisting of a composite dispersant of water glass and citric acid, a flocculant of sodium alginate, and a collector combination of sodium oleate and HEHEHP. This system specifically addresses the problems of dispersion, selective aggregation, and surface hydrophobicity of fine-grained minerals. The dispersant eliminates unavoidable ionic interactions through electrostatic repulsion and complexation, preventing harmful heterogeneous agglomeration and creating conditions for separation; as shown in Comparative Example 6, the lack of a dispersant leads to a significant decrease in concentrate grade. Under weakly acidic conditions and with pre-adsorption by the collector, the flocculant sodium alginate preferentially bridges the hydrophobic ilmenite fine particles, increasing their apparent particle size and floatability, directly improving the recovery rate; the significant decrease in recovery rate due to the absence of sodium alginate flocculant in Comparative Example 7 confirms its effect. The combination of sodium oleate and HEHEHP forms a dense hydrophobic layer with synergistic adsorption on the mineral surface. The sequential action of these three components forms a coherent technical solution for overcoming the challenges of fine-particle flotation.

[0024] This invention utilizes Fe under weakly acidic conditions of pH 5.0-6.0. 2+ The persulfate (PMS / PDS) Fenton system overcomes the dependence of the traditional Fenton process on a strongly acidic environment. The pH range is favorable for ilmenite flotation and allows persulfate to effectively generate SO4 under ferrous ion catalysis. •- It contains active species to achieve highly efficient targeted oxidation. This contrasts with the traditional H2O2 / Fe2O3 method, which requires strongly acidic conditions. 2+ Compared to other systems, the system of this invention is more adaptable to actual flotation environments, avoiding the problems of excessive acid adjustment and the generation of large amounts of iron sludge. It is a green activation method that is more suitable for the mineral processing field.

[0025] This invention eliminates interference through pre-desulfurization; deep slurry conditioning creates highly selective slurry conditions for flotation; multi-stage cleaning ensures high-grade concentrate; and scavenging reduces tailings loss. For different raw ores with TiO2 grades between 11.65% and 18.82% and a -0.038 mm particle size ratio exceeding 85%, as shown in Examples 1-4, this process consistently achieves excellent results with a TiO2 grade of approximately 47% and a recovery rate exceeding 78%, demonstrating its reliable separation effect and wide applicability to complex and difficult-to-process fine-grained ilmenite resources.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the flotation process for fine-grained ilmenite according to the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] In this embodiment, the TiO2 grade of the fine-grained ilmenite ore used was 14.16%, and the proportion of -0.038 mm particles was 90%. First, the slurry pH was adjusted to 6.0 using a 1200 g / t sulfuric acid solution. Then, 150 g / t butyl xanthate and 25 g / t No. 2 oil were added sequentially. The mixture was stirred at 1992 rpm for 3 min and 1 min respectively, followed by flotation for 5 min to obtain sulfur concentrate and desulfurized tailings. Sulfuric acid was added to the desulfurized tailings to adjust the slurry pH to 6.0. Then, a dispersant, flocculant, collector, and Fenton-like reagent were added sequentially, reacting for 5 min, 3 min, 3 min, and 10 min respectively, performing one roughing, four cleaning, and one scavenging step. The reagent addition regime is shown in Table 1, and the results are shown in Table 2.

[0032] Table 1. Pharmaceutical Addition System

[0033]

[0034] The final product obtained was a concentrate with a TiO2 grade of 47.02% and a recovery rate of 78.53%, and tailings with a TiO2 grade of 3.98% and a recovery rate of 21.47%.

[0035] Example 2

[0036] The processing conditions in this embodiment are the same as in Example 1, except that the TiO2 grade in the fine-grained ilmenite ore used is 16.52% and the proportion of -0.038 mm particles is 90%, as shown in Table 2.

[0037] The final product obtained was a concentrate with a TiO2 grade of 47.73% and a recovery rate of 81.94%, and tailings with a TiO2 grade of 4.16% and a recovery rate of 18.06%.

[0038] Example 3

[0039] The processing conditions in this embodiment are the same as in Example 1, except that the TiO2 grade in the fine-grained ilmenite ore used is 18.82% and the proportion of -0.038 mm particles is 95%, as shown in Table 2.

[0040] The final product obtained was a concentrate with a TiO2 grade of 47.25% and a recovery rate of 83.75%, and tailings with a TiO2 grade of 4.59% and a recovery rate of 16.25%.

[0041] Example 4

[0042] The processing conditions in this embodiment are the same as in Example 1, except that the TiO2 grade in the fine-grained ilmenite ore used is 11.65% and the proportion of -0.038 mm particles is 85%, as shown in Table 2.

[0043] The final product obtained was a concentrate with a TiO2 grade of 47.06% and a recovery rate of 80.63%, and tailings with a TiO2 grade of 2.82% and a recovery rate of 19.37%.

[0044] Table 2 Comparison of grade and recovery rate of fine-grained ilmenite concentrate after flotation in Examples 1-4

[0045]

[0046] Comparative Example 1

[0047] Comparative Example 1 differs from Example 1 in that: the Fenton-like reagent Fe 2+ -PMS was added in a different order than dispersants, flocculants, and collectors. The order of addition was Fenton-like reagent, dispersant, flocculant, and collector, with the collector added last. The results are shown in Table 3.

[0048] The final product obtained was a concentrate with a TiO2 grade of 45.11% and a recovery rate of 66.23%, and tailings with a TiO2 grade of 6.04% and a recovery rate of 33.79%.

[0049] Comparative Example 2

[0050] Comparative Example 2 differs from Example 2 in that: the Fenton-like reagent Fe 2+ -PMS was added in a different order than dispersants, flocculants, and collectors. The order of addition was Fenton-like reagent, dispersant, flocculant, and collector, with the collector added last. The results are shown in Table 3.

[0051] The final product obtained was a concentrate with a TiO2 grade of 46.18% and a recovery rate of 68.52%, and tailings with a TiO2 grade of 6.89% and a recovery rate of 31.48%.

[0052] Comparative Example 3

[0053] Comparative Example 3 differs from Example 3 in that: the Fenton-like reagent Fe 2+ -PMS was added in a different order than dispersants, flocculants, and collectors. The order of addition was Fenton-like reagent, dispersant, flocculant, and collector, with the collector added last. The results are shown in Table 3.

[0054] The final product obtained was a concentrate with a TiO2 grade of 45.94% and a recovery rate of 67.10%, and tailings with a TiO2 grade of 8.54% and a recovery rate of 32.90%.

[0055] Comparative Example 4

[0056] Comparative Example 4 differs from Example 4 in that: the Fenton-like reagent Fe 2+ -PMS was added in a different order than dispersants, flocculants, and collectors. The order of addition was Fenton-like reagent, dispersant, flocculant, and collector, with the collector added last. The results are shown in Table 3.

[0057] The final product obtained was a concentrate with a TiO2 grade of 45.34% and a recovery rate of 70.91%, and tailings with a TiO2 grade of 4.14% and a recovery rate of 29.09%.

[0058] Table 3 compares the grade and recovery rate of the fine-grained ilmenite concentrate after flotation in Comparative Examples 1–4.

[0059]

[0060] The comparative examples 1-4 above represent the flotation results of fine-grained ilmenite when the order of addition of Fenton-like reagent, dispersant, flocculant, and collector was changed. Table 3 shows that, under the same process and reagent regime, when the Fenton-like reagent was added first according to the conventional addition process, the grade and recovery rate of the fine-grained ilmenite concentrate in comparative examples 1-4 were lower than those in examples 1-4. This indicates that adding the Fenton-like reagent after the collector has a significant impact on the flotation recovery and grade of fine-grained ilmenite. This is because ilmenite and gangue minerals have similar surface properties. When the Fenton-like reagent is added first, it simultaneously activates the active sites on the surfaces of both ilmenite and gangue minerals, leading to non-selective adsorption of the collector and reducing the concentrate grade. When the Fenton-like reagent is added after the collector, the original Fe lattice on the ilmenite surface... 2+ / Ti 4+ The ore preferentially forms an adsorption layer with the collector, occupying the active sites; however, the active sites on the gangue mineral surface are pre-occupied due to the addition of inhibitors, resulting in low collector adsorption. Subsequent activation with a Fenton-like reagent targets and regulates the ilmenite surface and slurry environment, enhancing both the chemical adsorption of the collector and ilmenite and inhibiting the floatability of gangue minerals. Simultaneously, a dense synergistic adsorption layer is formed, improving the stability of particle and bubble adhesion.

[0061] Comparative Example 5

[0062] The processing conditions in this embodiment are the same as in Example 2, except that PMS in the Fenton-like reagent is replaced with PDS. The results are shown in Table 4.

[0063] The final product yielded a concentrate with a TiO2 grade of 47.15% and a recovery rate of 78.80%, and tailings with a TiO2 grade of 4.84% and a recovery rate of 21.20%. (The text abruptly ends here, likely due to an incomplete sentence or missing information.) 2+ Compared to -PMS, Fe 2+ The TiO2 grade and recovery rate of the concentrate in the PDS system decreased slightly. This may be because PMS, due to its asymmetric structure, produces SO4. •- It exhibits stronger catalytic capabilities in this aspect.

[0064] Comparative Example 6

[0065] The processing conditions in this embodiment are the same as in Example 2, except that no dispersant water glass and citric acid were added. The results are shown in Table 4.

[0066] The final product obtained was a concentrate with a TiO2 grade of 38.57% and a recovery rate of 84.77%, and tailings with a TiO2 grade of 3.95% and a recovery rate of 15.23%. Compared with the results of Example 2, the TiO2 grade in the concentrate decreased significantly. This may be due to heterogeneous agglomeration between fine-grained ilmenite and gangue mineral particles. Without the action of a dispersant, this agglomeration reduces the selectivity of the collector, thereby affecting the concentrate grade.

[0067] Comparative Example 7

[0068] The processing conditions in this embodiment are the same as in embodiment 2, except that no flocculant sodium alginate was added. The results are shown in Table 4.

[0069] The final product yielded a concentrate with a TiO2 grade of 39.94% and a recovery rate of 71.30%, and tailings with a TiO2 grade of 6.72% and a recovery rate of 28.70%. Compared with the results of Example 2, the TiO2 grade and recovery rate in the concentrate both decreased significantly, indicating that the addition of flocculant has a significant promoting effect on the flotation separation of fine-grained ilmenite. This is because flocculant can increase the apparent particle size through bridging, thereby improving mineral flotation efficiency.

[0070] Table 4 compares the grade and recovery rate of the fine-grained ilmenite concentrate after flotation in Comparative Examples 5–7.

[0071]

[0072] In summary, this invention proposes a beneficiation method to improve the flotation separation efficiency of fine-grained ilmenite. First, after desulfurizing the slurry, under pH 5.0–6.0 conditions, a composite dispersant of water glass and citric acid, a sodium alginate flocculant, and a combined collector consisting of sodium oleate (NaOL) and (2-ethylhexyl)phosphate mono-2-ethylhexyl ester (HEHEHP) are sequentially added to the desulfurization tailings and stirred. Then, a Fenton-like reagent composed of soluble ferrous salt and persulfate is added for targeted activation. Finally, titanium concentrate is obtained through one roughing, four cleaning, and one scavenging. This invention overturns the traditional "activation before collection" dosing mode. By using collector-led adsorption and post-enhanced Fenton-like reagent, synergistic dispersion and selective flocculation effectively solve the problems of easy agglomeration and poor separation selectivity of fine-grained ilmenite, achieving high-grade and high-recovery efficient separation in a weakly acidic environment.

[0073] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A beneficiation method for improving the efficiency of the flotation separation of fine-grained ilmenite, characterized by, The method comprises the following steps: The fine-grained ilmenite slurry is adjusted to pH 5.0-6.0 by a pH regulator, and then flotation desulfurization is performed by adding a xanthate collector and a frother to obtain a sulfur concentrate and a desulfurization tailing; The desulfurization tailing is adjusted to pH 5.0-6.0 by a pH regulator, and then a dispersant is added and stirred to react, and then a flocculant is added and stirred to react; A combined collector is added to the slurry and stirred to react, and then a Fenton-like reagent is added and stirred to react, wherein the Fenton-like reagent comprises a soluble ferrous salt and a peroxymonosulfate. The slurry is subjected to one roughing, multiple cleaning and one scavenging to obtain a titanium concentrate and a final tailing.

2. The beneficiation method of claim 1, wherein, The dispersant is a mixture of water glass and citric acid, the flocculant is sodium alginate, the combined collector is a mixture of sodium oleate NaOL and (2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester HEHEHP, and the peroxymonosulfate is peroxymonosulfate or peroxodisulfate.

3. The beneficiation method of claim 2, wherein, The mass ratio of the water glass to the citric acid is (2-8):1, the mass ratio of the sodium oleate to the (2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester is (1-9):1, and the mass ratio of the soluble ferrous salt to the peroxymonosulfate is (1-6):

1.

4. The beneficiation method of claim 1, wherein, In the fine-grained ilmenite, the mass fraction of particles with a particle size less than 0.038 mm is greater than 90%, and the grade of TiO2 is 11%-20%.

5. The beneficiation method of claim 1, wherein, The xanthate collector is butyl xanthate, and the dosage is 50-300 g / t of raw ore; the frother is No. 2 oil, and the dosage is 10-30 g / t of raw ore; and the flotation desulfurization is performed at a stirring speed of 1900-2100 r / min.

6. The beneficiation method of claim 2, wherein, The dosage of the water glass is 200-1000 g / t of the desulfurization tailing, the dosage of the citric acid is 50-250 g / t of the desulfurization tailing, and the stirring reaction time after addition is 3-6 min; the dosage of the sodium alginate is 50-500 g / t of the desulfurization tailing, and the stirring reaction time after addition is 2-5 min.

7. The beneficiation method of claim 2, wherein, The dosage of the sodium oleate is 300-3000 g / t of the desulfurization tailing, the dosage of the (2-ethylhexyl) phosphoric acid mono-2-ethylhexyl ester is 100-2000 g / t of the desulfurization tailing, and the stirring reaction time after addition is 3-6 min.

8. The beneficiation method of claim 2, wherein, Fe 2+ The amount of the soluble ferrous salt is 50-500 g / t of desulfurization tailings, the amount of the peroxymonosulfate is 50-500 g / t of desulfurization tailings, and the stirring reaction time after addition is 5-15 min.

9. The beneficiation method of claim 1, wherein, The flotation time of the roughing is 3-8 min, the number of cleaning is four, and the flotation time of each cleaning is 2-6 min, and the flotation time of the scavenging is 3-8 min.

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