Sulfur removal method for recycling flotation titanium tailings based on spiral reselection

Abstract

The invention discloses a desulfurization method for recycling flotation titanium tailings based on spiral reselection, and belongs to the technical field of mineral processing. The method sequentially comprises the steps of size pre-mixing, weak magnetic preselection, flotation desulfurization, secondary size mixing, spiral reselection and dehydration. According to the method, the collaborative innovation process of pre-removal of magnetic sulfur through low intensity magnetic separation, targeted collection of non-magnetic sulfur through alkaline flotation and deep recovery of titanium through spiral gravity separation is adopted, the problems that an existing single sulfur removal technology is low in efficiency, large in titanium loss and high in cost are successfully solved, the sulfur content of the high-sulfur (3.2%) flotation titanium tailings can be stably reduced to 0.8% or below, and the method is suitable for industrial production. Meanwhile, high-grade titanium middlings and sulfur concentrates capable of being sold are obtained, and efficient and economical recovery of resources is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mineral processing, and particularly relates to a sulfur removal method based on spiral re-election of flotation titanium tailings. BACKGROUND

[0002] Titanium metal is a rare resource, and it is of great significance to explore efficient recycling technology of titanium resources. At present, some titanium (ore) selection plants use flotation process to select titanium concentrate, and there is still a small amount of relatively coarse particle size in the tailings that can be recycled. One of the resource recycling methods is to recover the ilmenite in the tailings through spiral re-election process to prepare titanium middlings. However, there is usually a high content of sulfur element (up to more than 3%) in the flotation tailings. These sulfur-containing minerals (such as pyrite, pyrrhotite, etc.) not only affect the quality of titanium middlings products, but also produce harmful gases in the subsequent smelting process.

[0003] At present, the traditional sulfur removal methods mainly include single gravity separation, single magnetic separation and single flotation. Single gravity separation relies on the density difference of minerals. The density difference between sulfur minerals (such as pyrite, pyrrhotite, etc.) and target minerals (such as ilmenite) is small, and the separation efficiency is greatly reduced, which easily leads to the mixing of sulfur into the concentrate with the target minerals. The separation effect is poor for fine particle size sulfur-containing minerals, and it is difficult to reduce the sulfur content to the target value. It is difficult to handle the symbiotic sulfur. Single magnetic separation is difficult to fully capture fine pyrite, resulting in low sulfur removal efficiency. In the magnetic separation process, due to the possible weak magnetism of ilmenite or the close symbiosis of part of ilmenite and sulfides such as pyrrhotite, the magnetic separation equipment is easy to adsorb part of ilmenite together with the magnetic minerals such as pyrrhotite into the magnetic separation concentrate, resulting in a large loss of ilmenite and reducing the recovery rate of titanium middlings. It is greatly affected by the properties of the ore and is difficult to deal with complex symbiotic relationship. Single flotation has problems such as large reagent consumption, complex process, great influence of pulp environment, difficulty in effectively capturing weakly magnetic sulfides (such as pyrrhotite), and easy interference with the subsequent re-election process. In addition, the existing sulfur removal technology does not fully consider the characteristics of the flotation tailings and the connection with the spiral re-election process, resulting in low sulfur removal efficiency and high production cost. Therefore, it is urgent to develop an efficient and economic sulfur removal technology that can cooperate with the spiral re-election process to improve the quality of titanium middlings products. SUMMARY

[0004] In view of the above prior art, the application provides a sulfur removal method based on spiral re-election of flotation titanium tailings, which solves the problem of excessive sulfur content in the product titanium middlings.

[0005] In order to achieve the above purpose, the technical scheme adopted by the application is to provide a sulfur removal method based on spiral re-election of flotation titanium tailings, comprising the following steps: S1: Stir and dilute the raw material of the floatation titanium tailings to obtain a pre-conditioned ore slurry with a mass fraction of 18-22%; S2: Perform weak magnetic separation on the pre-conditioned ore slurry under a magnetic field strength of 850-1150GS to separate a weak magnetic separation concentrate and a weak magnetic separation tailings; S3: Add an adjusting agent, a collector and a frother to the weak magnetic separation tailings, stir for 3.5-4.5 minutes, and then perform floatation to separate a sulfur concentrate froth and a desulfurized ore slurry; S4: Dilute the desulfurized ore slurry with water to obtain a secondary-conditioned ore slurry with a mass fraction of 30-35%; S5: Feed the secondary-conditioned ore slurry into a spiral gravity separation system for separation to obtain a concentrate and a final tailings; S6: Dehydrate the concentrate to obtain a titanium middlings product.

[0006] Further, the adjusting agent is lime, and the addition amount is 600-900g / t of the ore slurry.

[0007] Further, the collector is butyl xanthate, and the addition amount is 90-140g / t of the ore slurry.

[0008] Further, the frother is pine oil, and the addition amount is 25-45g / t of the ore slurry.

[0009] Further, the separation by the spiral gravity separation system includes roughing and cleaning operations performed by a spiral chute with a diameter of Φ1200mm and a pitch of 720mm, and scavenging operations performed by a spiral chute with a diameter of Φ1200mm and a pitch of 640mm.

[0010] Further, the separation by the spiral gravity separation system is a multi-stage combined process including first roughing, second roughing, first cleaning, second cleaning, third cleaning, first scavenging, second scavenging, third scavenging and fourth scavenging.

[0011] The beneficial effects of the present application are: the method provided by the present application simultaneously realizes concentration dilution and particle deagglomeration in the pre-slurry preparation link, can avoid incomplete desulfurization caused by fine particle level pyrite agglomeration, and can also prevent ilmenite from being mudified due to excessive stirring; then, the magnetic pyrite and the wrapped impurities are preferentially separated through the weak magnetic separation, which can reduce the subsequent flotation load, and then the non-magnetic pyrite is captured by flotation targeting, forming a synergistic mechanism of "magnetic sulfur pre-removal-non-magnetic sulfur fine removal", which can improve the desulfurization efficiency by 30% compared with single flotation, reduce the sulfur content from 3.2% to about 0.75%, the desulfurization efficiency is 76.56%, and precise desulfurization is realized; moreover, the weak magnetic pre-separation reduces impurity interference, avoids ilmenite loss caused by single strong magnetic separation, and guarantees the recovery rate; the flotation reagent adopts a "low concentration and strong selectivity" combination, which can inhibit the surface active sites of ilmenite by regulating the alkaline environment of the ore slurry, and at the same time, the specific adsorption of the sulfhydryl group on the surface of pyrite and the collector is utilized, which can reduce the ilmenite loss rate by 60% compared with the traditional process; finally, the weak magnetic concentrate is flexibly treated by the spiral reselection system to further improve the recovery rate; and finally, the resources are recycled at low production cost. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 The process flow chart of the desulfurization method for recycling flotation titanium tailings based on spiral reselection. DETAILED DESCRIPTION

[0013] The specific embodiments of the present application will be described in detail below in combination with examples.

[0014] Embodiment A desulfurization method for recycling flotation titanium tailings based on spiral reselection, as shown in Figure 1 , includes the following steps: S1: Pumping the flotation titanium tailings raw material with a sulfur content of 3.2% into a pre-slurry preparation stirring tank, adding clean water for stirring and dilution to a mass fraction of 20%, and obtaining a pre-slurry; S2: Placing the pre-slurry into a weak magnetic separator, and separating under a magnetic field strength of 1000GS to obtain a weak magnetic concentrate and a weak magnetic tailings, wherein the weak magnetic concentrate is discharged into a tailings thickening system; S3: Adding lime (the addition amount is 750g / t of the ore slurry) to the weak magnetic tailings to adjust the pH of the ore slurry to 10, and then continuously adding butyl xanthate (the addition amount is 120g / t of the ore slurry) and pine oil (the addition amount is 35g / t of the ore slurry), and after stirring for 4min, carrying out air flotation to separate a sulfur concentrate froth and a desulfurized ore slurry; S4: The desulfurized ore slurry flows into a secondary slurry preparation stirring tank, and clean water is added to adjust the mass fraction to 30% to obtain a secondary slurry; S5: Feeding the secondary slurry into a spiral reselection system for separation to obtain a concentrate and a final tailings; S6: The concentrate is put into a vacuum filter for dewatering, to obtain a titanium middling product with a water content of 8%, a sulfur content of 0.75%, and a TiO2 grade of 30%; In the method, the step S5 specifically comprises: S51: The secondary conditioning slurry is allocated into a Φ1200mm spiral chute with a 720mm pitch for primary roughing, to obtain a primary roughing concentrate, a primary roughing middling, and a primary roughing tailing; S52: The primary roughing concentrate and the primary roughing middling are allocated into a Φ1200mm spiral chute with a 720mm pitch for secondary roughing, to obtain a secondary roughing concentrate, a secondary roughing middling, and a secondary roughing tailing, wherein the secondary roughing middling is returned for secondary roughing; S53: The secondary roughing concentrate and the primary roughing middling are allocated into a Φ1200mm spiral chute with a 720mm pitch for primary cleaning, to obtain a primary cleaning concentrate, a primary cleaning middling, and a primary cleaning tailing, wherein the primary cleaning middling is returned for primary cleaning; S54: The primary cleaning concentrate is allocated into a Φ1200mm spiral chute with a 720mm pitch for secondary cleaning, to obtain a secondary cleaning concentrate, a secondary cleaning middling, and a secondary cleaning tailing, wherein the secondary cleaning tailing is returned for primary cleaning, and the secondary cleaning middling is returned for secondary cleaning; S55: The secondary cleaning concentrate is allocated into a Φ1200mm spiral chute with a 720mm pitch for tertiary cleaning, to obtain a tertiary cleaning concentrate, a tertiary cleaning middling, and a tertiary cleaning tailing, wherein the tertiary cleaning tailing is returned for secondary cleaning, and the tertiary cleaning middling is returned for tertiary cleaning; S56: The primary roughing tailing and the secondary roughing tailing are allocated into a Φ1200mm spiral chute with a 640mm pitch for primary scavenging, to obtain a primary scavenging concentrate, a primary scavenging middling, and a primary scavenging tailing, wherein the primary scavenging concentrate is returned for secondary roughing, and the primary scavenging middling is returned for primary scavenging; S57: The primary scavenging tailing is allocated into a Φ1200mm spiral chute with a 640mm pitch for secondary scavenging, to obtain a secondary scavenging concentrate, a secondary scavenging middling, and a secondary scavenging tailing, wherein the secondary scavenging concentrate is returned for primary scavenging, and the secondary scavenging middling is returned for secondary scavenging; S58: The primary cleaning tailing is pumped by a slurry pump to a inclined plate thickener for thickening and classification, and the thickened underflow is mixed and allocated into a Φ1200mm spiral chute with a 640mm pitch for tertiary scavenging, to obtain a tertiary scavenging concentrate, a tertiary scavenging middling, and a tertiary scavenging tailing, wherein the tertiary scavenging concentrate is returned for primary cleaning, and the tertiary scavenging middling is returned for tertiary scavenging; S59: The tertiary scavenging tailing is allocated into a Φ1200mm spiral chute with a 640mm pitch for quaternary scavenging, to obtain a quaternary scavenging concentrate, a quaternary scavenging middling, and a quaternary scavenging tailing, wherein the quaternary scavenging concentrate is returned for tertiary scavenging, the quaternary scavenging middling is returned for quaternary scavenging, and the quaternary scavenging tailing is returned for primary scavenging. The three-stage fine concentrate is titanium middlings, and the tailings from the two-stage scavenging and the overflow from the inclined plate thickener are the final tailings. In this embodiment, the sulfur concentrate foam separated in step S3 can be sold as sulfur concentrate; the weak magnetic separation concentrate separated in step S2 is mixed with the final tailings and flows by gravity to a linear screen for slag removal. The +3.0mm portion is directly stacked, and the -3.0mm portion enters a Φ50m high-efficiency thickener for concentration. After concentration, it is pumped to the tailings pump pool by an underflow slurry pump and transported to the tailings dam through pipelines. The overflow water from the thickener is returned to the process for reuse through a return water circulation system. Therefore, the method of this application achieves efficient and economical resource recovery.

[0015] Comparative Example Using the same raw materials as in the embodiment, but omitting the S2 "weak magnetic pre-selection" step, the equipment specifications and process parameters for the remaining subsequent processes (secondary slurry conditioning, spiral gravity separation, and dewatering) are completely consistent with the patent embodiment. Simultaneously, a single flotation desulfurization test is conducted with the same flotation reagents but different dosages. The specific steps are as follows: S1: Pump the flotation titanium tailings raw material with a sulfur content of 3.2% into the pre-mixed slurry mixing tank, add clean water, stir and dilute to a mass fraction of 20% to obtain the pre-mixed slurry; S2: Add lime (900g / t slurry) to the pre-adjusted slurry to adjust the pH of the slurry to 10.5, then add butyl xanthate (150g / t slurry) and pine oil (50g / t slurry), stir for 4 minutes, and then aerate for flotation for 8 minutes to separate sulfur concentrate froth and desulfurized slurry; S3: Flow the desulfurized slurry into the secondary conditioning mixing tank, add clean water to adjust the slurry mass fraction to 30%, and obtain the secondary conditioning slurry; S4: The secondary conditioning slurry is fed into the spiral gravity separation system for separation to obtain concentrate and final tailings; S5: The concentrate is put into a vacuum filter for dehydration to obtain a titanium middlings product with a sulfur content of 1.32%; Step S4 of this comparative example uses the same spiral gravity separation process as step S5 of the example. The equipment specifications are: a Φ1200mm spiral chute with a pitch of 720mm for roughing and cleaning operations, and a Φ1200mm spiral chute with a pitch of 640mm for scavenging operations. The separation process is a multi-stage combination process of two-stage roughing, three-stage cleaning, and four-stage scavenging (the process sequence and middlings return path are completely consistent with those of examples S51-S59), to obtain concentrate and final tailings. Final dewatering: the three-stage cleaned concentrate is sent to a vacuum filter for dewatering to obtain titanium middlings product.

[0016] Results of single flotation desulfurization test: The sulfur content of the titanium ore was 1.32%, and the desulfurization efficiency was 58.75%.

[0017] Although the specific embodiments of the present application have been described in detail, it should be understood that the present patent is not limited to the details of the foregoing embodiments. Various modifications and changes can be made to the described embodiments without departing from the scope of the present patent.

Claims

1. A desulfurization method for recovering flotation titanium tailings based on spiral gravity separation, characterized in that, Includes the following steps: S1: Stir and dilute the flotation titanium tailings raw material to obtain a pre-adjusted slurry with a mass fraction of 18-22%; S2: The pre-adjusted slurry is subjected to weak magnetic separation under a magnetic field strength of 850~1150GS to separate weak magnetic concentrate and weak magnetic tailings. S3: Add modifier, collector and frother to the weak magnetic separation tailings and stir for 3.5~4.5 minutes, then carry out aerated flotation to separate sulfur concentrate froth and desulfurized slurry; S4: Add water to the desulfurized slurry to dilute it and obtain a secondary slurry with a mass fraction of 30-35%; S5: The secondary conditioning slurry is fed into the spiral gravity separation system for separation to obtain concentrate and final tailings; S6: Dehydrate the concentrate to obtain titanium middlings products.

2. The desulfurization method for recovering flotation titanium tailings based on spiral gravity separation according to claim 1, characterized in that: The modifier is lime, and the addition amount is 600~900g / t slurry.

3. The desulfurization method for recovering flotation titanium tailings based on spiral gravity separation according to claim 1, characterized in that: The collector is butyl xanthate, and the addition amount is 90~140g / t slurry.

4. The desulfurization method for recovering flotation titanium tailings based on spiral gravity separation according to claim 1, characterized in that: The foaming agent is pine oil, and the addition amount is 25~45g / t slurry.

5. The desulfurization method for recovering flotation titanium tailings based on spiral gravity separation according to claim 1, characterized in that: The spiral gravity separation system performs sorting operations including roughing and cleaning operations using a spiral chute with a diameter of 1200 mm and a pitch of 720 mm, and sweeping operations using a spiral chute with a diameter of 1200 mm and a pitch of 640 mm.

6. The desulfurization method for recovering flotation titanium tailings based on spiral gravity separation according to claim 1 or 5, characterized in that: The spiral re-selection system performs sorting in a multi-stage combined process, including one stage of coarse selection, two stages of coarse selection, one stage of fine selection, two stages of fine selection, three stages of fine selection, one stage of sweeping selection, two stages of sweeping selection, three stages of sweeping selection, and four stages of sweeping selection.

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