Method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings

Abstract

The invention discloses a method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings, which belongs to the technical field of resource recovery and comprises the following steps: (1) mixing the high-sulfur lead-zinc tailings into slurry; (2) roughing by adopting a drum magnetic separator; (3) screening and grading concentrate; (4) concentrating and grinding the magnetic separation rough concentrate with the size smaller than the screening size fraction; (5) carrying out magnetic separation and concentration on the ground material for 2-3 times, and simultaneously dispersing by adopting ultrasonic waves; (6) concentrating to a certain ore pulp concentration, and carrying out desulfurization flotation; and (7) the desulfurization flotation concentrate is subjected to reselection, the reselected concentrate is sulfur concentrate, and reselected tailings are returned for desulfurization flotation to recover magnetite in the tailings. Ultrasonic waves are adopted for magnetic separation and concentration to replace a chemical dispersing agent in the past, magnetic agglomeration of fine magnetite in a magnetic field is overcome, the problem that return water is difficult to use due to the chemical dispersing agent is solved, meanwhile, the sulfur content of iron ore concentrate is reduced, and high-quality sulfur concentrate is obtained; the method has certain practical and theoretical significance on comprehensive recovery of the high-sulfur iron ore.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive resource utilization, and in particular relates to a method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings. Background Art

[0002] As the world's largest steel producer, my country's iron ore imports have been increasing, with a foreign dependence rate exceeding 70%. The rational development of iron ore resources with excessive sulfur content is crucial for increasing my country's effective iron ore supply.

[0003] Sulfur content is a key indicator of iron ore quality. Every 0.1% increase in sulfur in iron ore increases the smelting coke ratio by 5%. This increase in coke ratio not only increases smelting costs but also negatively impacts steel quality. During the smelting process, some sulfur is converted into harmful SO2 gas, while some enters the pig iron, causing "hot brittleness" during hot working, reducing the quality of the steel.

[0004] Currently, the main methods for desulfurizing high-sulfur magnetite are magnetic separation and flotation. When the sulfur in the magnetite is primarily pyrrhotite, flotation is required to separate the pyrrhotite from the magnetite. When the sulfur is primarily in the form of weakly magnetic sulfide minerals such as pyrite and chalcopyrite, magnetic separation can be used to separate the magnetite from the sulfur minerals. When sulfur minerals such as magnetite and pyrite have fine particle sizes, fine grinding is required to dissociate the magnetite monomers. However, excessively fine magnetite particle size leads to severe magnetic agglomeration during magnetic separation, compromising the separation of the pyrite.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for comprehensive recovery of iron and sulfur from high-sulfur lead-zinc tailings. To solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings comprises the following steps: Step 1: Take high-sulfur lead-zinc tailings and add water to make slurry; Step 2: Using a drum magnetic separator to separate the slurry-mixed high-sulfur lead-zinc ore tailings, remove a large amount of gangue tailings, and obtain magnetically separated coarse concentrate and gangue tailings; Step 3: The magnetic separation coarse concentrate is screened and classified using a 160-180 mesh screen to remove the coarse particles of stubborn stone and low-grade intergrowth on the screen, thereby obtaining the coarse particles of stubborn stone and low-grade intergrowth on the screen and the fine particles of magnetic separation coarse concentrate under the screen; Step 4: The magnetic separation coarse concentrate smaller than the screening particle size is concentrated and then ground until the particle size is -37um and the content is greater than 90%; Step 5: Use a drum magnetic separator to beneficiate the ground materials 2 - 3 times. Meanwhile, apply ultrasonic dispersion in the magnetic separation area to avoid fine-grained gangue particles being mixed in due to the magnetic agglomeration of magnetite, and obtain beneficiated magnetic separation concentrate and beneficiated magnetic separation tailings; Step 6: After demagnetizing the beneficiated magnetite concentrate, concentrate it to a certain pulp concentration, add inhibitors, activators, collectors, and frothers, and conduct desulfurization flotation with one roughing, two scavengings, and two cleanings to obtain desulfurization flotation concentrate and desulfurization flotation tailings. Among them, the desulfurization flotation tailings are dehydrated into qualified iron concentrate; Step 7: Use gravity separation for the desulfurization flotation concentrate. The gravity separation concentrate is sulfur concentrate, and the gravity separation tailings are returned to the desulfurization flotation to recover the magnetite therein.

[0007] Further, in Step 2, the mass ratio of the high-sulfur lead-zinc tailing pulp concentration is 30 - 35%, and the magnetic induction intensity of the drum magnetic separator is 2000 - 2,400 GS.

[0008] Further, in Step 3, use a high-frequency vibrating screen or a gyratory vibrating screen for screening, and the screening particle size is 160 - 180 mesh.

[0009] Further, in Step 4, after concentrating the materials, the mass ratio of the pulp concentration is 40 - 45%, and wet grinding is carried out using a ball mill, with the content of particles with a grinding particle size of -37 μm being greater than 90%.

[0010] Further, in Step 5, the magnetic induction intensity for magnetic separation by the magnetic separator is 1200 - 1600 GS, and the number of beneficiation operations is 2 - 3 times; the ultrasonic frequency of the ultrasonic generator in the magnetic separation area is 19.5 - 20.5 KHz.

[0011] Further, in Step 6, the materials are concentrated to a pulp mass percentage concentration of 30 - 35%. The dosage of the inhibitor caustic starch is 100 - 120 g / t, the dosage of the activator sulfuric acid is 150 - 200 g / t, the dosage of the collector butyl xanthate is 80 - 120 g / t, and the dosage of the frother No. 2 oil is 30 g / t; the desulfurization flotation adopts one roughing, two scavengings, and two cleanings.

[0012] Further, in Step 7, a shaking table or a spiral chute is used for gravity separation of the desulfurization flotation concentrate; After adopting the above technical solutions, the present invention has the following beneficial effects compared with the prior art.

[0013] In the present invention, ultrasonic waves are used instead of the previous chemical dispersants for magnetic beneficiation, overcoming the magnetic agglomeration of fine magnetite in the magnetic field, avoiding the problem of difficult recycling of backwater caused by chemical dispersants, and at the same time reducing the sulfur content of the iron concentrate and obtaining high-quality sulfur concentrate, which has certain practical and theoretical significance for the comprehensive recovery of high-sulfur iron ore. Detailed Embodiments

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be described clearly and completely below. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0015] Example 1: First, a certain lead-zinc tailing is subjected to magnetic separation. The magnetic separation concentrate is finely ground until the content of -37um reaches 92%. Then, it is subjected to magnetic separation and concentration twice. By using ultrasonic dispersion with a frequency of 19.5KHz in the magnetic separation area, magnetic agglomeration in the fine magnetite magnetic field is avoided, and the grade of iron concentrate is improved. The multi-element analysis and sulfur phase analysis results of the concentrated iron concentrate are shown in Tables 1-1 and 1-2.

[0016] Table 1-1 Spectral analysis results of magnetic separation iron concentrate / % Element TFe <![CDATA[SiO2]]> MgO CaO <![CDATA[Al2O3]]> S <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[TiO2]]> Content 61.5 6.07 3.75 3.833 1.735 1.23 1.19 1.12 0.1 Table 1-2 Sulfur phase analysis results of magnetic separation iron concentrate / % Phase state Elemental sulfur Sulfur in sulfate Sulfur in sulfide Total sulfur Content 0.01 0.12 1.10 1.23 Distribution rate 0.81 9.76 89.43 100.00 The magnetic separation iron concentrate is concentrated to a pulp mass percentage concentration of 35%. The dosage of the inhibitor caustic starch is 100g / t, the dosage of the activator sulfuric acid is 150g / t, the dosage of the collector butyl xanthate is 80g / t, and the dosage of the frother No. 2 oil is 30g / t. The desulfurization flotation adopts a beneficiation process of one roughing, one scavenging, and two cleaning. The final grade of TFe in the iron concentrate is 62.2%, and the S content is 0.35%. At the same time, the desulfurization flotation foam of the iron concentrate is subjected to shaking table re-election, and the S content in the sulfur concentrate is 36.5% and the Fe content is 57.6%.

[0017] Example 2: A certain zinc tailing contains a certain amount of sulfur and iron. Phase analysis shows that the valuable components for recovery are magnetite and pyrrhotite. First, a large amount of tailings are removed by magnetic separation. Then, when the magnetic separation concentrate is finely ground until the content of -37um reaches 95%, it is concentrated twice by a drum magnetic separator. By using ultrasonic dispersion with a frequency of 20KHz in the magnetic separation area, the grade of the concentrated iron concentrate is increased from 58.6% to 62.1%. Then, the magnetic separation iron concentrate is concentrated to a pulp mass percentage concentration of 40%. The inhibitor caustic starch is added in an amount of 120g / t, the activator sulfuric acid is added in an amount of 200g / t, the collector butyl xanthate is added in an amount of 120g / t, and the frother No. 2 oil is added in an amount of 30g / t in sequence. The desulfurization flotation adopts a beneficiation process of one roughing, one scavenging, and two cleaning. The final grade of TFe in the iron concentrate is 63.5%, and the S content is 0.25%. At the same time, the desulfurization flotation foam of the iron concentrate is subjected to shaking table re-election, and the S content in the sulfur concentrate is 35.6% and the Fe content is 59.5%.

[0018] Example 3: In order to recover a certain amount of magnetite and pyrrhotite in a lead-zinc tailing, a large amount of tailings is first magnetically separated to reduce the grinding cost. Then, the coarse magnetic concentrate is finely ground to a -37um content of 98%, and then the drum magnetic separator is used for two concentrations. Ultrasonic dispersion and magnetic agglomeration are not used. The magnetic separation iron concentrate TFe grade is only 56.8%. Ultrasonic dispersion with a frequency of 20KHz is used in the magnetic separation area, and the iron concentrate reaches 61.8%; the iron concentrate is then concentrated to a pulp mass percentage concentration of 38%, and the inhibitor caustic starch is added in an amount of 110g / t, the activator sulfuric acid is added in an amount of 180g / t, the collector butyl xanthate is added in an amount of 110g / t, and the foaming agent 2# oil is added in an amount of 30g / t; the desulfurization flotation adopts a mineral processing process of one roughing, one scavenging and two concentrations, and the final iron concentrate TFe grade is 63.2%, and the S content is 0.2 %; At the same time, the desulfurization flotation foam of the iron ore is re-selected by a spiral chute, and the sulfur concentrate contains 35.2% S and 58.5% Fe.

[0019] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present invention can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings, characterized in that, It includes the following steps: Step 1: Take high-sulfur lead-zinc tailings and add water to adjust the pulp; Step 2: After pulp adjustment, use a drum magnetic separator for magnetic separation to obtain magnetic separation rough concentrate and gangue tailings; Step 3: Screen and classify the magnetic separation rough concentrate with 160 - 180 mesh to obtain oversize coarse-grained stubborn stones and low-grade intergrowths, and undersize fine-grained magnetic separation rough concentrate; Step 4: Concentrate and grind the undersize fine-grained magnetic separation rough concentrate until the content of particles with a particle size of -37um is greater than 90%; Step 5: Use a drum magnetic separator to conduct 2 - 3 times of cleaning on the ground material, and at the same time use ultrasonic dispersion in the magnetic separation area to avoid the inclusion of fine-grained gangue particles due to magnetic agglomeration of magnetite, to obtain magnetic separation cleaned concentrate and magnetic separation cleaned tailings; Step 6: Concentrate the magnetic separation cleaned concentrate to a certain pulp concentration, add inhibitor, activator, collector and frother, and conduct desulfurization flotation with one roughing, two scavengings and two cleanings to obtain desulfurization flotation concentrate and desulfurization flotation tailings. Dehydrate the desulfurization flotation tailings to obtain qualified iron concentrate; Step 7: Conduct gravity separation on the desulfurization flotation concentrate. The gravity separation concentrate is sulfur concentrate, and the gravity separation tailings are returned to Step 6 for desulfurization flotation to recover the magnetite therein.

2. The method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, wherein In Step 2, the pulp concentration of the high-sulfur lead-zinc tailings is 30 - 35% by mass ratio, and the magnetic induction intensity of the drum magnetic separator is 2000 - 2400 GS.

3. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, characterized in that, In Step 3, the screening is carried out using a high-frequency vibrating screen or a circular vibrating screen.

4. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, characterized in that, In Step 4, the pulp concentration after concentration is 40 - 45% by mass ratio, and wet grinding is carried out using a ball mill.

5. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, characterized in that, In Step 5, the magnetic induction intensity of the drum magnetic separator is 1200 - 1600 GS; the ultrasonic frequency of the ultrasonic generator is 19.5 - 20.5 KHz.

6. The method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, characterized in that, In Step 6, the magnetic separation cleaned concentrate is concentrated to a pulp mass percentage concentration of 30 - 35%. The inhibitor is caustic starch, the activator is sulfuric acid, the collector is butyl xanthate, and the frother is No. 2 oil.

7. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 6, characterized in that, The dosage of the inhibitor is 100 - 120 g / t, the dosage of the activator is 150 - 200 g / t, the dosage of the collector is 80 - 120 g / t, and the dosage of the frother is 30 g / t.

8. A method for comprehensively recovering iron and sulfur from high-sulfur lead-zinc tailings according to claim 1, characterized in that, In Step 7, the gravity separation of the desulfurization flotation concentrate is carried out using a shaking table or a spiral chute.