A method for resource utilization of low-zinc gas ash

Abstract

The present application belongs to the technical field of metallurgical solid waste resource utilization, and discloses a method for resource utilization of low-zinc gas ash, comprising the following steps: S1, dissociating and sieving the low-zinc gas ash; S2, preparing a slurry from the gas ash; S3, performing rough flotation; S4, performing fine flotation; S5, placing the flotation tailings into a sulfuric acid leaching device; S6, adding dilute sulfuric acid into the sulfuric acid leaching device to perform leaching reaction, filtering the leaching solution in the sulfuric acid leaching device to obtain a crude ferrous sulfate solution; S7, evaporating and concentrating the crude ferrous sulfate solution to obtain a sulfuric acid solution and ferrous sulfate solids, and the sulfuric acid solution is recycled to the sulfuric acid leaching device; and S8, dissolving the ferrous sulfate solids with ultrapure water to obtain a refined ferrous sulfate solution. The present application uses low-zinc gas ash as raw material, and through the flotation-leaching process, high-grade carbon powder and ferrous sulfate solution are obtained, providing a new way for the resource utilization of low-zinc gas ash.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical solid waste resource utilization technology, specifically relating to a method for the resource utilization of low-zinc gas ash. Background Technology

[0002] Gas ash is an important solid waste containing elements such as iron, carbon, and zinc generated during the iron and steel smelting process; low-zinc gas ash refers to dust with a low Zn content (usually <2%) collected by the dust removal system from the flue gas during the iron and steel smelting process.

[0003] Blast furnace gas ash is fine dust collected by the gas purification system during the blast furnace ironmaking process. It mainly originates from ore and coke powder in the furnace charge, as well as low-boiling-point metal vapors that volatilize and condense under high-temperature conditions. Depending on the dust removal method, it can be divided into dry bag filter ash and wet gas sludge. The two are basically similar in phase composition and chemical properties, mainly composed of iron oxides, carbonaceous particles, and a small amount of non-ferrous metal elements.

[0004] Traditional blast furnace gas ash typically contains high levels of zinc. Zinc accumulates and circulates within the blast furnace, negatively impacting operational stability. Therefore, the resource utilization of high-zinc gas ash focuses on zinc recovery. Currently, the mainstream treatment method is pyrometallurgical processes such as rotary kilns, which separate zinc through high-temperature volatilization. However, these processes suffer from high energy consumption, large equipment investment, and high operating costs, making them uneconomical for gas ash with low zinc content.

[0005] In contrast, low-zinc gas ash, due to its lower zinc content, lacks resource value centered on zinc recovery. Its resource attributes are primarily reflected in the recovery and utilization of iron and carbon. The goal of low-zinc treatment has shifted from zinc removal to the efficient separation and recovery of carbon and iron.

[0006] Therefore, low-zinc gas ash differs fundamentally from traditional high-zinc gas ash in terms of resource attributes and treatment objectives. Developing low-cost, high-efficiency carbon-iron separation technologies for low-zinc gas ash not only helps improve the resource utilization level of solid waste but also provides a new technological path for steel companies to reduce treatment costs and energy consumption. Summary of the Invention

[0007] The purpose of this invention is to provide a method for the resource utilization of low-zinc gas ash, in order to solve the problem mentioned in the background art that the current process does not have an economic advantage in the resource utilization of gas ash with low zinc content.

[0008] To achieve the above objectives, the present invention provides a method for the resource utilization of low-zinc gas ash, comprising the following steps:

[0009] S1. Mechanically dissociate the low-zinc gas ash and pass it through a 100-mesh sieve to obtain gas ash with a particle size of -100 mesh.

[0010] S2. Feed the obtained gas ash with a particle size of -100 mesh into the slurry machine, add water to adjust it into a slurry with a concentration of 15~20%;

[0011] S3. The obtained slurry is fed into the first flotation machine and aerated, and flotation reagents are added to the first flotation machine to carry out rough flotation to obtain rough flotation concentrate and rough flotation tailings.

[0012] S4. The obtained rough flotation concentrate is fed into the second flotation machine and aerated. Flotation reagents are added to the second flotation machine for fine flotation to obtain fine flotation concentrate and fine flotation tailings. The fine flotation concentrate is dewatered to obtain carbon powder.

[0013] S5. Combine the obtained rough flotation tailings and fine flotation tailings into flotation tailings, and place the flotation tailings into a sulfuric acid leaching device;

[0014] S6. Add dilute sulfuric acid to the sulfuric acid leaching device, stir, heat to carry out the leaching reaction, and after the leaching reaction is completed, filter the leaching liquid in the sulfuric acid leaching device to obtain crude ferric sulfate solution.

[0015] S7. The crude ferric sulfate solution is fed into an evaporation device, evaporated and concentrated to obtain sulfuric acid solution and ferric sulfate solid. The sulfuric acid solution is recycled to the sulfuric acid leaching device.

[0016] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0017] In one specific embodiment, the flotation reagent is diesel oil and 2-octanol.

[0018] In one specific implementation, in the first flotation machine, the amount of diesel fuel added is 560~700g / t, and the amount of 2-octanol added is 135~150g / t; in the second flotation machine, the amount of diesel fuel added is 240~300g / t, and the amount of 2-octanol added is 45~60g / t.

[0019] In one specific implementation, both the first flotation machine and the second flotation machine are single-cell flotation machines.

[0020] In one specific implementation, before adding flotation reagents to the first flotation machine, the pH of the pulp is adjusted to 6-7 using an HCl solution or a NaOH solution.

[0021] In one specific implementation, the aeration intensity in steps S3 and S4 is 200~300L / h.

[0022] In one specific embodiment, in step S6, the concentration of dilute sulfuric acid is 4~5 mol / L, and the volume ratio of the leaching solution to the mass ratio of the flotation tailings is 20~30.

[0023] In one specific embodiment, the leaching temperature of the leaching reaction is 70~80℃, the stirring intensity is 300~350r / min, and the leaching time is 600~660min.

[0024] In one specific embodiment, the evaporation temperature of the evaporation device is 60~80℃.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention uses low-zinc gas ash as raw material and achieves the separation of carbon elements from the low-zinc gas ash through a flotation-leaching process, while simultaneously leaching iron elements from the gas ash, to obtain high-grade carbon powder and ferric sulfate solution, providing a new approach for the resource utilization of low-zinc gas ash.

[0027] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The present invention will now be described in further detail. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 This is a flowchart of one embodiment of the present invention. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below. The specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0031] A method for the resource utilization of low-zinc gas ash includes the following steps:

[0032] S1. Mechanically dissociate the low-zinc gas ash and pass it through a 100-mesh sieve to obtain gas ash with a particle size of -100 mesh.

[0033] S2. Feed the obtained dissociated gas ash with a particle size of -100 mesh into the slurry machine, add water to adjust it into a slurry with a concentration of 15~20%;

[0034] S3. Feed the obtained slurry into the first flotation machine, adjust the aeration intensity to 200~300L / h and aerate. Use 4mol / L HCl solution or 4mol / L NaOH solution to adjust the pH of the slurry to 6~7, and add flotation reagents to the first flotation machine. It is preferred to use diesel and 2-octanol as flotation reagents. The amount of diesel added is 560~700g / t, and the amount of 2-octanol added is 135~150g / t. Rough flotation is carried out to obtain rough flotation concentrate and rough flotation tailings.

[0035] S4. The obtained rough flotation concentrate is fed into the second flotation machine, the aeration intensity is adjusted to 200~300L / h and aeration is carried out, and flotation reagents are added to the second flotation machine. Diesel and 2-octanol are preferably used as flotation reagents. The amount of diesel added is 240~300g / t and the amount of 2-octanol added is 45~60g / t. Fine flotation is carried out to obtain fine flotation concentrate and fine flotation tailings. The fine flotation concentrate is dewatered to obtain carbon powder. Both the first flotation machine and the second flotation machine are single-cell flotation machines.

[0036] S5. Combine the obtained rough flotation tailings and fine flotation tailings into flotation tailings. After the flotation pulp is settled, take the lower layer of precipitated mineral powder, dry it, and put the dried flotation tailings into a sulfuric acid leaching device.

[0037] S6. Add dilute sulfuric acid with a concentration of 4~5 mol / L to the sulfuric acid leaching device. The volume ratio of the leaching solution to the mass of the flotation tailings is 20~30. Stir and heat to carry out the leaching reaction. The leaching temperature of the leaching reaction is 70~80℃, the stirring intensity is 300~350 r / min, and the leaching time is 600~660 min. After the leaching reaction is completed, filter the leaching solution in the sulfuric acid leaching device to obtain crude ferric sulfate solution.

[0038] S7. The crude ferric sulfate solution is fed into an evaporation device for evaporation and concentration at a temperature of 60-80°C to obtain sulfuric acid solution and ferric sulfate solid. The sulfuric acid solution is recycled to the sulfuric acid leaching device.

[0039] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0040] Example 1

[0041] S1. The low-zinc gas ash is mechanically dissociated and passed through a 100-mesh sieve to obtain gas ash with an iron content of 45.17%, a carbon content of 17.6%, and a particle size of -100 mesh.

[0042] S2. The dissociated gas ash is fed into the slurry machine and mixed with water to form a slurry with a concentration of 16%.

[0043] S3. Feed 16% of the slurry into the single-cell flotation machine, adjust the aeration intensity to 200~300L / h and aerate; adjust the pH of the flotation slurry to 6.12 using 4mol / L HCl solution or 4mol / L NaOH solution, add diesel oil as collector at 560g / t (i.e., add 560g diesel oil per ton of slurry), and add 2-octanol as frother at 135g / t (i.e., add 135g 2-octanol per ton of slurry); start the single-cell flotation machine to perform rough flotation on the slurry.

[0044] S4. The roughing concentrate is fed into another single-cell flotation machine for fine flotation. Diesel fuel is added at a rate of 240 g / t as a collector, i.e., 240 g of diesel fuel is added per ton of slurry. Secondary octanol is added at a rate of 45 g / t as a frother, i.e., 45 g of secondary octanol is added per ton of slurry. The single-cell flotation machine is started to perform fine flotation on the flotation slurry. After fine flotation, the carbon content in the concentrate is 86.56%, and the carbon recovery rate is 90.01%.

[0045] S5. The tailings from rough flotation and fine flotation are combined into flotation tailings, and the iron content in the flotation tailings is 50.80%. After the flotation pulp is settled, the lower layer of precipitated mineral powder is taken out and dried. A certain amount of mineral powder is weighed and placed in a beaker.

[0046] S6. Add 4 mol / L of dilute sulfuric acid at a liquid-to-solid ratio of 20:1; in a magnetically stirred water bath, adjust the rotation speed to 300 r / min, the leaching temperature to 70 degrees Celsius, and the leaching time to 600 min. After the leaching reaction is completed, filter the turbid liquid to obtain a crude ferric sulfate solution with an iron leaching efficiency of 65.12%.

[0047] S7. The crude ferric sulfate solution was placed in an evaporation apparatus and concentrated by evaporation at 60°C, yielding 14.6 ml of solid ferric sulfate and sulfuric acid solution. The sulfuric acid solution was reused in the leaching reaction.

[0048] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0049] Example 2

[0050] S1. The low-zinc gas ash is mechanically dissociated and passed through a 100-mesh sieve to obtain gas ash with an iron content of 46.31%, a carbon content of 16.9%, and a particle size of -100 mesh.

[0051] S2. The dissociated gas ash is fed into the slurry machine and mixed with water to form a slurry with a concentration of 18%.

[0052] S3. Feed 18% of the slurry into the single-cell flotation machine, adjust the aeration intensity to 200~300L / h and aerate; adjust the pH of the flotation slurry to 6.48 using 4mol / L HCl solution or 4mol / L NaOH solution, add diesel oil as collector at 600g / t (600g diesel oil per ton of slurry), and add 2-octanol as frother at 140g / t (140g 2-octanol per ton of slurry); start the single-cell flotation machine to perform rough flotation on the slurry.

[0053] S4. The roughing concentrate is fed into another single-cell flotation machine for fine flotation. Diesel fuel is added at a rate of 240 g / t as a collector, i.e., 240 g of diesel fuel is added per ton of slurry. Secondary octanol is added at a rate of 50 g / t as a frother, i.e., 50 g of secondary octanol is added per ton of slurry. The single-cell flotation machine is started to perform fine flotation on the flotation slurry. After fine flotation, the carbon content in the concentrate is 84.51%, and the carbon recovery rate is 91.47%.

[0054] S5. The tailings from rough flotation and fine flotation are combined into flotation tailings, with an iron content of 51.43%. After sedimentation, the lower sediment ore powder is taken out and dried. A certain amount of ore powder is weighed and placed in a beaker.

[0055] S6. Add 5 mol / L dilute sulfuric acid at a liquid-to-solid ratio of 20:1; in a magnetically stirred water bath, adjust the rotation speed to 300 r / min, the leaching temperature to 80℃, and the leaching time to 600 min. After the leaching reaction is completed, filter the turbid liquid to obtain a crude ferric sulfate solution with an iron leaching efficiency of 68.26%.

[0056] S7. The crude ferric sulfate solution was placed in an evaporation apparatus and concentrated by evaporation at 80°C, yielding 12.7 ml of solid ferric sulfate and sulfuric acid solution. The sulfuric acid solution was reused in the leaching reaction.

[0057] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0058] Example 3

[0059] S1. The low-zinc gas ash is mechanically dissociated and passed through a 100-mesh sieve to obtain gas ash with an iron content of 47.31%, a carbon content of 16.9%, and a particle size of -100 mesh.

[0060] S2. The dissociated gas ash is fed into the slurry machine and mixed with water to form a slurry with a concentration of 18%.

[0061] S3. Feed 18% of the slurry into the single-cell flotation machine, adjust the aeration intensity to 200~300L / h and aerate; adjust the pH of the flotation slurry to 6.48 using 4mol / L HCl solution or 4mol / L NaOH solution, add diesel oil as collector at 600g / t (600g diesel oil per ton of slurry), and add 2-octanol as frother at 140g / t (140g 2-octanol per ton of slurry); start the single-cell flotation machine to perform rough flotation on the slurry.

[0062] S4. The rougher flotation concentrate is fed into another single-cell flotation machine for fine flotation. Diesel fuel is added at a rate of 240 g / t as a collector, i.e., 240 g of diesel fuel is added per ton of slurry. Secondary octanol is added at a rate of 50 g / t as a frother, i.e., 50 g of secondary octanol is added per ton of slurry. The single-cell flotation machine is started to perform fine flotation on the flotation slurry. After fine flotation, the carbon content in the concentrate is 84.51%, and the carbon recovery rate is 91.47%.

[0063] S5. The tailings from rough flotation and fine flotation are combined into flotation tailings, and the iron content in the flotation tailings is 51.2%. After the flotation pulp is settled, the lower layer of precipitated mineral powder is taken out and dried. A certain amount of mineral powder is weighed and placed in a beaker.

[0064] S6. Add 5 mol / L dilute sulfuric acid at a liquid-to-solid ratio of 20:1; in a magnetically stirred water bath, adjust the rotation speed to 300 r / min, the leaching temperature to 80℃, and the leaching time to 660 min. After the leaching reaction is completed, filter the turbid liquid to obtain a crude ferric sulfate solution with an iron leaching efficiency of 68.72%.

[0065] S7. The crude ferric sulfate solution was placed in an evaporation apparatus and concentrated by evaporation at 80°C, yielding 12.5 ml of solid ferric sulfate and sulfuric acid solution. The sulfuric acid solution was reused in the leaching reaction.

[0066] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0067] Example 4

[0068] S1. The low-zinc gas ash is mechanically dissociated and passed through a 100-mesh sieve to obtain gas ash with an iron content of 48.54%, a carbon content of 16.42%, and a particle size of -100 mesh.

[0069] S2. The dissociated gas ash is fed into the slurry machine and mixed with water to form a slurry with a concentration of 20%.

[0070] S3. Feed 20% of the slurry into the single-cell flotation machine, adjust the aeration intensity to 200~300L / h and aerate; adjust the pH of the flotation slurry to 6.52 using 4mol / L HCl solution or 4mol / L NaOH solution, add diesel oil as collector at 700g / t (i.e., add 700g diesel oil per ton of slurry), and add 2-octanol as frother at 150g / t (i.e., add 150g 2-octanol per ton of slurry); start the single-cell flotation machine to perform rough flotation on the slurry;

[0071] S4. The rougher flotation concentrate is fed into another single-cell flotation machine for fine flotation. Diesel fuel is added at 300g / t as a collector, i.e., 300g of diesel fuel is added per ton of slurry. 60g / t of 2-octanol is added as a frother, i.e., 60g of 2-octanol is added per ton of slurry. The single-cell flotation machine is started to perform fine flotation on the flotation slurry. After fine flotation, the carbon content in the concentrate is 82.07%, and the carbon recovery rate is 92.61%.

[0072] S5. The tailings from rough flotation and fine flotation are combined into flotation tailings, and the iron content in the flotation tailings is 52.14%. After the flotation pulp is settled, the lower layer of precipitated mineral powder is taken out and dried. A certain amount of mineral powder is weighed and placed in a beaker.

[0073] S6. Add 5 mol / L dilute sulfuric acid at a liquid-to-solid ratio of 30:1; in a magnetically stirred water bath, adjust the rotation speed to 300 r / min, the leaching temperature to 80℃, and the leaching time to 660 min. After the leaching reaction is completed, filter the turbid liquid to obtain a crude ferric sulfate solution with an iron leaching efficiency of 69.15%.

[0074] S7. The crude ferric sulfate solution was placed in an evaporation apparatus and concentrated by evaporation at 80°C, yielding 12.1 ml of solid ferric sulfate and sulfuric acid solution. The sulfuric acid solution was reused in the leaching reaction.

[0075] S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

[0076] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions and substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for the resource utilization of low-zinc gas ash, characterized in that, Includes the following steps: S1. Mechanically dissociate the low-zinc gas ash and pass it through a 100-mesh sieve to obtain gas ash with a particle size of -100 mesh. S2. Feed the obtained gas ash with a particle size of -100 mesh into the slurry machine, add water to adjust it into a slurry with a concentration of 15~20%; S3. The obtained slurry is fed into the first flotation machine and aerated, and flotation reagents are added to the first flotation machine to carry out rough flotation to obtain rough flotation concentrate and rough flotation tailings. S4. The obtained rough flotation concentrate is fed into the second flotation machine and aerated. Flotation reagents are added to the second flotation machine for fine flotation to obtain fine flotation concentrate and fine flotation tailings. The fine flotation concentrate is dewatered to obtain carbon powder. S5. Combine the obtained rough flotation tailings and fine flotation tailings into flotation tailings, and place the flotation tailings into a sulfuric acid leaching device; S6. Add dilute sulfuric acid to the sulfuric acid leaching device, stir, heat to carry out the leaching reaction, and after the leaching reaction is completed, filter the leaching liquid in the sulfuric acid leaching device to obtain crude ferric sulfate solution. S7. The crude ferric sulfate solution is fed into an evaporation device, evaporated and concentrated to obtain sulfuric acid solution and ferric sulfate solid. The sulfuric acid solution is recycled to the sulfuric acid leaching device. S8. Solid ferric sulfate is dissolved in ultrapure water to obtain a refined ferric sulfate solution.

2. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, The flotation reagents are diesel oil and 2-octanol.

3. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, In the first flotation unit, the amount of diesel fuel added is 560~700g / t, and the amount of 2-octanol added is 135~150g / t; in the second flotation unit, the amount of diesel fuel added is 240~300g / t, and the amount of 2-octanol added is 45~60g / t.

4. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, Both the first flotation machine and the second flotation machine are single-cell flotation machines.

5. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, Before adding flotation reagents to the first flotation machine, adjust the pH of the pulp to 6-7 using HCl or NaOH solution.

6. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, The aeration intensity in steps S3 and S4 is 200~300L / h.

7. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, In step S6, the concentration of dilute sulfuric acid is 4-5 mol / L, and the volume ratio of leaching solution to flotation tailings is 20-30.

8. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, The leaching reaction is carried out at a leaching temperature of 70-80℃, a stirring intensity of 300-350 r / min, and a leaching time of 600-660 min.

9. The method for resource utilization of low-zinc gas ash according to claim 1, characterized in that, The evaporation temperature of the evaporation device is 60~80℃.

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