Method for recovering low-concentration sulfur dioxide tail gas and zinc oxide fume leaching in coordination

Abstract

The present application relates to a kind of low concentration sulfur dioxide tail gas method for collaborative zinc oxide fume leaching recovery, belong to zinc smelting tail gas and fume comprehensive utilization technical field.The wet zinc production wastewater is added to zinc oxide fume and is slurried, and zinc oxide tail suction ore slurry is obtained;Low concentration sulfur dioxide tail gas is absorbed into zinc oxide tail suction ore slurry and reacts to generate zinc sulfite ore slurry;Zinc oxide fume containing zinc ferrite is added to zinc sulfite ore slurry, and wet zinc waste electrolyte is added to control the sulfuric acid concentration to 30~50g / L, and high-acid reduction leaching is carried out, and solid-liquid separation is carried out to obtain reduction leaching residue and zinc oxide fume acid leaching solution containing divalent iron ion.The present application can realize the collaborative utilization of sulfur dioxide and zinc oxide fume produced by zinc leaching residue rotary kiln volatilization process, improve resource utilization, and be beneficial to efficient and clean production of wet zinc.

Description

Technical Field

[0001] This invention relates to a method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust, belonging to the technical field of comprehensive utilization of zinc smelting tail gas and dust. Background Technology

[0002] Zinc leaching residue produced by conventional neutral leaching-weak acid leaching (or neutral leaching-weak acid leaching-low acid enhanced leaching) in hydrometallurgical zinc refining typically requires the zinc to be reduced and volatilized into the flue gas using a rotary kiln or fuming furnace. Zinc oxide dust is then recovered from the flue gas as a raw material for recovering zinc and associated indium and germanium. Low-concentration sulfur dioxide in the flue gas is absorbed using lime milk or ammonia. Patent application number 2013103615696 discloses a desulfurization method for flue gas containing low-concentration sulfur dioxide, which uses zinc oxide dust produced by pyrometallurgical treatment of zinc leaching residue to recover sulfur dioxide tail gas. However, zinc sulfite still needs to be analyzed to further recover sulfur dioxide for acid production. Patent application number 2017103615016 discloses a method for recovering tail gas during the reductive leaching process of hydrometallurgical zinc refining, which uses a recycling method to achieve the reductive leaching of zinc roasted sand, unlike the recovery and utilization of low-concentration sulfur dioxide flue gas generated during the pyrometallurgical treatment of zinc leaching residue.

[0003] In the zinc leaching residue rotary kiln volatilization process, the produced zinc oxide dust contains a certain amount of zinc ferrite. In order to achieve efficient leaching of zinc ferrite and ensure that the iron ions in the leaching solution are ferrous (Fe2+) to meet the requirements for the recovery of indium and germanium in the leaching solution, it is usually necessary to use the reduction leaching of zinc oxide dust or to reduce the zinc oxide dust leaching solution with ferric iron (Fe3+).

[0004] Low-concentration sulfur dioxide is generated simultaneously during the volatilization of zinc leaching residue in a rotary kiln to prepare zinc oxide. How to achieve the synergistic utilization of this sulfur dioxide and zinc oxide dust is of great significance to the zinc oxide dust leaching process. Summary of the Invention

[0005] To address the issue of co-utilizing sulfur dioxide and zinc oxide dust produced in the zinc leaching slag rotary kiln volatilization process, this invention proposes a method for the co-leaching and recovery of low-concentration sulfur dioxide tail gas and zinc oxide dust. The zinc oxide dust produced in the zinc leaching slag rotary kiln volatilization process is used to absorb sulfur dioxide from the tail gas to obtain zinc sulfite slurry. The zinc sulfite slurry is then used for high-acid reduction leaching of the zinc oxide dust to obtain an acid leaching solution containing ferrous ions. This invention enables the co-utilization of sulfur dioxide and zinc oxide dust produced in the zinc leaching slag rotary kiln volatilization process, improving resource utilization and facilitating efficient and clean hydrometallurgical zinc production.

[0006] A method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust includes the following specific steps: (1) Add the wet zinc smelting wastewater to the zinc oxide flue dust to prepare the slurry, and obtain the zinc oxide tailings slurry; (2) Low-concentration sulfur dioxide tail gas is introduced into zinc oxide tailings slurry for absorption and reaction to generate zinc sulfite slurry; (3) Add zinc oxide dust containing zinc ferrate to zinc sulfite slurry, add wet zinc smelting waste electrolyte to control sulfuric acid concentration to 30~50g / L, and carry out high acid reduction leaching to obtain zinc oxide dust acid leaching solution containing ferrous ions.

[0007] Preferably, the solid content in the zinc oxide tailings slurry in step (1) is 25~35wt%.

[0008] Preferably, in step (2), the sulfur dioxide content in the low-concentration sulfur dioxide tail gas is 0.3~0.5wt%, and the sulfite concentration in the zinc sulfite slurry is 1~1.5mol / L.

[0009] Preferably, the mass ratio of zinc oxide dust containing zinc ferrite in step (3) to zinc oxide dust in step (1) is 15~18:1.

[0010] Preferably, the temperature of the high acid reduction leaching in step (3) is 70~80℃, the time is 120~240min, and the mass ratio of the neutral leaching residue to the zinc sulfite slurry in the high acid reduction leaching process is 4~6:1.

[0011] The beneficial effects of this invention are: This invention utilizes zinc oxide dust produced by the zinc leaching slag rotary kiln volatilization process to absorb sulfur dioxide in the tail gas produced by the same process, thereby obtaining zinc sulfite slurry. The zinc sulfite slurry then performs high-acid reduction leaching on zinc ferrite in the zinc oxide dust. This achieves the synergistic utilization of sulfur dioxide and zinc oxide dust produced by the zinc leaching slag rotary kiln volatilization process, improving resource utilization. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0013] Example 1: A method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust, the specific steps of which are as follows: (1) The wastewater from the wet zinc smelting process is added to the zinc oxide dust (containing 4.12 wt% iron and 54.33 wt% zinc) produced by the zinc leaching slag rotary kiln volatilization process to form a slurry, thereby obtaining a zinc oxide tailings slurry; the solid content of the zinc oxide tailings slurry is 25 wt%. (2) The low-concentration sulfur dioxide tail gas (the sulfur dioxide content in the low-concentration sulfur dioxide tail gas is 0.31 wt%) produced by the zinc leaching residue rotary kiln volatilization process is passed into the zinc oxide tailings slurry for absorption and reaction to generate zinc sulfite slurry; the sulfite concentration in the zinc sulfite slurry is 1.0 mol / L; (3) Add zinc oxide dust containing zinc ferrate to zinc sulfite slurry, wherein the mass ratio of zinc oxide dust containing zinc ferrate to zinc oxide dust in step (1) is 18:1; add wet zinc smelting waste electrolyte to control sulfuric acid concentration to 31.25 g / L, and carry out high acid reduction leaching at 80℃ for 120 min, and separate solid and liquid to obtain reduction leaching residue and zinc oxide dust acid leaching solution containing divalent iron ions; wherein the mass ratio of neutral leaching residue to zinc sulfite slurry in the high acid reduction leaching process is 6:1; In this embodiment, the iron content in the reduction leaching residue is 0.25 wt%, the zinc content is 2.97 wt%, the concentration of ferrous iron in the high acid reduction leaching solution is 17.26 g / L, the concentration of ferric iron is 1.96 g / L, and the zinc ion concentration is 77.58 g / L; the recovery rate of SO2 tail gas is 99.38%, and the zinc leaching rate in zinc oxide dust is 97.82%.

[0014] Example 2: A method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust, the specific steps of which are as follows: (1) The wastewater from the wet zinc smelting process is added to the zinc oxide dust (containing 5.03 wt% iron and 52.78 wt% zinc) produced by the zinc leaching slag rotary kiln volatilization process to form a slurry, thereby obtaining a zinc oxide tailings slurry; the solid content of the zinc oxide tailings slurry is 30 wt%; (2) The low-concentration sulfur dioxide tail gas (the sulfur dioxide content in the low-concentration sulfur dioxide tail gas is 0.38wt%) produced by the zinc leaching residue rotary kiln volatilization process is passed into the zinc oxide tailings slurry for absorption and reaction to generate zinc sulfite slurry; the sulfite concentration in the zinc sulfite slurry is mol / L; (3) Add zinc oxide dust containing zinc ferrate to zinc sulfite slurry, wherein the mass ratio of zinc oxide dust containing zinc ferrate to zinc oxide dust in step (1) is 16:1; add wet zinc smelting waste electrolyte to control sulfuric acid concentration to 40.39 g / L, and carry out high acid reduction leaching at 75°C for 240 min, and separate solid and liquid to obtain reduction leaching residue and zinc oxide dust acid leaching solution containing ferrous ions; wherein the mass ratio of neutral leaching residue to zinc sulfite slurry in the high acid reduction leaching process is 4:1; In this embodiment, the iron content in the reduction leaching residue is 0.31 wt%, the zinc content is 2.91 wt%, the concentration of ferrous iron in the high acid reduction leaching solution is 17.55 g / L, the concentration of ferric iron is 1.83 g / L, and the zinc ion concentration is 74.34 g / L; the recovery rate of SO2 tail gas is 99.43%, and the zinc leaching rate in zinc oxide dust is 97.91%.

[0015] Example 3: A method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust, the specific steps of which are as follows: (1) The wastewater from the wet zinc smelting process is added to the zinc oxide dust (containing 5.93 wt% iron and 51.96 wt% zinc) produced by the zinc leaching slag rotary kiln volatilization process to form a slurry, thereby obtaining a zinc oxide tailings slurry; the solid content of the zinc oxide tailings slurry is 35 wt%. (2) The low-concentration sulfur dioxide tail gas (the sulfur dioxide content in the low-concentration sulfur dioxide tail gas is 0.49wt%) produced by the zinc leaching residue rotary kiln volatilization process is passed into the zinc oxide tailings slurry for absorption and reaction to generate zinc sulfite slurry; the sulfite concentration in the zinc sulfite slurry is mol / L; (3) Add zinc oxide dust containing zinc ferrate to zinc sulfite slurry, wherein the mass ratio of zinc oxide dust containing zinc ferrate to zinc oxide dust in step (1) is 15:1; add wet zinc smelting waste electrolyte to control sulfuric acid concentration to 49.76 g / L, and carry out high acid reduction leaching at 70°C for 180 min, and separate solid and liquid to obtain reduction leaching residue and zinc oxide dust acid leaching solution containing ferrous ions; wherein the mass ratio of neutral leaching residue to zinc sulfite slurry in the high acid reduction leaching process is 5:1; In this embodiment, the iron content in the reduction leaching residue is 0.37 wt%, the zinc content is 2.83 wt%, the concentration of ferrous iron in the high acid reduction leaching solution is 17.68 g / L, the concentration of ferric iron is 2.11 g / L, and the zinc ion concentration is 69.72 g / L; the recovery rate of SO2 tail gas is 99.51%, and the zinc leaching rate in zinc oxide flue dust is 97.96%.

[0016] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust, characterized in that, The specific steps are as follows: (1) Add the wet zinc smelting wastewater to the zinc oxide flue dust to prepare the slurry, and obtain the zinc oxide tailings slurry; (2) Low-concentration sulfur dioxide tail gas is introduced into zinc oxide tailings slurry for absorption and reaction to generate zinc sulfite slurry; (3) Add zinc oxide dust containing zinc ferrate to zinc sulfite slurry, add wet zinc smelting waste electrolyte to control sulfuric acid concentration to 30~50g / L, carry out high acid reduction leaching, and separate solid and liquid to obtain reduction leaching residue and zinc oxide dust acid leaching solution containing divalent iron ions.

2. The method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust according to claim 1, characterized in that: Step (1) The solid content in the zinc oxide tailings slurry is 25~35wt%.

3. The method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust according to claim 1, characterized in that: Step (2) The sulfur dioxide content in the low-concentration sulfur dioxide tail gas is 0.3~0.5wt%, and the sulfite concentration in the zinc sulfite slurry is 1~1.5mol / L.

4. The method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust according to claim 1, characterized in that: The mass ratio of zinc oxide dust containing zinc ferrite in step (3) to zinc oxide dust in step (1) is 15~18:

1.

5. The method for leaching and recovering low-concentration sulfur dioxide tail gas in conjunction with zinc oxide dust according to claim 1, characterized in that: Step (3) The high acid reduction leaching temperature is 70~80℃ and the time is 120~240min. The mass ratio of neutral leaching residue to zinc sulfite slurry in the high acid reduction leaching process is 4~6:1.