A process for the recovery of lead, zinc and iron from zinc leach residue

Abstract

The application discloses a method for recovering lead, zinc and iron from zinc leaching residue, comprising the following steps: 1) pretreatment of the zinc leaching residue; 2) heat treatment of the pretreated zinc leaching residue in a hydrogen-containing atmosphere, collection of volatilized lead vapor, and obtaining of a solid product, which is a residue containing Fe3O4 and Zn2SiO4; 3) mixing of the residue containing Fe3O4 and Zn2SiO4 with CaCl2, heat treatment of the mixture in a protective atmosphere, collection of volatilized ZnCl2 vapor, and obtaining of a solid product, which is a residue containing Fe3O4; and 4) grinding of the residue containing Fe3O4, magnetic separation of the residue, and obtaining of a magnetic separation concentrate containing Fe3O4. The zinc leaching residue treatment method has the advantages of simple process, low energy consumption, safety and environmental protection, and can selectively recover lead, zinc and iron from the zinc leaching residue, so that reasonable disposal of the zinc leaching residue and recycling of the valuable metals are realized.

Description

Technical Field

[0001] This invention relates to the field of zinc slag treatment technology, and more specifically to a method for recovering lead, zinc and iron from zinc leaching slag. Background Technology

[0002] Zinc leaching is the process of selectively dissolving zinc in zinc-containing materials in an aqueous solution using a leaching agent, and it is an important component of the hydrometallurgical zinc smelting process. Zinc leaching slag is a byproduct of hydrometallurgical zinc smelting, containing valuable metals such as zinc, iron, and copper, but also heavy metals such as lead and toxic and harmful substances such as sulfides, making its treatment challenging. Currently, zinc leaching slag is mostly stockpiled in smelting slag yards, which not only pollutes the soil and water environment but also wastes resources. Therefore, effective treatment and utilization of zinc leaching slag can not only help solve environmental pollution problems but also promote resource recycling and sustainable development.

[0003] Currently, the main methods for treating zinc leaching residue include wet and pyrometallurgical methods: 1) CN 102719668 A discloses a process for stepwise extraction of zinc, lead, and silver from zinc leaching residue using a fully wet process. This involves two-stage leaching with sulfuric acid solution under suitable conditions. After iron removal, zinc and lead precipitate through sulfidation, while silver is collected through cyanide leaching. This method suffers from problems such as the need for secondary treatment of waste liquid, high reagent consumption, and long reaction time. 2) CN 103421955 A discloses a high-temperature carbon reduction method for treating zinc leaching residue. This method involves mixing zinc leaching residue with coke powder and then feeding it into a volatilization kiln for reaction. Valuable metals such as lead and zinc are separated and collected from the flue gas in the form of steam, while the kiln slag is further smelted to enrich gold, silver, and copper. This method suffers from problems such as high energy consumption and large carbon dioxide emissions. The flue gas also requires further treatment and disposal, and it cannot achieve selective separation of metals from the zinc leaching residue. In summary, existing zinc leaching residue treatment methods all have obvious defects and cannot fully meet the requirements of practical applications.

[0004] Therefore, developing a simple, energy-efficient, safe, and environmentally friendly method for treating zinc leaching residue is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recovering lead, zinc and iron from zinc leaching residue.

[0006] The technical solution adopted in this invention is:

[0007] A method for recovering lead, zinc and iron from zinc leaching residue includes the following steps:

[0008] 1) Grind and dry the zinc leaching residue to obtain pretreated zinc leaching residue;

[0009] 2) The pretreated zinc leaching residue was placed in a hydrogen atmosphere for heat treatment, and the volatilized lead vapor was collected. The solid product obtained was a residue containing Fe3O4 and Zn2SiO4.

[0010] 3) The residue containing Fe3O4 and Zn2SiO4 is mixed with CaCl2 and dispersed in water, then dried, and then heat-treated in a protective atmosphere. The volatilized ZnCl2 vapor is collected, and the solid product obtained is the residue containing Fe3O4.

[0011] 4) Grind the Fe3O4-containing residue and then perform magnetic separation to obtain a magnetic concentrate containing Fe3O4.

[0012] Preferably, the volume percentage of hydrogen in the hydrogen-containing atmosphere in step 2) is 3% to 7%.

[0013] Preferably, the hydrogen-containing atmosphere in step 2) is a hydrogen-argon mixture.

[0014] Preferably, the flow rate of the hydrogen-containing atmosphere in step 2) is 80 mL / min to 120 mL / min.

[0015] Preferably, the specific operation of the heat treatment in step 2) is as follows: first, control the heating rate to 8℃ / min~12℃ / min to raise the temperature from room temperature (25℃±5℃) to 950℃~1050℃, and then keep it at that temperature for 40min~80min.

[0016] Preferably, the mass ratio of the residue containing Fe3O4 and Zn2SiO4 to CaCl2 in step 3) is 1:0.5 to 1.5.

[0017] More preferably, the mass ratio of the residue containing Fe3O4 and Zn2SiO4 to CaCl2 in step 3) is 1:0.8 to 1.3.

[0018] Preferably, the CaCl2 in step 3) is CaCl2·2H2O.

[0019] Preferably, the amount of water used in step 3) is 0.8 to 1.2 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2.

[0020] Preferably, the protective atmosphere in step 3) is either an argon atmosphere or a nitrogen atmosphere.

[0021] Preferably, the flow rate of the protective atmosphere in step 3) is 80 mL / min to 120 mL / min.

[0022] Preferably, the specific operation of the heat treatment in step 3) is as follows: first, control the heating rate to 8℃ / min~12℃ / min to raise the temperature from room temperature to 750℃~1000℃, and then hold the temperature for 60min~240min.

[0023] More preferably, the specific operation of the heat treatment in step 3) is as follows: first, control the heating rate to 800℃~1000℃ from room temperature at a rate of 8℃ / min~12℃ / min, and then hold the temperature for 150min~240min.

[0024] Preferably, the specific operation of magnetic separation in step 4) is as follows: the Fe3O4-containing residue after grinding is ultrasonically dispersed in an ethanol-water mixed solvent, and then magnetic separation is carried out under the condition of magnetic separation current of 150mA to 250mA.

[0025] Preferably, the ultrasonic dispersion time is 20 min to 40 min.

[0026] Preferably, the volume percentage of ethanol in the ethanol-water mixed solvent is 8% to 12%.

[0027] The beneficial effects of this invention are: the zinc leaching residue treatment method of this invention has the advantages of simple process, low energy consumption, safety and environmental protection, and can selectively recover lead, zinc and iron from zinc leaching residue, realizing the rational disposal of zinc leaching residue and the recycling and reuse of valuable metals, which is suitable for large-scale industrial application.

[0028] Specifically:

[0029] 1) This invention replaces the carbon reduction commonly used in the prior art with hydrogen reduction, thereby reducing greenhouse gas emissions and achieving cleaner production while realizing the reduction and dissociation of products. Furthermore, the reaction temperature is controlled through two-stage heat treatment to ensure the stepwise separation of valuable metals.

[0030] 2) By selecting a suitable chlorinating agent and controlling the reaction conditions, the present invention recovers zinc in the form of metal chloride. Compared with the prior art, the temperature required for direct reduction and volatilization of Zn in the form of elemental Zn is lower, which reduces the energy consumption required for the reaction to a certain extent. At the same time, it ensures that Fe remains in the remaining product in the form of magnetite, which is convenient for further recovery. Attached Figure Description

[0031] Figure 1 This is a process flow diagram of the method for recovering lead, zinc and iron from zinc leaching residue according to the present invention.

[0032] Figure 2 The image shows the XRD pattern of the zinc leaching residue from Example 1.

[0033] Figure 3The image shows the XRD pattern of the residue containing Fe3O4 and Zn2SiO4 in Example 1.

[0034] Figure 4 The images show the XRD patterns of the Fe3O4-containing residue and magnetic concentrate from Example 1.

[0035] Figure 5 The image shows the XRD pattern of the magnetically separated rough ore in Example 1. Detailed Implementation

[0036] The present invention will be further explained and described below with reference to specific embodiments.

[0037] The formulas for calculating the volatilization separation rates of zinc and lead are as follows:

[0038] V(%)=(Z0-Z) / Z0×100%;

[0039] In the formula, V is the volatile separation rate, Z0 is the content of zinc and lead in the sample before treatment, and Z is the content of zinc and lead in the sample after treatment. The elemental content is tested by ICP after sample digestion.

[0040] The formula for calculating the iron recovery rate is as follows:

[0041] R(%) = (F0 - F) / F0 × 100%;

[0042] In the formula, R is the recovery rate, F0 is the total mass of the sample before magnetic separation (in g), and F is the mass of the magnetic concentrate (in g), which is determined by an analytical balance.

[0043] Example 1:

[0044] A method for recovering lead, zinc and iron from zinc leaching residue (process flow diagram shown) Figure 1 (As shown), the steps are as follows:

[0045] 1) The zinc leaching residue (from a lead-zinc smelting enterprise in Hunan Province) was ground and dried to obtain pretreated zinc leaching residue;

[0046] 2) Place the pretreated zinc leaching residue in a tube furnace and fill it with a hydrogen-argon mixture (5% by volume of hydrogen). The flow rate of the hydrogen-argon mixture is 100 mL / min. Control the heating rate to rise from room temperature to 1000℃ at 10℃ / min and then hold it for 60 min. Collect the volatilized lead vapor and calculate the lead volatilization separation rate. The solid product obtained is a residue containing Fe3O4 and Zn2SiO4.

[0047] 3) Mix the residue containing Fe3O4 and Zn2SiO4 with CaCl2·2H2O at a mass ratio of 1:1, then add deionized water and mix evenly. The amount of deionized water is 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. Dry the mixture and place it in a tube furnace. Then, fill it with argon gas at a flow rate of 100 mL / min and control the heating rate to rise from room temperature to 800℃ at a rate of 10℃ / min. Hold the temperature for 240 min, collect the volatilized ZnCl2 vapor, and calculate the zinc volatilization separation rate. The solid product obtained is the residue containing Fe3O4.

[0048] 4) Grind the Fe3O4-containing residue, add it to an ethanol-water mixed solvent (ethanol volume percentage is 10%), ultrasonically disperse for 30 min, then perform magnetic separation under a magnetic separation current of 200 mA, and then dry it to obtain Fe3O4-containing magnetic concentrate (substance adsorbed by the magnetic pole) and magnetic crude ore (substance not adsorbed by the magnetic pole), and calculate the iron recovery rate.

[0049] According to the test results, the volatilization separation rate of Pb in this embodiment was 98.47%, the volatilization separation rate of Zn was 91.04%, and the recovery rate of Fe was 96.54%.

[0050] The X-ray diffraction (XRD) pattern of the zinc leaching residue in this embodiment is shown below. Figure 2 As shown.

[0051] Depend on Figure 2 It can be seen that the main phases of zinc leaching residue are zinc ferrite, lead sulfate, calcium sulfate dihydrate and zinc sulfate hexahydrate.

[0052] In addition, the main elemental contents of the zinc leaching residue were determined by X-ray fluorescence spectroscopy (XRF) as follows: Fe: 38.387%; Zn: 22.235%; Si: 9.773%; S: 8.249%; Pb: 6.783%.

[0053] The XRD pattern of the residue containing Fe3O4 and Zn2SiO4 in this embodiment is as follows: Figure 3 As shown.

[0054] Depend on Figure 3 It can be seen that the solid product obtained after heat treatment of zinc leaching residue in a hydrogen-argon mixture is indeed a residue containing Fe3O4 and Zn2SiO4.

[0055] The XRD patterns of the Fe3O4-containing residue and magnetic concentrate in this embodiment are as follows: Figure 4 As shown, the XRD pattern of the magnetically separated rough ore in this embodiment is as follows. Figure 5 As shown.

[0056] Depend on Figure 4and Figure 5 It can be seen that the solid product obtained by heat treatment of the residue containing Fe3O4 and Zn2SiO4 with CaCl2·2H2O is indeed the residue containing Fe3O4; the magnetic separation of the residue containing Fe3O4 does indeed yield the magnetic concentrate containing Fe3O4, while the main component of the remaining magnetic crude is Ca3Fe3(SiO4)3.

[0057] Example 2:

[0058] A method for recovering lead, zinc and iron from zinc leaching residue (process flow diagram shown) Figure 1 (As shown), the steps are as follows:

[0059] 1) The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1, and then deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 850°C at a rate of 10°C / min and held for 180 min. The volatilized ZnCl2 vapor was collected and the zinc volatilization separation rate was calculated. The solid product obtained was the residue containing Fe3O4.

[0060] 2) Grind the Fe3O4-containing residue, add it to an ethanol-water mixed solvent (ethanol volume percentage is 10%), ultrasonically disperse for 30 min, then perform magnetic separation under a magnetic separation current of 200 mA, and then dry it to obtain Fe3O4-containing magnetic concentrate and magnetic crude ore, and calculate the iron recovery rate.

[0061] According to the test results, the volatilization separation rate of Zn in this embodiment was 89.53%, and the recovery rate of Fe was 96.34%.

[0062] Example 3:

[0063] A method for recovering lead, zinc and iron from zinc leaching residue (process flow diagram shown) Figure 1 (As shown), the steps are as follows:

[0064] 1) The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1, and then deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 900℃ at a rate of 10℃ / min and held for 180 min. The volatilized ZnCl2 vapor was collected and the zinc volatilization separation rate was calculated. The solid product obtained was the residue containing Fe3O4.

[0065] 2) Grind the Fe3O4-containing residue, add it to an ethanol-water mixed solvent (ethanol volume percentage is 10%), ultrasonically disperse for 30 min, then perform magnetic separation under a magnetic separation current of 200 mA, and then dry it to obtain Fe3O4-containing magnetic concentrate and magnetic crude ore, and calculate the iron recovery rate.

[0066] According to the test results, the volatilization separation rate of Zn in this embodiment was 91.47%, and the recovery rate of Fe was 95.7%.

[0067] Comparative Example 1:

[0068] A method for recovering lead from zinc leaching residue, comprising the following steps:

[0069] The pretreated zinc leaching residue (same as in Example 1) was placed in a tube furnace and filled with a hydrogen-argon mixture (5% by volume of hydrogen). The flow rate of the hydrogen-argon mixture was 100 mL / min. The temperature was raised from room temperature to 800°C at a rate of 10°C / min and then held for 60 min. The volatilized lead vapor was collected and the lead volatilization separation rate was calculated. The resulting solid product was a residue containing Fe3O4 and Zn2SiO4.

[0070] According to the test, the volatile separation rate of Pb in this embodiment is 1.65%.

[0071] Comparative Example 2:

[0072] A method for recovering lead from zinc leaching residue, comprising the following steps:

[0073] The pretreated zinc leaching residue (same as in Example 1) was placed in a tube furnace and filled with a hydrogen-argon mixture (5% by volume of hydrogen). The flow rate of the hydrogen-argon mixture was 100 mL / min. The temperature was controlled to rise from room temperature to 900°C at a rate of 10°C / min, and then held for 60 min. The volatilized lead vapor was collected, and the lead volatilization separation rate was calculated. The solid product obtained was a residue containing Fe3O4 and Zn2SiO4.

[0074] According to the test, the volatile separation rate of Pb in this embodiment is 33.46%.

[0075] Based on the combined results of Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that the volatile separation rate of Pb is greatly affected by temperature.

[0076] Comparative Example 3:

[0077] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0078] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800℃ at a rate of 10℃ / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0079] According to the test, the volatile separation rate of Zn in this embodiment is 88.27%.

[0080] Comparative Example 4:

[0081] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0082] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 750°C at a rate of 10°C / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0083] According to the test, the volatile separation rate of Zn in this embodiment is 80.31%.

[0084] Comparative Example 5:

[0085] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0086] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 700°C at a rate of 10°C / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0087] According to the test, the volatile separation rate of Zn in this embodiment is 15.93%.

[0088] Based on Example 1 and Comparative Examples 3-5, it can be seen that the volatile separation rate of Zn is greatly affected by temperature.

[0089] Comparative Example 6:

[0090] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0091] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with MgCl2·6H2O at a mass ratio of 1:1. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and MgCl2·6H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800℃ at a rate of 10℃ / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0092] According to the test, the volatile separation rate of Zn in this embodiment is 17.86%.

[0093] Comparative Example 7:

[0094] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0095] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with NH4Cl at a mass ratio of 1:1, and then deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and NH4Cl. The mixture was then dried and placed in a tube furnace, which was filled with argon gas at a flow rate of 100 mL / min. The temperature was controlled to rise from room temperature to 800°C at a rate of 10°C / min, and then held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The solid product obtained was the residue containing Fe3O4.

[0096] According to the test, the volatile separation rate of Zn in this embodiment is 27.42%.

[0097] Based on the combined results of Example 1 and Comparative Examples 6-7, it can be seen that the volatilization separation rate of Zn is greatly affected by the type of chloride.

[0098] Comparative Example 8:

[0099] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0100] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1, and then deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min, and the temperature was raised from room temperature to 800℃ at a rate of 10℃ / min. The temperature was then maintained for 60 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The obtained solid product was the residue containing Fe3O4.

[0101] According to the test, the volatile separation rate of Zn in this embodiment is 64.74%.

[0102] Comparative Example 9:

[0103] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0104] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800℃ at a rate of 10℃ / min and held for 120 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0105] According to the test, the volatile separation rate of Zn in this embodiment is 73.61%.

[0106] Based on the combined results of Example 1 and Comparative Examples 8-9, it can be seen that the volatilization separation rate of Zn is greatly affected by the reaction time.

[0107] Comparative Example 10:

[0108] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0109] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:0.5. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800°C at a rate of 10°C / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0110] According to the test, the volatile separation rate of Zn in this embodiment is 62.24%.

[0111] Comparative Example 11:

[0112] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0113] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:0.75. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800°C at a rate of 10°C / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0114] According to the test, the volatile separation rate of Zn in this embodiment is 72.33%.

[0115] Comparative Example 12:

[0116] A method for recovering lead and zinc from zinc leaching residue includes the following steps:

[0117] The residue containing Fe3O4 and Zn2SiO4 (same as in Example 1) was mixed with CaCl2·2H2O at a mass ratio of 1:1.25. Then, deionized water was added and mixed evenly. The amount of deionized water was 1 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2·2H2O. The mixture was then dried and placed in a tube furnace. Argon gas was introduced at a flow rate of 100 mL / min. The temperature was raised from room temperature to 800℃ at a rate of 10℃ / min and held for 180 min. The volatilized ZnCl2 vapor was collected, and the zinc volatilization separation rate was calculated. The resulting solid product was the residue containing Fe3O4.

[0118] According to the test, the volatile separation rate of Zn in this embodiment is 90.31%.

[0119] Based on the combined results of Example 1 and Comparative Examples 10-12, it can be seen that the volatile separation rate of Zn is greatly affected by the amount of CaCl2·2H2O added.

[0120] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for recovering lead, zinc, and iron from zinc leaching residue, characterized in that, Includes the following steps: 1) Grind and dry the zinc leaching residue to obtain pretreated zinc leaching residue; 2) The pretreated zinc leaching residue was placed in a hydrogen atmosphere for heat treatment, and the volatilized lead vapor was collected. The solid product obtained was a residue containing Fe3O4 and Zn2SiO4. 3) The residue containing Fe3O4 and Zn2SiO4 is mixed with CaCl2 and dispersed in water, then dried, and then placed in a protective atmosphere for heat treatment. The volatilized ZnCl2 vapor is collected, and the solid product obtained is the residue containing Fe3O4. 4) Grind the Fe3O4-containing residue and then perform magnetic separation to obtain a magnetic concentrate containing Fe3O4; Step 2) The volume percentage of hydrogen in the hydrogen-containing atmosphere is 3% to 7%; Step 2) The heat treatment is carried out at a temperature of 950℃~1050℃; Step 3) The mass ratio of the residue containing Fe3O4 and Zn2SiO4 to CaCl2 is 1:0.5 to 1.5; Step 3) The heat treatment is carried out at a temperature of 750℃~1000℃.

2. The method for recovering lead, zinc, and iron from zinc leaching residue according to claim 1, characterized in that: Step 2) The hydrogen-containing atmosphere is a hydrogen-argon mixture.

3. The method for recovering lead, zinc, and iron from zinc leaching residue according to claim 1, characterized in that: Step 2) The flow rate of the hydrogen-containing atmosphere is 80 mL / min to 120 mL / min.

4. The method for recovering lead, zinc and iron from zinc leaching residue according to claim 1, characterized in that: Step 2) The specific operation of the heat treatment is as follows: first, control the heating rate to 8℃ / min~12℃ / min to raise the temperature from room temperature to 950℃~1050℃, and then keep it at that temperature for 40min~80min.

5. The method for recovering lead, zinc and iron from zinc leaching residue according to claim 1, characterized in that: Step 3) The amount of water used is 0.8 to 1.2 times the total weight of the residue containing Fe3O4 and Zn2SiO4 and CaCl2.

6. The method for recovering lead, zinc and iron from zinc leaching residue according to claim 1, characterized in that: Step 3) The protective atmosphere is either an argon atmosphere or a nitrogen atmosphere.

7. The method for recovering lead, zinc and iron from zinc leaching residue according to claim 1, characterized in that: Step 3) The specific operation of the heat treatment is as follows: first, control the heating rate to 8℃ / min~12℃ / min to raise the temperature from room temperature to 750℃~1000℃, and then hold the temperature for 60min~240min.

8. The method for recovering lead, zinc and iron from zinc leaching residue according to claim 1, characterized in that: Step 4) The specific operation of magnetic separation is as follows: the Fe3O4-containing residue after grinding is ultrasonically dispersed in an ethanol-water mixed solvent, and then magnetic separation is carried out under the condition of magnetic separation current of 150mA to 250mA.

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