A slag treatment system and process method

Abstract

The embodiment of the present invention provides a slag treatment system and process method, including a first slurrying tank, a second slurrying tank, a mixing tank, a first pickling tank, a second pickling tank, an intermediate tank, and a filter press. The first slurrying tank slurries the first stage purification slag, and the second slurrying tank slurries the second stage purification slag. The mixing tank is used to mix the liquid flowing out of the first slurrying tank and the liquid flowing out of the second slurrying tank. The first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank. The filter press transports the filtrate obtained by the filter press to a neutral leaching device. The slag treatment system collects and slurries the first stage purification slag and the second stage purification slag respectively by setting a slurrying tank, transports the slurried liquid by pipeline transportation, and pickles the slurried liquid. It has the advantages of timely slag transportation, low environmental pollution, reduced total slag after pickling, increased enrichment ratio of valuable metals in the filter residue after pickling while recovering zinc, and low recovery process cost.

Description

Technical Field

[0001] The present invention relates to the technical field of slag treatment, and more specifically to a slag treatment system and process method. Background Art

[0002] Hydrometallurgy refers to the process of dissolving zinc from zinc-containing minerals in aqueous solution to extract metallic zinc or zinc compounds. During the hydrometallurgy process, the leaching solution is subjected to primary purification and secondary purification in sequence to remove impurities. The slag discharge volume during the primary and secondary purification processes is large, and the slag is transported by vehicle, which will cause spillage along the way, making it difficult to stack on site and polluting the environment. If the transportation is not timely, insufficient stacking space will also affect continuous production. In addition, due to the large amount of slag, the recovery cost of valuable metals from a large amount of slag is high and the efficiency is low.

[0003] Although the related technology treats the first and second stage purification slag by grinding and adding sulfuric acid and oxidants, it does not address the problem of large amount of slag, which may be scattered along the way during transportation by vehicle and cause environmental pollution, as well as the problem of untimely transportation and insufficient stacking space affecting continuous production. Summary of the invention

[0004] The embodiment of the present invention provides a slag treatment system and process method, which are used to solve the problems in the related art that when the slag amount is large, the slag is scattered along the way during transportation by vehicle, causing environmental pollution, and the transportation is not timely and the stacking space is insufficient, which affects the continuous production.

[0005] The embodiment of the present invention provides a slag treatment system, characterized in that it includes a first slurry tank, a second slurry tank, a mixing tank, a first pickling tank, a second pickling tank, an intermediate tank, and a filter press device;

[0006] The first slurrying tank is used to slurry the first stage purification slag, and the second slurrying tank is used to slurry the second stage purification slag; the liquid outlet of the first slurrying tank is connected to the first liquid inlet located at the top of the mixing tank through a first pipeline, and the liquid outlet of the second slurrying tank is connected to the second liquid inlet located at the top of the mixing tank through a second pipeline; the first stage purification slag is the filter slag in the first stage purification process of the hydrometallurgical zinc smelting process, and the second stage purification slag is the filter slag in the second stage purification process of the hydrometallurgical zinc smelting process;

[0007] The mixing tank is used to mix the liquid flowing out of the first slurry tank and the liquid flowing out of the second slurry tank; the mixing tank also includes a first liquid outlet located at the bottom of the side, and the first liquid outlet is connected to the third liquid inlet located at the top of the first pickling tank through a third pipe; a first guide pipe is provided in the first pickling tank, and the first guide pipe is connected to the sixth liquid inlet located at the top of the side of the second pickling tank through a fourth pipe; the fourth liquid inlet on the top of the first pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a fifth pipe, and the fifth liquid inlet on the top of the second pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a sixth pipe; the electrolytic waste liquid in the electrolytic waste liquid tank is the waste liquid generated by the zinc electrowinning process, which is acidic;

[0008] The first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank;

[0009] A second guide pipe is provided in the second pickling tank, and the second guide pipe is connected to the seventh liquid inlet of the intermediate tank through a seventh pipeline; the second liquid outlet of the intermediate tank is connected to the filter press through an eighth pipeline; the filter press is used to separate the liquid flowing out of the second liquid outlet into solid and liquid to obtain filtrate and filter residue;

[0010] The filter press equipment is connected to the neutral leaching device via a ninth pipeline, which is used to transport the filtrate obtained by the filter press to the neutral leaching device.

[0011] Optionally, a water supply device is further included, and the water supply device is used to supply water for the slurrying process of the first slurrying tank and the second slurrying tank.

[0012] Optionally, the first end of the first flow guide pipe is located in the first pickling tank, and the distance from the bottom of the first pickling tank is less than a preset first distance threshold, and the second end of the first flow guide pipe is located at the top of the outer side of the first pickling tank;

[0013] The first end of the second flow guide pipe is located in the second pickling tank, and the distance from the bottom of the first pickling tank is less than the preset first distance threshold. The second end of the second flow guide pipe is located at the top of the outer side of the second pickling tank.

[0014] Optionally, the first pipeline, the second pipeline, the third pipeline, the fifth pipeline, the sixth pipeline and the eighth pipeline are all provided with variable frequency pumps for providing power for conveying liquid in the pipelines and regulating the flow rate of the liquid in the pipelines.

[0015] The embodiment of the present invention further provides a slag treatment process method, the process method comprising:

[0016] Adding water to a first slurrying tank containing a first stage of purification slag to obtain a first slurrying liquid, and adding water to a second slurrying tank containing a second stage of purification slag to obtain a second slurrying liquid; the first stage of purification slag is the filter residue in the first stage of purification process of the hydrometallurgical zinc smelting process, and the second stage of purification slag is the filter residue in the second stage of purification process of the hydrometallurgical zinc smelting process;

[0017] The first slurry is transported to a mixing tank through a first pipeline, and the second slurry is transported to the mixing tank through a second pipeline, and the liquids in the mixing tank are stirred uniformly to obtain a mixed liquid;

[0018] The mixed liquid is transported to the first pickling tank through the third pipeline, and the electrolytic waste liquid in the electrolytic waste liquid tank is transported to the first pickling tank through the fifth pipeline, and the liquid in the first pickling tank is stirred evenly to obtain a first pickling liquid;

[0019] Introducing the first pickling liquid into the second pickling tank through the first guide pipe and the fourth pipe in the first pickling tank, and continuing to stir the first pickling liquid to obtain the second pickling liquid;

[0020] Testing the pH value of the second pickling solution and controlling the pH value of the second pickling solution to be weakly acidic;

[0021] Introducing the second pickling liquid into the intermediate tank through the second guide pipe and the seventh pipeline in the second pickling tank;

[0022] The second pickling liquid in the intermediate tank is pumped into the filter press through the eighth pipeline for solid-liquid separation to obtain filtrate and filter residue, and the filtrate and filter residue are treated.

[0023] Optionally, the processing of the filtrate and the filter residue specifically includes:

[0024] The separated filtrate is transported to a neutral leaching device to recover zinc in the filtrate;

[0025] The filter residue is collected, and the metal in the filter residue is recovered.

[0026] Optionally, when the ratio of the volume of the mixed liquid in the mixing tank to the volume of the mixing tank is greater than a preset first ratio, the mixed liquid is passed into the first pickling tank, and the electrolytic waste liquid is added for pickling at the same time.

[0027] Optionally, controlling the pH of the second pickling solution to be weakly acidic specifically includes:

[0028] When the pH value of the second pickling liquid is less than the preset first pH value, the opening of the variable frequency pump arranged on the third pipeline is increased, or the opening of the variable frequency pump arranged on the fifth pipeline is reduced;

[0029] When the pH value of the second pickling solution is greater than the preset second pH value, the opening of the variable frequency pump provided on the third pipeline is reduced, or the opening of the variable frequency pump provided on the fifth pipeline is increased;

[0030] When the pH value of the second pickling solution is between the preset first pH value and the preset second pH value, the opening of the variable frequency pump is not adjusted.

[0031] Optionally, the liquid-to-solid mass ratio of the first slurry and the second slurry is 5:1.

[0032] Optionally, the preset first pH value is 4.5, and the preset second pH value is 5.0.

[0033] The embodiments of the present invention have at least the following beneficial effects:

[0034] The embodiment of the present invention provides a slag treatment system, including a first slurrying tank, a second slurrying tank, a mixing tank, a first pickling tank, a second pickling tank, an intermediate tank, and a filter press; the first slurrying tank is used to slurry the first stage purification slag, and the second slurrying tank is used to slurry the second stage purification slag; the mixing tank is used to mix the liquid flowing out of the first slurrying tank and the liquid flowing out of the second slurrying tank; the first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank; the filter press is used to transport the filtrate obtained by the filter press to a neutral leaching device. The slag treatment system collects and slurries the first stage purification slag and the second stage purification slag respectively by setting a slurrying tank, transports the slurried liquid by pipeline transportation, and pickles the slurried liquid. It has the advantages of timely slag transportation, low environmental pollution, reduced total slag volume after pickling, increased enrichment ratio of valuable metals in the filter residue after pickling while recovering zinc, and low recovery process cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A connection diagram of a slag treatment system provided by an embodiment of the present invention;

[0037] Figure 2 A flow chart of a slag treatment process method provided in an embodiment of the present invention.

[0038] Reference numerals:

[0039] 1-first slurry tank; 2-second slurry tank; 3-mixing tank; 4-first pipeline; 5-second pipeline; 6-first liquid inlet; 7-second liquid inlet; 8-first liquid outlet; 9-third pipeline; 10-third liquid inlet; 11-fourth liquid inlet; 12-fourth pipeline; 13-first guide pipe; 14-first pickling tank; 15-electrolytic waste liquid tank; 16-sixth pipeline; 17-fifth liquid inlet; 18-sixth liquid inlet; 19-second pickling tank; 20-second guide pipe; 21-seventh pipeline; 22-seventh liquid inlet; 23-middle tank; 24-second liquid outlet; 25-eighth pipeline; 26-filter press equipment; 27-ninth pipeline; 28-neutral leaching device; 29-fifth pipeline; 30-variable frequency pump. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Figure 1 A schematic diagram of a slag treatment system connection provided by an embodiment of the present invention. Figure 1 As shown, it includes a first slurry tank 1, a second slurry tank 2, a mixing tank 3, a first pickling tank 14, a second pickling tank 19, an intermediate tank, and a filter press 26;

[0042] The first slurrying tank 1 is used to slurry the first stage purified slag, and the second slurrying tank 2 is used to slurry the second stage purified slag; the liquid outlet of the first slurrying tank 1 is connected to the first liquid inlet 6 located at the top of the mixing tank 3 through a first pipeline 4, and the liquid outlet of the second slurrying tank 2 is connected to the second liquid inlet 7 located at the top of the mixing tank 3 through a second pipeline 5; the first stage purified slag is the filtered slag in the first stage purification process of the hydrometallurgical zinc smelting process, and the second stage purified slag is the filtered slag in the second stage purification process of the hydrometallurgical zinc smelting process;

[0043] The mixing tank is used to mix the liquid flowing out of the first slurry tank and the liquid flowing out of the second slurry tank; the mixing tank also includes a first liquid outlet located at the bottom of the side, and the first liquid outlet is connected to the third liquid inlet located at the top of the first pickling tank through a third pipe; a first guide pipe is provided in the first pickling tank, and the first guide pipe is connected to the sixth liquid inlet located at the top of the side of the second pickling tank through a fourth pipe; the fourth liquid inlet on the top of the first pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a fifth pipe, and the fifth liquid inlet on the top of the second pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a sixth pipe; the electrolytic waste liquid in the electrolytic waste liquid tank is the waste liquid generated by the zinc electrowinning process, which is acidic;

[0044] The first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank 3 .

[0045] Specifically, the neutral leaching tank contains an acidic aqueous solution. The wet zinc smelting process dissolves the zinc-containing ore in the neutral leaching tank, and soluble zinc such as zinc oxide and zinc sulfate is dissolved in the acidic aqueous solution to form a neutral supernatant. Insoluble solids are precipitated to form residues. In addition to zinc ions, the obtained neutral supernatant also contains impurities such as copper, cadmium, cobalt, and nickel.

[0046] The neutral supernatant is generally purified and removed in two stages. The first stage of purification is mainly to use zinc powder to remove copper and cadmium in the neutral supernatant. After the first stage of filtration, a first stage of purification residue and a first stage of purification liquid are obtained. The main valuable metals in the first stage of purification residue are copper and cadmium. In actual production, some redissolved cadmium will also exist in the first stage of purification liquid.

[0047] The second stage purification is to add excess zinc powder and zinc powder activator to the first stage purification liquid to replace the valuable metals such as cadmium, cobalt, nickel, etc. in the second stage purification liquid. After the second stage filtration, the second stage purification slag and the second stage purification liquid are obtained. Since the zinc powder is excessive, the second stage purification slag contains a large amount of elemental zinc. The obtained second stage purification liquid is used to recover zinc. The recovery of zinc is completed through the zinc electrolytic process. The zinc ions in the second stage purification liquid are recovered, and the generated electrolytic waste liquid is still acidic.

[0048] The first slurry tank 1 in the embodiment of the present invention is used to collect and slurry the first stage of purification slag, and the second stage slurry tank is used to collect and slurry the second stage of purification slag. The first slurry liquid is transported to the mixing tank 3 through the first pipeline 4 and the first liquid inlet 6, and the second slurry liquid is transported to the mixing tank 3 through the second pipeline 5 and the second liquid inlet 7, and the first slurry liquid and the second slurry liquid are mixed evenly in the mixing tank 3.

[0049] The mixing tank 3 is connected to the first pickling tank 14 through the third pipe 9. The liquid in the mixing tank 3 flows out through the first liquid outlet 8, passes through the third pipe 9, and enters the first pickling tank 14 through the third liquid inlet 10. The electrolytic waste liquid generated by the zinc electrowinning process enters the electrolytic waste liquid tank. The electrolytic waste liquid tank is connected to the fourth liquid inlet 11 of the first pickling tank 14 through the fifth pipe, and the electrolytic waste liquid is transported to the first pickling tank 14 through the fifth pipe. In the first pickling tank 14, the liquid flowing out of the mixing tank 3 and the electrolytic waste liquid are mixed and pickled. The first guide pipe 13 provided in the first pickling tank 14 serves as the liquid outlet of the first pickling tank 14. The first guide pipe 13 is connected to the sixth liquid inlet 18 of the second pickling tank 19 through the fourth pipe 12, and the liquid in the first pickling tank 14 is diverted into the second pickling tank 19. The fifth liquid inlet 17 at the top of the second pickling tank 19 is also connected to the electrolytic waste liquid tank, so that the electrolytic waste liquid in the electrolytic waste liquid tank 15 can be transported to the second pickling tank 19 through the sixth pipeline 16. In the second pickling tank 19, the liquid flowing out of the first pickling tank 14 and the electrolytic waste liquid continue to be mixed.

[0050] A second guide pipe is provided in the second pickling tank, and the second guide pipe is connected to the seventh liquid inlet of the intermediate tank through a seventh pipeline; the second liquid outlet of the intermediate tank is connected to the filter press through an eighth pipeline; the filter press is used to separate the liquid flowing out of the second liquid outlet into solid and liquid to obtain filtrate and filter residue;

[0051] The filter press equipment is connected to the neutral leaching device via a ninth pipeline, which is used to transport the filtrate obtained by the filter press to the neutral leaching device.

[0052] Specifically, the second guide pipe 20 provided in the second pickling tank 19 serves as the liquid outlet of the second pickling tank 19. The second guide pipe 20 is connected to the seventh liquid inlet 22 provided above the intermediate tank 23, and guides the liquid in the second pickling tank 19 into the intermediate tank 23 through the seventh pipe 21. The second liquid outlet 24 at the bottom of the side of the intermediate tank 23 is connected to the filter press 26, and the liquid in the intermediate tank 23 is transported to the filter press 26 through the eighth pipe 25. The filter press 26 performs filter pressing on the liquid to obtain filter residue and filtrate. A ninth pipe 27 is connected between the filter press 26 and the neutral leaching tank, and the ninth pipe 27 transports the filtrate to the neutral leaching device 28, precipitates and purifies again, and finally enters the zinc electrowinning process to recover zinc. The filter residue is collected at the filter residue collection point, waiting for the next step to recover the metal in the filter residue.

[0053] In summary, the embodiment of the present invention provides a slag treatment system, including a first slurrying tank, a second slurrying tank, a mixing tank, a first pickling tank, a second pickling tank, an intermediate tank, and a filter press; the first slurrying tank is used to slurry the first stage purification slag, and the second slurrying tank is used to slurry the second stage purification slag; the mixing tank is used to mix the liquid flowing out of the first slurrying tank and the liquid flowing out of the second slurrying tank; the first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank; the filter press is used to transport the filtrate obtained by the filter press to the neutral leaching tank. The slag treatment system collects and slurries the first stage purification slag and the second stage purification slag respectively by setting a slurrying tank, transports the slurried liquid by pipeline transportation, and pickles the slurried liquid. It has the advantages of timely slag transportation, low environmental pollution, reduced total slag volume after pickling, increased enrichment ratio of valuable metals in the filter residue after pickling while recovering zinc, and low recovery process cost.

[0054] In a possible implementation manner, a water supply device is further included, and the water supply device is used to supply water for the slurrying process of the first slurrying tank and the second slurrying tank.

[0055] Specifically, the slag treatment system also includes a water supply device, which can be a water tank, or a device such as a water pipe that can provide a water source to supply water to the primary purified slag in the first slurrying tank 1 and the secondary purified slag in the second slurrying tank 2 during slurrying.

[0056] In a possible implementation manner, the first end of the first flow guide pipe is located in the first pickling tank, and the distance from the bottom of the first pickling tank is less than a preset first distance threshold, and the second end of the first flow guide pipe is located at the top of the outer side of the first pickling tank;

[0057] The first end of the second flow guide pipe is located in the second pickling tank, and the distance from the bottom of the first pickling tank is less than the preset first distance threshold. The second end of the second flow guide pipe is located at the top of the outer side of the second pickling tank.

[0058] Specifically, the first guide tube 13 includes a first end and a second end. The first end penetrates into the first pickling tank 14, and the distance from the bottom of the first pickling tank 14 is less than a preset first distance threshold. The second end is located at the top of the outer side of the first pickling tank 14 and is connected to an external delivery pipeline. The liquid in the mixing tank 3 and the electrolytic waste liquid enter the first pickling tank 14 and start to react. As the two liquids are continuously added, the liquid in the first pickling tank 14 gradually increases. The closer the liquid is to the bottom of the first pickling tank 14, the longer the reaction time is. Until the first pickling tank 14 is full of liquid, the liquid near the bottom of the first pickling tank 14 first enters the first end of the first guide tube 13, and flows out from the second end of the first guide tube 13 after passing through the pipeline of the first guide tube 13. The first end penetrates into the bottom of the first pickling tank 14 to transport the liquid that has reacted for a period of time, thereby ensuring the reaction time.

[0059] Similarly, the second flow guide tube 20 also includes a first end and a second end, the first end penetrates into the second pickling tank 19, and the distance from the bottom of the second pickling tank 19 is less than the preset first distance threshold. The second end is located at the top of the outer side of the second pickling tank 19 and is connected to the external delivery pipeline. The liquid in the first pickling tank 14 enters the first pickling tank 14 and can continue to react. The liquid in the second pickling tank 19 gradually increases, and the liquid closer to the bottom of the second pickling tank 19 has a longer reaction time until the second pickling tank 19 is full of liquid. The liquid near the bottom of the second pickling tank 19 first enters the first end of the second flow guide tube 20, and flows out from the second end of the second flow guide tube 20 after passing through the pipeline of the second flow guide tube 20. The first end penetrates into the bottom of the second pickling tank to transport the liquid that has reacted for a period of time, thereby extending the reaction time. In an embodiment of the present invention, the preset first distance threshold is set to 8 cm, and other embodiments may also set other values ​​as the preset first distance threshold.

[0060] In a possible implementation, the first pipeline, the second pipeline, the third pipeline, the fifth pipeline, the sixth pipeline and the eighth pipeline are all provided with variable frequency pumps for providing power for conveying liquid in the pipelines and regulating the flow rate of the liquid in the pipelines.

[0061] Specifically, the variable frequency pump is used to control the flow rate of the liquid transported in the pipeline. Variable frequency pumps are arranged on the first pipeline 4, the second pipeline 5, the third pipeline 9, the fifth pipeline, the sixth pipeline 16 and the eighth pipeline 25. In different situations, the flow rate of the liquid in the corresponding pipeline is controlled by controlling the opening of the variable frequency pump on the corresponding pipeline.

[0062] In order to more clearly introduce the slag processing system provided by the embodiment of the present invention, the following is combined with Figure 2 , and the process method of this system is introduced in detail.

[0063] like Figure 2As shown, the process method of the slag treatment system includes the following steps:

[0064] Step 101, adding water to a first slurrying tank containing first-stage purified slag to obtain a first slurrying liquid, and adding water to a second slurrying tank containing second-stage purified slag to obtain a second slurrying liquid; the first-stage purified slag is the filtered slag in the first-stage purification process of the hydrometallurgical zinc smelting process, and the second-stage purified slag is the filtered slag in the second-stage purification process of the hydrometallurgical zinc smelting process.

[0065] Specifically, the first purification slag obtained by hydrometallurgical zinc smelting after a first purification process is mainly copper, cadmium, and a small amount of elemental zinc. The second purification slag obtained in the second purification process is mainly nickel, cobalt, a small amount of cadmium, and a large amount of elemental zinc. The first purification slag produced by the first purification directly enters the first slurry tank 1, and the second purification slag produced by the second purification directly enters the second slurry tank 2. Water is added to the first slurry tank 1 to obtain the first slurry liquid, and the second slurry liquid is obtained in the second slurry tank 2. Adding water effectively isolates the oxidation of the slag in the air, and keeps the activity of the excess elemental zinc powder in the slag from being over-oxidized to the greatest extent.

[0066] Step 102, transporting the first slurry to a mixing tank through a first pipeline, and transporting the second slurry to the mixing tank through a second pipeline, and stirring the liquid in the mixing tank to obtain a mixed liquid.

[0067] Specifically, after obtaining the first slurry and the second slurry, the variable frequency pump on the first pipeline 4 is turned on, and the first slurry is pumped into the mixing tank 3 through the first pipeline 4. The variable frequency pump on the second pipeline 5 is turned on, and the second slurry is pumped into the mixing tank 3 through the second pipeline 5, and the first slurry and the second slurry are uniformly stirred in the mixing tank 3 to obtain a mixed liquid of the first slurry and the second slurry.

[0068] Step 103, transporting the mixed liquid to the first pickling tank through the third pipeline, and transporting the electrolytic waste liquid in the electrolytic waste liquid tank to the first pickling tank through the fifth pipeline, stirring the liquid in the first pickling tank evenly to obtain the first pickling liquid.

[0069] Specifically, after obtaining the mixed liquid, turn on the frequency conversion pump on the third pipeline 9, and pump the mixed liquid into the first pickling tank 14 through the third pipeline 9. Turn on the frequency conversion pump on the fifth pipeline, and pump the electrolytic waste liquid in the electrolytic waste liquid tank 15 into the first pickling tank 14, and evenly mix the mixed liquid and the electrolytic waste liquid in the first pickling tank 14 so that the electrolytic waste liquid can fully react with the metal in the mixed liquid. The electrode potential of zinc is more negative than that of copper and cadmium. The electrolytic waste liquid provides an acidic environment for the reaction. There is also a zinc powder activator Sb2O3 in the solution, which is used to increase the activity of elemental zinc during the second-stage purification process. The specific reaction principle of the replacement reaction occurring in the first pickling tank 14 is as follows:

[0070] Cu+H + →Cu 2+ Cu 2+ +Zn→Cu+Zn 2+

[0071] Cd+H + →Cd 2+ Cd 2+ +Zn→Cd+Zn 2+

[0072] Co+H + →Co 2+

[0073] During the whole reaction process, heating is not performed at room temperature. The main reason is that the process of the reaction between elemental zinc and acid releases heat, and too high a temperature will increase the re-dissolution of cadmium, so heating is not required. After the pickling reaction, the elemental zinc existing as a solid is converted into zinc ions and dissolved in the first pickling solution, while copper, cadmium and cobalt still exist in the first pickling solution in the form of solid elements at the end of the replacement reaction. The first pickling solution is a solid-liquid mixture.

[0074] Step 104: introducing the first pickling liquid into the second pickling tank through the first guide pipe and the fourth pipe in the first pickling tank, and continuing to stir the first pickling liquid to obtain the second pickling liquid.

[0075] Specifically, when the volume of the first pickling liquid in the first pickling tank 14 exceeds the volume of the first pickling tank 14, the liquid at the bottom of the first pickling tank 14 enters the first pickling tube 13 through the first end of the first guide tube 13, and flows out from the second end of the first guide tube 13 into the fourth pipeline 12. After entering the second pickling tank 19 through the fourth pipeline 12, stirring is continued in the second pickling tank 19, and the replacement reaction continues in the second pickling tank 19 to obtain the second pickling liquid, which is a solid-liquid mixture with the same components as the first pickling liquid, but the ratio of each component is different from the ratio of each component in the first pickling liquid as the reaction continues.

[0076] Step 105, testing the pH value of the second pickling solution, and controlling the pH value of the second pickling solution to be weakly acidic.

[0077] Specifically, a small amount of liquid is taken from the second pickling liquid as a pH test sample liquid for pH test, and the pH value is controlled within a weakly acidic range to avoid re-dissolution of impurities when the pH value is too low and precipitation of zinc compounds when the pH value is too high.

[0078] Step 106: introduce the second pickling solution into the intermediate tank through the second guide pipe and the seventh pipeline in the second pickling tank.

[0079] Specifically, when the volume of liquid in the second pickling tank 19 is greater than the volume of the second pickling tank 19, the replacement reaction occurring during the pickling process has been carried out for a sufficiently long time, and the liquid at the bottom of the second pickling tank 19 first enters the second guide tube 20 through the first end of the second guide tube 20, and enters the intermediate tank 23 from the second end of the second guide tube 20.

[0080] Step 107, pumping the second pickling liquid in the intermediate tank into a filter press through an eighth pipeline for solid-liquid separation to obtain a filtrate and a filter residue, and treating the filtrate and the filter residue.

[0081] Specifically, the intermediate tank 23 is used as a liquid transfer tank, and the second pickling liquid entering the intermediate tank 23 is pumped into the filter press device 26 through the eighth pipeline 25. The filter press device 26 filters the second pickling liquid to achieve solid-liquid separation to obtain filtrate and filter residue. The filtrate and filter residue are processed separately.

[0082] In a possible implementation manner, the processing of the filtrate and the filter residue specifically includes:

[0083] The filtrate obtained by separation is transported to a neutral leaching device to recover zinc in the filtrate; the filter residue is collected at a filter residue collection point to recover the metal in the filter residue.

[0084] Specifically, after the second pickling liquid is filter-filtered to obtain the filtrate and the filter residue, since the filtrate contains a large amount of zinc ions and also contains some solids that are not completely precipitated, the filtrate is transported to the neutral leaching device 28 through the ninth pipeline 27, and precipitated again and subjected to subsequent first-stage purification and second-stage purification processes, and finally introduced into the zinc electrowinning process to recover the zinc ions in the solution. In addition, after the first-stage purification slag and the second-stage purification slag are pulped and pickled, some zinc-containing compounds and zinc elements are dissolved in the solution, and the total amount of filter residue obtained after filter pressing is greatly reduced, which increases the enrichment ratio of valuable metals in the slag and reduces the recovery cost during the recovery process. In the actual production process, after the pickling process is run, the leaching liquid containing Zn 2+ 110-140g / l, 200-300m3 of liquid is sent to the leaching process every day 3 , the amount of zinc metal recovered per day is about 15 tons.

[0085] In a possible implementation, when the ratio of the volume of the mixed liquid in the mixing tank to the volume of the mixing tank is greater than a preset first ratio, the mixed liquid is passed into the first pickling tank, and the electrolytic waste liquid is simultaneously added for pickling.

[0086] Specifically, when the ratio of the total volume of the mixed liquid of the first slurry and the second slurry in the mixing tank 3 to the volume of the mixing tank 3 is greater than the preset first ratio, the mixed liquid is passed into the first pickling tank 14, and the electrolyte is added for pickling at the same time, so as to avoid the need to pass the electrolytic waste liquid every time a small amount of mixed liquid is collected in the mixing tank 3. The whole process cannot be carried out continuously, and the subsequent first pickling tank 14 is intermittently operated, the production is difficult to manage, the equipment is continuously switched on and off, and the management cost of the investment increases. When the volume of the liquid in the mixing tank 3 reaches a certain amount, it is passed into the first pickling tank 14 for pickling. After the first pickling tank 14 is full of liquid, it enters the second pickling tank 19. In the embodiment of the present invention, the preset first ratio is set to 80%, and the volumes of the first pickling tank 14 and the second pickling tank 19 are both 80m 3 , the first pickling tank 14 and the second pickling tank 19 are both operated continuously, and the overall flow rate is controlled, so that the operation process of liquid inlet and liquid outlet for 4-6 hours can be realized, and the reaction time is further guaranteed. Other embodiments can set other ratios or tank volumes and quantities according to actual conditions.

[0087] In a possible implementation, controlling the pH of the second pickling solution to be weakly acidic specifically includes:

[0088] When the pH value of the second pickling liquid is less than the preset first pH value, the opening of the variable frequency pump arranged on the third pipeline is increased, or the opening of the variable frequency pump arranged on the fifth pipeline is reduced;

[0089] When the pH value of the second pickling solution is greater than the preset second pH value, the opening of the variable frequency pump provided on the third pipeline is reduced, or the opening of the variable frequency pump provided on the fifth pipeline is increased;

[0090] When the pH value of the second pickling solution is between the preset first pH value and the preset second pH value, the opening of the variable frequency pump is not adjusted.

[0091] Specifically, the mixed liquid in the mixing tank 3 is neutral. The pH value of the second pickling liquid in the second pickling tank 19 is controlled by the preset first pH value and the preset second pH value. When the pH value of the second pickling liquid is less than the preset first pH value, the opening of the variable frequency pump arranged on the third pipeline 9 is increased, that is, the flow rate of the mixed liquid entering the first pickling tank 14 is increased to increase the pH value of the first pickling liquid in the first pickling tank 14. After the pH value in the first pickling tank 14 increases, it finally enters the second pickling tank 19, and the pH value of the second pickling liquid in the second pickling tank 19 will also increase. Without adjusting the opening of the variable frequency pump arranged on the third pipeline 9, the flow rate of the electrolytic waste liquid entering the first pickling tank 14 can also be reduced by reducing the opening of the variable frequency pump arranged on the fifth pipeline 29.

[0092] When the pH value of the second pickling solution is greater than the preset second pH value, the opening of the variable frequency pump disposed on the third pipeline 9 is reduced to reduce the pH value of the first pickling solution in the first pickling tank 14. Without adjusting the opening of the variable frequency pump disposed on the third pipeline 9, the flow rate of the electrolytic waste liquid entering the first pickling tank 14 can also be increased by increasing the opening of the variable frequency pump disposed on the fifth pipeline 29.

[0093] When the pH value of the second pickling solution is between the preset first pH value and the preset second pH value, the opening of the variable frequency pump is not adjusted.

[0094] In addition to the above adjustment method to control the pH value of the second pickling liquid in the second pickling tank 19, when the pH value of the second pickling liquid is greater than the preset second pH value, the frequency conversion pump arranged on the sixth pipeline 16 can also be directly turned on to allow the acidic electrolytic waste liquid in the electrolytic waste liquid tank 15 to directly enter the second pickling tank, thereby reducing the pH value of the second pickling liquid.

[0095] In a possible implementation manner, the liquid-to-solid mass ratio of the first slurry and the second slurry is 5:1.

[0096] Specifically, the liquid-solid mass ratio of the first slurry and the second slurry is 5:1. When the liquid-solid ratio of the first slurry and the second slurry is less than 5:1, on the one hand, part of the zinc element is exposed to the air, and the activity of part of the elemental zinc cannot be maintained, and the subsequent pickling process and the replacement reaction effect are affected; on the other hand, the slurry has poor fluidity, and it is easy to get blocked during transportation in the pipeline, which affects the continuity of the production process. When the liquid-solid ratio of the first slurry and the second slurry is greater than 5:1, the volume that needs to be processed by the entire treatment system increases, which increases the processing capacity of the treatment system and reduces the treatment efficiency.

[0097] In a possible implementation manner, the preset first pH value is 4.5, and the preset second pH value is 5.0.

[0098] Specifically, in the embodiment of the present invention, the first pH value is preset to be 4.5, and the second pH value is preset to be 5.0.

[0099] When the pH value of the second pickling solution is greater than 5.0, the zinc ions in the solution will be precipitated by water to form zinc hydroxide precipitate, while when the pH value is less than 4.5, other solid metals will also dissolve in the solution in the form of ions.

[0100] Some beneficial effects of the present invention are described below by way of examples.

[0101] Example:

[0102] The first stage purification slag and the second stage purification slag produced in a production shift of hydrometallurgical zinc smelting were taken and divided into two portions, each portion of 8 tons of first stage purification slag and 20 tons of second stage purification slag. The valuable metal content in the first stage purification slag and the second stage purification slag in the first portion was analyzed. The valuable metal content in the filter residue obtained by slurrying and acid washing of the first stage purification slag and the second stage purification slag in the second portion was analyzed, and the results are shown in Table 1:

[0103] Table 1

[0104] name Cu Cd Zn Slag volume One stage purification slag 5-7％ 3-5％ 30-40％ 8 tons Second stage purification slag 0.2-0.4％ 0.5-1％ 35-45％ 20 tons Mixed pickling slag 15-25％ 7-13％ 25-30％ 9 tons

[0105] As can be seen from Table 1, the total slag volume after pickling is reduced by nearly 70% compared with the total slag volume of the first and second stage purification. After the total slag volume is reduced, the enrichment ratio of copper and cadmium is improved. In the subsequent recovery process of copper and cadmium, the difficulty of the recovery process is reduced, the production capacity is improved, the equipment utilization rate is improved, and the labor of workers is reduced.

[0106] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0107] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A slag treatment system, characterized in that: It includes a first slurry tank, a second slurry tank, a mixing tank, a first pickling tank, a second pickling tank, an intermediate tank, and a filter press; The first slurrying tank is used to slurry the first stage purification slag, and the second slurrying tank is used to slurry the second stage purification slag; the liquid outlet of the first slurrying tank is connected to the first liquid inlet located at the top of the mixing tank through a first pipeline, and the liquid outlet of the second slurrying tank is connected to the second liquid inlet located at the top of the mixing tank through a second pipeline; the first stage purification slag is the filter slag in the first stage purification process of the hydrometallurgical zinc smelting process, and the second stage purification slag is the filter slag in the second stage purification process of the hydrometallurgical zinc smelting process; The mixing tank is used to mix the liquid flowing out of the first slurry tank and the liquid flowing out of the second slurry tank; the mixing tank also includes a first liquid outlet located at the bottom of the side, and the first liquid outlet is connected to the third liquid inlet located at the top of the first pickling tank through a third pipe; a first guide pipe is provided in the first pickling tank, and the first guide pipe is connected to the sixth liquid inlet located at the top of the side of the second pickling tank through a fourth pipe; the fourth liquid inlet on the top of the first pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a fifth pipe, and the fifth liquid inlet on the top of the second pickling tank is connected to the liquid outlet of the electrolytic waste liquid tank through a sixth pipe; the electrolytic waste liquid in the electrolytic waste liquid tank is the waste liquid generated by the zinc electrowinning process, which is acidic; The first pickling tank and the second pickling tank are used to mix the electrolytic waste liquid and the liquid flowing out of the mixing tank; A second guide pipe is provided in the second pickling tank, and the second guide pipe is connected to the seventh liquid inlet of the intermediate tank through a seventh pipeline; the second liquid outlet of the intermediate tank is connected to the filter press through an eighth pipeline; the filter press is used to separate the liquid flowing out of the second liquid outlet into solid and liquid to obtain filtrate and filter residue; The filter press equipment is connected to the neutral leaching device through a ninth pipeline, which is used to transport the filtrate obtained by the filter press to the neutral leaching device; The first end of the first flow guide pipe is located in the first pickling tank, and the distance from the bottom of the first pickling tank is less than a preset first distance threshold, and the second end of the first flow guide pipe is located at the top of the outer side of the first pickling tank; The first end of the second flow guide pipe is located in the second pickling tank, and the distance from the bottom of the first pickling tank is less than the first distance threshold. The second end of the second flow guide pipe is located at the top of the outer side of the second pickling tank.

2. A slag treatment system according to claim 1, characterized in that: It also includes a water supply device, which is used to supply water for the slurrying process of the first slurrying tank and the second slurrying tank.

3. A slag treatment system according to claim 1, characterized in that: The first pipeline, the second pipeline, the third pipeline, the fifth pipeline, the sixth pipeline and the eighth pipeline are all provided with variable frequency pumps for providing power for conveying liquid in the pipelines and regulating the flow rate of the liquid in the pipelines.

4. A slag treatment process, characterized in that: Applied to the system according to any one of claims 1 to 3, the method comprises: Adding water to a first slurrying tank containing a first stage of purification slag to obtain a first slurrying liquid, and adding water to a second slurrying tank containing a second stage of purification slag to obtain a second slurrying liquid; the first stage of purification slag is the filter residue in the first stage of purification process of the hydrometallurgical zinc smelting process, and the second stage of purification slag is the filter residue in the second stage of purification process of the hydrometallurgical zinc smelting process; The first slurry is transported to a mixing tank through a first pipeline, and the second slurry is transported to the mixing tank through a second pipeline, and the liquids in the mixing tank are stirred uniformly to obtain a mixed liquid; The mixed liquid is transported to the first pickling tank through the third pipeline, and the electrolytic waste liquid in the electrolytic waste liquid tank is transported to the first pickling tank through the fifth pipeline, and the liquid in the first pickling tank is stirred evenly to obtain a first pickling liquid; Introducing the first pickling liquid into the second pickling tank through the first guide pipe and the fourth pipe in the first pickling tank, and continuing to stir the first pickling liquid to obtain the second pickling liquid; Testing the pH value of the second pickling solution and controlling the pH value of the second pickling solution to be weakly acidic; Introducing the second pickling liquid into the intermediate tank through the second guide pipe and the seventh pipeline in the second pickling tank; Pumping the second pickling liquid in the intermediate tank into a filter press through an eighth pipeline for solid-liquid separation to obtain a filtrate and a filter residue, and treating the filtrate and the filter residue; The liquid-to-solid mass ratio of the first slurry and the second slurry is 5:1; The preset first pH value is 4.5, and the preset second pH value is 5.

0.

5. The process according to claim 4, characterized in that: The processing of the filtrate and the filter residue specifically comprises: The separated filtrate is transported to a neutral leaching device to recover zinc in the filtrate; The filter residue is collected, and the metal in the filter residue is recovered.

6. The process according to claim 4, characterized in that: When the ratio of the volume of the mixed liquid in the mixing tank to the volume of the mixing tank is greater than a preset first ratio, the mixed liquid is passed into the first pickling tank, and the electrolytic waste liquid is added at the same time for pickling.

7. The process according to claim 4, characterized in that: The step of controlling the pH value of the second pickling solution to be weakly acidic specifically includes: When the pH value of the second pickling liquid is less than the preset first pH value, the opening of the variable frequency pump arranged on the third pipeline is increased, or the opening of the variable frequency pump arranged on the fifth pipeline is reduced; When the pH value of the second pickling solution is greater than the preset second pH value, the opening of the variable frequency pump provided on the third pipeline is reduced, or the opening of the variable frequency pump provided on the fifth pipeline is increased; When the pH value of the second pickling solution is between the preset first pH value and the preset second pH value, the opening of the variable frequency pump is not adjusted.

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