Method for purifying copper electrolyte by using bagging type antimony-based adsorbent

Abstract

The invention provides a method for purifying a copper electrolyte by using a bagging type antimony-based adsorbent, which specifically comprises the following steps: taking an antimony oxide as an adsorbent, taking a flexible grid type material as a protective sleeve, throwing the bagging type adsorbent into the copper electrolyte containing arsenic, antimony and bismuth, and after reacting for a period of time, taking out the bagging type adsorbent, washing and drying. And roasting to remove arsenic, condensing the arsenic-containing flue gas to obtain solid arsenic trioxide, and directly returning arsenic-removed slag as a new adsorbent to the copper electrolysis adsorption unit for purification and impurity removal. The method is simple in process and convenient to operate, physical and mechanical loss caused by strong dispersity of the antimony-based adsorbent can be remarkably reduced or avoided, a filtering unit is not needed, the use amount of washing water is reduced, the pyrogenic process regeneration process can effectively replace an acid process or alkaline process scheme, and the purification efficiency of the regenerated adsorbent on the copper electrolyte is equivalent to the effect of an initial adsorbent.

Description

Technical Field

[0001] The present invention relates to the field of hydrometallurgy, and particularly to a method for purifying copper electrolyte with a bagged antimony-based adsorbent. Background Art

[0002] During the copper electrolytic refining process, under the action of direct current, anode copper and metals with a potential more negative than copper (such as Ni, Fe, Pb, Zn, etc.) and elements with a potential close to copper (such as As, Sb, Bi) undergo electrochemical dissolution and enter the electrolyte, resulting in an excessive content of impurity ions in the electrolyte. Among them, the contents of As, Sb, and Bi with a potential close to copper pose the greatest threat to the quality of cathode copper. The "floating anode slime" formed by different valence states of As, Sb, and Bi in the electrolyte is easily adhered to or mechanically included in the cathode copper, resulting in an uneven cathode surface, rough crystallization, and deep stripes. At the same time, it will also greatly affect the current efficiency and the output of cathode copper. In order to maintain the normal progress of the electrolysis process, it is necessary to purify and adjust the electrolyte.

[0003] The electrowinning method for copper and impurity removal is a traditional copper electrolyte purification technology. As the electrolysis process progresses, when the copper ion concentration decreases to a certain value, impurity ions will precipitate on the cathode, and at the same time, highly toxic AsH3 gas is generated. The continuous induced copper and arsenic removal method is the most widely used purification technology in the industry at present. This method is more suitable for treating electrolytes with high contents of As, Sb, and Bi (the solution after copper sulfate crystallization), but this method has high energy consumption and low electrical energy utilization rate, and the produced black copper powder still needs to find a more economical and reasonable method for separating As.

[0004] Other methods for assisting copper electrolysis purification and impurity removal include: precipitation method, adsorption method, solvent extraction method, ion exchange method, etc. The above-mentioned impurity removal methods have single effects, high production costs, large subsequent treatment amounts of precipitates, cannot be recycled, and some even introduce new impurity ions, which greatly restricts the industrial application of the precipitation method for purifying electrolytes.

[0005] The copper electrolysis self-purification technology is a new purification technology proposed by utilizing the fact that As, Sb, and Bi in the solution can undergo coprecipitation reactions under certain conditions to form precipitates with very low solubility (such as SbAsO4, BiAsO4, AsSbO4, and BiSbO4) and enter the anode slime, including arsenate systems, arsenantimonate systems, and antimonate systems. The self-purification technology has high impurity removal efficiency and low energy consumption, and has certain industrial application prospects.

[0006] Chinese Patent CN104060295A discloses a method for purifying copper electrolyte by adsorption and impurity removal, and CN 107385471A discloses a method for arsenic removal and efficient open circuit of copper electrolysis waste liquid. In the above two methods, however, the loaded adsorbent is regenerated with alkali solutions such as NaOH and KOH, resulting in high alkali consumption and no consideration of the resource utilization of antimony and bismuth in the loaded adsorbent.

[0007] Chinese Patent CN117585711A discloses a green purification agent for copper electrolyte and its synthesis method; it discloses a method for synthesizing an antimony-based adsorbent from antimony pentoxide and antimony sulfate to remove arsenic, antimony, and bismuth in the electrolyte. However, the loaded adsorbent still needs to be regenerated by hydrolysis with sodium hydroxide, resulting in high alkali consumption and no consideration of the utilization of adsorbed antimony and bismuth resources.

[0008] Chinese Patent CN109055775A discloses a regeneration method for a complexing precipitant for purifying copper electrolyte; it discloses using antimony oxide as an adsorbent, BaSO4 and PbSO4 as precipitants for copper electrolyte purification. The deactivated adsorbent is separated by pickling, the filtrate is hydrolyzed, and the hydrolysis residue is regenerated by alkali washing to obtain a regenerated complexing adsorbent. The reagent consumption is large and the cost is high during the regeneration process, and the resource utilization of arsenic, antimony, and bismuth is not realized.

[0009] Chinese Patent CN109628953A discloses a method for removing arsenic, antimony, and bismuth in copper electrolyte. It discloses a method for adding transition-state antimony oxide to copper electrolyte to remove arsenic, antimony, and bismuth in the electrolyte. A large amount of hydrochloric acid and chlorine are required during the use process, and the recovery of arsenic is not concerned. The reagent consumption is large and the cost is high during the regeneration process, and the resource utilization of arsenic, antimony, and bismuth is not realized.

[0010] In summary, in the existing methods for removing arsenic, antimony, and bismuth in the electrolyte with antimony-based adsorbents, a large amount of liquid alkali or hydrochloric acid is required for regeneration and hydrolysis. The reagent cost is high and the hydrolysis conditions are harsh. In addition, since antimony oxide is an amphoteric compound, it is easy to form a colloid in acid solution. Especially, antimony pentoxide has a large solubility in strong acid and strong alkali environments, and there is a risk of redissolution during the processes of filtration and separation. Moreover, the antimony-based adsorbent needs to be pre-adjusted to a slurry material with water before impurity removal. The antimony oxide particles are small and have strong dispersibility, and physical and mechanical entrainment is likely to occur during the electrolyte purification process, resulting in additional loss of the adsorbent. The above problems have become one of the key problems restricting the application of antimony-based adsorbents in copper electrolyte purification. Summary of the Invention

[0011] The object of the present invention is to provide a method for purifying copper electrolyte with a bagged antimony-based adsorbent in view of the problems and deficiencies existing in the existing antimony-based adsorbents for removing impurities in copper electrolyte, such as small antimony oxide particles, strong dispersibility, high alkali consumption, large water consumption, and redissolution of high-valence antimony oxide in the hydrolysis process. Specifically, the object of the present invention has the following three points:

[0012] The first object of the present invention is to provide a method for purifying copper electrolyte with a bagged antimony-based adsorbent, which reduces or avoids the physical and mechanical loss of the antimony-based adsorbent caused by small particles and strong dispersibility, removes the filtration unit, and significantly reduces the water consumption for washing.

[0013] The second object of the present invention is to provide a pyrometallurgical regeneration method for a loaded adsorbent: to solve the problems of long process flows in the hydrometallurgical method including the acid method and the alkali method, and incomplete separation of arsenic, antimony, and bismuth. Pyrometallurgical roasting is used to remove arsenic, and solid arsenic trioxide is obtained after the arsenic-containing flue gas is condensed.

[0014] The third object of the present invention is to provide a method for the resource utilization of antimony and bismuth: it is judged whether to perform pyrolysis to obtain low-valent antimony oxide by the proportion of Sb(V) in the arsenic-removing slag to [Sb], and the pyrolysis product can be returned to the copper electrolyte adsorption unit for purification and impurity removal. T The content is used to judge whether to perform pyrolysis to obtain low-valent antimony oxide, and the pyrolysis product can be returned to the copper electrolyte adsorption unit for purification and impurity removal.

[0015] The object of the present invention is achieved in the following way: a method for purifying copper electrolyte with a bagged antimony-based adsorbent, comprising the following steps:

[0016] S1: Preparation of the loaded adsorbent. A flexible grid material with a porosity of 1-40 μm is used as a protective sleeve, and antimony oxide is filled in the protective sleeve as an adsorbent to construct a bagged antimony-based loaded adsorbent.

[0017] S2: Add the loaded adsorbent to the copper electrolytic acidic solution containing arsenic, antimony, and bismuth. After heating and stirring the copper electrolytic acidic solution for a period of time, take out the loaded adsorbent.

[0018] S3: Separate the protective sleeve and the adsorbent of the loaded adsorbent taken out in S2. After washing and drying the adsorbent, the dried adsorbent is subjected to arsenic removal treatment by oxidative roasting. After the arsenic-containing flue gas is condensed with oxygen, a solid arsenic trioxide product is obtained, and the remaining product after roasting is arsenic-removing slag.

[0019] S4: Perform secondary heating pyrolysis on the arsenic-removing slag in S3 to decompose the high-valent antimony oxide in the arsenic-removing slag into low-valent antimony oxide.

[0020] S5: Use the low-valent antimony oxide of the pyrolysis product in S4 as a regenerated adsorbent, and refill the regenerated adsorbent into the protective sleeve in S1 to form a loaded adsorbent for secondary adsorption of the copper electrolytic acidic solution.

[0021] Furthermore, the molar ratio between pentavalent antimony and trivalent antimony in the antimony oxide in S1 and the low-valent antimony oxide in S4 is 0-0.1:1. Specifically, the antimony oxide here is a mixture of antimony trioxide and antimony pentoxide.

[0022] Furthermore, the flexible material in step S1 is one of polytetrafluoroethylene, PFA plastic, phenolic vinyl resin, and silicone monomer resin. It should be noted that the aperture of the protective sleeve is determined according to the actual size of the adsorbent, aiming to wrap the adsorbent and prevent the loss of adsorbent particles due to dispersion problems. If analytical pure antimony oxide is used, the aperture of the bag is relatively small. If the adsorbent is pre-aggregated, the aperture of the protective sleeve can be appropriately increased.

[0023] Further, the addition amount of the adsorbent in step S2 is determined according to the arsenic content in the acidic copper electrolysis solution and the antimony content of the adsorbent, wherein the molar ratio of the arsenic content to the antimony content is 1:0.6 - 1.

[0024] Further, in step S2, the reaction temperature is 30 - 80°C, the reaction time is 30 - 120 min, and the stirring rate is 100 rpm - 400 rpm.

[0025] Further, the temperature of the oxidative roasting in step S3 is 600 - 900°C, and the roasting time is 1 - 4 h.

[0026] Further, in step S4, the temperature of the thermal pyrolysis during heating-up is 950 - 1200°C, the atmosphere is an inert atmosphere, and the heating time is 30 - 120 min.

[0027] Optionally, the gas used for the inert atmosphere is argon, helium, or nitrogen.

[0028] Optionally, it further includes S3.5: determining whether the proportion of Sb(V) in the arsenic-removed slag in the [Sb] T content is less than 10%. If the proportion of Sb(V) in the arsenic-removed slag in the [Sb] T content is less than 10%, it is directly refilled as an adsorbent into the protective sleeve of S1 to form a loaded adsorbent for secondary adsorption of the acidic copper electrolysis solution; if the proportion of Sb(V) in the arsenic-removed slag in the [Sb] T content is not less than 10%, then S4 is carried out.

[0029] It should be noted that the proportion of Sb(V) in the arsenic-removed slag in the [Sb] T content can be confirmed by chemical titration after the arsenic-removed slag is leached and dissolved with acid. In addition, the reason for determining the proportion of Sb(V) in the arsenic-removed slag in the [Sb] T content is mainly to consider carrying out the thermal pyrolysis treatment by heating. During the pyrolysis process, pentavalent antimony oxide can be decomposed into trivalent antimony oxide. Since the solubility of the high-valent antimony oxide is high and it is easy to cause the dissolution and loss of the adsorbent, whether to carry out the thermal pyrolysis operation is judged according to the proportion of Sb(V) in the system.

[0030] The present invention has the following advantages:

[0031] (1) The present invention uses a polytetrafluoroethylene flexible material as a protective sleeve and fills it with an antimony oxide adsorbent to construct a bag-type antimony-based adsorbent. The preparation method is simple and easy to scale up for mass production. The bag-type adsorbent is placed in a copper electrolyte containing arsenic, antimony, and bismuth. After reacting for a period of time, the adsorbent is rinsed and dried for regeneration of the loaded adsorbent. The bag-type antimony-based adsorbent can effectively avoid or reduce the physical and mechanical losses caused by the strong dispersibility of antimony oxide, remove the filtration unit, and significantly reduce the amount of washing water used. It solves the problems that antimony oxide has small particle size, strong dispersibility, and is prone to mechanical entrainment losses; effectively avoids the situation of large acid / alkali consumption, large washing water consumption, and generation of industrial wastewater during the wet desorption regeneration process; and also solves the problem that since antimony oxide is an amphoteric oxide, there is a risk of redissolution of antimony oxide, especially high-valent antimony oxide, in strong acidic solutions such as improper operation and too long filtration time.

[0032] (2) The loaded adsorption slag is calcined once by a pyrometallurgical process, and arsenic trioxide is obtained after the arsenic-containing flue gas is condensed. The pyrometallurgical impurity removal technology can effectively solve the problems of large reagent consumption, long process flow, and incomplete separation of arsenic, antimony, and bismuth in the wet process, and no industrial wastewater is generated.

[0033] (3) Whether to pyrolyze to obtain low-valent antimony oxide is judged by the proportion of Sb(V) in the arsenic removal slag in the [Sb] T content. The pyrolysis products are mainly low-valent antimony oxide and bismuth oxide. The above two phases can be applied to the self-purification of copper electrolyte and can be returned to the copper electrolyte adsorption unit for cyclic purification and impurity removal. In this way, there is no need for in-depth separation of antimony and bismuth, and both antimony oxide and bismuth oxide are integrated into the self-purification system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a process flow chart. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are given below for detailed description. Unless otherwise specified, the methods of the present invention are conventional methods in the art.

[0036] Example 1

[0037] Use polytetrafluoroethylene flexible material as the protective sleeve with a porosity of 1 μm for the protective sleeve. Add Sb2O5 and Sb2O3 into the protective outer sleeve according to a molar ratio of 0:1. Take 1 L of copper electrolytic refining electrolyte, add stibium-based adsorbent according to a molar ratio of Sb / As of 0.6:1, stir and react at 30 °C for 30 min with a stirring rate of 100 rpm. After completion, take out the loaded adsorbent, wash and dry it, then oxidize and roast it at 600 °C for 2 h. After the flue gas is condensed, arsenic trioxide is obtained, and the arsenic-removing slag is used for pyrolysis at elevated temperature. The pyrolysis product can be directly returned to the copper electrode liquid purification unit for reuse. The removal rates of arsenic, antimony, and bismuth in the electrolyte in the above process are 81%, 88%, and 90% respectively. The content of Sb(V) in the arsenic-removing slag accounts for [Sb] T is less than 10%, and it can be directly returned to the copper electrolysis purification system for secondary adsorption and impurity removal without pyrolysis. The removal rates of arsenic, antimony, and bismuth in the electrolyte are 85%, 90.5%, and 92.1% respectively.

[0038] Table 1. The composition of the electrolyte used in Example 1 is as follows

[0039]

[0040] Example 2

[0041] Use PFA plastic flexible material as the protective sleeve with a porosity of 40 μm for the protective sleeve. Add Sb2O5 and Sb2O3 into the protective outer sleeve according to a molar ratio of 0.1:1. Take 1 L of copper electrolytic refining electrolyte, add stibium-based adsorbent according to a molar ratio of Sb / As of 1:1, stir and react at 80 °C for 120 min with a stirring rate of 400 rpm. After completion, take out the loaded adsorbent, wash and dry it, then oxidize and roast it at 800 °C for 90 min. After the flue gas is condensed, arsenic trioxide is obtained, and the arsenic-removing slag is used for pyrolysis at elevated temperature. The pyrolysis product can be directly returned to the copper electrode liquid purification unit for reuse. The removal rates of arsenic, antimony, and bismuth in the electrolyte in the above process are 83%, 89.5%, and 95% respectively. The content of Sb(V) in the arsenic-removing slag accounts for [Sb] T is greater than 10%, and pyrolysis is required. The pyrolysis temperature is 1200 °C and the pyrolysis time is 120 min. The removal rates of arsenic, antimony, and bismuth in the copper electrolyte purified by the pyrolysis product are decomposed into 90.3%, 92.5%, and 99.2% respectively.

[0042] Table 2. The composition of the electrolyte used in Example 2 is as follows:

[0043]

[0044] Example 3

[0045] Use phenolic vinyl resin flexible material as the protective sleeve with a porosity of 20 μm for the protective sleeve. Add Sb2O5 and Sb2O3 into the protective outer sleeve according to the molar ratio of 0.05:1. Take 1 L of copper electrolytic refining electrolyte, add the antimony-based adsorbent according to the molar ratio of Sb / As of 0.8:1, stir and react at 60 °C for 60 min with a stirring rate of 300 rpm. After completion, take out the loaded adsorbent, wash and dry it, then oxidize and roast it at 700 °C for 120 min. After the flue gas is condensed, arsenic trioxide is obtained, and the arsenic-removing slag is used for temperature-raising pyrolysis. The pyrolysis product can be directly returned to the copper electrode liquid purification unit for repeated use. The removal rates of arsenic, antimony, and bismuth in the electrolyte in the above process are 88%, 90.5%, and 97.2% respectively. The content of Sb(V) in the arsenic-removing slag accounts for [Sb] T is greater than 10%, and pyrolysis is required. The pyrolysis temperature is 1100 °C and the pyrolysis time is 90 min. The removal rates of arsenic, antimony, and bismuth in the copper electrolyte purified by the pyrolysis product are decomposed into 92.3%, 93.5%, and 99.5%.

[0046] Table 3. The composition of the electrolyte used in Example 3 is as follows:

[0047]

[0048] Example 4

[0049] Use silicone monomer resin flexible material as the protective sleeve with a porosity of 10 μm for the protective sleeve. Add Sb2O5 and Sb2O3 into the protective outer sleeve according to the molar ratio of 0.01:1. Take 1 L of copper electrolytic refining electrolyte, add the antimony-based adsorbent according to the molar ratio of Sb / As of 0.9:1, stir and react at 40 °C for 60 min with a stirring rate of 200 rpm. After completion, take out the loaded adsorbent, wash and dry it, then oxidize and roast it at 800 °C for 60 min. After the flue gas is condensed, arsenic trioxide is obtained, and the arsenic-removing slag is used for temperature-raising pyrolysis. The pyrolysis product can be directly returned to the copper electrode liquid purification unit for repeated use. The removal rates of arsenic, antimony, and bismuth in the electrolyte in the above process are 82.5%, 88.5%, and 91.4% respectively. The content of Sb(V) in the arsenic-removing slag accounts for [Sb] T is greater than 10%, and pyrolysis is required. The pyrolysis temperature is 950 °C and the pyrolysis time is 60 min. The removal rates of arsenic, antimony, and bismuth in the copper electrolyte purified by the pyrolysis product are decomposed into 85.3%, 90.5%, and 94.2%.

[0050] Table 4. The composition of the electrolyte used in Example 4 is as follows:

[0051]

[0052] It can be clearly seen from the corresponding tables of the above Examples 1 to 4 that the method of the present invention has excellent use effects for removing arsenic, antimony, and bismuth in copper electrolyte. In addition, the pyrometallurgical regeneration process can effectively replace the acid method or the alkali method, and the regeneration adsorbent has a purification efficiency for copper electrolyte equivalent to that of the initial adsorbent. At the same time, a protective sleeve is used to wrap the adsorbent, thus solving the problem that the antimony oxide has small particle size, strong dispersibility, and is prone to mechanical entrainment loss.

Claims

1. A method for purifying copper electrolyte using a bagged antimony-based adsorbent, characterized in that: The following steps are involved: S1: Preparation of a loaded adsorbent, using a flexible mesh material with a porosity of 1-40 μm as a protective cover, and filling the protective cover with antimony oxide as an adsorbent to construct a bagged antimony-based loaded adsorbent; S2: adding the loaded adsorbent to the copper electrolytic acidic solution containing arsenic, antimony and bismuth, heating the copper electrolytic acidic solution and stirring it for a period of time, and then taking out the loaded adsorbent; S3: separating the protective cover and the adsorbent from the loaded adsorbent taken out in S2, washing and drying the adsorbent, and then removing arsenic from the dried adsorbent by oxidative roasting, condensing the oxygen in the arsenic-containing flue gas to obtain a solid arsenic trioxide product, and the remaining product after roasting is the arsenic removal slag; S4: subjecting the dearsenicating slag of S3 to secondary pyrolysis to decompose the high-valent antimony oxides in the dearsenicating slag into low-valent antimony oxides; S5: The low-valent antimony oxide produced by the pyrolysis in S4 is used as a regenerated adsorbent, and the regenerated adsorbent is refilled into the protective sleeve to form a loaded adsorbent for secondary adsorption of copper electrolysis acidic solution.

2. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: The molar ratio between pentavalent antimony and trivalent antimony in the antimony oxide of S1 and the low-valent antimony oxide of S4 is 0 to 0.1:

1.

3. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: The flexible material in step S1 is made of one of polytetrafluoroethylene, PFA plastic, phenolic vinyl resin and silicone monomer resin.

4. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: The amount of adsorbent added in step S2 is determined according to the arsenic content in the copper electrolysis acidic solution and the antimony content of the adsorbent, wherein the molar ratio of the arsenic content to the antimony content is 1:0.6-1.

5. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: In step S2, the reaction temperature is 30-80°C, the reaction time is 30-120 min, and the stirring rate is 100 rpm-400 rpm.

6. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: The oxidation roasting temperature in step S3 is 600-900° C. and the roasting time is 1-4 hours.

7. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 1, characterized in that: In step S4, the pyrolysis temperature is raised to 950-1200° C., the atmosphere is an inert atmosphere, and the heating time is 30-120 min.

8. The method for purifying copper electrolyte by using a bagged antimony-based adsorbent according to claim 7, characterized in that: The gas used in the inert atmosphere is argon, helium or nitrogen.

9. A method for purifying copper electrolyte with a bagged antimony-based adsorbent according to any one of claims 1 to 8, characterized in that: Also includes S3.5: Determination of arsenic removal slag Sb(V) accounts for [Sb] T Is the content less than 10%? If Sb(V) accounts for [Sb] T If the content is less than 10%, it is directly refilled into the protective cover of S1 as an adsorbent to form a loaded adsorbent for secondary adsorption of copper electrolysis acidic solution; if Sb(V) in the dearsenicating slag accounts for [Sb] T If the content is not less than 10%, proceed to S4.

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