Method for removing thallium in zinc sulfate solution

Abstract

The invention belongs to the technical field of zinc hydrometallurgy, and discloses a method for removing thallium in a zinc sulfate solution. The method comprises the following steps: adding the zinc electrolysis anode slime serving as an oxidizing agent into a thallium-containing zinc sulfate solution, stirring for reaction, and removing filter residues through solid-liquid separation to obtain the thallium-removed zinc sulfate solution. According to the method for removing thallium in the zinc sulfate solution, the zinc electrolysis anode slime is used as an oxidizing agent to treat thallium in the zinc sulfate solution, and the zinc electrolysis anode slime with manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide as main components has high oxidability and can achieve the effect of synergistically removing thallium in the zinc sulfate solution. According to the method, the removal rate of thallium can be increased on the premise of not introducing new impurities; and moreover, the by-product zinc electrolysis anode slime of zinc electrolysis can be reasonably utilized, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy of zinc, and in particular relates to a method for removing thallium from a zinc sulfate solution. Background Art

[0002] In the conventional hydrometallurgical zinc smelting process, there are two main sources of thallium in the zinc electrolyte. One is that the thallium in the zinc concentrate enters the neutral leachate after roasting and leaching in the fluidized roasting furnace. The other is that the thallium in the secondary zinc oxide powder produced by the rotary kiln enters the leachate after leaching and finally merges into the roasted sand leaching system. During the roasting process of zinc concentrate, more than 60% of the thallium enters the zinc roasted sand and enters the zinc sulfate solution in the subsequent leaching process. About 50% of the thallium in the secondary zinc oxide powder can be removed in the leaching and iron precipitation process, and the remaining thallium enters the zinc sulfate solution with the solution into the roasted sand leaching. The amount of thallium entering the system varies depending on the amount of secondary zinc oxide powder used in each smelter. When the thallium content in the leachate reaches a certain level, due to its high redox potential, it is difficult to completely purify it even if the zinc powder is greatly excessive during the purification process. When entering the electrolysis, it will precipitate at the cathode and cause serious burning of the plate, that is, a large number of holes appear on the back of the zinc sheet, and the reverse dissolution turns black. Therefore, selectively removing thallium from the electrolyte is of great significance to the stability of electrolytic production.

[0003] Specifically, copper, cadmium, cobalt, and nickel in zinc sulfate solution can be completely removed due to their high precipitation potential and small overpotential, meeting the requirements of electrolytic zinc production. However, thallium is difficult to be completely purified even when zinc powder is greatly excessive, and entering the electrolysis causes serious electrolysis "plate burning", that is, a large number of holes appear on the back of the zinc sheet, making it impossible for the zinc sheet to grow densely and to be smoothly mechanically stripped, which eventually leads to the shutdown of electrolytic production. Therefore, the thallium content needs to be strictly controlled during the purification process of the supernatant in zinc sulfate, and the current thallium removal method is still limited to high-concentration zinc sulfate solution and cannot play a good role.

[0004] At present, although some special thallium removal agents have high thallium removal efficiency, due to their special composition, their use in wet zinc smelting will introduce new impurity ions, such as polymer chelating groups or rare earth elements, which will cause inexplicable burning of the electrolytic plate; at the same time, the thallium removal slag cannot be completely opened and still circulates in the production system, so it has not been promoted and applied in wet zinc smelting industrial production.

[0005] Therefore, there is an urgent need to provide a method for removing thallium from a zinc sulfate system, to improve the removal rate of thallium without introducing new impurities, and to provide an important guarantee for the stable operation of the electrolysis system. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a method for removing thallium from zinc sulfate solution. The method provided by the present invention can improve the removal rate of thallium without introducing new impurities.

[0007] The invention provides a method for removing thallium from a zinc sulfate solution.

[0008] Specifically, a method for removing thallium from a zinc sulfate solution comprises the following steps:

[0009] The zinc electrolysis anode mud is used as an oxidant, added into the zinc sulfate solution containing thallium, and then stirred at 50-90°C for reaction, and then the filter residue is removed by solid-liquid separation to obtain the zinc sulfate solution with thallium removed;

[0010] The thallium-containing zinc sulfate solution is the supernatant in the leaching of zinc roasted sand or the solution after iron removal from zinc oxide powder; the thallium content in the thallium-containing zinc sulfate solution is 5-60 mg / L; and the pH value of the thallium-containing zinc sulfate solution is 3.5-5.5.

[0011] In some embodiments of the present invention, the zinc sulfate solution containing thallium is a solution obtained by leaching and removing iron from zinc oxide powder, that is, a solution obtained by removing iron from the zinc oxide powder leaching solution. Using the solution obtained by leaching and removing iron from zinc oxide powder with a relatively high thallium content can effectively utilize the raw material characteristics of suitable solution temperature and suitable pH, and does not require secondary treatment such as heating and adjusting pH of the raw material, which greatly simplifies the process and can improve the removal rate of thallium.

[0012] In some embodiments of the present invention, the iron content in the solution after leaching and iron removal of the secondary zinc oxide powder is less than 1 g / L.

[0013] In some embodiments of the present invention, the thallium content in the thallium-containing zinc sulfate solution is 20-60 mg / L, such as 20, 25, 30, 35, 40, 45, 50, 55, 60 mg / L.

[0014] In some embodiments of the present invention, the pH value of the zinc sulfate solution containing thallium is 4.5-5.0. By controlling the pH value of the zinc sulfate solution containing thallium, the hydrolysis and precipitation of thallium is facilitated, thereby improving the removal rate of thallium.

[0015] In some embodiments of the present invention, the zinc electrolysis anode mud contains manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0016] In some embodiments of the present invention, the zinc electrolysis anode mud is ground to a particle size of 100-200 mesh and then added to the thallium-containing zinc sulfate solution.

[0017] In some embodiments of the present invention, the mass ratio of the amount of zinc electrolysis anode mud added to the thallium in the thallium-containing zinc sulfate solution is (1-10): (0.005-0.06); preferably, the mass ratio of the amount of zinc electrolysis anode mud added to the thallium in the thallium-containing zinc sulfate solution is (1-10): (0.03-0.06). That is, when the thallium content in the thallium-containing zinc sulfate solution is 5-60 mg / L, 1-10 g / L of zinc electrolysis anode mud is added accordingly.

[0018] In some embodiments of the present invention, the stirring reaction temperature is 60-80°C, and the stirring reaction time is 0.5-2 hours, such as 60, 65, 70, 75, 80°C.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The method for removing thallium from zinc sulfate solution provided by the present invention uses zinc electrolysis anode mud as an oxidant to treat thallium in zinc sulfate solution. The zinc electrolysis anode mud, which mainly contains manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide, has strong oxidizing property and can play a synergistic effect of removing thallium from zinc sulfate solution. The main components of zinc electrolysis anode mud are high-valent compounds of elements such as lead and manganese, and their redox potential is 1.23-1.68V, which is higher than Tl 3+ The potential of Tl + The oxidant can + Oxidized and converted into Tl(OH)3 precipitation; while Pb in lead salt 2+ The ions and thallium can also form a coprecipitated metal alloy or compound to be removed. This method can not only improve the removal rate of thallium without introducing new impurities, but also make reasonable use of the zinc electrolysis anode mud, a byproduct of zinc electrolysis, and reduce production costs.

[0021] (2) The method for removing thallium from zinc sulfate solution provided by the present invention not only expands the thallium removal system of zinc sulfate solution, but also broadens the application of zinc electrolysis anode mud, a by-product of zinc electrolysis, to form an economical and effective thallium removal process, reduce zinc powder consumption, reduce production costs, improve the production control capability of hydrometallurgical zinc smelting plants over thallium, and eliminate the potential risk of zinc electrolysis plate burning caused by thallium. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the XRD pattern of zinc anode mud sample;

[0023] Figure 2 This is the backscattering diagram of the phase distribution characteristics in the zinc anode mud sample embedded with resin;

[0024] Figure 3It is the backscattering diagram of the phase distribution characteristics in the directly dispersed zinc anode mud sample;

[0025] Figure 4 The backscatter diagram of the distribution characteristics of calcium sulfate (1), strontium sulfate (2) and manganese oxide (3) in the zinc anode mud sample;

[0026] Figure 5 for Figure 4 Energy spectrum analysis diagram of calcium sulfate (1);

[0027] Figure 6 for Figure 4 Energy spectrum analysis diagram of strontium sulfate (2) in;

[0028] Figure 7 for Figure 4 Energy spectrum analysis diagram of manganese oxide (3);

[0029] Figure 8 The backscattering diagram of the distribution characteristics of lead sulfate (1), manganese oxide (2), and silicon (3) in zinc anode mud samples;

[0030] Fig. 9 for Figure 8 Energy spectrum analysis diagram of lead sulfate (1) in the medium;

[0031] Fig.10 for Figure 8 Energy spectrum analysis diagram of manganese oxide (2);

[0032] Fig.11 for Figure 8 Energy spectrum analysis diagram of silicon (3). DETAILED DESCRIPTION

[0033] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0034] Unless otherwise specified, the raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0035] XRD and SEM analyses were performed on the zinc electrolysis anode mud used in the examples of the present invention and some comparative examples (Comparative Examples 1-4, 7-8).

[0036] The XRD analysis results of zinc anode mud samples are as follows: Figure 1 According to the analysis results, the phases in the zinc anode mud sample include manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0037] Two methods were used to prepare samples for SEM analysis: 1. The powder samples were embedded in resin, and then the resin was cured, polished, and then carbon was sprayed for SEM analysis; 2. The powder samples were directly dispersed on carbon conductive glue and then carbon was sprayed for SEM analysis. Figure 2 This is the backscattering diagram of the phase distribution characteristics in the zinc anode mud sample embedded with resin; Figure 3 This is the backscattering diagram of the phase distribution characteristics in the directly dispersed zinc anode mud sample. Further energy spectrum analysis of the substances in the sample was performed. Figure 4 The distribution characteristic backscattering diagram of calcium sulfate (1), strontium sulfate (2), and manganese oxide (3) is shown in FIG. Figure 5-Figure 6 Energy spectrum analysis diagrams of calcium sulfate (1), strontium sulfate (2), and manganese oxide (3) respectively; Figure 8 The backscatter diagrams of the distribution characteristics of lead sulfate (1), manganese oxide (2), and silicon (3); Figure 9-11 The energy spectrum analysis diagrams are lead sulfate (1), manganese oxide (2), and silicon (3). Through analysis, it can be seen that the phases in the sample are mainly manganese oxide, calcium sulfate, lead sulfate, strontium sulfate, lead sulfide, and silicon.

[0038] Example 1

[0039] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0040] The following steps are involved:

[0041] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0042] (2) adding 2.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 200 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L of iron, 42.044 mg / L of thallium, and a pH value of 5.0);

[0043] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0044] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining the thallium-removed zinc sulfate solution A1.

[0045] Example 2

[0046] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0047] The following steps are involved:

[0048] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0049] (2) adding 1.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 200 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.6 g / L iron, 26.57 mg / L thallium, and pH 5.0);

[0050] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0051] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining the zinc sulfate solution A2 from which thallium is removed.

[0052] Example 3

[0053] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0054] The following steps are involved:

[0055] (1) Weigh 2.0 g of zinc electrolysis anode mud (2-10 mm);

[0056] (2) adding the zinc electrolysis anode mud weighed in step (1) into 200 mL of zinc oxide powder leaching and iron removal solution (containing 0.8 g / L iron, 42.044 mg / L thallium, and pH 5.0);

[0057] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0058] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining the thallium-removed zinc sulfate solution A3.

[0059] Example 4

[0060] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0061] The following steps are involved:

[0062] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0063] (2) adding 10.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 1000 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L iron, 17.68 mg / L thallium, and pH 5.0);

[0064] (3) Control the temperature to 65°C and stir the reaction for 0.5 hours;

[0065] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining the thallium-removed zinc sulfate solution C1.

[0066] Example 5

[0067] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0068] The following steps are involved:

[0069] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0070] (2) adding 10.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 1000 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L iron, 17.68 mg / L thallium, and pH 5.0);

[0071] (3) Control the temperature to 65°C and stir the reaction for 1.5 hours;

[0072] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a zinc sulfate solution C2 from which thallium has been removed.

[0073] Example 6

[0074] The present embodiment provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0075] The following steps are involved:

[0076] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0077] (2) adding 10.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 1000 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L iron, 17.68 mg / L thallium, and pH 5.0);

[0078] (3) Control the temperature to 65°C and stir the reaction for 2 hours;

[0079] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a zinc sulfate solution C3 from which thallium has been removed.

[0080] Comparative Example 1

[0081] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0082] The following steps are involved:

[0083] (1) Weigh 24.34 g of zinc electrolysis anode mud (2-10 mm);

[0084] (2) adding the zinc electrolysis anode mud weighed in step (1) into 2000 mL of zinc oxide powder leaching and iron removal solution (containing 0.6 g / L iron, 13 mg / L thallium, and pH 5.0);

[0085] (3) Control the temperature to 65°C and stir the reaction for 0.5 hours;

[0086] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution B1.

[0087] Comparative Example 2

[0088] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0089] The following steps are involved:

[0090] (1) Weigh 12.17 g of zinc electrolysis anode mud (2-10 mm);

[0091] (2) adding the zinc electrolysis anode mud weighed in step (1) into 2000 mL of zinc oxide powder leaching and iron removal solution (containing 0.6 g / L iron, 13 mg / L thallium, and pH 5.0);

[0092] (3) Control the temperature to 65°C and stir the reaction for 0.5 hours;

[0093] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution B2.

[0094] Comparative Example 3

[0095] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0096] The following steps are involved:

[0097] (1) Weigh 18.25 g of zinc electrolysis anode mud (2-10 mm);

[0098] (2) adding the zinc electrolysis anode mud weighed in step (1) into 2000 mL of zinc oxide powder leaching and iron removal solution (containing 0.6 g / L iron, 13 mg / L thallium, and pH 5.0);

[0099] (3) Control the temperature to 65°C and stir the reaction for 0.5 hours;

[0100] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution B3.

[0101] Comparative Example 4

[0102] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0103] The following steps are involved:

[0104] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0105] (2) adding 2.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 200 mL of secondary zinc oxide powder leaching solution (without iron removal treatment, iron content of 5 g / L, thallium content of 42.044 mg / L, pH value of 5.0);

[0106] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0107] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution D1.

[0108] Comparative Example 5

[0109] This comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include a zinc oxide powder leached solution after iron removal and an oxidant, wherein the oxidant is 50% MnO2 and 50% lead sulfate.

[0110] The following steps are involved:

[0111] (1) Grind MnO2 and lead sulfate to 100-200 mesh (0.07-0.15 mm);

[0112] (2) adding 2.0 g of the MnO2 and lead sulfate obtained by grinding in step (1) to 200 mL of the zinc oxide powder leaching solution after iron removal (containing 0.8 g / L of iron, 42.044 mg / L of thallium, and pH 5.0);

[0113] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0114] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a zinc sulfate solution D2 from which thallium has been removed.

[0115] Comparative Example 6

[0116] This comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include a zinc oxide powder leached iron removal solution and an oxidant, wherein the oxidant is 50% MnO2 and 50% calcium sulfate.

[0117] The following steps are involved:

[0118] (1) Grind MnO2 and calcium sulfate to 100-200 mesh (0.07-0.15 mm);

[0119] (2) adding 2.0 g of the MnO2 and calcium sulfate obtained by grinding in step (1) to 200 mL of the zinc oxide powder leaching solution after iron removal (containing 0.8 g / L of iron, 42.044 mg / L of thallium, and pH 5.0);

[0120] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0121] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a zinc sulfate solution D3 from which thallium has been removed.

[0122] Comparative Example 7

[0123] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0124] The following steps are involved:

[0125] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0126] (2) adding 2.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 200 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L of iron, 42.044 mg / L of thallium, and a pH value of 2.5);

[0127] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0128] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution D4.

[0129] Comparative Example 8

[0130] The comparative example provides a method for removing thallium from a zinc sulfate solution. The raw materials include zinc oxide powder leaching solution after iron removal and zinc electrolysis anode mud. The zinc electrolysis anode mud includes manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

[0131] The following steps are involved:

[0132] (1) Grinding zinc electrolysis anode mud to 100-200 mesh (0.07-0.15mm);

[0133] (2) adding 2.0 g of the zinc electrolysis anode mud obtained by grinding in step (1) into 200 mL of the secondary zinc oxide powder leaching and iron removal solution (containing 0.8 g / L of iron, 42.044 mg / L of thallium, and a pH value of 6.0);

[0134] (3) Control the temperature to 65°C and stir the reaction for 1 hour;

[0135] (4) After the stirring reaction is completed, liquid-solid separation is performed to remove the filter residue, thereby achieving efficient thallium removal and obtaining a thallium-removed zinc sulfate solution D5.

[0136] Product effect testing

[0137] Take the zinc sulfate solution (thallium removal filtrate) obtained in the embodiments and comparative examples in equal amounts for chemical analysis, measure the thallium content, and calculate the thallium removal rate (i.e., the Tl removal rate). The test results are shown in Tables 1 to 4.

[0138] Table 1

[0139]

[0140] Table 2

[0141]

[0142] Table 3

[0143]

[0144] Table 4

[0145]

[0146] It can be seen from the data of Examples 1-6 and Tables 1 and 2 of the present invention that the method for removing thallium from zinc sulfate solution provided by the present invention has a very good thallium removal effect, and the thallium removal rate reaches 98.53%, and the thallium removal rate can reach 98.48% in the case of half an hour of treatment. The method does not introduce new impurities, has high removal efficiency, good removal effect, is suitable for promotion and application in the field of hydrometallurgy containing thallium, is of great significance to the elimination of zinc electrolysis scorching plate, and has broad development prospects. It can be seen from Table 2 that by controlling the particle size of zinc electrolysis anode mud, under the condition of grinding, efficient thallium removal can be achieved in a very short time, and the thallium removal efficiency is as high as more than 96%, and the thallium removal efficiency is improved less by extending the reaction time. It can be seen from Comparative Examples 1-3 and Table 3 that when the particle size of zinc electrolysis anode mud is too large and the stirring reaction time is insufficient, the thallium removal efficiency will be significantly reduced.

[0147] It can be seen from Comparative Examples 4-8 and Table 4 that when the zinc oxide powder leaching solution is not subjected to iron removal treatment, its iron content is high, which will seriously affect the thallium removal effect, and the Tl removal rate is only 61.18%. When the components MnO2 and calcium sulfate, or MnO2 and lead sulfate in the zinc electrolysis anode mud are used to replace the zinc electrolysis anode mud, the thallium removal efficiency will also be significantly reduced. When the pH value of the solution after the zinc oxide powder leaching and iron removal is not in the range of 3.5-5.5, the thallium removal efficiency will also be significantly affected.

[0148] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for removing thallium from a zinc sulfate solution, characterized in that: The following steps are involved: The zinc electrolysis anode mud is used as an oxidant, added into the zinc sulfate solution containing thallium, and then stirred at 50-90°C for reaction, and then the filter residue is removed by solid-liquid separation to obtain the zinc sulfate solution with thallium removed; The thallium-containing zinc sulfate solution is the supernatant in the leaching of zinc roasted sand or the solution after iron removal from zinc oxide powder leaching; the thallium content in the thallium-containing zinc sulfate solution is 5-60 mg / L; and the pH value of the thallium-containing zinc sulfate solution is 3.5-5.

0.

2. The method according to claim 1, characterized in that The iron content in the solution after the secondary zinc oxide powder is leached and iron is removed is less than 1 g / L.

3. The method according to claim 1 or 2, characterized in that: The thallium content in the thallium-containing zinc sulfate solution is 20-60 mg / L.

4. The method according to claim 3, characterized in that The pH value of the thallium-containing zinc sulfate solution is 4.5-5.

0.

5. The method according to claim 1, characterized in that The zinc electrolysis anode mud contains manganese oxide, calcium sulfate, strontium sulfate, lead sulfate and lead sulfide.

6. The method according to claim 5, characterized in that The zinc electrolysis anode mud is ground to a particle size of 100-200 meshes and then added into the thallium-containing zinc sulfate solution.

7. The method according to claim 5 or 6, characterized in that: The mass ratio of the added amount of the zinc electrolysis anode mud to the thallium in the thallium-containing zinc sulfate solution is (1-10): (0.005-0.06).

8. The method according to claim 7, characterized in that The mass ratio of the added amount of the zinc electrolysis anode mud to the thallium in the thallium-containing zinc sulfate solution is (1-10): (0.03-0.06).

9. The method according to claim 1, characterized in that: The stirring reaction temperature is 60-80° C., and the stirring reaction time is 0.5-2 hours.

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