Method for improving settling performance of hematite zinc hydrometallurgy low-acid leaching ore pulp

Abstract

The invention discloses a method for improving the settling performance of hematite zinc hydrometallurgy low-acid leaching ore pulp, and the method comprises the steps that hematite iron-removed liquid and calcine are mixed to obtain treatment liquid with the pH value of 4-4.5, and the concentration of Fe < 3 + > in the treatment liquid is smaller than 1 g / L; adjusting the pH value of the treating fluid to enable the pH value of the treating fluid to be less than 2, and reacting to obtain ore pulp with the pH value of 2.5-3.5; the ore pulp is subjected to solid-liquid separation treatment to obtain supernate, the supernate comprises Zn < 2 + >, and the concentration of Fe < 3 + > in the supernate is smaller than 0.1 g / L. Therefore, by means of the method, the sedimentation performance of the ore pulp can be improved, the leaching rate of the calcine is increased, and the supernatant which is good in sedimentation and relatively pure is obtained.

Description

Technical Field

[0001] The present application relates to the field of metallurgical technology, and in particular to a method for improving the sedimentation performance of low-acid leaching slurry in hematite hydrometallurgy of zinc. Background Art

[0002] Hydrometallurgy refers to the process of dissolving zinc from zinc roasted ore or other zinc sulfide concentrates in a sulfuric acid solution to extract metallic zinc or zinc compounds. However, a large amount of waste slag is produced during the hydrometallurgy process. Currently, the waste slag is mainly treated by slag storage, which not only pollutes the environment, but also causes the loss of valuable metals such as zinc in the waste slag. Therefore, it is necessary to recycle and reuse the waste slag.

[0003] It should be noted that the above statements are only used to provide background technical information related to the present application and do not necessarily constitute prior art. Summary of the invention

[0004] In the first aspect of the present application, the present application provides a method for improving the sedimentation performance of low-acid leaching pulp of hematite hydrometallurgy, comprising: mixing the iron-removed liquid and roasted sand to obtain a treatment liquid with a pH of 4-4.5, wherein the Fe 3+ The concentration of Zn is less than 1 g / L; the pH of the treatment solution is adjusted to make the pH of the treatment solution less than 2, and the reaction is performed to obtain a slurry with a pH of 2.5-3.5; the slurry is subjected to solid-liquid separation to obtain a supernatant, wherein the supernatant includes Zn 2+ , Fe in the supernatant 3+ The concentration of H in the iron removal solution is less than 0.1 g / L. + , until the pH of the treated liquid reaches 4-4.5, the Fe in the liquid after iron removal 3+ Rapidly transform into iron hydroxide precipitation; then adjust the pH of the treatment solution to make the pH of the treatment solution less than 2.0, and at the same time, Fe 3+ The concentration is less than 1g / L, which meets the formation conditions of goethite. The generated iron hydroxide precipitate slowly reacts to become Fe 3+ At the same time, Fe 3+ The reaction generates goethite precipitation; compared with iron hydroxide precipitation, goethite is a larger particle precipitate, and large particle precipitates can improve the sedimentation ability of the slurry. Therefore, the method of the present application can improve the sedimentation performance of the slurry and increase the roasted sand leaching rate to obtain a well-settled and relatively pure supernatant.

[0005] In some embodiments, the roasted sand includes at least one of ZnO and ZnS. Thus, the ZnO and / or ZnS in the roasted sand can consume H in the iron removal solution. + , which in turn promotes Fe 3+and Al 3+ It is transformed into iron hydroxide precipitate and aluminum hydroxide precipitate. At the same time, the zinc element in the roasted sand is free Zn 2+ The calcined sand can be leached into the treatment liquid in the form of , so as to realize the reuse of the calcined sand.

[0006] In some embodiments, the roasted sand further comprises at least one of Fe2O3 and CuO. Thus, Fe2O3 and / or CuO can further consume H in the iron removal solution. + .

[0007] In some embodiments, the adjusting the pH of the treatment solution comprises: adding an acidic solution to the treatment solution; wherein the acidic solution comprises H2SO4, wherein the concentration of H2SO4 in the acidic solution is 120 g / L-180 g / L; and / or the acidic solution comprises waste electrolyte produced by hydrometallurgical zinc electrowinning. Thus, the waste produced in the hydrometallurgical zinc process can be reused, thereby reducing environmental pollution.

[0008] In some embodiments, the reaction to obtain a slurry with a pH of 2.5-3.5 includes sequentially obtaining a slurry with a pH of 2.5-2.8, a slurry with a pH of 2.8-3.0, and a slurry with a pH of 3.0-3.5. Thus, the segmented continuous reaction process facilitates the operator to monitor and adjust the entire reaction process to cope with fluctuations in the production process and promote stable reaction.

[0009] In some embodiments, the iron-removing solution includes Fe 3+ , H2SO4 and Zn 2+ , the Fe in the liquid after iron removal 3+ The concentration of H2SO4 in the deironing solution is 5g / L-10g / L, the concentration of Zn in the deironing solution is 40g / L-60g / L, 2+ The concentration of Fe in the iron removal solution is 60g / L-90g / L. 3+ The concentration is high, and it is necessary to remove the impurity ions in the iron removal liquid to obtain a purer Zn-containing 2+ of the extract.

[0010] In some embodiments, the iron removal solution further comprises Al 3+ , the Al in the liquid after iron removal 3+ The concentration of Al is 0.5g / L-2g / L. 3+ At a pH of 3.3, it begins to hydrolyze into aluminum hydroxide colloid, which has a serious impact on the sedimentation performance of the slurry. If the pH of the end point of the goethite reaction is controlled to be 3.0-3.5, Al 3+The hydrolysis is incomplete, which will seriously affect the sedimentation performance of the slurry. Therefore, in the mixing process of the iron removal liquid and roasted sand, the pH of the treated liquid is first controlled to be 4-4.5, so that the Al in the solution 3+ All of them are hydrolyzed into aluminum hydroxide precipitate, which is difficult to dissolve in the subsequent acidity reduction process. 3+ It is difficult to re-enter the reaction system, thereby reducing Al 3+ Effect on slurry settling properties.

[0011] In some embodiments, the supernatant satisfies at least one of the following conditions: the pH of the supernatant is 3-3.5; the Zn in the supernatant is 2+ The concentration of Zn in the iron removal solution is 100g / L-120g / L. 2+ Compared with the concentration of Zn 2+ concentration, thereby improving the recovery rate of zinc element.

[0012] In some embodiments, the slurry is subjected to solid-liquid separation to obtain an underflow slurry; the underflow slurry includes goethite. 3+ It can be converted into large-particle goethite precipitation, thereby improving the sedimentation capacity of the slurry and facilitating Fe 3+ The reaction system was separated.

[0013] In some embodiments, 10% to 30% of the supernatant by weight is added to the step of mixing the iron-removed liquid and the roasted sand. 3+ to reduce the formation of iron hydroxide colloid. At the same time, it can also dilute the concentration of other impurity ions.

[0014] In some embodiments, 10% to 30% of the underflow mud by weight is added to the step of mixing the iron-removed liquid and roasted sand, so that the underflow mud can be returned to the reaction system again to recover the zinc element in the underflow mud.

[0015] In some embodiments, in the step of mixing the iron-removed liquid and the roasted sand, the reaction conditions include: the reaction temperature is 80°C-90°C, and the reaction time is 1h-8h. + consumption, and promote the formation of hydroxide precipitation.

[0016] In some embodiments, in the step of adjusting the pH of the treatment solution, the reaction conditions include: a reaction temperature of 80° C. to 90° C. and a reaction time of 1 h to 8 h, thereby promoting the formation of goethite. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 It is a schematic diagram of the process flow of a method for improving the sedimentation performance of low-acid leaching slurry in hematite hydrometallurgy of zinc in one embodiment of the present application. DETAILED DESCRIPTION

[0019] Hereinafter, the implementation method of the method for improving the sedimentation performance of low-acid leaching slurry in hematite hydrometallurgy of zinc smelting of the present application is specifically disclosed with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0020] " Scope " disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be combined arbitrarily, that is, any lower limit can form a scope with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for a particular parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0022] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0023] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; unless otherwise specified, the numerical values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).

[0024] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. "First feature" and "second feature" may include one or more of the features.

[0025] In the description of the present application, "A and / or B" may include the case of A alone, the case of B alone, or any of the cases of A and B, where A and B are only used for examples and may be any technical feature connected by "and / or" in the present application.

[0026] There is still a large amount of zinc in the waste slag produced by hydrometallurgy, so it is necessary to remove the impurities from the waste slag to recover the residual zinc. The current waste slag removal process includes low-acid leaching, reduction leaching, copper removal, neutralization, iron removal and other steps, which are aimed at removing the impurity elements in the waste slag to obtain a purer iron-removed liquid containing zinc ions. However, even after these impurity removal steps, the iron-removed liquid still contains a high concentration of impurity ions, such as the impurity ion Fe 3+ The concentration range is 5g / L to 10g / L, and the impurity ion Al 3+ The concentration range is 0.5g / L to 2g / L. Therefore, it is necessary to reprocess the iron removal solution to remove impurity ions, so as to obtain a purer zinc ion-containing extract.

[0027] In the first aspect of the present application, the present application provides a method for improving the sedimentation performance of low-acid leaching slurry in hematite hydrometallurgy of zinc, referring to Figure 1 , the method comprising:

[0028] S100: Mixing the iron-removed liquid and roasted sand to obtain a treated liquid.

[0029] The iron-removed liquid used in the present application is the iron-removed liquid obtained by removing impurities from the waste slag produced by the hydrometallurgical zinc smelting.

[0030] In some embodiments, the iron-removed liquor includes Zn 2+ Among them, Zn 2+ The concentration is 60g / L-90g / L. The zinc element in the waste slag produced by hydrometallurgy is leached into the iron-removed liquid. As an example, Zn2+ The concentration can be 60g / L, 70g / L, 80g / L or 90g / L.

[0031] In some embodiments, the iron-removed liquid includes impurity ions, and the impurity ions include Fe 3+ , Fe 3+ The concentration of Fe in the solution after iron removal is 5g / L-10g / L. 3+ The concentration can be 5g / L, 6g / L, 7g / L, 8g / L, 9g / L or 10g / L.

[0032] In some embodiments, the impurity ions also include Al 3+ , Al 3+ The concentration of Al is 0.5 g / L-2 g / L. As an example, Al 3+ The concentration can be 0.5 g / L, 1 g / L, 1.5 g / L or 2 g / L.

[0033] In some embodiments, the iron removal solution includes H2SO4, and the concentration of H2SO4 is 40g / L-60g / L. + The concentration can be 40g / L, 45g / L, 50g / L, 55g / L or 60g / L.

[0034] In some embodiments, the roasted sand includes zinc, and the zinc is present in the roasted sand in the form of ZnO and / or ZnS. Roasted sand is a product obtained by roasting raw materials such as zinc concentrate, such as zinc roasted sand, whose main components are zinc oxide, zinc sulfide and other substances. The present application adopts a method of mixing the iron removal liquid and the zinc roasted sand, and the ZnO and / or ZnS in the zinc roasted sand can consume the H in the iron removal liquid. + , which in turn promotes Fe 3+ and Al 3+ It is transformed into iron hydroxide precipitate and aluminum hydroxide precipitate. At the same time, the zinc element in the roasted sand is free Zn 2+ The zinc roasted sand can be leached into the treatment liquid in the form of

[0035] In some embodiments, the roasted sand further includes other impurity elements. As an example, the impurity elements include at least one of iron and copper. The iron element exists in the roasted sand in the form of Fe2O3, and the copper element exists in the roasted sand in the form of CuO. Fe2O3 and / or CuO can further consume H in the iron removal solution. + .

[0036] In some embodiments, the roasted sand further includes other acid-insoluble impurities, such as SiO2 and / or zinc ferrite. SiO2 and / or zinc ferrite can be separated from the reaction system through a subsequent solid-liquid separation step.

[0037] In some embodiments, the pH of the treatment solution is 4-4.5. Thus, the roasted sand continuously consumes H in the iron removal solution. + Until the pH of the treated solution reaches 4-4.5, Fe 3+ Rapidly transform into iron hydroxide precipitate. For other impurity ions, such as Al 3+ Rapidly transformed into aluminum hydroxide precipitate, Cu 2+ It quickly turns into copper hydroxide precipitation. As an example, the pH of the treatment solution can be 4, 4.1, 4.2, 4.3, 4.4 or 4.5.

[0038] In some embodiments, the step of mixing the iron-removed liquid and the roasted sand is performed in the first reaction tank.

[0039] In some embodiments, the reaction temperature in the first reaction tank is 80°C-90°C, and the reaction time is 1h-8h. + consumption, and promote the formation of hydroxide precipitation.

[0040] As an example, the reaction temperature may be 80°C, 82°C, 84°C, 86°C, 88°C, or 90°C.

[0041] As an example, the reaction time may be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h.

[0042] S200: Adjust the pH value of the treatment liquid and react to obtain ore slurry.

[0043] In some embodiments, the acidic solution includes waste electrolyte produced by hydrometallurgical zinc electrowinning, thereby allowing the waste produced in the hydrometallurgical zinc process to be reused, thereby reducing environmental pollution.

[0044] In some embodiments, the acidic solution includes H2SO4, wherein the concentration of H2SO4 in the acidic solution is 120 g / L-180 g / L. Thus, the acidic solution can regulate the pH of the treatment solution. As an example, the concentration of H2SO4 in the acidic solution can be 120 g / L, 140 g / L, 160 g / L, or 180 g / L.

[0045] In some embodiments, the spent electrolyte also includes Zn 2+ Therefore, the zinc ions in the waste electrolyte can enter the reaction system and be purified again, so that the zinc element in the waste electrolyte can be recovered.

[0046] In some embodiments, the step of adjusting the pH of the treatment liquid is performed in the second reaction tank, and the water inlet of the second reaction tank is connected to the water outlet of the first reaction tank through a pipeline. A pH detector is provided at the water outlet of the first reaction tank, and when the pH of the solution at the water outlet of the first reaction tank is detected to reach 4-4.5, the valve on the pipeline between the first reaction tank and the second reaction tank is closed, and the treatment liquid can flow from the first reaction tank into the second reaction tank.

[0047] In some embodiments, the pH of the treatment solution in the second reaction tank is adjusted to 1.5-2.0. The waste electrolyte is added once to make the pH of the treatment solution reach 1.5-2.0, and the Fe 3+ The concentration is less than 1g / L, which meets the formation conditions of goethite.

[0048] In some embodiments, in the step of reacting to obtain a slurry, the iron hydroxide precipitate generated in step S100 slowly reacts to become Fe 3+ At the same time, Fe 3+ The reaction generates goethite precipitation; and as the reaction proceeds, the pH of the slurry gradually increases. The specific reaction equations involved in the reaction process include:

[0049] Fe(OH)3↓+3H + =Fe 3+ +3H2O

[0050] Fe 3+ +2OH - =FeOOH↓+H +

[0051] In some embodiments, the pH of the slurry is 2.5-3.5. Compared with iron hydroxide precipitation, goethite is a larger particle precipitate, and large particle precipitates can improve the sedimentation ability of the slurry. Controlling the pH of the slurry in the range of 2.5-3.5 can cause the iron hydroxide precipitation reaction to become Fe 3+ At the same time, Fe 3+ The reaction generates goethite precipitate. It is difficult for aluminum hydroxide and / or copper hydroxide precipitate to dissolve into Al in this pH range. 3+ and / or Cu 2+ .

[0052] As an example, the pH of the slurry may be 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, or 3.5.

[0053] In some embodiments, the slurry passes through the third reaction tank, the fourth reaction tank, and the fifth reaction tank in sequence. Specifically, the outlet of the second reaction tank is connected to the third reaction tank, the outlet of the third reaction tank is connected to the fourth reaction tank, and the outlet of the fourth reaction tank is connected to the fifth reaction tank. pH detectors are respectively provided at the outlets of the third reaction tank and the fourth reaction tank. As an example, the pH of the slurry in the third reaction tank is 2.5-2.8, the pH of the slurry in the fourth reaction tank is 2.8-3.0, and the pH of the slurry in the fifth reaction tank is 3.0-3.5. When the pH at the outlet of the third reaction tank is monitored to be 2.8-3.0, the slurry in the third reaction tank flows into the fourth reaction tank; when the pH at the outlet of the fourth reaction tank is monitored to be 3.0-3.5, the slurry in the fourth reaction tank flows into the fifth reaction tank. As a result, the continuous reaction tank system facilitates the operator to monitor and adjust the entire reaction process to cope with fluctuations in the production process and to promote stable reaction.

[0054] In some embodiments, the reaction temperatures in the second reaction tank, the third reaction tank, the fourth reaction tank, and the fifth reaction tank are independently 80° C. to 90° C., and the reaction times are independently 1 h to 8 h. Thus, the formation of goethite can be promoted.

[0055] As an example, the reaction temperature may be 80°C, 82°C, 84°C, 86°C, 88°C, or 90°C.

[0056] As an example, the reaction time may be 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h or 8 h.

[0057] S300: performing solid-liquid separation on the slurry to obtain a supernatant.

[0058] In some embodiments, a flocculant is further added to the slurry, and as an example, the flocculant includes polyacrylamide, thereby further improving the sedimentation capacity of the slurry.

[0059] In some embodiments, the solid-liquid separation process is performed in a thickener. As an example, the slurry in the fifth reaction tank enters the thickener from the water outlet, and the thickener can separate solid particles from liquid through the principle of gravity sedimentation, so that the solid particles are deposited at the bottom of the thickener.

[0060] In some embodiments, the pH of the supernatant is 3-3.5, so that the supernatant still maintains the formation conditions of goethite.

[0061] In some embodiments, the supernatant includes Zn 2+ , Zn 2+ The concentration of Zn in the iron removal solution is 100g / L-120g / L. 2+Compared with the concentration of Zn 2+ concentration, thereby improving the recovery rate of zinc. 2+ The concentration can be 100 g / L, 105 g / L, 110 g / L, 115 g / L or 120 g / L.

[0062] In some embodiments, the supernatant also includes Fe 3+ 、Al 3+ , Cu 2+ At least one of the following, wherein Fe 3+ The concentration is less than 0.1g / L, Al 3+ The concentration is less than 0.1g / L, Cu 2+ The concentration is less than 0.1 g / L. Therefore, after the iron removal liquid is treated, the impurity ion content in the supernatant is reduced, so that a purer supernatant containing zinc ions can be obtained.

[0063] As an example, Fe 3+ The concentration includes but is not limited to 0.001g / L, 0.01g / L, 0.02g / L, 0.04g / L, 0.06g / L, 0.08g / L, and 0.09g / L.

[0064] As an example, Al 3+ The concentration includes but is not limited to 0.001g / L, 0.01g / L, 0.02g / L, 0.04g / L, 0.06g / L, 0.08g / L, and 0.09g / L.

[0065] As an example, Cu 2+ The concentration includes but is not limited to 0.001g / L, 0.01g / L, 0.02g / L, 0.04g / L, 0.06g / L, 0.08g / L, and 0.09g / L.

[0066] In some embodiments, 10% to 30% of the supernatant by weight is added to the first reaction tank. 3+ If the concentration is too high, a large amount of iron hydroxide colloid will be generated, and the iron hydroxide colloid will affect the sedimentation of the slurry. Therefore, the supernatant is added to the first reaction tank to make the Fe 3+ The concentration of iron hydroxide is reduced to below 7 g / L to reduce the formation of iron hydroxide colloid. At the same time, the concentration of other impurity ions can also be diluted. The remaining supernatant can enter the next electrolytic deposition process to extract the zinc element therein.

[0067] In some embodiments, the slurry is subjected to a solid-liquid separation process to obtain bottom slag.

[0068] In some embodiments, the bottom slag includes goethite. Thus, large particles of goethite precipitate and settle at the bottom of the thickener.

[0069] In some embodiments, the bottom slag also includes at least one of aluminum hydroxide precipitate and copper hydroxide precipitate. Therefore, other impurities generated by the reaction system can also be deposited at the bottom of the thickener, thereby separating the reaction system.

[0070] In some embodiments, the bottom slag also includes other impurities, such as SiO2 insoluble in dilute sulfuric acid and / or zinc ferrite insoluble in dilute sulfuric acid. Therefore, the impurities in the roasted sand can be separated from the reaction system.

[0071] In some embodiments, the ore pulp is subjected to solid-liquid separation to obtain underflow mud. There is a layer of underflow mud with a large water content between the supernatant and the bottom slag. The underflow mud and the bottom slag have the same composition, but different densities, and the density of the bottom slag is greater than that of the underflow mud.

[0072] In some embodiments, the underflow slurry includes goethite.

[0073] In some embodiments, the underflow mud also includes at least one of aluminum hydroxide precipitate and copper hydroxide precipitate.

[0074] In some embodiments, the pH of the underflow slurry is 4-4.5. Some unreacted roasted sand can continue to react at the bottom of the thickener, so the pH of the underflow slurry continues to rise to 4-4.5.

[0075] In some embodiments, 10% to 30% of the underflow mud is added to the first reaction tank. Thus, the underflow mud can be returned to the reaction system again to recover the zinc element in the underflow mud. The remaining underflow mud enters the next separation and purification process to separate goethite, aluminum hydroxide, copper hydroxide, zinc ferrite, etc.

[0076] The scheme of the present application is described below by specific examples. It should be noted that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this area or the product instructions are used. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0077] Example 1

[0078] The iron-removing liquid used in this embodiment is the iron-removing liquid obtained by removing impurities from the waste slag produced by the hydrometallurgical zinc smelting, wherein the iron-removing liquid includes Zn with a concentration of 80 g / L. 2+ , concentration of 10g / L Fe 3+, Al concentration of 2g / L 3+ and H2SO4 with a concentration of 50 g / L.

[0079] S100: adding the iron-removed liquid and roasted sand into the first reaction tank, controlling the reaction temperature of the first reaction tank to 85°C, and reacting for 1 hour to obtain a treatment liquid with a pH of 4.5; wherein the roasted sand includes ZnO, ZnS, Fe2O3, CuO, SiO2 and zinc ferrite.

[0080] S200: The treated liquid flows into the second reaction tank, and an acidic solution is added to the second reaction tank to make the pH in the second reaction tank reach 2.0; in this embodiment, the acidic solution is the waste electrolyte produced by hydrometallurgical zinc electrowinning, wherein the waste electrolyte includes Zn with a concentration of 50 g / L. 2+ and H2SO4 with a concentration of 180g / L. When the pH of the mixed solution in the second reaction tank reaches 2.5, the mixed solution in the second reaction tank flows into the third reaction tank; when the pH of the mixed solution in the third reaction tank reaches 2.8, the mixed solution in the third reaction tank flows into the fourth reaction tank; when the pH of the mixed solution in the fourth reaction tank reaches 3, the mixed solution in the fourth reaction tank flows into the fifth reaction tank. After the reaction is completed, ore pulp is obtained.

[0081] S300: After adding flocculant polyacrylamide to the slurry, the slurry flows into the thickener for solid-liquid separation to obtain supernatant, underflow slurry and bottom slag. The bottom slag is deposited at the bottom of the thickener. The supernatant rate of the slurry after settling for 5 minutes is 80%.

[0082] In this example, the pH of the supernatant is 3, and the supernatant contains Zn at a concentration of 120 g / L. 2+ , concentration of 0.09 g / L Fe 3+ , concentration of 0.05g / L Al 3+ , concentration of 0.08g / L Cu 2+ .

[0083] The thickness of the bottom slag is 0.2m and the zinc content in the bottom slag is 14%.

[0084] The pH of the underflow mud is 4.5 and the density is 1.8 g / cm 3 , the discharge volume is 21m 3 / h.

[0085] The dense oil pressure is 0.5MPa.

[0086] The difference between Example 2 and Example 1 is that the pH of the treatment solution is controlled to be 4. The supernatant obtained in Example 2 includes Fe 3+ , Al concentration is 0.02g / L 3+, concentration of 0.08g / L Cu 2+ The supernatant rate of the slurry after settling for 5 minutes is 80%.

[0087] The difference between Example 3 and Example 1 is that the pH of the slurry in the fifth reaction tank is controlled to be 3.5. The supernatant obtained in Example 3 includes Fe 3+ , concentration of 0.01g / L Al 3+ , concentration of 0.08g / L Cu 2+ The supernatant rate of the slurry after settling for 5 minutes is 80%.

[0088] The difference between Comparative Example 1 and Example 1 is that the pH of the treatment solution is controlled to be 2 in step S100. The supernatant obtained in Comparative Example 1 includes Zn 2+ , concentration of 0.2 g / L Fe 3+ , concentration of 0.1g / L Al 3+ , concentration of 0.5g / L Cu 2+ The supernatant rate of the slurry after settling for 5 minutes is 60%.

[0089] The thickness of the bottom slag is 1.5m and the zinc content in the bottom slag is 24%.

[0090] The pH of the underflow mud is 5 and the density is 1.6 g / cm 3 ; The discharge volume of bottom flow mud is increased to 30m 3 / h, but the thickener oil pressure is still 2.0MPa. This is because a large amount of Fe(OH)3 colloid and Al(OH)3 colloid will be generated in step S100 of comparative example 1, resulting in poor sedimentation performance of the slurry and reduced supernatant rate; excessive colloid content will further lead to a lower density of the underflow mud, which will affect the sedimentation performance of the slurry even if the discharge volume is increased, resulting in the thickener oil pressure being higher than that of Example 1.

[0091] The difference between Comparative Example 2 and Example 1 is that the pH of the treatment solution is controlled to be 5 in step S100. The supernatant obtained in Comparative Example 2 includes Fe 3+ , concentration of 0.06 g / L Al 3+ , concentration of 0.6 g / L Cu 2+ The supernatant rate of the slurry after settling for 5 minutes is 60%.

[0092] The difference between Comparative Example 3 and Example 1 is that the pH of the slurry in the fifth reaction tank is controlled to be 4. The supernatant obtained in Comparative Example 3 includes Fe 3+ , concentration of 0.08g / L Al 3+ , concentration of 0.6 g / L Cu2+ The supernatant rate of the slurry after 5 minutes of sedimentation is 55%. Therefore, the formation conditions of goethite are not met, and the iron hydroxide precipitation cannot be transformed into large-particle goethite precipitation, which will reduce the sedimentation performance of the slurry.

[0093] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for improving the sedimentation performance of low-acid leaching slurry in hematite hydrometallurgy of zinc, characterized in that: include: The iron-removed liquid and roasted sand are mixed to obtain a treatment liquid with a pH of 4-4.5, wherein the Fe 3+ The concentration is less than 1g / L; Adjusting the pH of the treatment liquid so that the pH of the treatment liquid is less than 2, and reacting to obtain a slurry with a pH of 2.5-3.5; The slurry is subjected to solid-liquid separation to obtain a supernatant, wherein the supernatant includes Zn 2+ , Fe in the supernatant 3+ The concentration is less than 0.1g / L.

2. The method according to claim 1, characterized in that The roasted sand includes at least one of ZnO and ZnS.

3. The method according to claim 2, characterized in that The roasted sand also includes at least one of Fe2O3 and CuO.

4. The method according to any one of claims 1 to 3, characterized in that: The step of adjusting the pH of the treatment liquid comprises: adding an acidic solution to the treatment liquid; wherein: The acidic solution includes H2SO4, and the concentration of H2SO4 in the acidic solution is 120g / L-180g / L; and / or, The acidic solution includes waste electrolyte produced by hydrometallurgical zinc electrowinning.

5. The method according to any one of claims 1 to 3, characterized in that: The reaction to obtain a slurry with a pH of 2.5-3.5 includes sequentially obtaining a slurry with a pH of 2.5-2.8, a slurry with a pH of 2.8-3.0, and a slurry with a pH of 3.0-3.

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6. The method according to any one of claims 1 to 3, characterized in that: The iron removal liquid includes Fe 3+ , H2SO4 and Zn 2+ , the Fe in the liquid after iron removal 3+ The concentration of H2SO4 in the deironing solution is 5g / L-10g / L, the concentration of Zn in the deironing solution is 40g / L-60g / L, 2+ The concentration is 60g / L-90g / L; and / or, The iron removal liquid also includes Al 3+ , the Al in the liquid after iron removal 3+ The concentration is 0.5g / L-2g / L.

7. The method according to any one of claims 1 to 3, characterized in that: The supernatant satisfies at least one of the following conditions: The pH of the supernatant is 3-3.5; The Zn in the supernatant 2+ The concentration is 100g / L-120g / L.

8. The method according to any one of claims 1 to 3, characterized in that: The ore pulp is subjected to solid-liquid separation treatment to obtain underflow mud; wherein the underflow mud includes goethite.

9. The method according to claim 8, characterized in that Taking 10%-30% of the supernatant by weight and adding it to the step of mixing the iron-removed liquid and roasted sand; and / or, 10%-30% of the underflow slurry by weight is taken and added into the step of mixing the iron-removed liquid and roasted sand.

10. The method according to any one of claims 1 to 9, characterized in that: In the step of mixing the iron-removed liquid and roasted sand, the reaction conditions include: a reaction temperature of 80° C. to 90° C. and a reaction time of 1 h to 8 h; and / or, In the step of adjusting the pH of the treatment solution, the reaction conditions include: a reaction temperature of 80° C.-90° C., and a reaction time of 1 h-8 h.

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