Method for removing iron in high-zinc-content zinc sulfate solution at medium temperature

Abstract

The invention discloses a medium-temperature iron removal method for a high-zinc-content zinc sulfate solution, and relates to the technical field of hydrometallurgy, the iron removal adopts medium-temperature mineralization iron precipitation, and the process parameters are as follows: the reaction temperature is 135-160 DEG C, the oxygen pressure is 0.7-0.8 MPa, the acid content is 10-30 g / L, and the reaction time is 90-160 minutes. According to the method, a hydrothermal method is adopted for iron precipitation, mineralization and solidification of iron ions are achieved by regulating and controlling process parameters such as reaction temperature, oxygen partial pressure, solution acidity and iron-containing product dehydration and mineralization time, high-iron-content materials are produced, iron removal efficiency is improved, reaction time is shortened, iron-containing minerals produced through the method have high grade and stability, and the method is suitable for industrial production. The method is simple in operation and convenient for subsequent separation and recovery, the resource utilization value of the iron slag is improved, the production efficiency is improved, and the operation difficulty and uncertainty are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for removing iron at medium temperature from a high-zinc-containing zinc sulfate solution. Background Art

[0002] In the process of wet zinc smelting, the leaching solution produced often contains a high concentration of zinc sulfate and a certain amount of ferrous sulfate and ferric sulfate. The iron impurities in these solutions not only affect the purity of zinc, but also increase the complexity of subsequent processing.

[0003] Although the traditional iron removal process can achieve the separation of zinc and iron to a certain extent, there are many problems in the consumption of auxiliary materials, operation complexity, iron removal efficiency and resource utilization of iron slag. These problems not only affect the overall benefits of wet zinc smelting, but also put pressure on the environment. For example, there are the following problems: (1) Large consumption of auxiliary materials: In the process of wet zinc smelting, in order to remove iron impurities, a large amount of reagents such as oxidants, neutralizers, polyacrylamide, etc. are often required. The addition of these reagents not only increases the production cost, but also may cause a certain load and pollution to the environment and equipment. Especially when the iron content is high, the consumption of reagents will increase significantly, resulting in a significant decrease in economic benefits; (2) Complex operation and low iron removal efficiency: The traditional iron removal process is often accompanied by complex operation steps in the process of wet zinc smelting, which not only It requires a lot of time and manpower, and also increases the difficulty and uncertainty of operation. For example, the potassium ferroaluminate method, goethite method and other iron precipitation methods require precise control of multiple key parameters such as reaction temperature, pH value and the amount of oxidant, and the entire reaction process takes a long time. Although these traditional methods can remove iron impurities in zinc sulfate solution to a certain extent, due to the constraints of various factors, their iron removal efficiency is often unsatisfactory and it is difficult to meet the needs of modern industrial production for high efficiency, energy saving and environmental protection. (3) It is difficult to recycle iron slag resources: the iron slag produced by traditional iron removal processes often contains high impurity content and low grade, which is difficult to be directly used for ironmaking or other industrial purposes. The treatment and disposal of these iron slags has also become a problem, which not only increases environmental pressure but also wastes resources.

[0004] Therefore, providing an efficient and environmentally friendly iron precipitation process is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for removing iron at medium temperature from a zinc sulfate solution with a high zinc content. The method adopts a hydrothermal method to precipitate iron. By adjusting process parameters such as reaction temperature, oxygen partial pressure, solution acidity and dehydration mineralization time of iron-containing products, the mineralization and solidification of iron ions are achieved to produce a high-iron-containing material.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for removing iron from a zinc sulfate solution with high zinc content at medium temperature. The iron removal adopts medium temperature mineralization iron precipitation. The process parameters are: reaction temperature of 135-160°C, oxygen pressure of 0.7-0.8MPa, and acid content of 10-30g / L.

[0008] The present invention firstly controls the reaction temperature within the range of 135-160°C by temperature regulation, thereby ensuring that the iron ions can effectively undergo a mineralization reaction within this temperature range to generate stable iron-containing minerals. The setting of this temperature range not only avoids the increase in energy consumption and equipment corrosion caused by excessively high temperatures, but also ensures that the reaction is fully carried out. Secondly, the oxygen partial pressure is regulated. During the reaction process, oxygen is introduced into the reactor and the oxygen pressure is controlled within the range of 0.7-0.8MPa to provide a sufficient oxidizing atmosphere for the reaction, thereby promoting the oxidation and mineralization of the iron ions. This step is crucial for improving the iron removal efficiency and producing high-quality iron-containing minerals. The acidity of the solution is controlled. The acidity of the solution is one of the important factors affecting the mineralization reaction. The present invention ensures that the reaction is carried out under suitable acid-base conditions by regulating the acidity of the solution, thereby optimizing the generation of the mineralized product.

[0009] Preferably, the reaction temperature is controlled by steam.

[0010] Preferably, the reaction time of the process step is 90-160 min.

[0011] The present invention optimizes the dehydration and mineralization time of the iron-containing product. After the reaction is completed, the generated iron-containing minerals are made more stable through reasonable dehydration and mineralization time treatment, which is convenient for subsequent separation and recovery. This step is of great significance for improving the resource utilization value of iron slag.

[0012] Preferably, the pre-liquid for iron removal contains 105-160 g / L of zinc.

[0013] The front solution of the present invention has high zinc content, low system solution circulation volume and low energy consumption.

[0014] Preferably, the front liquid is a liquid obtained by precipitating copper and indium in a first leaching liquid.

[0015] Preferably, the first stage leaching solution is direct two-stage oxygen-enriched pressure leaching of zinc sulfide concentrate.

[0016] The mineralized iron precipitation pre-liquid of the present invention adopts a two-stage oxygen-enriched pressure leaching process technology, and the zinc sulfide concentrate is directly pressure-leached without generating sulfuric acid during the process.

[0017] Preferably, the specific step of copper precipitation is: adding iron powder to the first stage leaching solution to replace the copper precipitation.

[0018] Preferably, the specific steps of indium precipitation are: using a neutralizer (ordinary neutralizer) to pre-neutralize the solution after copper precipitation, and controlling the acid at 3-5g / L; then using a high-indium neutralizer to neutralize the supernatant of the pre-neutralization, adjusting the solution pH to 4.5-5.0, and precipitating the solution indium into the slag.

[0019] Preferably, after the medium-temperature mineralization and iron precipitation are completed, it also includes room-temperature hydrolysis to remove iron.

[0020] The present invention adopts a two-stage combined iron removal. The first stage adopts medium-temperature iron removal to produce hematite, and the iron content of the solution is controlled to be less than 2.0 g / L; the second stage adopts normal temperature hydrolysis to remove iron in the solution to less than 20 mg / L, which can reduce the investment in equipment and facilities.

[0021] Preferably, the process step of de-ironing by hydrolysis at room temperature is: de-ironing the mineralized iron-precipitated liquid by hydrolysis in a normal pressure working tank.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) High efficiency: The present invention improves the iron removal efficiency and shortens the reaction time by optimizing the process parameters. The iron-containing minerals produced by the present invention have high grade and stability, which is convenient for subsequent separation and recovery, thereby increasing the resource utilization value of iron slag, improving production efficiency, and reducing operational difficulty and uncertainty.

[0024] (2) Environmental protection: The present invention reduces the amount of reagents used, reduces environmental pollution, and avoids corrosion and pollution of the environment and equipment by reagents. At the same time, the iron-containing minerals produced have a high resource utilization value, which is in line with the concept of green and sustainable development;

[0025] (3) Economical: The present invention reduces production costs, improves economic benefits, and provides new technical support for the improvement and upgrading of the hydrometallurgical zinc smelting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings in this description are only embodiments of the present invention.

[0027] Figure 1 The present invention is a process flow chart of a method for removing iron from a high-zinc sulfate solution according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention.

[0029] The preparation steps of mineralization iron precipitation pre-liquid are:

[0030] The zinc concentrate is washed with water and slurried by the system, then ground. The qualified slurry is directly leached through two stages of oxygen-enriched pressure to produce a leachate with an iron content of 8-12g / L.

[0031] Iron powder is added to the first leaching solution to replace copper precipitation, and copper precipitation liquid and copper slag are produced, containing 100-300 mg / L copper;

[0032] The post-copper precipitation liquid is pre-neutralized with a neutralizer (limestone powder) to control the acid at 3-5g / L; the pre-neutralized supernatant is neutralized with a neutralizer (high indium neutralizer zinc oxide) to adjust the solution pH to 4.5-5.0, and the indium in the solution is precipitated into the slag to obtain a mineralized iron precipitation pre-liquid.

[0033] Example 1

[0034] like Figure 1 The present invention provides a method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature, which specifically comprises the following steps:

[0035] (1) The technical parameters of the mineralization iron precipitation pre-liquid are: acid content 10.26g / L, iron 7.20g / L, zinc 140.85g / L;

[0036] (2) adding the pre-ferrification solution to the reactor, introducing steam to raise the temperature to 151° C., introducing oxygen into the reactor while raising the temperature, controlling the pressure at 0.7 MPa, and reacting for 128 min to carry out the mineralization and iron precipitation;

[0037] (3) after the reaction is completed, solid-liquid separation is performed to obtain hematite and mineralized iron precipitation liquid, wherein the technical parameters of the mineralized iron precipitation liquid are liquid acid content of 18.65 g / L, iron content of 1585.75 mg / L, and zinc content of 139.41 g / L; the technical parameters of the output hematite are iron content of 55.11% and zinc content of 2.06%;

[0038] (4) The mineralized iron precipitation liquid is hydrolyzed to remove iron under normal pressure, and low-pressure steam is introduced to control the temperature at 78°C, and oxygen or air is introduced to oxidize part of the divalent iron into trivalent iron. The hydrolysis time is controlled at 3.8 hours, and the parameters of the iron-removing supernatant are iron content 9.11 mg / L, pH value 5.0, and zinc content 145.12 g / L.

[0039] Example 2

[0040] like Figure 1 The present invention provides a method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature, which specifically comprises the following steps:

[0041] (1) The technical parameters of the mineralization iron precipitation pre-liquid are: acid content 11.68g / L, iron 6.17g / L, zinc 133.22g / L;

[0042] (2) adding the pre-ferrification solution to the reactor, introducing steam to raise the temperature to 144° C., introducing oxygen into the reactor while raising the temperature, controlling the pressure at 0.75 MPa, and reacting for 92 minutes to carry out the mineralization and iron precipitation;

[0043] (3) After the reaction is completed, solid-liquid separation is performed to obtain hematite and mineralized iron precipitation liquid, wherein the technical parameters of the mineralized iron precipitation liquid are liquid acid content of 19.30 g / L, iron content of 1044.21 mg / L, and zinc content of 122.21 g / L; the technical parameters of the output hematite are iron content of 51.36% and zinc content of 2.12%.

[0044] (4) The mineralized iron precipitation liquid is hydrolyzed to remove iron under normal pressure, low-pressure steam is introduced to control the temperature at 75°C, and oxygen or air is introduced to oxidize part of the divalent iron into trivalent iron. The hydrolysis time is controlled at 3.5 hours, and the parameters of the iron-removing supernatant are iron content 7.51 mg / L, pH value 5.2, and zinc content 139.51 g / L.

[0045] Example 3

[0046] like Figure 1 The present invention provides a method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature, which specifically comprises the following steps:

[0047] (1) The technical parameters of the mineralization iron precipitation pre-liquid are: acid content 11.14 g / L, iron 9.46 g / L, zinc 121.42 g / L;

[0048] (2) adding the pre-ferrification solution to the reactor, introducing steam to raise the temperature to 137° C., introducing oxygen into the reactor while raising the temperature, controlling the pressure at 0.8 MPa, and reacting for 126 min to carry out the mineralization and iron precipitation;

[0049] (3) After the reaction is completed, solid-liquid separation is performed to obtain hematite and mineralized iron precipitation liquid, wherein the technical parameters of the mineralized iron precipitation liquid are liquid acid content of 13.30 g / L, iron content of 1016.34 mg / L, and zinc content of 118.64 g / L; the technical parameters of the output hematite are iron content of 48.38% and zinc content of 4.07%.

[0050] (4) The mineralized iron precipitation liquid is hydrolyzed to remove iron under normal pressure, low-pressure steam is introduced to control the temperature at 79°C, and oxygen or air is introduced to oxidize part of the divalent iron into trivalent iron. The hydrolysis time is controlled at 3.6 hours, and the parameters of the iron-removing supernatant are iron content 11.10 mg / L, pH value 4.8, and zinc content 127.61 g / L.

[0051] Example 4

[0052] like Figure 1The present invention provides a method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature, which specifically comprises the following steps:

[0053] (1) The technical parameters of the mineralization iron precipitation pre-liquid are: acid content 13.61g / L, iron 9.32g / L, zinc 145.81g / L;

[0054] (2) adding the pre-ferrification solution to the reactor, introducing steam to raise the temperature to 159° C., introducing oxygen into the reactor while raising the temperature, controlling the pressure at 0.73 MPa, and reacting for 98 minutes to carry out the mineralization and iron precipitation;

[0055] (3) after the reaction is completed, solid-liquid separation is performed to obtain hematite and mineralized iron precipitation liquid, wherein the technical parameters of the mineralized iron precipitation liquid are liquid acid content 28.49 g / L, iron 1893 mg / L, and zinc 146.45 g / L; the technical parameters of the output hematite are iron content 57.10% and zinc 1.46%;

[0056] (4) The mineralized iron precipitation liquid is hydrolyzed and iron is removed under normal pressure. Low-pressure steam is introduced to control the temperature at 79°C, and oxygen or air is introduced to oxidize part of the divalent iron into trivalent iron. The hydrolysis time is controlled at 3.5 hours. The parameters of the iron removal supernatant are iron content 15.10 mg / L, pH value 5.1, and zinc content 159.12 g / L

[0057] Comparative Example 5

[0058] like Figure 1 The present invention provides a method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature, which specifically comprises the following steps:

[0059] (1) The technical parameters of the mineralization iron precipitation pre-liquid are: acid content 9.58g / L, iron 6.71g / L, zinc 109g / L;

[0060] (2) adding the pre-ferrification solution to the reactor, introducing steam to raise the temperature to 135° C., introducing oxygen into the reactor while raising the temperature, controlling the pressure at 0.76 MPa, and reacting for 102 min to carry out the mineralization and iron precipitation;

[0061] (3) after the reaction is completed, solid-liquid separation is performed to obtain hematite and mineralized iron precipitation liquid, wherein the technical parameters of the mineralized iron precipitation liquid are liquid acid content of 17.61 g / L, iron content of 1816 mg / L, and zinc content of 114 g / L; the technical parameters of the output hematite are iron content of 45% and zinc content of 1.92%;

[0062] (4) The mineralized iron precipitation liquid is hydrolyzed to remove iron under normal pressure, and low-pressure steam is introduced to control the temperature at 76°C, and oxygen or air is introduced to oxidize part of the divalent iron into trivalent iron. The hydrolysis time is controlled at 3.5 hours, and the parameters of the iron-removing supernatant are iron content 14.10 mg / L, pH value 5.0, and zinc content 124 g / L.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for removing iron from a high-zinc sulfate solution at medium temperature, characterized in that: The iron removal adopts medium-temperature mineralization iron precipitation, and the process parameters are: reaction temperature is 135-160°C, oxygen pressure is 0.7-0.8MPa, and acid content is 10-30g / L.

2. The method for removing iron at a medium temperature in a high zinc sulfate solution according to claim 1, wherein: The reaction temperature is controlled by steam.

3. The method for removing iron at a medium temperature in a high zinc sulfate solution according to claim 1, wherein: The reaction time of the process step is 90-160 min.

4. The method for removing iron at a medium temperature in a high zinc-containing zinc sulfate solution according to claim 1, wherein: The zinc content of the pre-liquid for iron removal is 105-160 g / L.

5. The method for removing iron at medium temperature in a high zinc-containing zinc sulfate solution according to claim 4, characterized in that: The pre-liquid is a liquid obtained after a section of the leaching liquid is subjected to copper precipitation and indium precipitation.

6. The method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature according to claim 5, characterized in that: The first stage leaching solution is direct two-stage oxygen-enriched pressure leaching of zinc sulfide concentrate.

7. The method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature according to claim 5, characterized in that: The specific step of copper precipitation is: adding iron powder to the first stage leaching solution to replace the copper precipitation.

8. The method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature according to claim 5, characterized in that: The specific steps of indium precipitation are: pre-neutralization with a neutralizer in the solution after copper precipitation to control the acid at 3-5 g / L; then neutralization with a high-indium neutralizer in the pre-neutralized supernatant to adjust the solution pH to 4.5-5.0, and precipitation of the solution indium into the slag.

9. The method for removing iron from a high-zinc-containing zinc sulfate solution at medium temperature according to claim 1, characterized in that: After the medium-temperature mineralization and iron precipitation are completed, the process also includes water removal of iron at room temperature.

10. A method for removing iron from a high-zinc sulfate solution at medium temperature according to claim 9, characterized in that: The process steps of hydrolysis and iron removal are: hydrolysis and iron removal of the mineralized iron precipitation liquid in a normal pressure working tank.

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