Recovery method of iron resource in hydrometallurgy leachate
Through the two-stage hydrometallurgical iron resource recovery method, chemical precipitation is first performed, and then hydrothermal reaction is carried out in the autoclave, which successfully increases the dry-based iron content and reduces the inclusion of valuable metals, solving the problem of low iron resource recovery efficiency in the prior art.
Patent Information
- Application Number
- CN202411918575.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-04-18
AI Technical Summary
The low dry-based iron content and high inclusions of valuable metals caused by the existing iron resource recovery method in hydrometallurgy limit the reuse of iron-containing waste slag.
A two-stage iron resource recovery method is adopted: first, the iron ions are converted into iron hydroxide precipitation through chemical precipitation, and then a hydrothermal reaction is carried out in the autoclave to control the temperature, time, pH and pressure, so that the iron ions are converted into hematite precipitation, and the inclusion of other metal elements is avoided as much as possible.
The content of dry-based iron is increased, and the inclusion of other metals in hematite is significantly reduced, so that the obtained hematite precipitation has a high iron content and purity, which is suitable for reuse.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of iron removal and resource recovery in the field of hydrometallurgy, and more specifically, to a method for recovering iron resources in a hydrometallurgical leaching solution. Background Art
[0002] Hydrometallurgy is a method of bringing ores, concentrates enriched by beneficiation or other raw materials into contact with aqueous solutions or other liquids, and then transferring the useful metals contained in the raw materials into the liquid phase through chemical reactions, and then separating and enriching the various useful metals contained in the liquid phase, and finally recovering them in the form of metals or other compounds. It mainly includes unit operations such as leaching, liquid-solid separation, solution purification, metal extraction from solution and wastewater treatment.
[0003] The hydrometallurgical leaching solution includes a variety of metal ions, for example, valuable metal ions such as zinc, nickel, cobalt, and copper. Among them, the most widely used method for recovering iron resources is the precipitation method, that is, first adding an oxidant to convert divalent iron ions into trivalent iron ions, and then adding alkali such as calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, and sodium carbonate to adjust the pH value of the solution, so that the trivalent iron ions are converted into ferric hydroxide precipitates.
[0004] However, in the process of converting trivalent iron into ferric hydroxide precipitate by the above-mentioned precipitation method, other metal ions such as nickel, copper, cobalt and zinc are also partially converted into hydroxide precipitate, which is mixed with the ferric hydroxide precipitate to form iron-containing waste slag. Such iron-containing waste slag not only has a high moisture content, but also has a dry basis iron content of only 10-40%, which requires a large storage space, and contains high content of valuable metal elements such as zinc, nickel, cobalt and copper in the dry basis. The above-mentioned valuable metal elements are heavy metals and will cause serious harm to the ecological environment. Therefore, the above-mentioned iron-containing waste slag can usually only be stored in a tailings pond, which cannot meet the indicators of repeated reuse, thereby limiting the reuse of the iron-containing waste slag. Summary of the invention
[0005] The object of the present invention is to overcome the above-mentioned defects of the prior art and provide a method for recovering iron resources in a hydrometallurgical leaching solution, which not only improves the dry basis rate but also reduces the inclusion amount of valuable metals.
[0006] To achieve the above object, the technical solution of the present invention is as follows:
[0007] A method for recovering iron resources in a hydrometallurgical leaching solution comprises the following steps:
[0008] Providing a hydrometallurgical leachate, the leachate comprising divalent and / or trivalent iron ions, the leachate further comprising other metal ions, the other metal ions comprising one or more of zinc ions, cobalt ions, nickel ions and copper ions;
[0009] adding an oxidant to the leachate to carry out an oxidation reaction, so that the divalent iron ions in the leachate are converted into trivalent iron ions, thereby obtaining an oxidized leachate;
[0010] adding alkali to the oxidized leaching solution to carry out a chemical precipitation reaction to obtain a precipitate;
[0011] The precipitate is placed in an autoclave and a water solvent is added to perform a hydrothermal reaction. The temperature of the hydrothermal reaction is controlled to be 180° C. to 220° C., the reaction time is 2 h to 4 h, the pH is 1 to 3, and the pressure is 10 MPa to 15 MPa to obtain a hematite precipitate.
[0012] Implementing the embodiments of the present invention will have the following beneficial effects:
[0013] The embodiment of the present invention adopts a two-stage iron resource recovery method, firstly uses a chemical precipitation method to convert the iron ions in the leachate into hydroxide precipitates, and then transfers the precipitates to an autoclave for hydrothermal reaction. By controlling the temperature, time, pH value and pressure value of the hydrothermal reaction, the iron ions are converted into hematite precipitates, and at the same time, the inclusion of other metal elements is avoided as much as possible. DETAILED DESCRIPTION
[0014] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0015] The invention discloses a method for recovering iron resources in a hydrometallurgical leaching solution, comprising the following process:
[0016] 1) providing a hydrometallurgical leaching solution, wherein the leaching solution includes divalent and / or trivalent iron ions, and the leaching solution also includes other metal ions, wherein the other metal ions include one or more of zinc ions, cobalt ions, nickel ions and copper ions.
[0017] 2) adding an oxidant to the leachate to carry out an oxidation reaction, so that the divalent iron ions in the leachate are converted into trivalent iron ions, thereby obtaining an oxidized leachate.
[0018] Specifically, the oxidant may include one or more of hydrogen peroxide, sodium hypochlorite and potassium permanganate.
[0019] Preferably, the leaching solution is heated in a water bath before the oxidation reaction, and the water bath heating temperature is 70° C. to 90° C., so that the subsequent oxidation reaction and chemical precipitation reaction are carried out under heating conditions, thereby accelerating the reaction speed.
[0020] 3) adding alkali to the oxidized leaching solution to carry out a chemical precipitation reaction to obtain a precipitate.
[0021] In this step, alkali is gradually added to the oxidized leachate while stirring, so that a chemical precipitation reaction occurs. Preferably, when the pH is 2-4, the addition of alkali and stirring are stopped, and a precipitate is obtained after a period of aging.
[0022] The main purpose of this step is to completely convert the trivalent iron ions into ferric hydroxide precipitates through a chemical precipitation reaction. The trivalent iron ions can be fully converted into ferric hydroxide precipitates when the pH is 2-4. At the same time, at this pH value, the excessive precipitation of other metal ions such as cobalt, nickel, copper or zinc can be suppressed, and hydroxide precipitates are partially generated. At the same time, this pH range can also promote the full oxidation of divalent iron into trivalent iron.
[0023] In a specific embodiment, the alkali may include one or more of sodium hydroxide, sodium carbonate and ammonia water.
[0024] 4) placing the precipitate in an autoclave and adding a water solvent for a hydrothermal reaction, controlling the temperature of the hydrothermal reaction to be 180° C. to 220° C., the reaction time to be 2 h to 4 h, the pH to be 1 to 3, and the pressure to be 10 MPa to 15 MPa to obtain a hematite precipitate.
[0025] In this step, the present invention controls the temperature, reaction time, pH value and pressure value of the hydrothermal reaction so that the precipitated crystals of the hydrothermal product are high-purity hematite crystals, which not only have a high iron content, but also significantly reduce the inclusion amount of other metals in the hematite crystals, so that the obtained hematite crystals can be reused. Nickel hydroxide, copper hydroxide, zinc hydroxide or cobalt hydroxide undergoes a hydrothermal reaction under acidic conditions to generate corresponding ions, which are dissolved in the solution, thereby inhibiting the precipitation of the corresponding oxides.
[0026] In this step, if the temperature of the hydrothermal reaction is too high, the reaction time is too long, or the pH range is different, other metal ions will be precipitated in the form of oxides.
[0027] In a specific embodiment, the pH value of the hydrothermal reaction can be adjusted to 1-3 by adding acid, and the acid can include one or more of hydrochloric acid, sulfuric acid, and nitric acid.
[0028] Preferably, during the hydrothermal reaction, an oxidant is also added to fully convert the iron hydroxide into hematite, thereby improving the purity of the hematite.
[0029] Specifically, the oxidant may include one or more of hydrogen peroxide, sodium hypochlorite and potassium permanganate.
[0030] In a specific embodiment, the concentration of the oxidant may be 1 mol / L to 3 mol / L.
[0031] In a specific embodiment, in the leaching solution of step 1), the concentration of iron ions may be 2 g / L to 10 g / L, and the concentration of other metal ions may be 10 g / L to 100 g / L.
[0032] The following are specific embodiments.
[0033] Example 1
[0034] Step 1): Provide a hydrometallurgical leaching solution. Prepare a simulated hydrometallurgical sulfuric acid leaching solution, the main components of which are: ZnSO4 (100 g / L), CoSO4 (60 g / L), and FeSO4 (2 g / L).
[0035] Step 2): Take 1 L of the sulfuric acid leaching solution prepared in step 1) and heat it to 80° C. in a water bath.
[0036] Step 3): 16 mL of 1.76 mol / L H2O2 oxidation solution is added to the solution of step 2) to ensure that the ferrous ions are completely oxidized to ferric ions, and then a 1 mol / L NaOH solution is gradually added until the pH of the solution reaches 4, and then stirring is stopped. After a period of aging, a precipitate is obtained.
[0037] Step 4): The precipitate was transferred to an autoclave, and 0.5 L of water solvent was added to perform a hydrothermal reaction. The pH of the solution was adjusted to about 1.5 with dilute sulfuric acid, heated to 180° C., pressurized to 10 MPa, and reacted for 3 h to obtain a hematite precipitate.
[0038] Example 2
[0039] The difference between Example 2 and Example 1 is that the temperature and pressure of the hydrothermal reaction are different, as follows:
[0040] Step 1): Provide a hydrometallurgical leaching solution. Prepare a simulated hydrometallurgical sulfuric acid leaching solution, the main components of which are: ZnSO4 (100 g / L), CoSO4 (60 g / L), and FeSO4 (2 g / L).
[0041] Step 2): Take 1 L of the sulfuric acid leaching solution prepared in step 1) and heat it to 80° C. in a water bath.
[0042] Step 3): 16 mL of 1.76 mol / L H2O2 oxidation solution is added to the solution of step 2) to ensure that the ferrous ions are completely oxidized to ferric ions, and then a 1 mol / L NaOH solution is gradually added until the pH of the solution reaches 4, and then stirring is stopped. After a period of aging, a precipitate is obtained.
[0043] Step 4): The precipitate was transferred to an autoclave, and 0.5 L of water solvent was added to perform a hydrothermal reaction. The pH of the solution was adjusted to about 1.5 with 0.01 mol / L of dilute sulfuric acid, and the solution was heated to 220° C. and pressurized to 15 MPa. After reacting for 3 h, a hematite precipitate was obtained.
[0044] Example 3
[0045] The difference between Example 3 and Example 1 is that an oxidant is further added to the hydrothermal reaction, as follows:
[0046] Step 1): Provide a hydrometallurgical leaching solution. Prepare a simulated hydrometallurgical sulfuric acid leaching solution, the main components of which are: ZnSO4 (100 g / L), CoSO4 (60 g / L), and FeSO4 (2 g / L).
[0047] Step 2): Take 1 L of the sulfuric acid leaching solution prepared in step 1) and heat it to 80° C. in a water bath.
[0048] Step 3): 16 mL of 1.76 mol / L H2O2 oxidation solution is added to the solution of step 2) to ensure that the ferrous ions are completely oxidized to ferric ions, and then a 1 mol / L NaOH solution is gradually added until the pH of the solution reaches 4, and then stirring is stopped. After a period of aging, a precipitate is obtained.
[0049] Step 4): The precipitate was transferred to an autoclave, and 0.5 L of water solvent and 10 mL of 1.76 mol / L H2O2 solution were added for hydrothermal reaction. The pH of the solution was adjusted to about 1.5 with 0.01 mol / L dilute sulfuric acid, heated to 180°C, pressurized to 10 MPa, and reacted for 3 h to obtain hematite precipitate.
[0050] Comparative Example 1
[0051] The difference between Comparative Example 1 and Example 3 is that the pH in step 3) is adjusted to 8, and the other parameters are the same.
[0052] Comparative Example 2
[0053] The difference between Comparative Example 2 and Example 3 is that the pH in step 4) is adjusted to 8, and the other parameters are the same.
[0054] Comparative Example 3
[0055] The difference between Comparative Example 3 and Example 3 is that the temperature of step 4) is 100° C., and the other parameters are the same.
[0056] Comparative Example 4
[0057] The difference between Comparative Example 4 and Example 3 is that the temperature of step 4) is 350° C., and the other parameters are the same.
[0058] Test Case
[0059] The hematite precipitates obtained in each embodiment and comparative example were dried, weighed, and the iron content, zinc content, and cobalt content were tested. The results are shown in Table 1.
[0060] Table 1: Composition table of hematite obtained in various embodiments and comparative examples
[0061] Hematite precipitation weight / g Iron content / g Zinc content / g Cobalt content / g Example 1 0.9526 0.6268 0.0221 0.0351 Example 2 0.9835 0.6484 0.0284 0.0145 Example 3 1.0285 0.6985 0.0185 0.0121 Comparative Example 1 0.9853 0.5764 0.0324 0.0395 Comparative Example 2 0.4218 0.1539 0.1085 0.0934 Comparative Example 3 0.8827 0.4678 0.0957 0.1187 Comparative Example 4 0.9632 0.6405 0.0217 0.0265
[0062] It can be seen from Table 1 that the hydrothermal reaction of the method of the present invention has high selectivity, and can crystallize iron ions in the form of iron oxide while introducing less impurities.
[0063] Comparison of Comparative Example 1 and Example 3 shows that the contents of zinc and cobalt introduced in Comparative Example 1 are relatively high, which may be due to the introduction of too much zinc hydroxide precipitate and cobalt hydroxide precipitate in the chemical precipitation step.
[0064] Comparison of Comparative Examples 2 to 4 with Example 3 shows that the conditions of the hydrothermal reaction have a significant effect on the selectivity of the crystallization precipitation.
[0065] 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 application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these 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 recovering iron resources from a hydrometallurgical leaching solution, characterized in that: The process includes: Providing a hydrometallurgical leachate, wherein the leachate includes divalent and / or trivalent iron ions, and the leachate also includes other metal ions, wherein the other metal ions include one or more of zinc ions, cobalt ions, nickel ions and copper ions; adding an oxidant to the leachate to carry out an oxidation reaction, so that the divalent iron ions in the leachate are converted into trivalent iron ions, thereby obtaining an oxidized leachate; adding alkali to the oxidized leaching solution to carry out a chemical precipitation reaction to obtain a precipitate; The precipitate is placed in an autoclave and a water solvent is added to perform a hydrothermal reaction. The temperature of the hydrothermal reaction is controlled to be 180° C. to 220° C., the reaction time is 2 h to 4 h, the pH is 1 to 3, and the pressure is 10 MPa to 15 MPa to obtain a hematite precipitate.
2. The recycling method according to claim 1, characterized in that: The pH of the chemical precipitation reaction is 2-4.
3. The recovery method according to claim 1 or 2, characterized in that: During the hydrothermal reaction, an oxidant is also added.
4. The recycling method according to claim 3, characterized in that: The concentration of the oxidant is 1 mol / L to 3 mol / L.
5. The recycling method according to claim 3, characterized in that: The oxidant includes one or more of hydrogen peroxide, sodium hypochlorite and potassium permanganate.
6. The recycling method according to claim 1, characterized in that: During the hydrothermal reaction, acid is added to adjust the pH of the hydrothermal reaction to 1-3.
7. The recycling method according to claim 6, characterized in that: The acid includes one or more of sulfuric acid, hydrochloric acid and nitric acid.
8. The recycling method according to claim 1, characterized in that: The alkali includes one or more of sodium hydroxide, sodium carbonate and ammonia water.
9. The recycling method according to claim 1, characterized in that: Before the oxidation reaction, the method further comprises: heating the leaching solution in a water bath, wherein the water bath heating temperature is 70° C. to 90° C.
10. The recycling method according to claim 1, characterized in that: The oxidant includes one or more of hydrogen peroxide, potassium permanganate and sodium hypochlorite.