A method for resource utilization of hematite type waste residue

Abstract

The application provides a resource utilization method of hematite type waste residue, which comprises the following steps: firstly, mixing the hematite type waste residue with hydrochloric acid to carry out leaching reaction; secondly, mixing the leaching solution with a composite extraction phase comprising TBP, N235 and / or N263 to carry out extraction treatment; thirdly, mixing the obtained iron-containing loaded organic phase with water to carry out stripping treatment; and finally, evaporating and concentrating the stripping solution, and then cooling and crystallizing to obtain a ferric chloride product. The resource utilization method of the application does not need high-temperature roasting, has a short process, high recovery rate and high product purity, and can extract iron in the waste residue to prepare the ferric chloride crystal product, which can be used as a basic chemical raw material in the chemical, metallurgical and water treatment industries, and can realize better low-energy-consumption and resource utilization of the hematite type waste residue.

Description

Technical Field

[0001] This invention belongs to the field of waste resource recycling and treatment, and relates to a method for the resource utilization of hematite-type waste residue. Background Technology

[0002] Laterite nickel ore, as an important component of global nickel resources, plays a crucial role in alleviating nickel shortages through its development and utilization. Currently, the processing of laterite nickel ore generates a large amount of solid waste, primarily hematite-type slag. With the continuous expansion of the nickel industry, the stockpiles of this hematite slag have increased dramatically, becoming a key environmental and technological bottleneck restricting the industry's sustainable development. The chemical composition of hematite-type waste residue is complex. Although it contains high-grade iron, it also contains various impurities such as aluminum, silicon, chromium, nickel, and sulfur. Furthermore, the iron mineral phase and these gangue minerals containing aluminum, silicon, and chromium often exhibit a close symbiotic relationship, with the impurity components and iron components intertwined and embedded in extremely fine particles. This makes the resource recovery process for this type of waste residue extremely complex and costly. Therefore, the current industrial practice for treating this type of hematite-type waste residue is still predominantly direct stockpiling or landfilling. This method not only occupies a large amount of land resources and poses environmental pollution risks, but also results in the long-term idleness and waste of the large amount of iron resources contained in the waste residue.

[0003] To achieve better resource utilization of waste residue, existing technologies have adopted process routes combining pyrometallurgical roasting with magnetic separation or reduction smelting to obtain products such as iron concentrate, reduced iron, or crude iron ingots. However, these methods all rely on high-temperature roasting or high-temperature smelting environments, have long process flows, and consume extremely high energy, which not only increases production costs but also hinders energy conservation and emission reduction in the industrial sector. Secondly, because the impurities in the waste residue are tightly bound to the iron components, existing pyrometallurgical processes cannot achieve complete separation of impurities, resulting in generally low iron recovery rates and low product purity in the final product. This makes it difficult to prepare high-purity, high-value-added iron-based products, greatly limiting their economic value and application scope. Summary of the Invention

[0004] In view of the difficulties and problems in the recycling and treatment of hematite-type waste residue generated from the hydrometallurgical processing of laterite nickel ore in existing technologies, this invention provides a method for the resource utilization of hematite-type waste residue. This method first involves mixing the hematite-type waste residue with hydrochloric acid for a leaching reaction. Then, the leachate is mixed with a composite extraction phase including TBP, N235, and / or N263 for extraction. The resulting iron-loaded organic phase only needs to be back-extracted with water. The back-extraction solution is then evaporated, concentrated, cooled, and crystallized to obtain ferric chloride. This resource utilization method does not require high-temperature roasting, has a short process, high recovery rate, and high product purity. The iron extracted from the waste residue is prepared into ferric chloride crystals, which can be used as a basic chemical raw material in the chemical, metallurgical, and water treatment industries, achieving better low-energy and resource-efficient utilization of hematite-type waste residue.

[0005] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for the resource utilization of hematite-type waste residue, comprising the following steps: Hematite-type waste residue is mixed with hydrochloric acid and leached to obtain leachate; The leachate is mixed with a composite extractive phase, which includes a first extractant and a second extractant; the first extractant includes TBP (tributyl phosphate extractant), and the second extractant includes N235 (trioctyldecyl tertiary amine) and / or N263 (methyltrialkylammonium chloride); the extraction process is performed to obtain an iron-supported organic phase; The iron-supported organic phase is mixed with a back-extraction agent, wherein the back-extraction agent is water, and back-extraction is performed to obtain a back-extraction solution. The back-extraction solution is evaporated, concentrated, cooled, and crystallized to obtain ferric chloride product.

[0006] The resource utilization method provided by this invention constructs a complete process chain of "hydrochloric acid leaching—composite extraction—water back-extraction—evaporation crystallization". It adopts a synergistic extraction system of TBP and tertiary / quaternary ammonium salts (N235 / N263). TBP improves the polarity of the organic phase, which helps dissolve the ammonium salts of N235 / N263 and prevents the formation of a third phase. Moreover, the combination of the two greatly improves the ease of back-extraction of the extractant, thereby supporting the back-extraction of ferric chloride with pure water, and thus realizing the efficient and highly selective extraction of iron from hematite waste. The process flow is short, and high-purity ferric chloride back-extraction liquid can be obtained without complicated impurity removal procedures. The final product has high added value and can effectively solve the problems of high separation difficulty, incomplete separation, low product purity and low value, and high energy consumption in existing recycling schemes.

[0007] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0008] This invention does not limit the source of hematite-type waste residue. Typically, hematite-type waste residue has α-Fe2O3 as the main iron-containing phase. In some embodiments, the total iron content in the hematite-type waste residue can be 30wt%~65wt% (or about 40wt%~93wt% based on Fe2O3), and it can mainly include one or more of Zn, Ca, Mg, Al, Mn, Ti or S.

[0009] As a preferred embodiment of the present invention, the mass percentage concentration of the hydrochloric acid is 20% to 35%. For example, it can be 20%, 23%, 25%, 28%, 30%, 33%, 35%, etc.

[0010] Preferably, the mass ratio of hydrochloric acid to hematite-type waste residue is (3~5):1. For example, it can be 3:1, 3.5:1, 4:1, 4.5:1, or 5:1, etc. Too low a hydrochloric acid concentration leads to insufficient iron leaching rate, and the subsequent back-extraction solution will have insufficient hydrochloric acid content and acidity, easily causing iron ion hydrolysis; too high a concentration not only increases costs but also introduces excessive free acid into subsequent extraction, increasing the back-extraction and evaporation load.

[0011] As a preferred embodiment of the present invention, the leaching reaction temperature is 30℃~80℃, and the reaction time is 6h~12h. For example, the temperature can be 30℃, 40℃, 50℃, 60℃, 70℃, or 80℃, etc.; the time can be 6h, 7h, 8h, 9h, 10h, 11h, or 12h, etc. This is beneficial for ensuring the reaction rate while controlling the volatilization of hydrochloric acid, thereby maximizing the extraction of iron resources.

[0012] As a preferred embodiment of the present invention, the volume percentage of the first extractant is 10% to 20%, with the volume of the composite extractant phase being 100%. For example, it can be 10%, 12%, 14%, 16%, 18%, or 20%, etc.

[0013] Preferably, the volume percentage of the second extractant is 30% to 40% of the volume of the composite extractant phase, which is 100%. For example, it could be 30%, 32%, 34%, 36%, 38%, or 40%. Thus, a suitable TBP percentage allows it to better function as a "co-solvent" and "modifier," increasing the ease of back-extraction of the organic phase; a suitable N235 / N263 percentage ensures extremely high extraction capacity and good extraction effect. The synergy of these two components gives the organic phase both high loading capacity and good flowability and ease of back-extraction, solving the problem of low extraction saturation capacity or low back-extraction rate of a single extractant under high acidity.

[0014] As a preferred embodiment of the present invention, the composite extraction phase further includes a modifier, wherein the modifier includes octanol.

[0015] Preferably, the volume percentage of the modifier is 15% to 20% based on the volume of the composite extractable phase as 100%. For example, it can be 15%, 16%, 17%, 18%, 19%, or 20%. This invention preferably uses octanol as a modifier, which can effectively inhibit the formation of a third phase, improve phase separation characteristics, reduce emulsification, and also slightly increase the extraction kinetics rate.

[0016] As a preferred embodiment of the present invention, the composite extraction phase further includes a diluent, wherein the diluent includes kerosene.

[0017] Preferably, the volume percentage of the diluent is 30% to 35% based on the volume of the composite extractable phase as 100%. For example, it can be 30%, 31%, 32%, 33%, 34%, or 35%. This invention preferably uses kerosene as a diluent, which helps reduce the density and viscosity of the organic phase, ensuring rapid phase separation in the mixing and clarifying tank (organic phase floats, aqueous phase sinks), thereby significantly reducing operating costs.

[0018] As a preferred technical solution of the present invention, the extraction process includes countercurrent extraction with 5 to 10 extraction stages, for example, 5, 6, 7, 8, 9 or 10 stages.

[0019] Preferably, the extraction temperature is 30℃~50℃. For example, it can be 30℃, 35℃, 40℃, 45℃, 50℃, etc.

[0020] As a preferred embodiment of the present invention, the back-extraction process includes countercurrent back-extraction with 5 to 10 stages, for example, 5, 6, 7, 8, 9, or 10 stages. Countercurrent operation allows the fresh organic phase to contact the near-equilibrium leachate, maximizing iron extraction and reducing the iron concentration in the raffinate to a lower level.

[0021] Preferably, the temperature of the back-extraction process is 30℃~50℃. For example, it can be 30℃, 35℃, 40℃, 45℃, 50℃, etc.

[0022] Back-extraction using traditional amine extractants typically requires high concentrations of acids, bases, or salts, and may introduce new impurity ions (such as Na+). + Ca 2+(etc.), affecting the purity of the final ferric chloride product. This invention utilizes the unique characteristics of a composite extraction system, requiring only pure water to achieve highly efficient back-extraction; further, 5-10 stages of countercurrent back-extraction ensure complete elution of iron from the loaded organic phase, resulting in a high-concentration back-extraction solution free of impurity anions. The organic phase can be recycled after regeneration. Furthermore, the resulting back-extraction solution is acidic, meeting the requirements for subsequent crystallization; after crystallization, solid-liquid separation and drying yield the qualified product.

[0023] It should be noted that, due to space limitations and to avoid redundancy, this invention does not exhaustively list all point values ​​within the above numerical range, but it is not limited to the listed values ​​either; other unlisted values ​​within the above numerical range are also applicable.

[0024] Compared with existing technical solutions, the present invention has at least the following beneficial effects: The resource utilization method for hematite-type waste provided by this invention constructs a complete process chain of "hydrochloric acid leaching—composite extraction—water back-extraction—evaporation crystallization". It adopts a synergistic extraction system of TBP and tertiary / quaternary ammonium salts (N235 / N263). TBP improves the polarity of the organic phase, which helps dissolve the ammonium salts of N235 / N263 and prevents the formation of a third phase. The combination of the two greatly improves the back-extraction of the organic phase, thereby supporting the back-extraction of ferric chloride with pure water, and thus achieving efficient and highly selective extraction of iron from hematite waste. The process flow is short, and high-purity ferric chloride back-extraction liquid can be obtained without complicated impurity removal procedures. The final product has high added value and can effectively solve the problems of high separation difficulty, incomplete separation, low product purity and low value, and high energy consumption in existing recycling schemes. Detailed Implementation

[0025] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0026] Those skilled in the art will understand that the embodiments described are merely illustrative of the invention and should not be construed as limiting the invention.

[0027] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0028] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0029] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0030] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0031] Example 1 This embodiment provides a method for the resource utilization of hematite-type waste residue, including the following steps: S1. Leaching: Hematite-type waste residue (containing approximately 40 wt% Fe2O3) is mixed with hydrochloric acid and then subjected to a leaching reaction. The mass percentage concentration of the hydrochloric acid is 31%, and the mass ratio of the hydrochloric acid to the hematite-type waste residue is 4.0:1. The leaching reaction temperature is 57°C, and the reaction time is 9 hours. After the reaction, solid and liquid are separated to obtain the leachate. S2. Iron Extraction: The obtained leachate is mixed with the composite extractive phase and subjected to extraction treatment. The composite extractive phase includes the first extractant TBP and the second extractant N235, as well as the modifier octanol and the diluent kerosene. Based on the volume of the composite extractive phase being 100%, the volume ratio of the first extractant, the second extractant, the modifier, and the diluent is 15%:35%:18.5%:31.5%. The extraction treatment is performed by countercurrent extraction with 8 extraction stages at a temperature of 40°C, resulting in an iron-loaded organic phase. S3. Back-extraction: The obtained iron-rich supported organic phase is mixed with the back-extraction agent pure water and back-extraction is performed. The back-extraction method is countercurrent back-extraction, with 8 back-extraction stages and a temperature of 40°C, to obtain the back-extraction solution. S4. Concentration and Crystallization: The obtained back-extraction solution is evaporated and concentrated, and then the concentrated solution is cooled and crystallized. The resulting crystals are separated by solid-liquid separation and vacuum dried to obtain high-purity ferric chloride crystal products.

[0032] Example 2 In step S2, the second extractant in the composite extraction phase is replaced with N263 instead of N235. Except for the above, the other conditions are exactly the same as in Example 1.

[0033] Example 3 In step S2, the second extractant in the composite extraction phase is replaced by N235 with N235 and N263 in a volume ratio of 1:1. Except for the above, the other conditions are exactly the same as in Example 1.

[0034] Example 4 The difference from Example 1 is that in step S2, the volume ratio of the first extractant, the second extractant, the modifier, and the diluent in the composite extract phase is adjusted from 15%:35%:18.5%:31.5% to 10%:40%:18.5%:31.5%. Apart from the above, the other conditions are exactly the same as in Example 1.

[0035] Example 5 The difference from Example 1 is that in step S2, the volume ratio of the first extractant, the second extractant, the modifier, and the diluent in the composite extract phase is adjusted from 15%:35%:18.5%:31.5% to 20%:30%:18.5%:31.5%. Apart from the above, the other conditions are exactly the same as in Example 1.

[0036] Example 6 The difference from Example 1 is that in step S1, the amount of hydrochloric acid is adjusted so that the mass ratio of the hydrochloric acid to the hematite-type waste residue is changed from 4.0:1 to 3.0:1. Apart from the above, the other conditions are exactly the same as in Example 1.

[0037] Example 7 The difference from Example 1 is that in step S1, the amount of hydrochloric acid is adjusted so that the mass ratio of the hydrochloric acid to the hematite-type waste residue is changed from 4.0:1 to 5.0:1. Apart from the above, the other conditions are exactly the same as in Example 1.

[0038] Comparative Example 1 The difference from Example 1 is that in step S2, only the first extractant TBP is used as the extraction phase. Apart from the above, the other conditions are exactly the same as in Example 1.

[0039] Comparative Example 2 The difference from Example 1 is that in step S2, only the second extractant N235 is used as the extraction phase. Apart from the above, the other conditions are exactly the same as in Example 1.

[0040] Comparative Example 3 The difference from Example 1 is that in step S2, only the second extractant N263 is used as the extraction phase. Apart from the above, the other conditions are exactly the same as in Example 1.

[0041] The above examples and comparative examples were monitored, detected, or calculated to obtain the leaching rate, extraction rate, back-extraction rate, recovery rate of ferric chloride crystals, and purity. The results are recorded in Table 1.

[0042] Table 1 As shown in Table 1, under the appropriate extractant ratios in Examples 1-3, the extraction system exhibited good effects on both iron extraction and subsequent back-extraction, with extraction and back-extraction rates both exceeding 95%, and the purity of ferric chloride crystals exceeding 98%. In Example 4, reducing the TBP:N235 ratio significantly decreased the back-extraction rate. In Example 5, increasing the TBP:N235 ratio resulted in a decrease in extraction rate but an increase in back-extraction rate, indicating that TBP plays a crucial role in regulating the ease of back-extraction of the organic phase in the co-extraction system. Further comparison with Comparative Examples 1-3 revealed that both N235 and N263 exhibited excellent iron extraction performance, but their back-extraction effects were poor in pure water systems. TBP, on the other hand, showed relatively weaker extraction capacity but excellent back-extraction performance. Poor extraction capacity leads to a lower iron recovery rate, while poor back-extraction results in a portion of the active sites in the organic phase being occupied by iron, leading to low utilization and ultimately lower extraction and recovery rates. Furthermore, it results in a lower iron concentration in the back-extraction liquid, increasing the cost of subsequent evaporation and concentration. Therefore, the synergistic use of the two types of extractants in appropriate proportions can achieve ideal overall performance in the extraction and back-extraction of the organic phase. As can be seen from Examples 6-7, the amount of hydrochloric acid is crucial; insufficient acid will not only reduce the leaching rate but also decrease the extraction effect. This is because in this extraction system, Fe mainly reacts with Cl... - FeCl4 is formed - The complex anions are extracted by the extractant, and increasing the amount of hydrochloric acid can provide sufficient Cl. - While hydrochloric acid promotes the extraction reaction, excessive use can also cause the extractant to react with FeCl4. - The strong complexation of the complex anions makes it difficult for Fe to be back-extracted from the pure water system. Therefore, the amount of hydrochloric acid used must be within the appropriate range to achieve good results; too little or too much hydrochloric acid is detrimental to iron recovery.

[0043] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for the resource utilization of hematite-type waste residue, characterized in that, Includes the following steps: Hematite-type waste residue is mixed with hydrochloric acid and leached to obtain leachate; The leachate is mixed with a composite extraction phase, the composite extraction phase comprising a first extractant and a second extractant; the first extractant comprises TBP, and the second extractant comprises N235 and / or N263; extraction is performed to obtain an iron-loaded organic phase. The iron-supported organic phase is mixed with a back-extraction agent, wherein the back-extraction agent is water, and back-extraction is performed to obtain a back-extraction solution. The back-extraction solution is evaporated, concentrated, cooled, and crystallized to obtain ferric chloride product.

2. The method for resource utilization of hematite-type waste residue according to claim 1, characterized in that, The hydrochloric acid has a mass percentage concentration of 20% to 35%. Preferably, the mass ratio of the hydrochloric acid to the hematite-type waste residue is (3~5):

1.

3. The method for resource utilization of hematite-type waste residue according to claim 1 or 2, characterized in that, The leaching reaction is carried out at a temperature of 30℃ to 80℃ for a reaction time of 6h to 12h.

4. The method for resource utilization of hematite-type waste residue according to any one of claims 1-3, characterized in that, With the volume of the composite extraction phase being 100%, the volume percentage of the first extractant is 10% to 20%.

5. The method for resource utilization of hematite-type waste residue according to any one of claims 1-4, characterized in that, With the volume of the composite extractive phase being 100%, the volume percentage of the second extractant is 30% to 40%.

6. The method for resource utilization of hematite-type waste residue according to any one of claims 1-5, characterized in that, The composite extraction phase further includes a modifier, which includes octanol; Preferably, the volume percentage of the modifier is 15% to 20%, based on the volume of the composite extract phase being 100%.

7. The method for resource utilization of hematite-type waste residue according to any one of claims 1-6, characterized in that, The composite extraction phase also includes a diluent, which includes kerosene; Preferably, the volume percentage of the diluent is 30% to 35%, based on the volume of the composite extract phase being 100%.

8. The method for resource utilization of hematite-type waste residue according to any one of claims 1-7, characterized in that, The extraction process includes countercurrent extraction with 5 to 10 extraction stages. Preferably, the extraction temperature is 30℃~50℃.

9. The method for resource utilization of hematite-type waste residue according to any one of claims 1-8, characterized in that, The back-extraction process includes countercurrent back-extraction, with 5 to 10 back-extraction stages; Preferably, the temperature of the back-extraction process is 30℃~50℃.

10. The method for resource utilization of hematite-type waste residue according to any one of claims 1-9, characterized in that, After cooling and crystallization, the resulting crystals are subjected to solid-liquid separation and vacuum drying to obtain ferric chloride product.

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