Method for removing internal inclusions of iron tailings roughed quartz particles

Abstract

Disclosed in the present invention is a method for removing inclusions inside roughing quartz particles of hematite tailings. The method comprises the following steps: S1: roasting and water quenching: roasting the roughing quartz particles of hematite tailings at 650-700 °C for 2-5 hours, followed by water quenching; S2: grinding: grinding the water-quenched quartz particles in step S1 to 500-400 meshes; S3: magnetic separation: removing mineral inclusions from the quartz particles obtained in step S2 by means of a superconducting high-gradient magnetic separator; S4: roasting: roasting the quartz particles obtained in step S3 at 1000-1250 °C for 2-5 hours, followed by cooling, and then roasting at 750-1000 °C for 4-5 hours, the step being repeated 3-5 times; and S5: acid leaching: subjecting the quartz particles obtained in step S4 to three-stage cyclic acid leaching to remove mineral and gas-liquid inclusions from the quartz particles, so as to obtain high-purity quartz sand. The high-purity quartz prepared by the present invention has a SiO2 grade as high as 99.9% or above, which meets the standard of refined quartz sand, thereby effectively achieving the purpose of high-value and resource utilization of hematite tailings.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of solid waste resource cyclic utilization, in particular to a method for removing internal inclusions of iron tailings roughed quartz particles. BACKGROUND ART

[0002] Iron tailings are rich in valuable elements, where the SiO2 content exceeds 70%, which is a valuable quartz resource. How to effectively separate, purify, and recycle the quartz resources from iron tailings and achieve high added-value of iron tailings is a major issue facing enterprise production.

[0003] In response to the above demands, researchers have successively developed technologies for preparing high-purity quartz from iron tailings, including multi-stage flotation, combination of magnetic separation and flotation, chemical leaching, and high-temperature calcination. Since hematite is seriously occurred with quartz in iron tailings and a large amount of hematite and fluid inclusions are wrapped inside quartz particles, it is difficult to separate them from quartz particles by processes of multi-stage flotation or combination of magnetic separation and flotation, resulting in large acid consumption and high operation costs in the chemical leaching process at the rear end. In addition, chemical acid leaching has little effect on the removal of fluid inclusions in quartz particles. At present, the removal of fluid inclusions in quartz particles is mainly achieved through the process of soaking in ammonium nitrate solution, drying, and water quenching, requiring the addition of chemical reagents, which is costly and prone to generating wastewater and polluting the environment. SUMMARY

[0004] The present disclosure provides a method for removing internal inclusions of iron tailings roughed quartz particles, which overcomes the disadvantages of complex processes, large acid consumption and high operation costs in existing technologies. In view of problems of hematite occurred with quartz ore and complex and difficult to treat 2024287289   26 Jun 2026 inclusions in quartz particles in hematite tailings, the present disclosure achieves the removal of inclusions inside the hematite tailings roughed quartz particles and the preparation of high-purity quartz by means of calcination, water quenching, fine grinding, magnetic separation, microwave calcination, and three-stage cyclic acid leaching.

[0005] To achieve the above objectives, some embodiments of the present disclosure may use the following technical solutions:

[0006] The present disclosure provides a method for removing internal inclusions of hematite tailings roughed quartz particles, including the following steps of:

[0007] S1, Calcination and water quenching: calcining the hematite tailings roughed quartz particles at 650-700 °C for 2-5 hours, followed by water quenching the calcined quartz particles;

[0008] S2, Grinding: grinding the quartz particles after water quenching in step S1 to 500 to -400 meshes;

[0009] S3, Magnetic separation: removing mineral inclusions in the quartz particles obtained in step S2 by a superconducting high-gradient magnetic separator;

[0010] S4, Calcination: calcining the quartz particles obtained in step S3 at 10001250 °C for 2-5 hours, then calcining the quartz particles at 750-1000 °C for 4-5 hours after cooling, and repeating this step 3-5 times; and

[0011] S5, Acid leaching: performing three-stage cyclic acid leaching on the quartz particles obtained in step S4 to remove mineral inclusions and fluid inclusions in the quartz particles to obtain high-purity quartz sand.

[0012] The process of three-stage cyclic acid leaching is as follows:

[0013] After a first-stage acid leaching reaction, the reaction product is separated into a first-stage acid leaching solution and a first-stage leaching residue, after a second-stage acid leaching reaction, the reaction product is separated into a second-stage acid leaching solution and a second-stage leaching residue, and after a third-stage acid leaching reaction, the reaction product is separated into a third-stage acid leaching solution and a third-stage leaching residue.

[0014] The first-stage acid leaching solution is used for adjusting the pH of the hematite tailings flotation, the second-stage acid leaching solution and the quartz particles are 2024287289   26 Jun 2026 mixed for the first-stage acid leaching reaction, the third-stage acid leaching solution and the first-stage leaching residue are mixed for the second-stage acid leaching reaction, and a new acid solution and the second-stage leaching residue are mixed for the third-stage acid leaching reaction.

[0015] In the above technical solutions, further, in step S1, a SiO2 content in the hematite tailings roughed quartz particles is more than 95%.

[0016] In the above technical solutions, further, in step S3, a magnetic gradient of the superconducting high-gradient magnetic separator is 2.5-4.5 T.

[0017] In the above technical solutions, further, in step S5, the new acid solution is a mixed acid of hydrochloric acid and sulfuric acid with a volume ratio of 1:1 , and a liquidsolid ratio of the acid leaching reaction is 4:1-9:1.

[0018] In the above technical solutions, further, in step S5, a reaction temperature of the three-stage cyclic acid leaching is 60-90 °C, and a reaction time is 3-9 hours.

[0019] In the above technical solutions, further, a SiO2 content in the high-purity quartz sand is more than or equal to 99.9%.

[0020] The acid leaching of the present disclosure can be vibration-assisted or microwave-assisted to improve the acid leaching effect. The known vibration-assisted or microwave-assisted method in the field can be used for the present disclosure.

[0021] Compared with the prior art, the present disclosure has the following beneficial effects:

[0022] 1. The present disclosure adopts calcination, water quenching, fine grinding, and strong magnetic separation to dissociate and strong magnetic remove the intergrowth and the hematite tailing inclusions in the hematite tailings roughed quartz particles, which can not only deeply remove the mineral inclusions inside the quartz particles through physical means and reduce the chemical leaching acid consumption at the rear end, but also can increase the specific surface area of the quartz particles and the acid leaching solution through fine grinding and reduce the acid leaching time.

[0023] 2. The grade of SiO2 in the high-purity quartz prepared by the present disclosure is up to more than 99.9%, which meets the refined quartz sand standard, and effectively realizes the objective of high added-value and resource utilization of the hematite tailings. 2024287289   26 Jun 2026 BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 shows a schematic diagram of the three-stage cyclic acid leaching process. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following is a further description of the present disclosure in conjunction with embodiments, and do not limit the present disclosure in any way. Taking the hematite tailings roughed quartz particles of Anshan Iron and Steel Group Co., Ltd. as an example, high-purity quartz products with a SiO2 content of not less than 99% was finally obtained through the following experimental procedures for purifying. The chemical compositions of the raw materials in Examples 1-3 are shown in Table 1. Table 1 Chemical compositions of quartz particles (wt%) SiO2    Na2O   P2O5   Fe2O3  AI2O3   CaO     Cl     K2O    SO3    MgO 95.448   0.385   0.383   2.348   0.626     0.3     0.191   0.153   0.112   0.053 Example 1

[0026] S1, Calcination and water quenching: the hematite tailings roughed quartz particles were calcined at 700 °C for 2 hours, and then were water-quenched;

[0027] S2, Grinding: the quartz particles after water quenching in step S1 were ground to 500 to -400 meshes to make the mineral in the quartz particles dissociated from the quartz particles;

[0028] S3, Magnetic separation: the impurity mineral inclusions dissociated from the quartz particles were separated with a superconducting high-gradient magnetic separator, which can reduce the using amount of mixed acid for the following fine purification, wherein the magnetic field gradient of the superconducting high-gradient magnetic separator was 2.5 T;

[0029] S4, Calcination: the fine-gained quartz particles obtained in step S3 were calcined at 1250 °C for 5 hours and followed by cooling, then were calcined again at 750 °C for 5 hours; this step was repeated 5 times to remove the fluid inclusions in the fine-gained quartz particles; and

[0030] S5, Acid leaching: the fine-gained quartz particles obtained in step S4 were subjected to fine purification by means of three-stage cyclic acid leaching to further remove the mineral inclusions and the fluid inclusions in the quartz particles. 2024287289   26 Jun 2026

[0031] The three-stage cyclic acid leaching process was as follows: after a first-stage acid leaching reaction, the reaction product was separated into a first-stage acid leaching solution and a first-stage leaching residue; after a second-stage acid leaching reaction, the reaction product was separated into a second-stage acid leaching solution and a second-stage leaching residue; and after a third-stage acid leaching reaction, the reaction product was separated into a third-stage acid leaching solution and a third-stage leaching residue.

[0032] The first-stage acid leaching solution was used for adjusting the pH of hematite tailings flotation, the second-stage acid leaching solution and the quartz particles were mixed for the first-stage acid leaching reaction, the third-stage acid leaching solution and the first-stage leaching residue were mixed for the second-stage acid leaching reaction, and a new acid solution and the second-stage leaching residue were mixed for the third-stage acid leaching reaction.

[0033] In the three-stage cyclic acid leaching process, the new acid solution was a mixed acid of hydrochloric acid and sulfuric acid with a volume ratio of 1:1 , and a liquidsolid ratio of the acid leaching reaction was 4:1, the reaction temperature was 80 °C, and the reaction time was 6 hours.

[0034] The SiO2 content in the high-purity quartz sand obtained in Example 1 was more than or equal to 99.911%. Example 2

[0035] S1, Calcination and water quenching: the hematite tailings roughed quartz particles were calcined at 650 C for 5 hours, and then were water-quenched;

[0036] S2, Grinding: the quartz particles after water quenching in step S1 were ground to 500 to -400 meshes to make the mineral in the quartz particles dissociated from the quartz particles;

[0037] S3, Magnetic separation: the impurity mineral inclusions dissociated from the quartz particles were separated with a superconducting high-gradient magnetic separator, which can reduce the using amount of mixed acid for the following fine purification, wherein the magnetic field gradient of the superconducting high-gradient magnetic separator was 4.5 T;

[0038] S4, Calcination: the fine-gained quartz particles obtained in step S3 were calcined at 1000 °C for 2 hours and followed by cooling, then were calcined again at 1000 °C for 2024287289   26 Jun 2026 4 hours; this step was repeated 3 times to remove the fluid inclusions in the fine-gained quartz particles; and

[0039] S5, Acid leaching: the fine-gained quartz particles obtained in step S4 were subjected to fine purification by means of three-stage cyclic acid leaching to further remove the mineral inclusions and the fluid inclusions in the quartz particles.

[0040] The three-stage cyclic acid leaching process was as follows: after a first-stage acid leaching reaction, the reaction product was separated into a first-stage acid leaching solution and a first-stage leaching residue; after a second-stage acid leaching reaction, the reaction product was separated into a second-stage acid leaching solution and a second-stage leaching residue; and after a third-stage acid leaching reaction, the reaction product was separated into a third-stage acid leaching solution and a third-stage leaching residue.

[0041] The first-stage acid leaching solution was used for adjusting the pH of hematite tailings flotation, the second-stage acid leaching solution and the quartz particles were mixed for the first-stage acid leaching reaction, the third-stage acid leaching solution and the first-stage leaching residue were mixed for the second-stage acid leaching reaction, and a new acid solution and the second-stage leaching residue were mixed for the third-stage acid leaching reaction.

[0042] In the three-stage cyclic acid leaching process, the new acid solution was a mixed acid of hydrochloric acid and sulfuric acid with a volume ratio of 1:1, and a liquidsolid ratio of the acid leaching reaction was 7:1, the reaction temperature was 80 °C, and the reaction time was 7 hours.

[0043] The SiO2 content in the high-purity quartz sand obtained in Example 1 was more than or equal to 99.929%. Example 3

[0044] S1, Calcination and water quenching: the hematite tailings roughed quartz particles were calcined at 680 C for 3 hours, and then were water-quenched;

[0045] S2, Grinding: the quartz particles after water quenching in step S1 were ground to 500 to -400 meshes to make the mineral in the quartz particles dissociated from the quartz particles; 2024287289   26 Jun 2026

[0046] S3, Magnetic separation: the impurity mineral inclusions dissociated from the quartz particles were separated with a superconducting high-gradient magnetic separator, which can reduce the using amount of mixed acid for the following fine purification, wherein the magnetic field gradient of the superconducting high-gradient magnetic separator was 23 T;

[0047] S4, Calcination: the fine-gained quartz particles obtained in step S3 were calcined at 1100 °C for 4 hours and followed by cooling, then were calcined again at 900 °C for 4.5 hours; this step was repeated 4 times to remove the fluid inclusions in the fine-gained quartz particles; and

[0048] S5, Acid leaching: the fine-gained quartz particles obtained in step S4 were subjected to fine purification by means of three-stage cyclic acid leaching to further remove the mineral inclusions and the fluid inclusions in the quartz particles.

[0049] The three-stage cyclic acid leaching process was as follows: after a first-stage acid leaching reaction, the reaction product was separated into a first-stage acid leaching solution and a first-stage leaching residue; after a second-stage acid leaching reaction, the reaction product was separated into a second-stage acid leaching solution and a second-stage leaching residue; and after a third-stage acid leaching reaction, the reaction product was separated into a third-stage acid leaching solution and a third-stage leaching residue.

[0050] The first-stage acid leaching solution was used for adjusting the pH of hematite tailings flotation, the second-stage acid leaching solution and the quartz particles were mixed for the first-stage acid leaching reaction, the third-stage acid leaching solution and the first-stage leaching residue were mixed for the second-stage acid leaching reaction, and a new acid solution and the second-stage leaching residue were mixed for the third-stage acid leaching reaction.

[0051] In the three-stage cyclic acid leaching process, the new acid solution was a mixed acid of hydrochloric acid and sulfuric acid with a volume ratio of 1:1, and a liquidsolid ratio of the acid leaching reaction was 7:1, the reaction temperature was 70 °C, and the reaction time was 6 hours.

[0052] The SiO2 content in the high-purity quartz sand obtained in Example 1 was more than or equal to 99.904%. 2024287289   26 Jun 2026

[0053] For those skilled in the art, without departing of the scope of the technical solution of the present disclosure, many possible changes and modifications can be made to the technical solution of the present disclosure by using the technical contents disclosed above, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present disclosure without departing of the technical solution of the present disclosure shall still belong to the protection scope of the technical solution of the present disclosure.

[0054] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as, an acknowledgement or admission or any form of suggestion that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

[0055] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

1. A method for removing internal inclusions of hematite tailings roughed quartz particles, comprising the following steps of:S1, calcination and water quenching: calcining the hematite tailings roughed quartz particles at 650-700 °C for 2-5 hours, followed by water quenching the calcined quartz particles;S2, grinding: grinding the quartz particles after water quenching in step S1 to 500 to -400 meshes;S3, magnetic separation: removing mineral inclusions in the quartz particles obtained in step S2 by a superconducting high-gradient magnetic separator;S4, calcination: calcining the quartz particles obtained in step S3 at 1000-1250 °C for 2-5 hours, then calcining the quartz particles at 750-1000 °C for 4-5 hours after cooling, and repeating this step 3-5 times; andS5, acid leaching: performing three-stage cyclic acid leaching on the quartz particles obtained in step S4 to remove mineral inclusions and fluid inclusions in the quartz particles to obtain high-purity quartz sand;wherein a process of three-stage cyclic acid leaching is as follows:after a first-stage acid leaching reaction, the reaction product is separated into a first-stage acid leaching solution and a first-stage leaching residue, after a second-stage acid leaching reaction, the reaction product is separated into a second-stage acid leaching solution and a second-stage leaching residue, and after a third-stage acid leaching reaction, the reaction product is separated into a third-stage acid leaching solution and a third-stage leaching residue; andthe first-stage acid leaching solution is used for adjusting the pH of the hematite tailings flotation, the second-stage acid leaching solution and the quartz particles are mixed for the first-stage acid leaching reaction, the third-stage acid leaching solution and the first-stage leaching residue are mixed for the second-stage acid leaching reaction, and a new acid solution and the second-stage leaching residue are mixed for the third-stage acid leaching reaction.2024287289   26 Jun 20262. The method for removing internal inclusions of hematite tailings roughed quartz particles according to claim 1, wherein in step S1, a SiO2 content in the hematite tailings roughed quartz particles is more than 95%.

3. The method for removing internal inclusions of hematite tailings roughed quartz particles according to either claim 1 or 2, wherein in step S3, a magnetic gradient of the superconducting high-gradient magnetic separator is 2.5-4.5 T.

4. The method for removing internal inclusions of hematite tailings roughed quartz particles according to any one of claims 1 to 3, wherein in step S5, the new acid solution is a mixed acid of hydrochloric acid and sulfuric acid with a volume ratio of 1:1 , and a liquid-solid ratio of the acid leaching reaction is 4:1-9:1.

5. The method for removing internal inclusions of hematite tailings roughed quartz particles according to any one of claims 1 to 4, wherein in step S5, a reaction temperature of the three-stage cyclic acid leaching is 60-90 °C, and a reaction time is 3-9 hours.

6. The method for removing internal inclusions of hematite tailings roughed quartz particles according to any one of claims 1 to 5, wherein a SiO2 content in the high-purity quartz sand is more than or equal to 99.9%.

Images