Method for removing inclusions inside roughing quartz particles of iron tailings

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

A method for removing inclusions inside quartz particles in the roughing process of iron tailings Technical Field

[0001] This invention belongs to the field of solid waste resource recycling technology, specifically relating to a method for removing inclusions inside quartz particles in the roughing process of iron tailings. Background Technology

[0002] Iron tailings contain abundant valuable elements, with SiO2 content exceeding 70%, making them a precious quartz resource. How to effectively separate, purify, and recycle the quartz resources in iron tailings to achieve high added value is a major challenge for enterprises.

[0003] To address these needs, researchers have successively developed technologies such as multi-stage flotation, combined magnetic separation and flotation, chemical leaching, and high-temperature calcination for the preparation of high-purity quartz from iron tailings. Due to the severe intergrowth of hematite and quartz in iron tailings, and the large amount of hematite and gas-liquid inclusions within the quartz particles, multi-stage flotation or combined magnetic separation and flotation processes struggle to separate them from the quartz particles, resulting in high acid consumption and operating costs during the downstream chemical leaching process. Furthermore, chemical acid leaching has little impact on the removal of gas-liquid inclusions from quartz particles. Currently, the main method for removing gas-liquid inclusions from quartz particles is through ammonium nitrate solution soaking-drying-water quenching; however, this process requires the addition of chemical reagents, is costly, and easily generates wastewater, polluting the environment.

[0004] Summary of the Invention

[0005] This invention provides a method for removing inclusions from quartz particles in the roughing process of iron tailings, overcoming the shortcomings of existing technologies such as complex processes, high acid consumption, and high operating costs. Addressing the problems of severe quartz intergrowth in hematite tailings and the complex and difficult-to-treat inclusions in quartz particles, this invention achieves the removal of inclusions from roughing quartz particles and the preparation of high-purity quartz through a process of roasting and water quenching, fine grinding, magnetic separation, microwave roasting, and a three-stage circulating acid leaching.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] This invention provides a method for removing inclusions from the interior of quartz particles in the roughing process of hematite tailings, the method comprising the following steps:

[0008] S1: Roasting and water quenching: Roast the rough quartz particles of hematite tailings at 650-700℃ for 2-5 hours, followed by water quenching;

[0009] S2: Grinding: Grind the water-quenched quartz particles from step S1 to 500 to -400 mesh;

[0010] S3: Magnetic separation: Remove mineral inclusions from the quartz particles obtained in step S2 using a superconducting high gradient magnetic separator;

[0011] S4: Calcination: The quartz particles obtained in step S3 are calcined at 1000-1250℃ for 2-5 hours, then cooled, and then calcined at 750-1000℃ for 4-5 hours. This step is repeated 3-5 times.

[0012] S5: Acid leaching: The quartz particles obtained in step S4 are subjected to three-stage circulating acid leaching to remove minerals and gas-liquid inclusions from the quartz particles and obtain high-purity quartz sand.

[0013] The three-stage circulating acid leaching process is as follows:

[0014] After a first-stage acid leaching reaction, a first-stage acid leaching solution and a first-stage leaching residue are obtained; after a second-stage acid leaching reaction, a second-stage acid leaching solution and a second-stage leaching residue are obtained; and after a third-stage acid leaching reaction, a third-stage acid leaching solution and a third-stage leaching residue are obtained.

[0015] The first stage acid leaching solution is used to adjust the pH of hematite tailings flotation. The second stage acid leaching solution is mixed with quartz particles for the first stage acid leaching. The third stage acid leaching solution is mixed with the first stage leaching residue for the second stage acid leaching. The new acid solution is mixed with the second stage leaching residue for the third stage acid leaching.

[0016] In the above technical solution, further, in step S1, the SiO2 content of the roughing quartz particles of the hematite tailings is greater than 95%.

[0017] In the above technical solution, further, in step S3, the magnetic field gradient of the superconducting high gradient magnetic separator is 2.5 to 4.5 T.

[0018] In the above technical solution, further, in step S5, the new acid solution is a mixture of hydrochloric acid and sulfuric acid, wherein the volume ratio of hydrochloric acid to sulfuric acid is 1:1 and the liquid-solid ratio is 4:1 to 9:1.

[0019] In the above technical solution, further, in step S5, the reaction temperature of the three-stage cyclic acid leaching is 60-90℃, and the reaction time is 3-9h.

[0020] In the above technical solution, the SiO2 content in the high-purity quartz sand is ≥99.9%.

[0021] The acid leaching process of the present invention can improve the acid leaching effect by vibration or microwave assistance, and the vibration or microwave assistance is carried out in a manner well known in the art.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) This invention employs roasting-water quenching-fine grinding-strong magnetic separation to dissociate and remove intergrowths and hematite tailings inclusions from rough quartz particles in hematite tailings using strong magnetic separation. This not only removes mineral inclusions inside quartz particles through physical means, reducing the acid consumption of downstream chemical leaching, but also increases the specific surface area of ​​quartz particles and acid leaching solution through fine grinding, thereby reducing acid leaching time.

[0024] 2) The high-purity quartz prepared by this invention has a SiO2 content of over 99.9%, which meets the standards for refined quartz sand and effectively realizes the purpose of high-value and resource utilization of hematite tailings. Attached Figure Description

[0025] Figure 1 is a schematic diagram of the three-stage circulating acid leaching process. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments, but this does not limit the invention in any way. The following example uses roughing of quartz particles from hematite tailings from the Anshan Iron and Steel Group as an example to describe the step-by-step purification process to obtain a high-purity quartz product with a SiO2 content of not less than 99.9%. The chemical composition of the raw materials in Examples 1-3 is shown in Table 1.

[0027] Table 1 Chemical composition of quartz particles (wt%)

[0028] Example 1

[0029] S1: Calcination and water quenching: Quartz particles obtained from the roughing of hematite tailings are calcined at 700℃ for 2 hours and then water quenched.

[0030] S2: Grinding: Grind the water-quenched quartz particles from step S1 to 500 to -400 mesh to separate the mineral inclusions from the quartz particles.

[0031] S3: Magnetic separation: The impurity minerals dissociated from the quartz particles are separated by a superconducting high-gradient magnetic separator, which reduces the amount of mixed acid used in subsequent refining; the magnetic field gradient of the superconducting high-gradient magnetic separator is 2.5T.

[0032] S4: Calcination: The fine quartz particles obtained in step S3 are calcined at 1250°C for 5 hours and then cooled, and then calcined at 750°C for 5 hours. This step is repeated 5 times to remove gas-liquid inclusions from the fine quartz particles.

[0033] S5: Acid leaching: The fine quartz particles obtained in step S4 are purified by three-stage circulating acid leaching to deeply remove minerals and gas-liquid inclusions from the quartz particles.

[0034] The three-stage circulating acid leaching process is as follows: after the first stage acid leaching reaction, a first stage acid leaching solution and a first stage leaching residue are obtained; after the second stage acid leaching reaction, a second stage acid leaching solution and a second stage leaching residue are obtained; and after the third stage acid leaching reaction, a third stage acid leaching solution and a third stage leaching residue are obtained.

[0035] The first stage acid leaching solution is used to adjust the pH of hematite tailings flotation. The second stage acid leaching solution is mixed with quartz particles for the first stage acid leaching. The third stage acid leaching solution is mixed with the first stage leaching residue for the second stage acid leaching. The new acid solution is mixed with the second stage leaching residue for the third stage acid leaching.

[0036] In the three-stage circulating acid leaching process, the new acid solution is a mixture of hydrochloric acid and sulfuric acid, with a volume ratio of hydrochloric acid to sulfuric acid of 1:1 and a liquid-to-solid ratio of 4:1. The reaction temperature is 80℃ and the reaction time is 6h.

[0037] The high-purity quartz sand obtained in Example 1 has a SiO2 content of ≥99.911%.

[0038] Example 2

[0039] S1: Calcination and water quenching: Quartz particles obtained from the roughing of hematite tailings are calcined at 650℃ for 5 hours and then water quenched.

[0040] S2: Grinding: Grind the water-quenched quartz particles from step S1 to 500 to -400 mesh to separate the mineral inclusions from the quartz particles.

[0041] S3: Magnetic separation: The impurity minerals dissociated from the quartz particles are separated by a superconducting high-gradient magnetic separator, which reduces the amount of mixed acid used in subsequent refining; the magnetic field gradient of the superconducting high-gradient magnetic separator is 4.5T.

[0042] S4: Calcination: The fine quartz particles obtained in step S3 are calcined at 1000℃ for 2 hours and then cooled, and then calcined at 1000℃ for 4 hours. This step is repeated 3 times to remove gas-liquid inclusions in the fine quartz particles.

[0043] S5: Acid leaching: The fine quartz particles obtained in step S4 are purified by three-stage circulating acid leaching to deeply remove minerals and gas-liquid inclusions from the quartz particles.

[0044] The three-stage circulating acid leaching process is as follows: after the first stage acid leaching reaction, a first stage acid leaching solution and a first stage leaching residue are obtained; after the second stage acid leaching reaction, a second stage acid leaching solution and a second stage leaching residue are obtained; and after the third stage acid leaching reaction, a third stage acid leaching solution and a third stage leaching residue are obtained.

[0045] The first stage acid leaching solution is used to adjust the pH of hematite tailings flotation. The second stage acid leaching solution is mixed with quartz particles for the first stage acid leaching. The third stage acid leaching solution is mixed with the first stage leaching residue for the second stage acid leaching. The new acid solution is mixed with the second stage leaching residue for the third stage acid leaching.

[0046] In the three-stage circulating acid leaching process, the new acid solution is a mixture of hydrochloric acid and sulfuric acid, with a volume ratio of hydrochloric acid to sulfuric acid of 1:1 and a liquid-to-solid ratio of 7:1. The reaction temperature is 80℃ and the reaction time is 7h.

[0047] The final high-purity quartz sand has a SiO2 content of ≥99.929%.

[0048] Example 3

[0049] S1: Calcination and water quenching: Quartz particles obtained from the roughing of hematite tailings are calcined at 680℃ for 3 hours and then water quenched.

[0050] S2: Grinding: Grind the water-quenched quartz particles from step S1 to 500 to -400 mesh to separate the mineral inclusions from the quartz particles.

[0051] S3: Magnetic separation: The impurity minerals dissociated from the quartz particles are separated by a superconducting high-gradient magnetic separator, which reduces the amount of mixed acid used in subsequent refining; the magnetic field gradient of the superconducting high-gradient magnetic separator is 3T.

[0052] S4: Calcination: The fine quartz particles obtained in step S3 are calcined at 1100℃ for 4 hours and then cooled, and then calcined at 900℃ for 4.5 hours. This step is repeated 4 times to remove gas-liquid inclusions in the fine quartz particles.

[0053] S5: Acid leaching: The fine quartz particles obtained in step S4 are purified by three-stage circulating acid leaching to deeply remove minerals and gas-liquid inclusions from the quartz particles.

[0054] The three-stage circulating acid leaching process is as follows: after the first stage acid leaching reaction, a first stage acid leaching solution and a first stage leaching residue are obtained; after the second stage acid leaching reaction, a second stage acid leaching solution and a second stage leaching residue are obtained; and after the third stage acid leaching reaction, a third stage acid leaching solution and a third stage leaching residue are obtained.

[0055] The first stage acid leaching solution is used to adjust the pH of hematite tailings flotation. The second stage acid leaching solution is mixed with quartz particles for the first stage acid leaching. The third stage acid leaching solution is mixed with the first stage leaching residue for the second stage acid leaching. The new acid solution is mixed with the second stage leaching residue for the third stage acid leaching.

[0056] In the three-stage circulating acid leaching process, the new acid solution is a mixture of hydrochloric acid and sulfuric acid, with a volume ratio of hydrochloric acid to sulfuric acid of 1:1 and a liquid-to-solid ratio of 7:1. The reaction temperature is 70℃ and the reaction time is 6h.

[0057] The final high-purity quartz sand has a SiO2 content of ≥99.904%.

[0058] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A method for removing inclusions from the interior of quartz particles in the roughing process of hematite tailings, characterized in that, The method includes the following steps: S1: Roasting and water quenching: Roast the rough quartz particles of hematite tailings at 650-700℃ for 2-5 hours, followed by water quenching; S2: Grinding: Grind the water-quenched quartz particles from step S1 to 500 to -400 mesh; S3: Magnetic separation: Remove mineral inclusions from the quartz particles obtained in step S2 using a superconducting high gradient magnetic separator; S4: Calcination: The quartz particles obtained in step S3 are calcined at 1000-1250℃ for 2-5 hours, then cooled, and then calcined at 750-1000℃ for 4-5 hours. This step is repeated 3-5 times. S5: Acid leaching: The quartz particles obtained in step S4 are subjected to three-stage circulating acid leaching to remove minerals and gas-liquid inclusions from the quartz particles and obtain high-purity quartz sand. The three-stage circulating acid leaching process is as follows: After a first-stage acid leaching reaction, a first-stage acid leaching solution and a first-stage leaching residue are obtained; after a second-stage acid leaching reaction, a second-stage acid leaching solution and a second-stage leaching residue are obtained; and after a third-stage acid leaching reaction, a third-stage acid leaching solution and a third-stage leaching residue are obtained. The first stage acid leaching solution is used to adjust the pH of hematite tailings flotation. The second stage acid leaching solution is mixed with quartz particles for the first stage acid leaching. The third stage acid leaching solution is mixed with the first stage leaching residue for the second stage acid leaching. The new acid solution is mixed with the second stage leaching residue for the third stage acid leaching.

2. The method for removing inclusions inside quartz particles in the roughing process of hematite tailings according to claim 1, characterized in that, In step S1, the SiO2 content of the roughing quartz particles in the hematite tailings is greater than 95%.

3. The method for removing inclusions inside quartz particles in the roughing process of hematite tailings according to claim 1, characterized in that, In step S3, the magnetic field gradient of the superconducting high gradient magnetic separator is 2.5 to 4.5 T.

4. The method for removing inclusions inside quartz particles in the roughing process of hematite tailings according to claim 1, characterized in that, In step S5, the new acid solution is a mixture of hydrochloric acid and sulfuric acid, wherein the volume ratio of hydrochloric acid to sulfuric acid is 1:1 and the liquid-solid ratio is 4:1 to 9:

1.

5. The method for removing inclusions from the internal structure of quartz particles in the roughing process of hematite tailings according to claim 1, characterized in that, In step S5, the reaction temperature of the three-stage cyclic acid leaching is 60-90℃, and the reaction time is 3-9h.

6. The method for removing inclusions inside quartz particles in the roughing process of hematite tailings according to claim 1, characterized in that, The high-purity quartz sand contains ≥99.9% SiO2.

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