A beneficiation method for preparing super-pure iron concentrate from magnetite

Abstract

The present invention discloses a beneficiation method for preparing super-pure iron concentrate by using magnetite, belonging to the technical field of beneficiation. The steps of the present invention are as follows: (1) rough selection experiment; (2) stage grinding and flotation test on the rough concentrate, four times of cleaning experiments; (3) leaching experiment; (4) acid leaching experiment: adding the leached concentrate into dilute sulfuric acid with a mass fraction of 5%, carrying out the acid leaching experiment, washing the obtained ore to neutrality, and the washed concentrate is the super-pure iron concentrate. The present invention realizes the efficient impurity removal of iron concentrate through the combined physical-chemical method, improves the grade of iron concentrate, and significantly reduces the content of silicon dioxide. The TFe grade in the finally obtained super-pure iron concentrate is as high as 72.29%, the Fe3O4 purity of the concentrate can be increased to 99.90%, the content of SiO2 is reduced to 0.07%, and the content of Al2O3 is reduced to 0.03%. The indexes of the super-pure iron concentrate prepared by the present invention are at a relatively high level in the current super-pure iron concentrate preparation industry.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, and more specifically, to an ore dressing method for preparing super pure iron concentrate by using magnetite. Background Art

[0002] With the continuous development of China's industry, especially the automotive and home appliance industries, the demand for permanent magnetic materials and high-quality reduced iron powder in China is increasing. At present, the raw materials for industries such as permanent magnetic materials and reduced iron powder in China are mainly iron phosphide and iron oxide red, but their chemical compositions are complex and their properties are unstable, making it difficult to produce permanent magnetic materials with stable quality. Therefore, there is an urgent need to find a new cheap raw material to replace them.

[0003] Super pure iron concentrate has the characteristics of high purity, few harmful impurities, high stability and large mining volume, and has been widely used in the preparation of ferrites at home and abroad. Super pure iron concentrate generally refers to iron concentrate with an iron grade higher than 71% and a silica content lower than 0.2%. Super pure iron concentrate is a new type of iron-based material with certain development potential and has a very broad development prospect.

[0004] Although China is rich in iron resources, the average grade of China's iron ore resources is relatively low, about 25% on average, and most of them are lean ores. Therefore, it is necessary to prepare super pure iron concentrate through ore dressing processes. At present, the preparation processes of super pure iron concentrate are divided into magnetic separation - flotation method and grinding - gravity separation combined process. The magnetic separation - flotation method process is mainly that magnetite is ground and magnetically separated to obtain magnetic separation concentrate, and the magnetic separation concentrate is reground and then reverse flotation desilication is carried out using amine collectors to prepare super pure iron concentrate. The grinding - gravity separation combined process is mainly that magnetite is ground and magnetically separated, the magnetic separation concentrate is reground, and magnetic separation is carried out multiple times, and the magnetic separation concentrate is classified to obtain super pure iron concentrate. The iron grade of the super pure iron concentrate prepared by the above methods is still not ideal, and SiO2 still cannot be effectively removed. Summary of the Invention

[0005] 1. Technical Problems to be Solved by the Invention

[0006] Aiming at the defects and deficiencies of the existing technology, such as low iron grade and high SiO2 content, the present invention provides an ore dressing method for preparing super pure iron concentrate by using magnetite. The present invention realizes the efficient impurity removal of iron concentrate through a physical - chemical combined method, improves the grade of iron concentrate, and significantly reduces the content of silicon dioxide. The TFe grade in the finally obtained super pure iron concentrate is as high as 72.29%, the Fe3O4 purity of the concentrate can be increased to 99.90%, the content of SiO2 is reduced to 0.07%, and the content of Al2O3 is reduced to 0.03%. The indexes of the super pure iron concentrate prepared by the present invention are at a relatively high level in the current super pure iron concentrate preparation industry.

[0007] 2. Technical Solutions

[0008] To achieve the above object, the technical solution provided by the present invention is as follows:

[0009] A beneficiation method for preparing super pure iron concentrate from magnetite according to the present invention comprises the following steps:

[0010] (1) Rough selection experiment: Magnetite with a TFe content of 65.56% is put into a flotation cell, collector D is added, stirred for 3 min, and then rough selection is carried out to obtain rough concentrate and tailings;

[0011] (2) Staged grinding and flotation test on the rough concentrate, four times of cleaning experiments:

[0012] The rough concentrate obtained in step (1) is added to a ball mill. After ball milling for a period of time, the first cleaning is carried out to obtain concentrate 1 and middling 1;

[0013] After the obtained concentrate 1 is ball milled for a period of time, the second cleaning experiment is carried out to obtain concentrate 2 and middling 2;

[0014] After the obtained concentrate 2 is ball milled for a certain period of time, the third cleaning experiment is carried out to obtain concentrate 3 and middling 3;

[0015] After the obtained concentrate 3 is ball milled for a certain period of time, the fourth cleaning experiment is carried out to obtain flotation concentrate and middling 4;

[0016] (3) Leaching experiment: The flotation concentrate obtained in step (2) is added to a high-pressure reactor, a certain amount of NaOH is added, the temperature of the high-pressure reactor is set at 140 °C, and the rotation speed is 300 r / min; the obtained concentrate after leaching is washed multiple times to obtain leached concentrate;

[0017] (4) Acid leaching experiment: The leached concentrate obtained in step (3) is added to dilute sulfuric acid with a mass fraction of 5% for acid leaching experiment, and the obtained ore is washed to neutrality. The washed concentrate is the super pure iron concentrate.

[0018] Further, in the step (1), the rough selection collector D is a collector containing amino or fatty acid.

[0019] Further, in the step (1), the dosage of the rough selection collector D is 135 g / t.

[0020] Further, in the step (2), the grinding times in the four staged grinding and flotation processes are 20 - 60 s, 40 s, 20 - 60 s, and 0 - 50 s respectively.

[0021] Further, in the step (2), sulfuric acid is used as the pH adjuster in the four staged grinding and flotation processes to adjust the pulp pH value to 7.

[0022] Further, in the step (2), the collector used in the first and second roughing is Collector D, and Collector D is a collector containing amino groups or fatty acids; the collector used in the third and fourth roughing is Collector C-O, and Collector C-O is a collector containing fatty acids or sulfonic acid groups.

[0023] Further, in the step (2), the dosage of Collector D in the first roughing is 50 - 70 g / t, the dosage of Collector D in the second roughing is 50 - 70 g / t, the dosage of Collector C-O in the third roughing is 30 - 60 g / t; the dosage of Collector C-O in the fourth roughing is 0 - 50 g / t.

[0024] Further, in the step (2), the roughing time in the four - stage grinding and flotation process is 3 min.

[0025] Further, in the step (3), the addition amount of NaOH is 100 - 450 g / L.

[0026] 3. Beneficial effects

[0027] Adopting the technical solution provided by the present invention, compared with the prior art, it has the following beneficial effects:

[0028] The present invention realizes the efficient impurity removal of iron concentrate through a physical - chemical combined method, improves the grade of iron concentrate, and significantly reduces the content of silicon dioxide. The TFe grade in the finally obtained ultra - pure iron concentrate is as high as 72.29%, the Fe3O4 purity of the concentrate can be increased to 99.90%, the content of SiO2 is reduced to 0.07%, and the content of Al2O3 is reduced to 0.03%. The indexes of the ultra - pure iron concentrate prepared by the present invention are at a relatively high level in the current ultra - pure iron concentrate preparation industry. Description of the drawings

[0029] Figure 1 It is the process flow chart of the present invention. Specific embodiments

[0030] In the specific embodiments disclosed by the present invention: the TFe in the selected magnetite raw ore is 65.56%, the purity is 90.60%, the Al2O3 content is 0.38%, and the SiO2 content is 8.28%. Through the analysis of the properties of the raw ore, it can be known that the dissemination size of this magnetite is relatively fine.

[0031] The following further describes the present invention with reference to the drawings and embodiments:

[0032] Example 1

[0033] To verify the influence of the grinding time in the staged grinding and flotation process of the present invention on the iron grade of the prepared ultra-pure iron concentrate, the beneficiation method in this embodiment is used for separation. The methods in this embodiment are the same, except for the different grinding and flotation times in the staged grinding and flotation, so as to compare the influence of different grinding times in this embodiment on the grade of ultra-pure iron concentrate.

[0034] From Figure 1 It can be seen that a beneficiation method for preparing ultra-pure iron concentrate using magnetite in this embodiment has the following steps:

[0035] (1) Rough selection experiment: Magnetite with a TFe content of 65.56% is put into a flotation cell, and collector D is added, stirred for 3 min, and then rough selection is carried out to obtain rough concentrate and tailings;

[0036] (2) Staged grinding and flotation test on the rough concentrate, four times of cleaning experiments:

[0037] The rough concentrate obtained in step (1) is added to a ball mill. After ball milling for a period of time, the first cleaning is carried out to obtain concentrate 1 and middling 1;

[0038] After the obtained concentrate 1 is ball milled for a period of time, the second cleaning experiment is carried out to obtain concentrate 2 and middling 2;

[0039] After the obtained concentrate 2 is ball milled for a certain time, the third cleaning experiment is carried out to obtain concentrate 3 and middling 3;

[0040] After the obtained concentrate 3 is ball milled for a certain time, the fourth cleaning experiment is carried out to obtain flotation concentrate and middling 4;

[0041] (3) Leaching experiment: The flotation concentrate obtained in step (2) is added to a high-pressure reactor, and a certain amount of NaOH is added. The temperature of the high-pressure reactor is set to 140 °C and the rotation speed is 300 r / min; the obtained concentrate after leaching is washed multiple times to obtain leached concentrate;

[0042] (4) Acid leaching experiment: The leached concentrate obtained in step (3) is added to dilute sulfuric acid with a mass fraction of 5% for acid leaching experiment. The obtained ore is washed to neutrality, and the washed concentrate is the ultra-pure iron concentrate.

[0043] In step (1), the rough selection collector D is a collector containing amino or fatty acid.

[0044] In step (1), the dosage of the rough selection collector D is 135 g / t.

[0045] In step (2), the grinding times in the four times of staged grinding and flotation are 20 - 60 s, 40 s, 20 - 60 s, and 0 - 50 s respectively.

[0046] In step (2), sulfuric acid is used as the pH adjuster in the four-stage grinding and flotation process to adjust the pH value of the pulp to 7.

[0047] In step (2), the collector used in the first roughing and the second roughing is Collector D, and Collector D is a collector containing amino groups or fatty acids; the collector used in the third roughing and the fourth roughing is Collector C-O, and Collector C-O is a collector containing fatty acids or sulfonic acid groups.

[0048] In step (2), the dosage of Collector D in the first roughing is 65 g / t, the dosage of Collector D in the second roughing is 55 g / t, the dosage of Collector C-O in the third roughing is 45 g / t; the dosage of Collector C-O in the fourth roughing is 45 g / t.

[0049] In step (2), the roughing time in the four-stage grinding and flotation process is 3 min.

[0050] In step (3), the addition amount of NaOH is 400 g / L.

[0051] Table 1 Influence of grinding time on iron grade of ultra-pure iron concentrate in the staged grinding and flotation test

[0052]

[0053] As can be seen from Table 1, when the four grinding times are 30 s, 40 s, 50 s and 20 s respectively, the grade of the ultra-pure iron concentrate can reach 72.10%.

[0054] Example 2

[0055] In order to verify the influence of the dosage of the roughing agent in the staged grinding and flotation process of the present invention on the iron grade of the prepared ultra-pure iron concentrate, the beneficiation method in this example is used for separation. The method in this example is the same, except that the dosage of the roughing agent in the staged grinding and flotation is different, so as to compare the influence of different dosages of the roughing agent in this example on the grade of the ultra-pure iron concentrate.

[0056] From Figure 1 It can be seen that a beneficiation method for preparing ultra-pure iron concentrate from magnetite in this example comprises the following steps:

[0057] (1) Roughing experiment: Magnetite with a TFe content of 65.56% is put into a flotation cell, and Collector D is added, and it is stirred for 3 min, and then roughing is carried out to obtain rough concentrate and tailings;

[0058] (2) The rough concentrate is subjected to a staged grinding and flotation test, and four roughing experiments are carried out:

[0059] Add the rough concentrate obtained in step (1) to a ball mill. After ball milling for a period of time, conduct the first beneficiation to obtain concentrate 1 and middlings 1;

[0060] After ball milling the obtained concentrate 1 for a period of time, conduct the second beneficiation experiment to obtain concentrate 2 and middlings 2;

[0061] After ball milling the obtained concentrate 2 for a certain period of time, conduct the third beneficiation experiment to obtain concentrate 3 and middlings 3;

[0062] After ball milling the obtained concentrate 3 for a certain period of time, conduct the fourth beneficiation experiment to obtain flotation concentrate and middlings 4;

[0063] (3) Leaching experiment: Add the flotation concentrate obtained in step (2) to a high-pressure reactor, and add a certain amount of NaOH. Set the temperature of the high-pressure reactor to 140 °C and the rotation speed to 300 r / min; Wash the leached concentrate multiple times to obtain leached concentrate;

[0064] (4) Acid leaching experiment: Add the leached concentrate obtained in step (3) to dilute sulfuric acid with a mass fraction of 5%, conduct an acid leaching experiment, wash the obtained ore to neutrality, and the washed concentrate is super pure iron concentrate.

[0065] In step (1), the roughing collector D is a collector containing amino or fatty acid.

[0066] In step (1), the dosage of the roughing collector D is 135 g / t.

[0067] In step (2), the grinding times in the four-stage grinding and flotation are 30 s, 40 s, 50 s, and 20 s respectively.

[0068] In step (2), sulfuric acid is used as the pH adjuster in the four-stage grinding and flotation process to adjust the pulp pH value to 7.

[0069] In step (2), the collectors for the first beneficiation and the second beneficiation are collector D, and collector D is a collector containing amino or fatty acid; the collectors for the third beneficiation and the fourth beneficiation are collector C-O, and collector C-O is a collector containing fatty acid or sulfonic acid group.

[0070] In step (2), the dosage of collector D in the first beneficiation is 50 - 70 g / t, the dosage of collector D in the second beneficiation is 50 - 70 g / t, the dosage of collector C-O in the third beneficiation is 30 - 60 g / t; the dosage of collector C-O in the fourth beneficiation is 0 - 50 g / t.

[0071] In step (2), the beneficiation time in the four-stage grinding and flotation process is 3 min.

[0072] In step (3), the addition amount of NaOH is 450 g / L

[0073] Table 2 Influence of the dosage of beneficiation reagents in the stage grinding and flotation tests on the iron grade of ultra-pure iron concentrate

[0074]

[0075] As can be seen from Table 2, the dosage of collector D in the first roughing is 65 g / t, the dosage of collector D in the second roughing is 55 g / t, the dosage of collector C-O in the third roughing is 55 g / t, and the dosage of collector C-O in the fourth roughing is 45 g / t. At this time, the iron grade of the prepared ultra-pure iron concentrate is 72.10%.

[0076] Example 3

[0077] In order to verify the influence of the NaOH dosage in the alkali leaching process of the present invention on the iron grade of the prepared ultra-pure iron concentrate, the beneficiation method in this example is used for separation. The method in this example is the same, except that the NaOH dosage in the alkali leaching process is different, so as to compare the influence of different NaOH dosages in this example on the grade of ultra-pure iron concentrate.

[0078] From Figure 1 It can be seen that a beneficiation method for preparing ultra-pure iron concentrate from magnetite in this example has the following steps:

[0079] (1) Roughing experiment: Magnetite with a TFe content of 65.56% is put into a flotation cell, and collector D is added, stirred for 3 min, and then roughing is carried out to obtain rough concentrate and tailings;

[0080] (2) The rough concentrate is subjected to stage grinding and flotation tests, and four roughing experiments:

[0081] The rough concentrate obtained in step (1) is added to a ball mill. After ball milling for a period of time, the first roughing is carried out to obtain concentrate 1 and middling 1;

[0082] After the obtained concentrate 1 is ball milled for a period of time, the second roughing experiment is carried out to obtain concentrate 2 and middling 2;

[0083] After the obtained concentrate 2 is ball milled for a certain period of time, the third roughing experiment is carried out to obtain concentrate 3 and middling 3;

[0084] After the obtained concentrate 3 is ball milled for a certain period of time, the fourth roughing experiment is carried out to obtain flotation concentrate and middling 4;

[0085] (3) Leaching experiment: Add the flotation concentrate obtained in step (2) into a high-pressure reactor, and add a certain amount of NaOH. Set the temperature of the high-pressure reactor to 140 °C and the rotation speed to 300 r / min; Wash the concentrate obtained by leaching multiple times to obtain the leached concentrate.

[0086] (4) Acid leaching experiment: Add the leached concentrate obtained in step (3) into dilute sulfuric acid with a mass fraction of 5%, conduct an acid leaching experiment, wash the obtained ore to neutrality, and the washed concentrate is the ultra-pure iron concentrate.

[0087] In step (1), the rougher collector D is a collector containing amino groups or fatty acids.

[0088] In step (1), the dosage of the rougher collector D is 135 g / t.

[0089] In step (2), the grinding times in the four-stage sequential grinding and flotation are 30 s, 40 s, 50 s, and 20 s respectively.

[0090] In step (2), sulfuric acid is used as the pH adjuster in the four-stage sequential grinding and flotation process to adjust the pulp pH value to 7.

[0091] In step (2), the collector for the first cleaning and the second cleaning is collector D, and collector D is a collector containing amino groups or fatty acids; the collector for the third cleaning and the fourth cleaning is collector C-O, and collector C-O is a collector containing fatty acids or sulfonic acid groups.

[0092] In step (2), the dosage of collector D in the first cleaning is 65 g / t, the dosage of collector D in the second cleaning is 55 g / t, the dosage of collector C-O in the third cleaning is 45 g / t; the dosage of collector C-O in the fourth cleaning is 45 g / t.

[0093] In step (2), the cleaning time in the four-stage sequential grinding and flotation process is 3 min.

[0094] In step (3), the addition amount of NaOH is 100 - 450 g / L

[0095] Table 3 Influence of NaOH dosage in the alkali leaching process on the iron grade of ultra-pure iron concentrate

[0096]

[0097]

[0098] As can be seen from Table 3, when the dosage of NaOH is 400 g / L, the iron grade of the prepared ultra-pure iron concentrate can reach 72.29%. At this time, the purity of Fe3O4 is 99.90%, the content of SiO2 drops to 0.07%, and the content of Al2O3 drops to 0.03%.

[0099] In the beneficiation method for preparing ultra-pure iron concentrate from magnetite according to the present invention, the iron grade of the prepared ultra-pure iron concentrate can reach 72.29%, the purity of Fe3O4 is 99.90%, and the content of SiO2 drops to 0.07%.

[0100] The present invention realizes the efficient impurity removal of iron concentrate through a combined physical-chemical method, improves the grade of iron concentrate, and significantly reduces the content of silicon dioxide. The TFe grade in the finally obtained ultra-pure iron concentrate is as high as 72.29%, the purity of Fe3O4 in the concentrate can be increased to 99.90%, the content of SiO2 drops to 0.07%, and the content of Al2O3 drops to 0.03%. The indexes of the ultra-pure iron concentrate prepared by the present invention are at a relatively high level in the current ultra-pure iron concentrate preparation industry.

[0101] The present invention and its embodiments are schematically described above. The description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural modes and embodiments without creative work without departing from the spirit of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A beneficiation method for preparing super pure iron concentrate from magnetite, characterized in that: The steps are as follows: (1) Rough selection experiment: Put magnetite with a TFe content of 65.56% into a flotation cell, add collector D, stir for 3 min, and then conduct rough selection to obtain rough concentrate and tailings; (2) Conduct stage grinding and flotation experiments on the rough concentrate, with four fine selection experiments: Add the rough concentrate obtained in step (1) to a ball mill. After ball milling for a period of time, conduct the first fine selection to obtain concentrate 1 and middlings 1; After ball milling the obtained concentrate 1 for a period of time, conduct the second fine selection experiment to obtain concentrate 2 and middlings 2; After ball milling the obtained concentrate 2 for a certain period of time, conduct the third fine selection experiment to obtain concentrate 3 and middlings 3; After ball milling the obtained concentrate 3 for a certain period of time, conduct the fourth fine selection experiment to obtain flotation concentrate and middlings 4; (3) Leaching experiment: Add the flotation concentrate obtained in step (2) to a high-pressure reactor, add a certain amount of NaOH, set the temperature of the high-pressure reactor to 140 °C, and the rotation speed to 300 r / min; Wash the leached concentrate multiple times to obtain leached concentrate; (4) Acid leaching experiment: Add the leached concentrate obtained in step (3) to dilute sulfuric acid with a mass fraction of 5% for acid leaching experiment. Wash the obtained ore to neutrality, and the washed concentrate is super pure iron concentrate.

2. The beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 1, characterized in that: In the said step (1), the rough selection collector D is a collector containing amino or fatty acid.

3. The beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 2, characterized in that: In the said step (1), the dosage of the rough selection collector D is 135 g / t.

4. A beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 1, characterized in that: In the said step (2), the grinding times in the four-stage grinding and flotation are 20 - 60 s, 40 s, 20 - 60 s, and 0 - 50 s respectively.

5. A beneficiation method for preparing super-pure iron concentrate using magnetite according to claim 4, characterized in that: In the said step (2), sulfuric acid is used as the pH adjuster in the four-stage grinding and flotation process to adjust the pulp pH value to 7.

6. The beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 1, characterized in that: In the said step (2), the collectors for the first and second fine selections are collector D, and collector D is a collector containing amino or fatty acid; The collectors for the third and fourth fine selections are collector C - O, and collector C - O is a collector containing fatty acid or sulfonic acid group.

7. The beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 6, characterized in that: In the said step (2), the dosage of collector D in the first fine selection is 50 - 70 g / t, the dosage of collector D in the second fine selection is 50 - 70 g / t, the dosage of collector C - O in the third fine selection is 30 - 60 g / t; The dosage of collector C - O in the fourth fine selection is 0 - 50 g / t.

8. The beneficiation method for preparing super pure iron concentrate by using magnetite according to claim 7, characterized in that: In the said step (2), the fine selection time in the four-stage grinding and flotation process is 3 min.

9. The ore dressing method for preparing super pure iron concentrate by using magnetite according to claim 1, characterized in that: In the said step (3), the addition amount of NaOH is 100 - 450 g / L.

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