Phosphorite double-reverse flotation method

Abstract

The invention relates to the technical field of phosphorite flotation, and particularly provides a phosphorite double-reverse flotation method. The method comprises the following steps: (1) ore pretreatment; (2) primary flotation is conducted, specifically, 10-15 kg / t of raw ore mixed acid and 1-1.5 kg / t of raw ore first collecting agent are added into the ore pulp, reverse flotation is conducted, foam is removed, and primary flotation ore pulp is obtained; the mixed acid comprises sulfuric acid, caffeic acid and phosphoric acid; the first collecting agent comprises sodium laurate and sodium linolenate; (3) secondary flotation is conducted, specifically, alkali is added into the primary flotation ore pulp, then a second collecting agent accounting for 0.8-1.3 kg / t of raw ore is added, reverse flotation is conducted, foam is removed, and phosphate concentrate is obtained; and the second collecting agent comprises lauryl amine, sodium carbonate and polyacrylonitrile. Compared with the prior art, the double-reverse flotation method has the advantages that high-quality phosphate concentrate products can be obtained, consumption of chemicals is reduced, and production cost is lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphate ore flotation, and more specifically to a double reverse flotation method for phosphate ore. Background Art

[0002] Phosphorus is of great significance to ensuring national food production safety and promoting the sustainable and healthy development of the mineral industry. It is also an indispensable raw material for the production of phosphorus industrial products and is irreplaceable. More than 75% of phosphate resources come from sedimentary origin. Most phosphate ores are not suitable for direct use in the acidification process due to their low P2O5 content and the presence of gangue minerals. Due to the small particle size, rich content and complex structural structure of collophanite, there are certain difficulties in using this phosphate ore for the phosphide industry. However, through scientific management and control and technological transformation, the dependence on this phosphate ore can be greatly reduced, thereby better exerting its value. This will help to improve the utilization rate of phosphorus resources and extend the mining life of phosphate ore.

[0003] Therefore, how to economically and efficiently develop these low-grade phosphate ores is a major challenge facing the phosphate beneficiation industry. Therefore, the improvement of the grade of medium and low-grade phosphate ores and the output of related phosphate industrial products are of great significance to alleviating the phosphorus resource crisis and promoting the green and environmental protection of the phosphorus chemical industry.

[0004] Common phosphate ore beneficiation methods include flotation, magnetic separation, chemical beneficiation and gravity separation. Since the floating of silicate and carbonate gangue minerals mostly depends on mineralized foam, phosphate ore beneficiation mainly adopts froth flotation, especially for low-grade sedimentary phosphate ore. To remove silicate gangue from phosphate ore, reverse flotation is generally used to capture gangue silicon and other impurities. The existing reverse flotation has a poor beneficiation effect on low-grade raw ores, and it is difficult to obtain high-quality phosphate concentrate products. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a double reverse flotation method for phosphate ore. Through the method of the present invention, high-quality phosphate concentrate products can be obtained, while reducing the consumption of reagents and lowering production costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A double reverse flotation method for phosphate ore, comprising:

[0008] (1) Ore pretreatment: Mix the raw ore with water to make a slurry with a concentration of 20-30wt%;

[0009] (2) Primary flotation: 10-15 kg / t of mixed acid and 1-1.5 kg / t of first collector are added to the pulp to perform reverse flotation to remove foam and obtain primary pulp;

[0010] The mixed acid includes sulfuric acid, caffeic acid and phosphoric acid;

[0011] The first collector includes sodium laurate and sodium linolenate;

[0012] (3) Secondary flotation: add alkali to the primary ore pulp, then add 0.8-1.3 kg / t of the second collector to perform reverse flotation to remove the foam and obtain phosphate concentrate;

[0013] The second collector includes dodecylamine, sodium carbonate and polyacrylonitrile.

[0014] Preferably, in step (2), the amount of the mixed acid added is 12kg / t, 15kg or 10kg; the amount of the first collector added is 1.3kg / t, 1.4kg / t or 1.0kg / t.

[0015] Preferably, in step (3), the amount of the second collector added is 0.8 kg / t, 1.1 kg / t or 0.9 kg / t.

[0016] Preferably, the mass ratio of sulfuric acid, caffeic acid and phosphoric acid is (1-5):(1-2):2, more preferably 3:1:2 or 3:2:2.

[0017] Preferably, the mass ratio of sodium laurate to sodium linolenate is (3-6):2, more preferably 3:2 or 5:2.

[0018] Preferably, the sodium linolenate includes sodium α-linolenate;

[0019] The weight average molecular weight of the polyacrylonitrile is 50,000 to 100,000 g / mol.

[0020] Preferably, the mass ratio of dodecylamine, sodium carbonate and polyacrylonitrile is (8-10):(3-4):1, more preferably 10:3:1, 10:4:1 or 9:3:1.

[0021] Preferably, in step (1), the ore is crushed and rod-milled before being mixed with water.

[0022] Preferably, the ore is subjected to the pulverization and rod milling treatment until the grinding fineness is -200 mesh accounting for 90%.

[0023] Preferably, the base includes one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide, preferably sodium hydroxide.

[0024] Preferably, alkali is added to the primary ore pulp to adjust the pH to 7.0-8.0.

[0025] Preferably, after adding the first collector, the system is aerated at a rate of 150 to 200 L / h;

[0026] After adding the second collector, the system is aerated with a gas volume of 150 to 200 L / h.

[0027] Compared with the prior art, the double reverse flotation method of phosphate ore of the present invention first pre-treats the ore to make the ore into slurry, and then performs primary flotation and secondary flotation; wherein, the primary flotation adopts a mixed acid including sulfuric acid, caffeic acid and phosphoric acid as an acid regulator, which is used in combination with a first collector including sodium laurate and sodium linolenate, and is mainly used to remove magnesium impurities in the slurry; the secondary flotation adopts a second collector including dodecylamine, sodium carbonate and polyacrylonitrile for flotation, and is mainly used to remove silicon impurities in the slurry; dodecylamine, sodium carbonate and polyacrylonitrile are used in combination, and the adsorption capacity is enhanced, so that high-quality phosphate concentrate products can be obtained, while reducing the consumption of reagents and reducing production costs. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to further illustrate the present invention, the following examples are used to provide a detailed description. The raw materials used in the following examples and comparative examples of the present invention are all commercially available products, wherein the weight average molecular weight of polyacrylonitrile is 50000 g / mol.

[0030] Example 1

[0031] The double reverse flotation method of phosphate rock of the present embodiment comprises the following steps:

[0032] (1) Ore pretreatment: The phosphate ore (grade 22.5%) is crushed and rod-milled until the grinding fineness of -200 mesh accounts for 90%, and water is added to make a slurry with a concentration of 20wt%.

[0033] (2) Primary flotation: at 20°C, the pulp was placed in a flotation machine for flotation, 12 kg / t of mixed acid and 1.3 kg / t of the original ore were added to the flotation machine, and stirred for 10 minutes; the mixed acid was sulfuric acid, caffeic acid and phosphoric acid in a mass ratio of 3:1:2; the first collector was sodium laurate and sodium α-linolenate in a mass ratio of 3:2; then, the flotation machine aeration switch was turned on, the aeration volume was adjusted to 150 L / h, reverse flotation was performed, foam was removed, and primary slurry was obtained.

[0034] (3) Secondary flotation: adjust the pH of the primary ore pulp to 7.0 with NaOH, stir for 5 minutes, then add the second collector to the ore pulp and stir for 10 minutes; the amount of the second collector added is 0.9 kg / t of the original ore, and the second collector is dodecylamine, sodium carbonate and polyacrylonitrile in a mass ratio of 10:3:1; then, turn on the flotation machine inflation switch, adjust the inflation volume to 150 L / h, perform reverse flotation, remove the foam, and obtain phosphate concentrate.

[0035] Through the above process, the grade of phosphate concentrate can reach 36.4%, the recovery rate is 84.7%, the magnesium oxide content is 0.37%, and the sesquioxide content is 5.42%.

[0036] Example 2

[0037] The double reverse flotation method of phosphate rock of the present embodiment comprises the following steps:

[0038] (1) Ore pretreatment: The phosphate ore (grade 22.5%) was crushed and rod-milled until the grinding fineness of -200 mesh accounted for 90%, and water was added to the phosphate ore to prepare a slurry with a concentration of 30wt%.

[0039] (2) Primary flotation: at 20°C, the pulp was placed in a flotation machine for flotation, 15 kg / t of mixed acid and 1.4 kg / t of the original ore were added to the flotation machine, and stirred for 10 minutes; the mixed acid was sulfuric acid, caffeic acid and phosphoric acid in a mass ratio of 3:2:2; the first collector was sodium laurate and sodium α-linolenate in a mass ratio of 5:2; then, the flotation machine aeration switch was turned on, the aeration volume was adjusted to 200 L / h, reverse flotation was performed, foam was removed, and primary slurry was obtained.

[0040] (3) Secondary flotation: Use NaOH to adjust the pH of the primary ore pulp to 7.0, stir for 3 minutes, then add the second collector to the ore pulp and stir for 10 minutes; the amount of the second collector added is 1.1 kg / t of the original ore, and the second collector is dodecylamine, sodium carbonate and polyacrylonitrile in a mass ratio of 10:4:1; then, turn on the flotation machine inflation switch, adjust the inflation volume to 200 L / h, perform reverse flotation, remove the foam, and obtain phosphate concentrate.

[0041] Through the above process, the grade of phosphate concentrate can reach 37.7%, the recovery rate is 85.2%, the magnesium oxide content is 0.33%, and the sesquioxide content is 5.30%.

[0042] Example 3

[0043] The double reverse flotation method of phosphate rock of the present embodiment comprises the following steps:

[0044] (1) Ore pretreatment: The phosphate ore (grade 22.5%) was crushed and rod-milled until the grinding fineness of -200 mesh accounted for 90%, and water was added to the phosphate ore to prepare a slurry with a concentration of 25wt%.

[0045] (2) Primary flotation: at 20°C, the pulp was placed in a flotation machine for flotation, 10 kg / t of mixed acid and 1.0 kg / t of the original ore were added to the flotation machine, and stirred for 10 minutes; the mixed acid was sulfuric acid, caffeic acid and phosphoric acid in a mass ratio of 3:1:2; the first collector was sodium laurate and sodium α-linolenate in a mass ratio of 3:2; then, the flotation machine aeration switch was turned on, the aeration volume was adjusted to 150 L / h, reverse flotation was performed, the foam was removed, and the primary ore pulp was obtained.

[0046] (3) Secondary flotation: adjust the pH of the primary ore pulp to 7.0 with NaOH, stir for 2 minutes, then add the second collector to the ore pulp and stir for 10 minutes; the amount of the second collector added is 0.8 kg / t of the original ore, and the second collector is dodecylamine, sodium carbonate and polyacrylonitrile in a mass ratio of 9:3:1; then, turn on the flotation machine inflation switch, adjust the inflation volume to 150 L / h, perform reverse flotation, remove the foam, and obtain phosphate concentrate.

[0047] Through the above process, the grade of phosphate concentrate can reach 35.6%, the recovery rate is 83.1%, the magnesium oxide content is 0.45%, and the sesquioxide content is 5.63%.

[0048] Comparative Example 1

[0049] The double reverse flotation method for phosphate rock in this comparative example is different from that in Example 1 only in that the caffeic acid in the mixed acid is omitted in this comparative example, and the missing amount of caffeic acid is distributed to the corresponding components according to the ratio of sulfuric acid to phosphoric acid.

[0050] The phosphate rock product of this comparative example has a grade of 30.6%, a magnesium oxide content of 5.72%, and a sesquioxide content of 5.51%.

[0051] Comparative Example 2

[0052] The double reverse flotation method for phosphate rock in this comparative example is different from that in Example 1 only in that the first collector in this comparative example is adjusted to sodium laurate and sodium α-linolenate in a mass ratio of 6:1.

[0053] The phosphate rock product of this comparative example has a grade of 28.5%, a magnesium oxide content of 7.42%, and a sesquioxide content of 5.33%.

[0054] Comparative Example 3

[0055] The double reverse flotation method for phosphate rock in this comparative example is different from that in Example 1 only in that the polyacrylonitrile in the second collector is omitted in this comparative example, and the missing amount of polyacrylonitrile is distributed to the corresponding components according to the ratio of dodecylamine and sodium carbonate.

[0056] The phosphate rock product of this comparative example has a grade of 26.3%, a magnesium oxide content of 0.58%, and a sesquioxide content of 19.2%.

[0057] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A double reverse flotation method for phosphate ore, characterized in that: include: (1) Ore pretreatment: Mix the raw ore with water to make a slurry with a concentration of 20-30wt%; (2) Primary flotation: 10-15 kg / t of mixed acid and 1-1.5 kg / t of first collector are added to the pulp to perform reverse flotation to remove foam and obtain primary pulp; The mixed acid includes sulfuric acid, caffeic acid and phosphoric acid; The first collector includes sodium laurate and sodium linolenate; (3) Secondary flotation: add alkali to the primary ore pulp, then add 0.8-1.3 kg / t of the second collector to perform reverse flotation to remove the foam and obtain phosphate concentrate; The second collector includes dodecylamine, sodium carbonate and polyacrylonitrile.

2. The double reverse flotation method of phosphate rock according to claim 1, characterized in that: The mass ratio of the sulfuric acid, caffeic acid and phosphoric acid is (1-5):(1-2):

2.

3. The double reverse flotation method of phosphate rock according to claim 1, characterized in that: The mass ratio of sodium laurate to sodium linolenate is (3-6):

2.

4. The double reverse flotation method of phosphate ore according to claim 1, characterized in that: The sodium linolenate includes sodium α-linolenate; The weight average molecular weight of the polyacrylonitrile is 50,000 to 100,000 g / mol.

5. The double reverse flotation method of phosphate rock according to claim 1, characterized in that: The mass ratio of dodecylamine, sodium carbonate and polyacrylonitrile is (8-10):(3-4):

1.

6. The double reverse flotation method of phosphate ore according to claim 1, characterized in that: In the step (1), the ore is crushed and rod-milled before being mixed with water.

7. The double reverse flotation method of phosphate rock according to claim 6, characterized in that: The ore is crushed and rod-milled until the grinding fineness is -200 mesh accounting for 50% to 90%.

8. The double reverse flotation method of phosphate rock according to claim 1, characterized in that: The alkali includes one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide.

9. The double reverse flotation method for phosphate ore according to claim 1 or 8, characterized in that: Add alkali to the primary ore pulp to adjust the pH to 7.0-8.

0.

10. The double reverse flotation method of phosphate rock according to claim 1, characterized in that: After adding the first collector, the system is aerated at a rate of 150 to 200 L / h; After adding the second collector, the system is aerated with a gas volume of 150 to 200 L / h.