A combined activator for flotation desulfurization of high-sulfur magnetite and its application

Abstract

The present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and its application. The combined activator is composed of sodium sulfide, sulfuric acid, copper sulfate, sodium fluorosilicate, and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na). The specific application is to first crush the raw ore into a ball mill for grinding, add the activator sodium sulfide during the grinding process, and achieve a grinding fineness of 200 mesh, accounting for 50% to 90%. The ore pulp concentration is adjusted and enters the flotation tank, and the combined activator is added for stirring and activation. A collector and a foaming agent are added for stirring and aeration, and the sulfur concentrate is collected. The ore pulp after flotation enters a drum magnetic separator for magnetic separation, achieving efficient separation of magnetite and gangue. The present invention adopts a combined activator + composite collector method, which can achieve an effect of 1+1 greater than 2, solves the problem of the existing technology in removing pyrrhotite from high-sulfur magnetite, and achieves efficient separation of magnetite and pyrrhotite. Satisfactory results are achieved.

Description

Technical Field

[0001] The invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and application thereof, and relates to the field of mineral processing. Background Art

[0002] Iron ore is the primary raw material for the steel industry and a key national strategic resource. However, most Chinese iron ore is characterized by being "poor, fine, and impure," requiring beneficiation. Therefore, research and production efforts must strive to improve the grade of iron concentrate and reduce the levels of harmful impurities such as S, P, Al2O3, and SiO2. Foreign iron ore, with high iron content and low silicon, aluminum, phosphorus, and sulfur, offers similar landed prices to domestically produced iron concentrate, making it highly competitive in the Chinese market. Consequently, domestic iron mines must prioritize improving the grade of their iron concentrates and reducing impurities.

[0003] The sulfur content in iron ore will directly affect the quality of the steel produced, so iron ore desulfurization becomes a very important part of the iron ore beneficiation process.

[0004] The grinding-magnetic-flotation combined process is usually used to extract iron and reduce sulfur in high-sulfur magnetite ore. That is, the ore is first ground to a suitable grinding particle size, and then the tailings are discarded by weak magnetic separation to obtain magnetite concentrate with qualified iron grade, and then the magnetite concentrate is subjected to reverse flotation desulfurization.

[0005] The chemical composition of pyrite is FeS2. Since pyrite is rich in sulfur, it is usually used as the main mineral raw material for extracting sulfur and making sulfuric acid in sulfuric acid plants. 2- Ions form anion clusters [S2] 2- When pyrite is crushed, it presents complete crystals. Its cleavage surface is oleophilic and hydrophobic. Xanthate collectors can easily form hydrophobic dixanthate on its surface, which is beneficial to the flotation of pyrite. Therefore, the flotation separation of pyrite and magnet is relatively easy.

[0006] Pyrrhotite Fe 1-X S (X = 0.1-0.2) is an iron sulfide mineral in the pyrrhotite family. It contains up to 40% sulfur and can be used as a raw material for sulfuric acid production. Pyrrhotite has a metallic luster and a dark bronze-yellow color with a reddish hue. Pyrrhotite exhibits polymorphic variations in the monoclinic, hexagonal, and orthorhombic crystal systems. Orthorhombic pyrrhotite is rare, with most occurring as a mixture of monoclinic and hexagonal crystals. Pyrrhotite's physical properties, chemical composition, and crystal structure directly determine its flotation characteristics, surface oxidation susceptibility, and brittleness. Its floatability is poor, making it a difficult-to-float iron sulfide mineral.

[0007] The desulfurization problem of magnetite has become a problem that hinders the quality of iron ore concentrate products. This is mainly because pyrrhotite is difficult to separate from magnetite. The reasons can be summarized into four aspects: (1) Magnetite and pyrrhotite have similar densities and magnetic properties. Even by reducing the magnetic induction intensity, pyrrhotite cannot be effectively separated. In addition, magnetite and pyrrhotite are not only easy to produce magnetic agglomeration themselves, but also easy to produce heterogeneous magnetic agglomeration through the effect of residual magnetism after magnetic separation. Fine-grained pyrrhotite will adhere to the surface of magnetite due to magnetization. When the mineral particle size is fine, the magnetic agglomeration phenomenon will be more serious, making it difficult to effectively separate the two. This has been confirmed in many industrial practices; (2) The floatability of hexagonal pyrrhotite is worse than that of single crystal pyrrhotite. The floatability of the two is different. It is difficult to remove the pyrrhotite of the two crystal systems from magnetite under the same separation conditions; (3) The surface oxidation rate of pyrrhotite is very fast. According to reports, under the same conditions, the oxidation rate of pyrrhotite is 20 or even 100 times that of pyrite. Under certain conditions, Although elemental sulfur is generated when the surface of the lower pyrrhotite is oxidized to form Fe2(SO4)3 and FeSO4, its surface area increases after mudification, which makes it easy to be severely oxidized, and further forms a hydrophilic layer of iron hydroxide on the surface, resulting in a decrease in its floatability; (4) Experimental studies have shown that if bubbles want to adhere to mineral particles, the energy barrier between the bubbles and the mineral particles must be overcome first, and only in this case can effective adhesion occur when the contact angle is greater than 0 degrees. The existence of energy barrier is the primary obstacle that makes the adhesion process difficult. The fine-grained pyrrhotite after mudification has a low mass and momentum, and the probability of collision with bubbles is low. It is difficult to overcome the energy barrier between the fine-grained pyrrhotite and the bubbles and adhere to the bubble surface, making it difficult for the pyrrhotite to float.

[0008] In order to solve the problem that magnetite and pyrrhotite are difficult to separate by flotation, relevant technicians have done a lot of work and research and concluded that the existing activators for pyrrhotite include copper sulfate, sodium sulfide, sodium fluorosilicate and oxalic acid, sulfuric acid, MHH-1 and NH, copper sulfate + sulfuric acid, oxalic acid + copper sulfate, sodium thiosulfate + water glass + sulfuric acid, copper sulfate + water glass, etc. These activators are effective for the flotation separation of some magnetite and pyrrhotite, but due to the different properties of different sulfur-containing minerals, the above activators cannot be used to separate the two activators. While the flotation separation of all magnetite and pyrrhotite minerals is satisfactory, the aforementioned activator proved ineffective in flotation separation of magnetite and pyrrhotite at a high-sulfur magnetite mine in Daye City, Hubei Province. The raw ore contained 56% TFe and 9.8% TS, and 90% of the sulfur-bearing minerals were pyrrhotite. The iron ore concentrate recovered after flotation and magnetic separation using the aforementioned activator contained a sulfur content of approximately 9%. This extremely high sulfur content deterred steelmakers from purchasing the concentrate, resulting in unsaleable goods that were unsold. Despite extensive research by numerous research institutions and departments, the high sulfur content in the iron ore concentrate remained unresolved, resulting in significant economic losses for the mine. Therefore, the development of effective and adaptable pyrrhotite activators and new technologies for desulfurization of magnetite is an urgent research priority. Summary of the Invention

[0009] To address the problems identified in the aforementioned background technology, the present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and its application. The combined activator can effectively activate pyrrhotite and reduce the sulfur content in iron ore concentrate to below 0.3%.

[0010] To achieve the above object, the present invention provides the following combined activator:

[0011] A combined activator for flotation desulfurization of high-sulfur magnetite, characterized in that the combined activator consists of sodium sulfide, sulfuric acid, copper sulfate, sodium fluorosilicate, and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na);

[0012] The above-mentioned combined activator for flotation desulfurization of high-sulfur magnetite has a mass ratio of sodium sulfide: sulfuric acid: copper sulfate: sodium fluorosilicate: ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) = 2-4: 4-8: 1: 3-5: 1-3:

[0013] Furthermore, a combined activator for flotation desulfurization of high-sulfur magnetite is provided, wherein the dosage ratio by mass is sodium sulfide: sulfuric acid: copper sulfate: sodium fluorosilicate: ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) = 3:6:1:4:2.

[0014] The present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and its application. The dosage of the combined activator varies with the content of pyrrhotite in the magnetite, and the amount of the combined activator and the collector added is proportional to the content of pyrrhotite in the magnetite.

[0015] The present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and application thereof. The sodium sulfide as one of the combined activators is added in full at the feed port of a ball mill, the sulfuric acid is added in full at a flotation roughing tank, the other combined activators and collectors and foaming agents are added in a proportion of 40% to 60% of the total amount of the added agents in the roughing, and the addition proportions of the first to fourth scavenging processes account for 40% to 60% of the total amount of the added agents.

[0016] The invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and application thereof. For certain high-sulfur magnetite, a satisfactory effect can be obtained by adding a small amount of activators such as sodium sulfide, sulfuric acid and copper sulfate or even no activators.

[0017] A combined activator for flotation desulfurization of high-sulfur magnetite and its application, the specific application includes the following steps:

[0018] 1) The raw ore is crushed and ground into a ball mill. 0-1000 g / t of sodium sulfide is added based on the dry weight of the ore. The solid-liquid ratio of the grinding is 1:1, and the grinding fineness reaches -200 mesh, accounting for 50%-90%;

[0019] 2) Adjust the slurry concentration to 35%-50% before entering the flotation tank, calculate the dosage according to the dry weight of the mineral, and add the combined activator sulfuric acid 0-2000 g / ton, copper sulfate 0-250 g / ton, sodium fluorosilicate 400-1200 g / ton, and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) 80-500 g / ton in sequence, and stir and activate for 3-7 minutes;

[0020] 3) Add 100-500 g / ton of isoamyl xanthate and 40-200 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 3-5 minutes;

[0021] 4) Add 10-120 g / ton of foaming agent based on the dry weight of the mineral, stir and activate for 2-3 minutes, aerate and scoop out the sulfur concentrate;

[0022] 5) Flotation adopts a process of roughing first, scavenging second to fourth to separate sulfur ore, and cleaning third to fourth to purify sulfur concentrate;

[0023] 6) The slurry after flotation enters the drum magnetic separator for magnetic separation to separate the magnetite from the non-magnetic gangue and obtain qualified magnetite concentrate.

[0024] The present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and its application. Sodium sulfide, one of the combined activators, is added to the feed port of a ball mill. Sodium sulfide is commonly used in the sulfide flotation of oxide ores, that is, as a sulfiding agent for oxide ores, it can form a sulfide ore film on the surface of the oxide ore, and can effectively alleviate the mudification and oxidation of pyrrhotite during the grinding process.

[0025] Sulfuric acid, one of the combined activators, can adjust the Ph value of the slurry. Secondly, after grinding, part of the pyrrhotite will become muddy and oxidized, resulting in a decrease in its floatability. Therefore, its surface needs to be cleaned and the iron hydroxide film on its surface is dissolved, which is conducive to the formation of hydrophobic dixanthate on the surface of the pyrrhotite, which can effectively improve the flotation effect of the pyrrhotite.

[0026] Copper sulfate, one of the combined activators, is widely used as a conventional activator for pyrrhotite. Its principle is to form an activation film on the surface of the activated mineral by a double decomposition reaction. 2+ It will be preferentially adsorbed on the surface of pyrrhotite, and its adsorption stability to xanthate anions is enhanced.

[0027] Sodium fluorosilicate, one of the combined activators, can produce hydrofluoric acid upon hydrolysis, which can effectively clean the surface of sulfide mineral particles and also has a strong sludge dispersing effect.

[0028] Ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na), one of the activators in the combination, is an amide polymer containing two benzene rings. It exhibits a strong chelating effect on calcium and magnesium ions, twice as effective as EDTA. Due to its symmetrical benzene ring structure, it can also strongly chelate heavy metal ions such as iron, zinc, and copper, making it an excellent metal ion scavenger. Ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) is widely used in water treatment agents, detergents, cosmetics, antibacterial agents, dispersants, leather making, pharmaceuticals, hydrogels, and boiler water cooling systems. It exhibits high scale inhibition properties and is considered a green scale inhibitor. It effectively removes calcium, magnesium, and iron ions from the slurry, forming a precipitate that protects the pyrrhotite surface from contamination under acidic conditions, thereby reducing the consumption of scavenger molecules.

[0029] The present invention discloses a combined activator for flotation desulfurization of high-sulfur magnetite and its application. The combined activator and composite capture method employ a flotation-first, then magnetization process, achieving a significant 1+1 greater than 2 effect. Tests and industrial production have verified that the sulfur content of iron concentrate is reduced to approximately 0.1%, the sulfur content of iron concentrate is approximately 68%, and the iron recovery rate reaches approximately 89%. This effectively solves the difficulty in separating magnetite from pyrrhotite in existing technologies, achieving efficient separation of magnetite and pyrrhotite and achieving highly satisfactory results. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the process flow chart of combined activation flotation desulfurization. DETAILED DESCRIPTION

[0031] Example 1

[0032] A high-sulfur magnetite mine in Daye City, Hubei Province has a raw ore content of TFe 56%, TS 9.8%, and 90% of the sulfur minerals are pyrrhotite.

[0033] 1) The raw ore is crushed and ground into a ball mill. 1000 g / t of sodium sulfide is added based on the dry weight of the ore. The solid-liquid ratio of the grinding is 1:1, and the grinding fineness reaches -200 mesh, accounting for 80%;

[0034] 2) Adjust the slurry concentration to 40% before entering the flotation tank. Calculate the dosage based on the dry weight of the minerals and add the combined activator of sulfuric acid 1500 g / ton, copper sulfate 150 g / ton, sodium fluorosilicate 600 g / ton, and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) 200 g / ton in sequence. Stir and activate for 6 minutes.

[0035] 3) Add 100 g / ton of isoamyl xanthate and 35 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 5 minutes;

[0036] 4) Add 50 g / ton of foaming agent based on the dry weight of the mineral, stir for 2 minutes, aerate and scrape the sulfur ore for 5 minutes;

[0037] 5) After the roughing is completed, add 50 g / ton of copper sulfate, 300 g / ton of sodium fluorosilicate, and 100 g / ton of ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) in this order and stir to activate for 4 minutes;

[0038] 6) Add 50 g / ton of isoamyl xanthate and 17 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 3 minutes;

[0039] 7) Add 20 g / ton of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep the sulfur ore for 5 minutes;

[0040] 8) After the scavenging is completed, add 50 g / ton of copper sulfate, 300 g / ton of sodium fluorosilicate, and 100 g / ton of ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) and stir to activate for 4 minutes;

[0041] 9) Add 30 g / ton of isoamyl xanthate and 10 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 4 minutes;

[0042] 10) Add 10 g / t of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep the sulfur concentrate for 3 minutes;

[0043] 11) After the second scavenging, add 30 g / t of isoamyl xanthate and 10 g / t of butyl ammonium xanthate in order based on the dry weight of the minerals, and stir to activate for 3 minutes;

[0044] 12) Add 10 g / t of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep the sulfur ore for 3 minutes;

[0045] 13) After flotation, the pulp enters the drum magnetic separator for magnetic separation, where the magnetite is separated from the non-magnetic gangue to obtain qualified magnetite concentrate powder.

[0046] Testing revealed that the iron concentrate powder contained 68.8% iron and 0.092% sulfur, while the sulfur concentrate contained 38.6% sulfur. The iron recovery rate was 89.22%, achieving excellent results and solving a major problem for the mining company while also bringing significant economic benefits to the company.

[0047] Example 2

[0048] In a high-sulfur magnetite mine in Ezhou City, Hubei Province, the original ore contains TFe 58.7%, TS 4.3%, and 70% of the sulfur minerals are pyrrhotite.

[0049] 1) The raw ore is crushed and ground into a ball mill. 700 g / t of sodium sulfide is added based on the dry weight of the ore. The solid-liquid ratio of the grinding is 1:1, and the grinding fineness reaches -200 mesh, accounting for 75%;

[0050] 2) The ore pulp concentration is adjusted to 45% before entering the flotation tank. The dosage is calculated based on the dry weight of the ore. The combined activator of sulfuric acid 1000 g / ton, copper sulfate 120 g / ton, sodium fluorosilicate 500 g / ton, and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) 160 g / ton are added in sequence and stirred for 6 minutes.

[0051] 3) Add 80 g / ton of isoamyl xanthate and 30 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 5 minutes;

[0052] 4) Add 35 g / ton of foaming agent based on the dry weight of the mineral, stir for 2 minutes, aerate and scrape the sulfur ore for 4 minutes;

[0053] 5) After the roughing is completed, add 60 g / ton of copper sulfate, 250 g / ton of sodium fluorosilicate, and 80 g / ton of ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) in sequence and stir to activate for 4 minutes;

[0054] 6) Add 40 g / t of isoamyl xanthate and 15 g / t of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 4 minutes;

[0055] 7) Add 20 g / ton of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep the sulfur ore for 4 minutes;

[0056] 8) After the scavenging is completed, add 50 g / ton of copper sulfate, 200 g / ton of sodium fluorosilicate, and 60 g / ton of ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) and stir to activate for 4 minutes;

[0057] 9) Add 30 g / ton of isoamyl xanthate and 10 g / ton of butyl ammonium xanthate collectors in order based on the dry weight of the mineral, and stir to activate for 4 minutes;

[0058] 10) Add 10 g / t of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep the sulfur concentrate for 3 minutes;

[0059] 11) After the second scavenging, add 30 g / t of isoamyl xanthate and 10 g / t of butyl ammonium xanthate in order based on the dry weight of the minerals, and stir to activate for 3 minutes;

[0060] 12) Add 10 g / t of foaming agent based on the dry weight of the mineral, stir for 2 minutes, and aerate and sweep to select 3 mm of sulfur ore;

[0061] 13) After flotation, the pulp enters the drum magnetic separator for magnetic separation, where the magnetite is separated from the non-magnetic gangue to obtain qualified magnetite concentrate powder.

[0062] Testing revealed that the iron concentrate powder contained 68.7% iron and 0.12% sulfur, while the sulfur concentrate contained 39.1% sulfur. The iron recovery rate was 87.90%, achieving excellent results and solving a difficult problem for the mining company while also bringing significant economic benefits to the company.

[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A combined activator for flotation desulfurization of high-sulfur magnetite, characterized by: The combined activator consists of sodium sulfide, sulfuric acid, copper sulfate, sodium fluorosilicate and ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na).

2. The combined activator according to claim 1, characterized in that: The mass ratio of each component is sodium sulfide: sulfuric acid: copper sulfate: sodium fluorosilicate: ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) = 2-4: 4-8: 1: 3-5: 1-3.

3. The combined activator according to claim 1, characterized in that: The mass ratio of each component is sodium sulfide: sulfuric acid: copper sulfate: sodium fluorosilicate: ethylenediamine di-o-hydroxyphenyl sodium acetate (EDDHA-Na) = 3:6:1:4:

2.

4. A flotation desulfurization method for high-sulfur magnetite using the combined activator according to claim 1, characterized in that The steps include: (1) After the raw ore is crushed, it enters the ball mill for grinding. 0-1500 g / t of sodium sulfide is added based on the dry weight of the ore. The grinding solid-liquid ratio is 1:1, and the fineness reaches -200 mesh, accounting for 50%-90%; (2) Adjust the pulp concentration to 35%-50% before entering the flotation tank. Add 0-2000 g / ton of sulfuric acid, 0-250 g / ton of copper sulfate, 400-1800 g / ton of sodium fluorosilicate, and 80-400 g / ton of EDDHA-Na in order according to the dry weight of the minerals, and stir to activate for 3-7 minutes; (3) Add 100-500 g / ton of isopentyl xanthate and 50-200 g / ton of butyl ammonium xanthate, and stir to activate for 3-5 minutes; (4) adding 10-120 g / ton of foaming agent, stirring and activating for 2-3 minutes, and then aerating and scraping the sulfur concentrate; (5) The flotation process uses a roughing process, two to four scavenging processes to separate the sulfur ore, and three to four cleaning processes to purify the sulfur concentrate; (6) After flotation, the pulp is subjected to magnetic separation by a drum magnetic separator to separate magnetite and non-magnetic gangue.

5. The method according to claim 4, characterized in that: The sodium sulfide is added at the feed port of the ball mill.

6. The method according to claim 4, characterized in that: When treating specific high-sulfur magnetite, the dosage of sodium sulfide, sulfuric acid and copper sulfate is 0.

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