Beneficiation process of a magnetic hematite-limonite iron ore

Abstract

The application discloses a beneficiation process of a magnetic and hematite mixed iron ore. The magnetic and hematite mixed iron ore is first crushed into ore powder with a particle size of less than or equal to 2 mm, then the ore powder is treated by water immersion and microwave treatment to obtain pretreated ore powder; then the pretreated ore powder is subjected to ball milling treatment under the action of a grinding aid, weak magnetic separation, strong magnetic separation, to obtain a strong magnetic separation concentrate, positive flotation, to obtain a positive flotation concentrate, and reverse flotation, to obtain an iron concentrate. The beneficiation process is simple, the beneficiation cost is low, and the beneficiation process has very good beneficiation effect on the magnetic and hematite mixed iron ore with high magnetic iron content and fine embedded particle size, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of iron ore beneficiation technology, specifically relating to a beneficiation process for magnetohemorrhagic mixed iron ore. Background Technology

[0002] Steel is a crucial and widely used metallic material in the national economy, and iron ore is the raw material for steelmaking. Years of mining have led to increasingly scarce iron ore resources, resulting in ores that are low in quality, fine in texture, and complex in composition. This is especially true for complex and difficult-to-process iron oxide ores, including hematite, specular hematite, limonite, and siderite, which present significant challenges in beneficiation technology and high processing costs. Large quantities of mixed magnetite and iron oxide ores further complicate beneficiation, resulting in even more complex processes and higher processing costs.

[0003] In magnetite-hematite mixed ore, magnetite and hematite exhibit significant magnetic differences and are closely intergrown and intercalated, making separation extremely difficult and resulting in exceptionally high processing costs. Currently, to completely liberate magnetite and hematite, ball mills are typically used to grind the ore to over 80-90% of its original size (-200 mesh, -0.074 mm). Furthermore, two-stage or even three-stage grinding is usually required to achieve basic individual ore liberation before proceeding to the beneficiation process. Grinding operations consume a large amount of electricity and require grinding media (steel balls), contributing significantly to the overall beneficiation cost.

[0004] For magnesite mixed iron ore, a lower-cost and simpler magnetic separation process is typically used first to separate the magnetite, obtaining high-grade magnetite concentrate. Then, high-intensity magnetic separation is used to enrich the hematite to a certain grade, which is then used as flotation feed. Finally, reverse flotation is performed to obtain qualified iron concentrate. In detail, the process flow is roughly selected from the following:

[0005] 1. Stage grinding, weak magnetic separation-strong magnetic separation-anion reverse flotation process;

[0006] 2. Continuous grinding, weak magnetic separation-strong magnetic separation-anion reverse flotation process;

[0007] 3. Staged grinding, coarse and fine separation - gravity separation - magnetic separation - anion reverse flotation process;

[0008] 4. Stage grinding, coarse and fine separation - magnetic separation - gravity separation - anion reverse flotation process.

[0009] However, in the existing magnetite-hematite mixed iron ore, the iron ore grade is getting lower and lower, which leads to a large amount of magnetite entering the flotation operation. The energy consumption (flotation reagents) and cost of the flotation operation are much higher than those of magnetic separation, resulting in excessively high beneficiation costs.

[0010] Patent application CN103386361A discloses a beneficiation method for magnetohemite mixed iron ore, comprising the following steps:

[0011] a) The magnetohemite mixed iron ore is subjected to the first stage of grinding and the second stage of grinding in sequence to obtain the slurry;

[0012] b) The overflow slurry obtained after the slurry is classified is subjected to a first flocculation and desliming process to obtain sludge and sediment.

[0013] c) After the sand is classified, a third grinding stage is performed. The slurry obtained from the third grinding stage is then classified and subjected to a second grinding stage.

[0014] Secondary flocculation and desliming yields sludge and sediment;

[0015] d) Perform reverse flotation on the sediment obtained in step c).

[0016] The patent application uses a three-stage grinding process, which results in high beneficiation costs and a low grade of iron concentrate, leading to a low recovery rate that cannot meet current beneficiation needs. Summary of the Invention

[0017] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a beneficiation process for maghemite mixed iron ore, which greatly reduces the beneficiation cost and has a very good beneficiation effect on maghemite mixed iron ore with high magnetic iron content and fine particle size, and has good application prospects.

[0018] To achieve the above objectives, the present invention adopts the following technical solution:

[0019] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0020] (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder.

[0021] (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate.

[0022] The grinding aid is prepared by mixing sodium tannate, diethylenetriaminepentamethylphosphonic acid, and enzymatically hydrolyzed starch solution. For positive flotation, a positive flotation reagent is used, which is obtained by mixing sodium 2-hydroxy-5-butylbenzoic acid amine salt and sodium silicate at a mass ratio of 10:2-3. For reverse flotation, a reverse flotation reagent is used, which is obtained by mixing sodium octadecanoate, sodium silicate, sodium fluoride, carboxymethyl cellulose, sodium lignosulfonate, and sodium hydroxide at a mass ratio of 50-60:8-10:7-9:7-9:10-12:3-5.

[0023] Preferably, the grinding aid is obtained by adding sodium tannate and diethylenetriaminemethylenephosphonic acid to the enzymatically hydrolyzed starch solution and stirring until well mixed; wherein the mass ratio of sodium tannate to diethylenetriaminemethylenephosphonic acid added to the enzymatically hydrolyzed starch solution is 8-10:8-10:100.

[0024] Preferably, the enzymatically hydrolyzed starch solution is prepared by the following method, based on parts by weight: first, 0.5 to 1 part of corn starch is stirred and dispersed in 100 parts of water, then 0.5 to 1 part of α-amylase is added, and the mixture is stirred for 110 to 120 minutes. Then, a 0.5 to 1% sodium hydroxide solution is added, and the mixture is stirred for another 50 to 60 minutes to obtain the solution.

[0025] Preferably, the sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: first, methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, then 1-2 mol / L sodium hydroxide solution is added, the mixture is stirred and mixed, and the reaction is carried out at 30-32°C for 6-7 hours, followed by vacuum drying; wherein, the molar amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0026] Preferably, in step (1), the amount of water used is 2 to 3 times the mass of the mineral powder.

[0027] Preferably, in step (1), the process conditions for the immersion treatment are: immersion at room temperature for 80 to 100 minutes.

[0028] Preferably, in step (1), the microwave treatment process conditions are: frequency 2500MHz, first 500-700W microwave irradiation for 3-5 minutes, then 400-600W microwave irradiation for 15-17 minutes, and finally 800-1000W microwave irradiation for 7-9 minutes.

[0029] Preferably, in step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added to the ball mill, and then a grinding aid is added. The amount of grinding aid is 0.8 to 1‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35 mm, 25 mm, and 20 mm, with a mass ratio of 2:3:5, a material-to-ball ratio of 0.8, and a media filling rate of 40 to 45%. The portion of the ball milled to a particle size of less than 0.074 mm accounts for more than 90%.

[0030] Preferably, in step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 250-300mT, and the magnetic field strength of the strong magnetic separation is 1000-1200mT.

[0031] Preferably, in step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.5 to 0.7‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.6 to 0.7‰ of the mass of the positive flotation concentrate.

[0032] Preferably, in step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings, and the reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention first crushes the maghematolin mixed iron ore into powder with a particle size ≤2mm. Then, the powder is treated with water leaching and microwave treatment to obtain pretreated powder. Next, under the action of a grinding aid, the pretreated powder is ball-milled, subjected to weak magnetic separation, strong magnetic separation to obtain strong magnetic separation concentrate, direct flotation to obtain direct flotation concentrate, and reverse flotation to obtain iron.

[0035] Concentrate. The mineral processing technology of this invention is simple and has low processing cost. It has a very good mineral processing effect on maghemite mixed iron ore with high magnetic iron content and fine particle size, and has good application prospects.

[0036] The grinding aid is a mixture of sodium tannate, diethylenetriaminepentamethylenephosphonic acid, and enzymatically hydrolyzed starch solution. Sodium tannate reduces the strength of the mineral powder, diethylenetriaminepentamethylenephosphonic acid has a good complexing ability with iron, and enzymatically hydrolyzed starch solution improves the fluidity of the slurry. Through the synergistic effect of these three components, the mineral powder is fully dispersed and flows, improving the ball milling effect and reducing the ball milling cost.

[0037] The direct flotation reagent is obtained by mixing sodium 2-hydroxy-5-butylbenzoate and sodium silicate; the reverse flotation reagent is obtained by mixing sodium stearate, sodium silicate, sodium fluoride, carboxymethyl cellulose, sodium lignosulfonate, and sodium hydroxide. This invention combines direct and reverse flotation, with the components of the direct and reverse flotation reagents working synergistically to fully enrich hematite while discarding tailings in advance, thus reducing the amount of flotation reagents used and significantly lowering beneficiation costs.

[0038] This invention involves soaking mineral powder in water, filling the internal pores of the mineral powder with water, and then subjecting it to microwave treatment. First, the powder is irradiated with 500-700W microwaves for 3-5 minutes, then with 400-600W microwaves for 15-17 minutes, and finally with 800-1000W microwaves for 7-9 minutes. As the powder is irradiated with microwaves, water molecules leave the mineral powder, damaging the powder structure, reducing the difficulty and cost of ball milling. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0040] Unless otherwise specified, all products in this invention were purchased through market channels.

[0041] The magnetite-hematite mixtures in the following examples and comparative examples were all mined from the same iron ore surface deposit. The main mineral was magnetite, followed by hematite. The gangue minerals were mainly quartz. The magnetite was fine-grained, ranging from 0.01 to 0.02 mm, and the hematite was disseminated in the gangue minerals, with a grain size between 0.001 and 0.02 mm. The iron grade was 22.4%.

[0042] Example 1

[0043] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0044] (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder.

[0045] (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate.

[0046] The grinding aid is prepared by adding 8 kg of sodium tannate and 8 kg of diethylenetriaminemethylenephosphonic acid to 100 kg of enzymatically hydrolyzed starch solution and stirring until homogeneous. For positive flotation, a positive flotation reagent is used, which is prepared by stirring and mixing 10 kg of sodium 2-hydroxy-5-butylbenzoate and 2 kg of sodium silicate. For reverse flotation, a reverse flotation reagent is used, which is prepared by mixing 50 kg of sodium stearate, 8 kg of sodium silicate, 7 kg of sodium fluoride, 7 kg of carboxymethyl cellulose, 10 kg of sodium lignosulfonate, and 3 kg of sodium hydroxide.

[0047] The enzymatically hydrolyzed starch solution is prepared by the following method: First, 0.5 kg of corn starch is stirred and dispersed in 100 kg of water. Then, 0.5 kg of α-amylase is added, and the mixture is stirred and reacted for 110 minutes. Finally, a 0.5% sodium hydroxide solution is added, and the mixture is stirred and reacted for another 50 minutes to obtain the final solution.

[0048] Sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, then 1 mol / L sodium hydroxide solution is added, and the mixture is stirred and mixed. The mixture is stirred at 30°C for 6 hours and then dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0049] In step (1), the amount of water used is twice the mass of the mineral powder. The impregnation process conditions are: impregnation at room temperature for 80 minutes. The microwave treatment process conditions are: frequency 2500MHz, first 500W microwave irradiation for 3 minutes, then 400W microwave irradiation for 15 minutes, and finally 800W microwave irradiation for 7 minutes.

[0050] In step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added to the ball mill, and then the grinding aid is added. The amount of grinding aid is 0.8‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35mm, 25mm and 20mm, and the mass ratio of the three is 2:3:5. The material-to-ball ratio is 0.8 and the media filling rate is 40%. The portion of the ball milled to a particle size of less than 0.074mm accounts for more than 90%.

[0051] In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 250mT, and the magnetic field strength of the strong magnetic separation is 1000mT.

[0052] In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.5‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.6‰ of the mass of the positive flotation concentrate.

[0053] In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0054] Example 2

[0055] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0056] (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder.

[0057] (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate.

[0058] The grinding aid is prepared by adding 10 kg of sodium tannate and 10 kg of diethylenetriaminemethylenephosphonic acid to 100 kg of enzymatically hydrolyzed starch solution and stirring until homogeneous. For positive flotation, a positive flotation reagent is used, which is prepared by stirring and mixing 10 kg of sodium 2-hydroxy-5-butylbenzoate and 3 kg of sodium silicate. For reverse flotation, a reverse flotation reagent is used, which is prepared by mixing 60 kg of sodium stearate, 10 kg of sodium silicate, 9 kg of sodium fluoride, 9 kg of carboxymethyl cellulose, 12 kg of sodium lignosulfonate, and 5 kg of sodium hydroxide.

[0059] The enzymatically hydrolyzed starch solution is prepared by the following method: First, 1 kg of corn starch is stirred and dispersed in 100 kg of water, then 1 kg of α-amylase is added, and the mixture is stirred for 120 minutes. Then, a 1% sodium hydroxide solution is added, and the mixture is stirred for another 60 minutes to obtain the solution.

[0060] Sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, followed by the addition of 2 mol / L sodium hydroxide solution, and the mixture is stirred and mixed. The mixture is then stirred at 32°C for 7 hours and dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0061] In step (1), the amount of water used is 3 times the mass of the mineral powder. The impregnation process conditions are: impregnation at room temperature for 100 minutes. The microwave treatment process conditions are: frequency 2500MHz, first irradiation with 700W microwave for 5 minutes, then irradiation with 600W microwave for 17 minutes, and finally irradiation with 1000W microwave for 9 minutes.

[0062] In step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added to the ball mill, and then the grinding aid is added. The amount of grinding aid is 1‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35mm, 25mm and 20mm, and the mass ratio of the three is 2:3:5. The material-to-ball ratio is 0.8 and the media filling rate is 45%. The portion of the ball milled to a particle size of less than 0.074mm accounts for more than 90%.

[0063] In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 300mT, and the magnetic field strength of the strong magnetic separation is 1200mT.

[0064] In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.7‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.7‰ of the mass of the positive flotation concentrate.

[0065] In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0066] Example 3

[0067] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0068] (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder.

[0069] (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate.

[0070] The grinding aid is prepared by adding 8 kg of sodium tannate and 10 kg of diethylenetriaminemethylenephosphonic acid to 100 kg of enzymatically hydrolyzed starch solution and stirring until homogeneous. For positive flotation, a positive flotation reagent is used, which is prepared by stirring and mixing 10 kg of sodium 2-hydroxy-5-butylbenzoate and 2 kg of sodium silicate. For reverse flotation, a reverse flotation reagent is used, which is prepared by mixing 60 kg of sodium stearate, 8 kg of sodium silicate, 9 kg of sodium fluoride, 7 kg of carboxymethyl cellulose, 12 kg of sodium lignosulfonate, and 3 kg of sodium hydroxide.

[0071] The enzymatically hydrolyzed starch solution is prepared by the following method: First, 1 kg of corn starch is stirred and dispersed in 100 kg of water. Then, 0.5 kg of α-amylase is added, and the mixture is stirred for 120 minutes. Next, a 0.5% sodium hydroxide solution is added, and the mixture is stirred for another 60 minutes to obtain the final solution.

[0072] Sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, followed by the addition of 1 mol / L sodium hydroxide solution, and the mixture is stirred and mixed. The mixture is then stirred at 32°C for 6 hours and dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0073] In step (1), the amount of water used is 3 times the mass of the mineral powder. The impregnation process conditions are: impregnation at room temperature for 80 minutes. The microwave treatment process conditions are: frequency 2500MHz, first irradiation with 700W microwave for 3 minutes, then irradiation with 600W microwave for 15 minutes, and finally irradiation with 1000W microwave for 7 minutes.

[0074] In step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added to the ball mill, and then the grinding aid is added. The amount of grinding aid is 0.8‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35mm, 25mm and 20mm, and the mass ratio of the three is 2:3:5. The material-to-ball ratio is 0.8 and the media filling rate is 45%. The portion of the ball milled to a particle size of less than 0.074mm accounts for more than 90%.

[0075] In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 250mT, and the magnetic field strength of the strong magnetic separation is 1200mT.

[0076] In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.5‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.7‰ of the mass of the positive flotation concentrate.

[0077] In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0078] Example 4

[0079] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0080] (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder.

[0081] (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate.

[0082] The grinding aid is prepared by adding 9 kg of sodium tannate and 9 kg of diethylenetriaminemethylenephosphonic acid to 100 kg of enzymatically hydrolyzed starch solution and stirring until homogeneous. For positive flotation, a positive flotation reagent is used, which is prepared by stirring and mixing 10 kg of sodium 2-hydroxy-5-butylbenzoate and 2.5 kg of sodium silicate. For reverse flotation, a reverse flotation reagent is used, which is prepared by mixing 55 kg of sodium stearate, 9 kg of sodium silicate, 8 kg of sodium fluoride, 8 kg of carboxymethyl cellulose, 11 kg of sodium lignosulfonate, and 4 kg of sodium hydroxide.

[0083] The enzymatically hydrolyzed starch solution is prepared by the following method: First, 0.8 kg of corn starch is stirred and dispersed in 100 kg of water. Then, 0.8 kg of α-amylase is added, and the mixture is stirred for 115 minutes. Finally, a 0.8% sodium hydroxide solution is added, and the mixture is stirred for another 55 minutes to obtain the final solution.

[0084] Sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, followed by the addition of 2 mol / L sodium hydroxide solution, and the mixture is stirred and mixed. The mixture is then stirred at 31°C for 6.5 hours and dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0085] In step (1), the amount of water used is 2.5 times the mass of the mineral powder. The impregnation process conditions are: impregnation at room temperature for 90 minutes. The microwave treatment process conditions are: frequency 2500MHz, first 600W microwave irradiation for 4 minutes, then 500W microwave irradiation for 16 minutes, and finally 900W microwave irradiation for 8 minutes.

[0086] In step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added into the ball mill, and then the grinding aid is added. The amount of grinding aid is 0.9‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35mm, 25mm and 20mm, and the mass ratio of the three is 2:3:5. The material-to-ball ratio is 0.8 and the media filling rate is 42%. The portion of the ball milled to a particle size of less than 0.074mm accounts for more than 90%.

[0087] In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 300mT, and the magnetic field strength of the strong magnetic separation is 1100mT.

[0088] In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.6‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.65‰ of the mass of the positive flotation concentrate.

[0089] In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0090] Comparative Example

[0091] A beneficiation process for a magnetohemite mixed iron ore, the specific steps of which are as follows:

[0092] (1) First, crush the magnesite mixed iron ore into mineral powder with a particle size ≤2mm;

[0093] (2) Then, under the action of grinding aid, the ore powder is ball-milled, weak magnetic separation, strong magnetic separation to obtain strong magnetic separation concentrate, positive flotation to obtain positive flotation concentrate, and reverse flotation to obtain iron concentrate;

[0094] The grinding aid is prepared by adding 8 kg of sodium tannate and 8 kg of diethylenetriaminemethylenephosphonic acid to 100 kg of enzymatically hydrolyzed starch solution and stirring until homogeneous. For positive flotation, a positive flotation reagent is used, which is prepared by stirring and mixing 10 kg of sodium 2-hydroxy-5-butylbenzoate and 2 kg of sodium silicate. For reverse flotation, a reverse flotation reagent is used, which is prepared by mixing 50 kg of sodium stearate, 8 kg of sodium silicate, 7 kg of sodium fluoride, 7 kg of carboxymethyl cellulose, 10 kg of sodium lignosulfonate, and 3 kg of sodium hydroxide.

[0095] The enzymatically hydrolyzed starch solution is prepared by the following method: First, 0.5 kg of corn starch is stirred and dispersed in 100 kg of water. Then, 0.5 kg of α-amylase is added, and the mixture is stirred and reacted for 110 minutes. Finally, a 0.5% sodium hydroxide solution is added, and the mixture is stirred and reacted for another 50 minutes to obtain the final solution.

[0096] Sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, then 1 mol / L sodium hydroxide solution is added, and the mixture is stirred and mixed. The mixture is stirred at 30°C for 6 hours and then dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

[0097] In step (2), the specific method of ball milling is as follows: add the mineral powder into the ball mill, then add the grinding aid. The amount of grinding aid is 0.8‰ of the mineral powder mass. Use steel balls with diameters of 35mm, 25mm and 20mm for ball milling. The mass ratio of the three is 2:3:5, the material-to-ball ratio is 0.8, and the media filling rate is 40%. The portion of the ball milled to a particle size of less than 0.074mm accounts for more than 90%.

[0098] In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 250mT, and the magnetic field strength of the strong magnetic separation is 1000mT.

[0099] In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.5‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.6‰ of the mass of the positive flotation concentrate.

[0100] In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.

[0101] The iron grade in the iron concentrates obtained in Examples 1-4 and the comparative example was tested according to GB / T6730.73-2016 "Determination of Total Iron Content in Iron Ore by EDTA Photometric Titration".

[0102] The recovery rate is calculated using the following formula: Recovery rate = Iron concentrate mass × Iron concentrate grade / (Magnetic hematite mixed iron ore mass × Magnetic hematite mixed iron ore grade) × 100%.

[0103] The results of the investigation are shown in Table 1.

[0104] Table 1. Results of the investigation on mineral processing methods

[0105] Iron concentrate grade (%) Recovery rate (%) Example 1 66.85 92.07 Example 2 66.91 91.96 Example 3 67.47 91.87 Example 4 67.96 91.82 Comparative Example 58.03 82.97

[0106] As can be seen from Table 1, the mineral processing processes in Examples 1 to 4 have high recovery rates and high iron concentrate grades, indicating that efficient mineral processing of magnetohemorrhagic mixed iron ore has been achieved.

[0107] The recovery rate of the ore powder without pretreatment was significantly reduced, and the grade of the iron concentrate was significantly lower. This indicates that necessary pretreatment of the ore powder helps to reduce the difficulty of subsequent ball milling and works synergistically with grinding aids to improve the ball milling effect.

[0108] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of individual raw materials in the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A beneficiation process for a magnetohemorrhagic mixed iron ore, characterized in that, The specific steps are as follows: (1) First, crush the magma hematite mixed iron ore into mineral powder with a particle size ≤2mm. Then, soak the mineral powder in water and microwave it to obtain pretreated mineral powder. (2) Then, under the action of grinding aid, the pretreated ore powder is ball-milled, weakly magnetically separated, strongly magnetically separated to obtain strongly magnetically separated concentrate, directly flotated to obtain directly flotated concentrate, and then reversed flotated to obtain iron concentrate. The grinding aid is prepared by mixing sodium tannate, diethylenetriaminepentamethylphosphonic acid, and enzymatically hydrolyzed starch solution. For positive flotation, a positive flotation reagent is used, which is obtained by mixing sodium 2-hydroxy-5-butylbenzoic acid amine salt and sodium silicate at a mass ratio of 10:2-3. For reverse flotation, a reverse flotation reagent is used, which is obtained by mixing sodium octadecanoate, sodium silicate, sodium fluoride, carboxymethyl cellulose, sodium lignosulfonate, and sodium hydroxide at a mass ratio of 50-60:8-10:7-9:7-9:10-12:3-5.

2. The beneficiation process for a magnetochore mixed iron ore according to claim 1, characterized in that, The grinding aid is obtained by adding sodium tannate and diethylenetriaminemethylenephosphonic acid to an enzymatically hydrolyzed starch solution and stirring until well mixed; wherein the mass ratio of sodium tannate to diethylenetriaminemethylenephosphonic acid added to the enzymatically hydrolyzed starch solution is 8-10:8-10:

100.

3. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, The enzymatically hydrolyzed starch solution is prepared by the following method: first, 0.5 to 1 part of corn starch is stirred and dispersed in 100 parts of water, then 0.5 to 1 part of α-amylase is added, and the mixture is stirred for 110 to 120 minutes. Then, a 0.5 to 1% sodium hydroxide solution is added, and the mixture is stirred for another 50 to 60 minutes to obtain the solution.

4. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, The sodium 2-hydroxy-5-butylbenzoate is prepared by the following method: first, methyl 5-ethyl-2-hydroxybenzoate and hydroxylamine hydrochloride are mixed in equal molar amounts, then 1-2 mol / L sodium hydroxide solution is added, and the mixture is stirred and mixed. The mixture is stirred at 30-32°C for 6-7 hours, and then dried under vacuum. The amount of sodium hydroxide in the sodium hydroxide solution is twice that of methyl 5-ethyl-2-hydroxybenzoate.

5. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (1), the amount of water used is 2 to 3 times the mass of the mineral powder.

6. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (1), the process conditions for immersion treatment are: immersion at room temperature for 80 to 100 minutes; the process conditions for microwave treatment are: frequency 2500MHz, first irradiation with 500 to 700W microwave for 3 to 5 minutes, then irradiation with 400 to 600W microwave for 15 to 17 minutes, and finally irradiation with 800 to 1000W microwave for 7 to 9 minutes.

7. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (2), the specific method of ball milling is as follows: the pretreated mineral powder is added to the ball mill, and then the grinding aid is added. The amount of grinding aid is 0.8 to 1‰ of the mass of the pretreated mineral powder. The ball mill uses steel balls with diameters of 35 mm, 25 mm and 20 mm, and the mass ratio of the three is 2:3:

5. The material-to-ball ratio is 0.8 and the media filling rate is 40 to 45%. The portion of the ball milled to a particle size of less than 0.074 mm accounts for more than 90%.

8. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (2), the weak magnetic separation concentrate is retained, the weak magnetic separation tailings are fed into strong magnetic separation, the strong magnetic separation concentrate is fed into positive flotation, and the strong magnetic separation tailings are discharged as tailings; the magnetic field strength of the weak magnetic separation is 250-300mT, and the magnetic field strength of the strong magnetic separation is 1000-1200mT.

9. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (2), the positive flotation concentrate is fed into the reverse flotation, and the positive flotation tailings are discharged as tailings; the amount of positive flotation reagent is 0.5 to 0.7‰ of the mass of the strong magnetic separation concentrate, and the amount of reverse flotation reagent is 0.6 to 0.7‰ of the mass of the positive flotation concentrate.

10. The beneficiation process for a magnetohemorrhagic mixed iron ore according to claim 1, characterized in that, In step (2), the reverse flotation process adopts 1 roughing, 1 cleaning, and 3 scavenging. After the reverse flotation is completed, the reverse flotation tailings are discharged as tailings. The reverse flotation concentrate and the weak magnetic separation concentrate are combined to obtain the iron concentrate.