Titanium ore grading technology through magnetic levitation and electricity combined process

Abstract

The invention provides a magnetic levitation and electricity combined process titanium ore separation process, the mineral dissociation degree is optimized through multi-section wet type ore grinding, and efficient recovery of titanium ore resources is achieved in combination with a collaborative separation mechanism of gradient magnetic field separation, composite reagent flotation and microwave pretreatment enhanced electric separation. Firstly, multi-section wet type ore grinding is conducted, and mineral particle size distribution is accurately controlled; and then titanium minerals are preliminarily enriched through low-intensity magnetic separation, and residual titanium resources are recycled from tailings through high-gradient magnetic separation. A collecting agent and an inhibitor are introduced in the flotation stage, and the selective adsorption efficiency of titanium minerals is remarkably improved by adopting a one-roughing, three-refining and two-sweeping process; the surface characteristics of minerals are activated through microwave irradiation before electric separation, electric field separation conditions are stabilized in combination with a two-stage dehydration process, residual impurities are removed through secondary magnetic separation, and high-grade titanium concentrate is obtained. According to the method, the advantages of magnetic separation, flotation separation and electric separation are combined, the limitation of a single separation technology is broken through, and efficient enrichment of titanium minerals is achieved while the loss of tailings is reduced through parameter collaborative optimization and middling circulation treatment.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing technology, and in particular to a magnetic levitation and electric combined process for separating titanium ore. Background Art

[0002] Titanium ore is an important type of metal mineral resource rich in titanium, mainly including ilmenite, rutile, leucoxene and other mineral types. Ilmenite (FeTiO3) is the most common titanium ore resource, often closely associated with magnetite, hematite and various gangue minerals such as pyroxene, titanite and feldspar. The close combination of titanium and iron elements in its crystal structure and the uneven distribution of particle size increase the difficulty of sorting; rutile (TiO2) is the mineral with the highest titanium content, with a stable crystal structure and excellent optical and electrical properties, but its reserves in nature are relatively small; leucoxene is a cryptocrystalline or colloidal mineral aggregate formed by weathering and alteration of ilmenite, with complex properties, and the separation and recovery technology still needs to be broken through.

[0003] Titanium ore is the core raw material for the preparation of titanium materials, and its efficient sorting is a key link in resource development. At present, the mainstream process of titanium ore sorting is mainly a single or binary combination of magnetic separation, flotation or electrostatic separation, such as "weak magnetic separation-flotation" and "magnetic separation-electrostatic separation". However, there are still the following technical bottlenecks: (1) Low sorting efficiency: The recovery rate of weakly magnetic ilmenite and non-magnetic rutile in the traditional single magnetic separation process is generally less than 40%, resulting in a large loss of titanium resources. The conventional flotation process has complex mineral surface properties and poor collector selectivity, and a large amount of inhibitors need to be added, which not only increases production costs but also brings serious environmental governance pressure. Electrostatic separation is highly dependent on the difference in mineral conductivity, but the traditional process does not pretreat the flotation concentrate. Water and surface impurities affect the mineral charging efficiency, and the sorting efficiency of fine-grained titanium ore is low. (2) Poor process synergy: The particle size distribution of traditional grinding is uneven, the dissociation degree of mineral monomers is low, and the intergrowth particles lead to misjudgment of magnetic separation and increased consumption of flotation reagents. Flotation reagents mostly use a single fatty acid collector, which has poor selectivity for ilmenite and complex gangue, and lacks a gradient concentration process, making it difficult to achieve step-by-step stripping of impurities. The concentrate grade is generally less than 50%. (3) High energy consumption and poor stability: Thermal drying is generally used in the pretreatment stage of electrostatic separation, with energy consumption as high as 50kWh / t or more, and it is easy to cause mineral surface oxidation, seriously affecting the efficiency of electric field separation. In view of these technical bottlenecks, it is urgent to develop a new type of titanium ore separation process that is efficient, low-consumption and environmentally friendly, so as to improve the comprehensive utilization rate of titanium resources, break through the bottlenecks of titanium ore separation in grade, recovery rate and environmental protection, and meet the growing market demand. Summary of the invention

[0004] In view of this, the present invention proposes a magnetic levitation and electric combined process for separating titanium ore to solve the above problems.

[0005] The technical solution of the present invention is implemented as follows: A magnetic levitation and electric combined process for separating titanium ore, including the following steps:

[0006] S1. Crush the titanium ore raw materials and then perform multi-stage grinding treatment;

[0007] S2. Conduct primary magnetic separation on the ore materials to separate primary magnetic separation concentrate and primary magnetic separation tailings;

[0008] S3. Float the primary magnetic separation concentrate. First, adjust the pulp concentration and pH value, and then sequentially add a collector and an inhibitor; The flotation adopts a one-roughing, three-cleaning and two-scavenging process: The roughing time is 8 - 12 min; The roughing concentrate enters the three cleaning operations in sequence, and each cleaning time is 3 - 5 min; The roughing tailings enter the two scavenging operations in sequence, and each scavenging time is 3 - 5 min, obtaining flotation concentrate and flotation tailings;

[0009] S4. After the flotation concentrate is pretreated by microwave irradiation and dehydrated, it is separated by a high-voltage electric field to obtain electrostatic separation concentrate and electrostatic separation tailings;

[0010] S5. The electrostatic separation concentrate is purified by secondary magnetic separation to obtain the final titanium concentrate.

[0011] Further, it specifically includes the following steps:

[0012] S1. Crush the titanium ore raw ore to a particle size of <15 mm, and use a high-pressure roller mill for multi-stage wet grinding to control the grinding fineness of the ore materials with a particle size <0.074 mm accounting for ≥80%;

[0013] S2. Conduct primary magnetic separation on the ore materials, using a weak magnetic separator with a magnetic field intensity of 800 - 1200 Gs to obtain primary magnetic separation concentrate and primary magnetic separation tailings;

[0014] S3. Float the primary magnetic separation concentrate. The flotation adopts a one-roughing, three-cleaning and two-scavenging process: First, adjust the pulp concentration to 25 - 35 wt%, adjust the pulp pH value to 4.8 - 6.5, and then sequentially add a collector and an inhibitor. The dosage of the collector is 200 - 400 g / t, and the dosage of the inhibitor is 100 - 200 g / t. Stir for 3 - 5 min at a stirring speed of 200 - 300 rpm and then conduct roughing. The roughing time is 8 - 12 min; The roughing concentrate enters the three cleaning operations in sequence, with a pH value of 4.5 - 4.8, and each cleaning time is 3 - 5 min; The roughing tailings enter the two scavenging operations in sequence, and each scavenging time is 3 - 5 min, finally obtaining flotation concentrate and flotation tailings;

[0015] S4. After the flotation concentrate is pretreated by microwave irradiation and dehydrated, it is subjected to electrostatic separation. The microwave frequency is 2.45 - 3.58 GHz, and the power density is 1.5 - 3 kW / m 2, the irradiation time is 60 - 120 s, the electrostatic separation voltage is 8000 - 12000 V, and the electrostatic separation time is 5 - 10 min to obtain electrostatic separation concentrate and electrostatic separation tailings;

[0016] S5. Subject the electrostatic separation concentrate to secondary magnetic separation, adjust the pulp concentration to 30 - 40 wt%, and the magnetic field intensity to 1500 - 2000 Gs to obtain the final titanium concentrate.

[0017] Furthermore, the multi-stage wet grinding in step S1 includes coarse grinding and fine grinding:

[0018] Coarse grinding: Mix the ore crushed to < 15 mm with water to form a pulp with a concentration of 60 - 70 wt%, and conduct coarse grinding under the conditions of a roll pressure of 4.0 - 5.5 MPa and a rotational speed of 1.2 - 1.5 m / s. The proportion of the particle size < 0.074 mm in the discharged material is 50 - 60%;

[0019] Fine grinding: Return the coarse particles > 0.15 mm in the underflow after coarse grinding to the first stage for re-grinding, and feed the fine particles ≤ 0.15 mm in the overflow into the second-stage high-pressure roll mill for secondary fine grinding under the conditions of a roll pressure of 6 - 8 MPa and a rotational speed of 0.8 - 1.2 m / s, and separate them by a dewatering screen. The proportion of the particle size < 0.074 mm in the discharged material is ≥ 80%.

[0020] Furthermore, the weak magnetic separator in step S2 is a cylindrical magnetic separator, and the magnetic medium is filled with a combination of magnetic stainless steel wool with a diameter of 0.3 - 0.6 mm and steel balls with a diameter of 1.0 - 1.4 mm at a volume ratio of 2 - 4:1, and the rotational speed of its cylinder is 20 - 30 r / min.

[0021] Furthermore, the collector in step S3 is oxidized paraffin soap, sodium oleate and hydroxamic acid with a mass ratio of (5 - 7):(2 - 3):1, and the hydroxamic acid is selected from C7 - 9 alkyl hydroxamic acid.

[0022] Furthermore, the inhibitor in step S3 is sulfuric acid, water glass and sodium fluorosilicate with a mass ratio of (3.0 - 4.0):(1.5 - 2.5):1.

[0023] Furthermore, the rough selection in step S3 is maintained at 45 - 55 °C, and the temperatures of the three-stage cleaning are 45 - 50 °C, 42 - 48 °C, and 40 - 45 °C respectively.

[0024] Furthermore, the dehydration of the flotation concentrate in step S4 adopts a two-stage pressure filtration process, with the pressure of the first stage being 0.8 - 1.2 MPa and the pressure of the second stage being 2.5 - 3.5 MPa, so that the moisture content is lower than 10%.

[0025] Furthermore, in step S4, a roll-type electrostatic separator is used for electrostatic separation, the electrode spacing is 15 - 25 mm, the rotational speed of the roller is 150 - 250 r / min, and the feeding speed is 10 - 20 kg / min.

[0026] Further, the process also includes a step of reprocessing the primary magnetic separation tailings. The primary magnetic separation tailings are subjected to high-gradient magnetic separation with a magnetic field intensity of 3000 - 5000 Gs to obtain high-gradient magnetic separation concentrate and high-gradient magnetic separation tailings. The high-gradient magnetic separation concentrate is returned to the primary magnetic separation process.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] Through the combined process of magnetic separation, flotation, and electrostatic separation, and by integrating key technologies such as multi-stage grinding, gradient beneficiation, microwave pretreatment, and tailings recycling, the present invention forms an efficient separation system of "dissociation - impurity removal - quality improvement - recycling", significantly improving the utilization efficiency of titanium ore resources. The process uses a high-pressure roller mill to precisely control mineral dissociation and combines gradient magnetic field separation to preliminarily enrich titanium minerals; in the flotation stage, a collector and an inhibitor are introduced, and temperature control is used to improve selectivity; before electrostatic separation, microwave activation is used to modify the surface properties of minerals, and two-stage dehydration is combined to stabilize the electric field separation. The TiO2 grade of the titanium concentrate obtained by this process reaches 56.8%, the recovery rate is 87.63%, and the TiO2 loss rate of the tailings is less than 2.6%.

[0029] The innovation of this process lies in the combined application of three separation principles of magnetic separation, flotation, and electrostatic separation, significantly improving the grade and recovery rate of titanium concentrate and reducing the metal loss in tailings. Specific Embodiments

[0030] To better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0031] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0032] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can all be obtained from commercial channels.

[0033] Example 1

[0034] Properties of the raw ore: A certain titanium ore with a TiO2 grade of 12.8%, and the main minerals are ilmenite, magnetite, pyrite, and gangue minerals such as quartz and feldspar.

[0035] Process flow for separating titanium ore by the combined magnetic - flotation - electrostatic process:

[0036] S1. The raw titanium ore is crushed to a particle size of < 15 mm by a jaw crusher and a cone crusher, and multi - stage wet grinding is carried out using a high - pressure roller mill:

[0037] Coarse grinding: The ore crushed to < 15 mm is mixed with water to form a slurry with a concentration of 60 wt%, and is coarsely ground under the conditions of a roll pressure of 4.0 MPa and a rotational speed of 1.2 m / s. The proportion of the - 0.074 mm particle size in the discharged material is ≥ 80%;

[0038] Fine grinding: Coarse particles larger than 0.15 mm in the underflow after rough grinding are returned to the first stage for re-grinding, and fine particles smaller than or equal to 0.15 mm in the overflow enter the second-stage high-pressure roller mill for secondary fine grinding under the conditions of a roll pressure of 6 MPa and a rotational speed of 0.8 m / s. After separation by a dewatering screen, the proportion of particles with a particle size less than 0.074 mm in the discharged material is ≥80%.

[0039] S2. Use a drum magnetic separator to perform primary magnetic separation on the ore material. The magnetic field intensity is 800 Gs, the rotational speed of the cylinder is 20 r / min, and the magnetic medium is filled with 0.3 mm steel wool and 1.0 mm steel balls in a volume ratio of 2:1 to obtain primary magnetic separation concentrate and primary magnetic separation tailings. The primary magnetic separation tailings are subjected to high-gradient magnetic separation at 3000 Gs, and the concentrate is returned to the primary magnetic separation.

[0040] S3. Float the primary magnetic separation concentrate. The pulp concentration is 25 wt%, and pH = 4.8; the collector is oxidized paraffin soap, sodium oleate, and C7-9 alkyl hydroxamic acid with a mass ratio of 5:2:1, and the dosage is 200 g / t; the inhibitor is sulfuric acid, water glass, and sodium fluorosilicate with a mass ratio of 3.0:1.5:1, and the dosage is 100 g / t;

[0041] Adopt a one-roughing, three-cleaning, and two-scavenging process:

[0042] Roughing: Stir for 3 min at a stirring speed of 200 r / min and rough for 8 min at 45 °C;

[0043] Three cleanings: Clean three times at pH = 4.5, 3 min each time, and the temperatures are 45 °C, 42 °C, and 40 °C respectively;

[0044] Two scavengings: Each scavenging time is 3 min to obtain flotation concentrate and flotation tailings.

[0045] S4. The flotation concentrate is pretreated by microwave: the frequency is 2.45 GHz, the power density is 1.5 kW / m 2 , and the irradiation time is 60 s;

[0046] Two-stage pressure filtration for dehydration: The pressure of the first stage is 0.8 MPa, and the pressure of the second stage is 2.5 MPa to make the moisture content less than 10%;

[0047] Electrostatic separation: Use a roller electrostatic separator. The electrode spacing is 15 mm, the voltage is 8000 V, the rotational speed of the roller is 150 r / min, the feeding speed is 10 kg / min, and the electrostatic separation time is 5 min to obtain electrostatic separation concentrate and electrostatic separation tailings.

[0048] S5. Perform secondary magnetic separation on the electrostatic separation concentrate. The pulp concentration is 30 wt%, and the magnetic field intensity is 1500 Gs to obtain the final titanium concentrate.

[0049] Example 2

[0050] The properties of the raw ore are the same as those in Example 1.

[0051] Process for beneficiating titanium ore by combined magnetic and electric separation process:

[0052] S1. The titanium ore raw ore is crushed to a particle size of <15 mm by a jaw crusher and a cone crusher, and multi-stage wet grinding is carried out by a high-pressure roller mill:

[0053] Coarse grinding: The ore crushed to <15 mm is mixed with water to form a pulp with a concentration of 70 wt%, and is coarsely ground under the conditions of a roll pressure of 5.5 MPa and a rotational speed of 1.5 m / s. The proportion of the -0.074 mm particle size in the discharged material is ≥80%;

[0054] Fine grinding: The coarse particles >0.15 mm in the underflow after coarse grinding are returned to the first stage for regrinding, and the fine particles ≤0.15 mm in the overflow enter the second-stage high-pressure roller mill and are finely ground again under the conditions of a roll pressure of 8 MPa and a rotational speed of 1.2 m / s, and are separated by a dewatering screen. The proportion of the -0.074 mm particle size in the discharged material is ≥80%.

[0055] S2. The ore material is subjected to primary magnetic separation by a drum magnetic separator, with a magnetic field intensity of 1200 Gs, a rotational speed of the cylinder of 30 r / min, and a magnetic medium filled with 0.6 mm steel wool and 1.4 mm steel balls in a volume ratio of 4:1, to obtain primary magnetic separation concentrate and primary magnetic separation tailings. The primary magnetic separation tailings are subjected to high-gradient magnetic separation at 5000 Gs, and the concentrate is returned to primary magnetic separation.

[0056] S3. The primary magnetic separation concentrate is subjected to flotation, with a pulp concentration of 35 wt% and pH = 6.5; the collector is oxidized paraffin soap, sodium oleate and C7-9 alkyl hydroxamic acid with a mass ratio of 7:3:1, and the dosage is 400 g / t; the inhibitor is sulfuric acid, water glass and sodium fluorosilicate with a mass ratio of 4.0:2.5:1, and the dosage is 200 g / t;

[0057] A one-roughing, three-cleaning and two-scavenging process is adopted:

[0058] Roughing: Stir for 5 min at a stirring speed of 300 r / min and carry out roughing for 12 min at 55 °C;

[0059] Three times of cleaning: Clean three times at pH = 4.8, 5 min each time, and the temperatures are 50 °C, 48 °C and 45 °C respectively;

[0060] Two times of scavenging: Each scavenging time is 5 min to obtain flotation concentrate and flotation tailings.

[0061] S4. The flotation concentrate is pretreated by microwave: frequency 3.58 GHz, power density 3 kW / m 2 , irradiation time 120 s;

[0062] Two-stage pressure filtration dehydration: the pressure of the first stage is 1.2 MPa, and the pressure of the second stage is 3.5 MPa, so that the moisture content is lower than 10%;

[0063] Electrostatic separation: a roller-type electrostatic separator is used, the electrode spacing is 25 mm, the voltage is 12000 V, the roller speed is 250 r / min, the feeding speed is 20 kg / min, and the electrostatic separation time is 10 min to obtain electrostatic separation concentrate and electrostatic separation tailings.

[0064] S5. Perform secondary magnetic separation on the electrostatic separation concentrate, with a pulp concentration of 40 wt% and a magnetic field intensity of 2000 Gs to obtain the final titanium concentrate.

[0065] Example 3

[0066] The properties of the original ore are the same as those in Example 1.

[0067] Process flow for separating titanium ore by combined magnetic flotation and electrostatic separation process:

[0068] S1. Crush the titanium ore raw ore to a particle size of <15 mm by a jaw crusher and a cone crusher, and perform multi-stage wet grinding using a high-pressure roller mill:

[0069] Coarse grinding: Mix the ore crushed to <15 mm with water to form a pulp with a concentration of 65 wt%, and perform coarse grinding under the conditions of a roll pressure of 5.0 MPa and a speed of 1.3 m / s. The proportion of the -0.074 mm particle size fraction in the discharged material is ≥80%;

[0070] Fine grinding: Return the coarse particles >0.15 mm in the underflow after coarse grinding to the first stage for re-grinding, and send the fine particles ≤0.15 mm in the overflow to the second high-pressure roller mill for secondary fine grinding under the conditions of a roll pressure of 7 MPa and a speed of 1.0 m / s, and separate by a dewatering screen. The proportion of the -0.074 mm particle size fraction in the discharged material is ≥80%.

[0071] S2. Perform primary magnetic separation on the ore material using a drum magnetic separator, with a magnetic field intensity of 1000 Gs, a cylinder speed of 25 r / min, and a magnetic medium filled with 0.5 mm steel wool and 1.2 mm steel balls in a volume ratio of 3:1 to obtain primary magnetic separation concentrate and primary magnetic separation tailings. The primary magnetic separation tailings are subjected to high-gradient magnetic separation at 4000 Gs, and the concentrate is returned to the primary magnetic separation.

[0072] S3. Perform flotation on the primary magnetic separation concentrate, with a pulp concentration of 30 wt% and pH = 5.5; the collector is oxidized paraffin soap, sodium oleate, and C7-9 alkyl hydroxamic acid with a mass ratio of 6:3:1, and the dosage is 300 g / t; the inhibitor is sulfuric acid, water glass, and sodium fluorosilicate with a mass ratio of 3.5:2:1, and the dosage is 150 g / t;

[0073] Adopt a one-roughing, three-cleaning, and two-scavenging process:

[0074] Rough selection: Stir for 4 min at a stirring speed of 250 r / min and conduct rough selection at 50 °C for 10 min;

[0075] Three-stage cleaning: Conduct cleaning three times at pH = 4.6, 4 min each time, and the temperatures are 48 °C, 45 °C, and 42 °C respectively;

[0076] Two-stage scavenging: The scavenging time is 4 min each time to obtain flotation concentrate and flotation tailings.

[0077] S4. Pretreat the flotation concentrate by microwave: The frequency is 3.05 GHz, the power density is 2.5 kW / m 2 , and the irradiation time is 90 s;

[0078] Two-stage filter pressing for dehydration: The pressure in the first stage is 1.0 MPa, and the pressure in the second stage is 3.0 MPa to make the moisture content less than 10%;

[0079] Electrostatic separation: Use a roller electrostatic separator with an electrode spacing of 20 mm, a voltage of 10000 V, a roller speed of 200 r / min, a feeding speed of 15 kg / min, and an electrostatic separation time of 8 min to obtain electrostatic separation concentrate and electrostatic separation tailings.

[0080] S5. Conduct secondary magnetic separation on the electrostatic separation concentrate with a pulp concentration of 35 wt% and a magnetic field intensity of 1800 Gs to obtain the final titanium concentrate.

[0081] Comparative example 1: One-stage grinding process

[0082] The difference between this comparative example and Example 3 is that in step S1, a ball mill is used for one-stage grinding to <0.074 mm accounting for 80%, replacing the two-stage high-pressure roller grinding in Example 3.

[0083] Comparative example 2: No secondary magnetic separation

[0084] The difference between this comparative example and Example 3 is that: step S5 is omitted, specifically, the electrostatic separation concentrate obtained in step S4 is the final titanium concentrate.

[0085] Comparative example 3: Adjust the proportion of collector

[0086] The difference between this comparative example and Example 3 is that: the collector in step S3 is oxidized paraffin soap, sodium oleate, and C7-9 alkyl hydroxamic acid with a mass ratio of 1:1:1.

[0087] Comparative example 4: The collector lacks hydroxamic acid

[0088] The difference between this comparative example and Example 3 is that: the collector in step S3 is oxidized paraffin soap and sodium oleate with a mass ratio of 6:3.

[0089] Comparative example 5: The cleaning temperature is not controlled

[0090] The difference between this comparative example and Example 3 lies in that: the temperature of the three-stage cleaning in the flotation of step S3 is the same as the roughing temperature of 50 °C.

[0091] Comparative Example 6: The three-stage cleaning is replaced by one-stage cleaning

[0092] The difference between this comparative example and Example 3 lies in that: the three-stage cleaning in the flotation of step S3 is replaced by one-stage cleaning, and the cleaning is carried out at pH = 4.6 and 45 °C for 4 min.

[0093] Comparative Example 7: Omit the microwave pretreatment

[0094] The difference between this comparative example and Example 3 lies in that: microwave pretreatment is not carried out in step S4. Specifically, the flotation concentrate is dehydrated and then subjected to electrostatic separation.

[0095] Comparative Example 8: Without dehydration

[0096] The difference between this comparative example and Example 3 lies in that: the dehydration step is not carried out in step S4. Specifically, the flotation concentrate is subjected to microwave pretreatment and then electrostatic separation.

[0097] The methods of the examples and comparative examples are respectively used for ore dressing, and the grades, total recovery rates and tailing loss rates of the obtained final titanium concentrates are recorded. The results are shown in Table 1.

[0098] Table 1:

[0099]

[0100]

[0101] Combined with the data in Table 1, it can be seen that the grades of the titanium concentrates in the example group are 55.7 - 56.8%, and the total recovery rates are 86.91 - 87.63%, which are significantly better than all comparative examples. Moreover, the TiO2 loss rate of the tailings is 2.4 - 2.6%, indicating that the combined magnetic flotation and electrostatic separation process of the present invention has achieved technological breakthroughs in three aspects: grade improvement, resource recovery and tailing control.

[0102] In Comparative Example 1, one-stage ball milling is used, and due to uneven particle size distribution, the selectivity of flotation may decrease and the grade of the concentrate may be reduced; it shows that Example 3 uses a high-pressure roller mill for two-stage grinding (rough grinding + fine grinding and classification return), controlling the proportion of -0.074 mm ≥ 80%, improving the monomer dissociation degree, and providing high-purity monomer minerals for subsequent magnetic separation and flotation.

[0103] After omitting the secondary magnetic separation in Comparative Example 2, the content of magnetic impurities in the electrostatic separation concentrate increases, resulting in a 3.2% decrease in grade, indicating that the secondary magnetic separation can remove the weakly magnetic impurities remaining after electrostatic separation, such as fine particles of hematite and magnetite.

[0104] In Comparative Example 3, after adjusting the collector ratio, the hydroxamic acid ratio was too high, resulting in non-selective collection of gangue, a decrease in the grade of titanium concentrate, and the tailing loss rate increased to 5.6%. In Comparative Example 4, the collector lacked hydroxamic acid, and the grade decreased by 9.3%, with a significant decrease in the collection ability, indicating that hydroxamic acid has a good specific collection effect on the surface of ilmenite.

[0105] In Comparative Example 5, the constant-temperature flotation caused a 4.4% decrease in the concentrate grade. In Comparative Example 6, single-stage cleaning led to a 2.7% increase in tailing loss, insufficient cleaning times, incomplete separation of locked particles, or insufficient separation of impurities, indicating that the three-stage cleaning and temperature gradient control of the present invention can significantly improve selectivity.

[0106] In Comparative Example 7, microwave pretreatment was not carried out, the mineral surface was not activated, and the electrostatic separation efficiency decreased, indicating that microwave irradiation can effectively activate the surface charge of minerals and improve the electrostatic separation accuracy.

[0107] In Comparative Example 8, electrostatic separation was carried out directly without dehydration, resulting in excessive moisture, poor conductivity of wet ore, and electric field disorder, and a sharp increase in tailing loss, indicating that stable electrostatic separation operation can be achieved after dehydration.

[0108] The above are only the 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A process for separating titanium ore by a combined magnetic levitation and electric process, characterized in that: It includes the following steps: S1. After crushing the titanium ore raw material, it is subjected to multi-stage grinding treatment; S2. Conduct a primary magnetic separation on the ore material to separate the primary magnetic separation concentrate and the primary magnetic separation tailings; S3. Float the primary magnetic separation concentrate. First, adjust the pulp concentration and pH value, and then sequentially add a collector and an inhibitor; The flotation adopts a one-roughing, three-cleaning and two-scavenging process: the roughing time is 8 - 12 min; The roughing concentrate enters the three cleaning operations in sequence, and the cleaning time for each time is 3 - 5 min; The roughing tailings enter the two scavenging operations in sequence, and the scavenging time for each time is 3 - 5 min, obtaining the flotation concentrate and the flotation tailings; S4. The flotation concentrate is dehydrated after microwave irradiation pretreatment and then separated by a high-voltage electric field to obtain the electrostatic separation concentrate and the electrostatic separation tailings; S5. The electrostatic separation concentrate is purified by secondary magnetic separation to obtain the final titanium concentrate.

2. The beneficiation process of titanium ore by a combined magnetic levitation and electric process according to claim 1, characterized in that: Specifically, it includes the following steps: S1. Crush the titanium ore raw ore to a particle size of <15 mm, and adopt a high-pressure roller mill for multi-stage wet grinding, controlling the proportion of ore material with a grinding fineness of <0.074 mm to be ≥80%; S2. Conduct a primary magnetic separation on the ore material, using a weak magnetic separator with a magnetic field intensity of 800 - 1200 Gs to obtain the primary magnetic separation concentrate and the primary magnetic separation tailings; S3. Float the primary magnetic separation concentrate. The flotation adopts a one-roughing, three-cleaning and two-scavenging process: First, adjust the pulp concentration to 25 - 35 wt%, adjust the pulp pH value to 4.8 - 6.5, and then sequentially add a collector and an inhibitor. The dosage of the collector is 200 - 400 g / t, and the dosage of the inhibitor is 100 - 200 g / t. Stir for 3 - 5 min at a stirring speed of 200 - 300 rpm and then conduct roughing, and the roughing time is 8 - 12 min; The roughing concentrate enters the three cleaning operations in sequence, with a pH value of 4.5 - 4.8, and the cleaning time for each time is 3 - 5 min; The roughing tailings enter the two scavenging operations in sequence, and the scavenging time for each time is 3 - 5 min, obtaining the flotation concentrate and the flotation tailings; S4. Subject the flotation concentrate to dehydration after microwave irradiation pretreatment and then conduct electrostatic separation. The microwave frequency is 2.45 - 3.58 GHz, the power density is 1.5 - 3 kW / m 2 , the irradiation time is 60 - 120 s, the electrostatic separation voltage is 8000 - 12000 V, and the electrostatic separation time is 5 - 10 min to obtain electrostatic separation concentrate and electrostatic separation tailings; S5. Conduct secondary magnetic separation on the electrostatic separation concentrate, adjust the pulp concentration to 30 - 40 wt%, and the magnetic field intensity is 1500 - 2000 Gs to obtain the final titanium concentrate.

3. The beneficiation process of titanium ore by a combined magnetic levitation and electric process according to claim 2, characterized in that: The multi-stage wet grinding described in step S1 includes rough grinding and fine grinding: Rough grinding: Mix the ore crushed to <15 mm with water to form a pulp with a concentration of 60 - 70 wt%, and conduct rough grinding under the conditions of a roll pressure of 4.0 - 5.5 MPa and a rotational speed of 1.2 - 1.5 m / s. The proportion of the particle size <0.074 mm in the discharged material is 50 - 60%; Fine grinding: Return the coarse particles >0.15 mm in the underflow after rough grinding to the first stage for re-grinding, and the overflow fine particles ≤0.15 mm enter the second-stage high-pressure roller mill for secondary fine grinding under the conditions of a roll pressure of 6 - 8 MPa and a rotational speed of 0.8 - 1.2 m / s, and are separated by a dewatering screen. The proportion of the particle size <0.074 mm in the discharged material is ≥80%.

4. The beneficiation process of titanium ore by a combined magnetic levitation and electric process according to claim 2, characterized in that: The weak magnetic separator described in step S2 is a cylindrical magnetic separator, and the magnetic medium is filled with a combination of magnetic stainless steel wool with a diameter of 0.3 - 0.6 mm and steel balls with a diameter of 1.0 - 1.4 mm in a volume ratio of 2 - 4:1, and its cylindrical rotational speed is 20 - 30 r / min.

5. The beneficiation process of titanium ore by the combined magnetic levitation and electric process according to claim 2, characterized in that: The collector described in step S3 is oxidized paraffin soap, sodium oleate and hydroxamic acid with a mass ratio of (5-7):(2-3):1, and the hydroxamic acid is selected from C7-9 alkyl hydroxamic acid.

6. The beneficiation process of titanium ore by a combined magnetic levitation and electric process according to claim 2, characterized in that: The inhibitor described in step S3 is sulfuric acid, water glass and sodium fluorosilicate with a mass ratio of (3.0-4.0):(1.5-2.5):

1.

7. The beneficiation process of titanium ore by a combined magnetic levitation and electric process according to claim 2, characterized in that: The rough selection in step S3 is maintained at 45-55°C, and the temperatures of the three-stage cleaning are 45-50°C, 42-48°C, and 40-45°C respectively.

8. The beneficiation process of titanium ore by the combined magnetic levitation and electric process according to claim 2, characterized in that: The dehydration of the flotation concentrate in step S4 adopts a two-stage pressure filtration process, with the first-stage pressure of 0.8-1.2 MPa and the second-stage pressure of 2.5-3.5 MPa, so that the water content is less than 10%.

9. The beneficiation process of titanium ore by a combined magnetic and electric floating process according to claim 2, wherein: In step S4, a roller-type electrostatic separator is used for electrostatic separation, the electrode spacing is 15-25 mm, the roller speed is 150-250 r / min, and the feeding speed is 10-20 kg / min.

10. The beneficiation process of titanium ore by a combined magnetic levitation and electric process as claimed in claim 1, characterized in that: It also includes a step of reprocessing the primary magnetic separation tailings. The primary magnetic separation tailings are subjected to high-gradient magnetic separation with a magnetic field intensity of 3000-5000 Gs to obtain high-gradient magnetic separation concentrate and high-gradient magnetic separation tailings. The high-gradient magnetic separation concentrate is returned to the primary magnetic separation process.

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