A beneficiation method for ilmenite sand tailings

Abstract

The present invention belongs to the technical field of ore dressing, and particularly relates to an ore dressing method for recycling titanium from ilmenite separation tailings and overflow. The present invention classifies and concentrates the coarse-grained gravity separation tailings slurry, fine-grained gravity separation tailings slurry and classification overflow: obtaining their respective sedimentation underflow and overflow; then the present invention performs magnetic waste rejection and flocculation magnetic capture on the classified and concentrated underflow through classified magnetic separation to improve the feed grade of titanium dioxide and greatly reduce the subsequent operation processing volume; subsequently, the present invention only grinds the first magnetic concentrate obtained from the coarse-grained gravity separation tailings slurry to make it fully dissociated monomerically, achieving the purpose of selective grinding; then the ground product is accurately classified to realize the narrow particle size feed of materials; the coarse-grained and fine-grained products classified are subjected to full-process physical field separation; the flocculation magnetic capture concentrate is subjected to back-carrying foam separation to obtain titanium concentrate. The present invention realizes the high-quality recovery of titanium dioxide from ilmenite separation tailings and overflow, and also improves the total recovery rate of titanium dioxide.

Description

Technical Field

[0001] The present invention belongs to the technical field of ore dressing, and particularly relates to a method for dressing ilmenite tailings in sand. Background Art

[0002] Strategic metal titanium is mainly used for producing titanium materials and titanium dioxide, and the raw materials all come from ilmenite and rutile. China's ilmenite resources mainly include primary vanadium-titanium magnetite and placer, the former is mainly distributed in the Panxi area and the Chengde area, and the latter is mainly distributed in the Yunnan and Hainan areas. Among them, Yunnan is mainly weathered crust lateritic placer, and Hainan is mainly river alluvial coastal placer. Different ore-forming conditions form different deposit types, resulting in greatly different mining and dressing processes. The separation processes for ilmenite in vanadium-titanium magnetite mainly include high-intensity magnetic separation-flotation, high-intensity magnetic separation-gravity separation, gravity separation-flotation, etc., but the recovery rate of titanium dioxide is only about 40%. The separation process for coastal placer mainly is the combined process of gravity-magnetic-electricity, and flotation is not widely used. The weathered crust lateritic placer has the characteristics of complete weathering, large mud content, high calcium and magnesium content, etc. The mining process is mainly hydraulic mining and water transportation, and the ore dressing process is mainly the process of "weak magnetic separation-high-intensity magnetic separation-classification-gravity separation". The main gravity separation equipment is the spiral chute. Since ilmenite is a friable ore, over-grinding is inevitable during the grinding process. And since the lower limit of the separation particle size of the spiral chute is generally 37μm, a large amount of ilmenite is lost in the classification overflow and gravity separation tailings, and the loss rate is as high as more than 50%. In addition, due to the loss of coarse-grained gangue minerals and the intergrowth of ilmenite and gangue minerals in the tailings, the particle size distribution of minerals in the tailings is uneven and the mineral symbiotic relationship is complex. Therefore, the weathered crust lateritic titanium tailings are a kind of complex and difficult-to-dress titanium tailings. How to effectively recover ilmenite and associated minerals in the weathered crust lateritic titanium tailings is an effective measure to improve the economic benefits of titanium enterprises.

[0003] Chinese Patent CN202210348910.3 uses the process of screening-grinding-magnetic separation for the titanium tailings produced by the weak magnetic separation of iron-high-intensity magnetic separation of titanium process for vanadium-titanium magnetite, where TiO2 is about 7%, to obtain a flotation feed with a titanium dioxide content of about 16%. However, the titanium dioxide grade of the flotation feed is low, resulting in high production costs, and it does not involve the recovery of ilmenite in the classified slime and overflow, and the total recovery rate of titanium dioxide is low. Chinese Patent CN201710599141.3 developed two ore dressing components of high-intensity magnetic separation and classification thickening tank and two components of tailings pulp thickening and strong dehydration for the recovery of valuable metals and wastewater recycling in the titanium tailings of weathered crust lateritic placer. However, the pulsating high-gradient magnetic separator and the spiral chute have limited recovery of -37 micron particles, resulting in a large amount of fine-grained ilmenite still being lost in the tailings, and the total recovery rate of titanium dioxide is low.

[0004] In short, the existing reported methods for treating titanium tailings are difficult to be applicable to the re-election of weathered crust lateritic titanium tailings, and it is impossible to obtain high-quality titanium concentrate with high recovery rate. Summary of the Invention

[0005] The object of the present invention is to provide a beneficiation method for recycling titanium from ilmenite beneficiation tailings and overflow. Aiming at the low-grade titanium dioxide in the weathered crust lateritic ilmenite beneficiation tailings and overflow, the beneficiation method provided by the present invention adopts a three-point method of "classification and grading separation", realizing the high-quality recovery of ilmenite in the ilmenite beneficiation tailings and overflow, and at the same time improving the total recovery rate of titanium dioxide.

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

[0007] The present invention provides a beneficiation method for recycling titanium from ilmenite beneficiation tailings and overflow, comprising the following steps:

[0008] First concentrate the coarse-grained gravity separation tailings slurry to obtain a first underflow and a first overflow respectively, wherein the particle size of the solid particles in the coarse-grained gravity separation tailings slurry is +0.074~-0.20mm;

[0009] Second concentrate the fine-grained gravity separation tailings slurry to obtain a second underflow and a second overflow respectively, wherein the particle size of the solid particles in the fine-grained gravity separation tailings slurry is +0.020~-0.074mm;

[0010] Mix the classified overflow with a first flocculant for the first time and then perform a third concentration to obtain a third underflow and a third overflow respectively, wherein the particle size of the solid particles in the classified overflow is -0.020mm;

[0011] Perform first magnetic separation on the first underflow to obtain a first magnetic concentrate and a first tailing respectively;

[0012] Perform second magnetic separation on the second underflow to obtain a second magnetic concentrate and a second tailing respectively;

[0013] Mix the third underflow with a second flocculant and then perform flocculation magnetic trapping to obtain a third magnetic concentrate and a third tailing respectively;

[0014] Grind and screen the first magnetic concentrate to obtain an oversize product and an undersize product respectively;

[0015] Classify the undersize product to obtain a first classified product, a second classified product and a third classified product respectively; the particle size of the solid particles in the first classified product is +0.074~-0.10mm, the particle size of the solid particles in the second classified product is +0.02~-0.074mm, and the particle size of the solid particles in the third classified product is -0.02mm;

[0016] Perform first gravity separation on the first classified product to obtain a first titanium concentrate and a fourth tailing respectively;

[0017] After the second classification product and the second magnetic concentrate are secondarily mixed, a second gravity separation is performed to respectively obtain a second titanium concentrate and a fifth tailing;

[0018] After the third magnetic concentrate, a carrier material, a first collector, and a first inhibitor are thirdly mixed, a back-carrying foam separation is performed to obtain a third titanium concentrate and a sixth tailing; the carrier material is obtained by the reaction of ilmenite, a second collector, and a second inhibitor.

[0019] Preferably, the mass percentage content of TiO2 in the dry-based materials of the coarse-grained gravity separation tailing slurry, the fine-grained gravity separation tailing slurry, and the classification overflow is independently 2-4%;

[0020] The solid content of the first underflow is 50-75%;

[0021] The solid content of the second underflow is 25-45%;

[0022] The solid content of the third underflow is 45-65%.

[0023] Preferably, the raw materials for the first mixing further include the second overflow and / or the third classification product;

[0024] The dosage of the first flocculant is 50-120 g / t.

[0025] Preferably, the dosage of the second flocculant is ≤40 g / t.

[0026] Preferably, the conditions for the first magnetic separation and the second magnetic separation include: the magnetic field strength is 0.5-1.5 T, the magnetic medium is rod medium, and the diameter of the rod medium is 3-5 mm;

[0027] The conditions for the flocculation magnetic capture include: the magnetic field strength is 0.7-1.8 T, the magnetic medium is rod medium, and the diameter of the rod medium is 1-3 mm.

[0028] Preferably, the solid content of the first magnetic concentrate is 55-70%; the size of the sieve hole for screening is 0.10 mm.

[0029] Preferably, the first gravity separation is carried out by using a fine sand shaking table, and the working parameters of the fine sand shaking table separation include: the feeding concentration is 16-22%, the working slope is 3-6°, the stroke is 14-22 mm, and the impulse frequency is 240-270 times / min; the working process of the first gravity separation is: performing a first rough separation, a first scavenging separation, and a first cleaning separation, the number of times of the first rough separation is 1 time, the number of times of the first scavenging separation is 1-2 times, and the number of times of the first cleaning separation is 2-3 times;

[0030] The working process of the second re - selection is as follows: second rough selection, second scavenging, and second cleaning are carried out. The second rough selection uses a slime bed for rough selection, and the number of times of the second rough selection is 1 time. The second scavenging uses a grooved bed for scavenging, and the number of times of the second scavenging is 1 - 2 times. The second cleaning uses a slime bed for cleaning and a rotary film concentrator for cleaning, and the number of times of the second cleaning is 2 - 3 times. The working parameters of the slime bed rough selection, the grooved bed scavenging, and the slime bed cleaning independently include: the feed concentration is 14 - 18%, the working slope is 0 - 3°, the stroke is 10 - 14 mm, and the stroke frequency is 340 - 380 times per minute. The working parameters of the rotary film concentrator cleaning include: the vibration frequency is 36 - 40 Hz, and the rotation frequency is 8 - 12 Hz.

[0031] Preferably, when the third mixing is carried out, the mass ratio of the carrier material to the third magnetic concentrate is 1:3 - 8; the first inhibitor is an organic acid - modified water glass, the first collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate, the number of carbon atoms in the alkyl group of the sodium alkyl oleate and the sodium alkyl sulfate is independently 12 - 18, and the mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is 3 - 5:1; the dosage of the first inhibitor is 300 - 600 g / t, and the dosage of the first collector is 800 - 1500 g / t;

[0032] The third mixing is carried out under stirring conditions. The rotation speed of the stirring is 1800 - 2900 r / min, and the stirring time is 30 - 60 min;

[0033] The pH value of the back - mounted foam separation is 3 - 6;

[0034] The working process of the back - mounted foam separation is as follows: third rough selection, third cleaning, and third scavenging are carried out. The number of times of the third rough selection is 1 - 2 times, the number of times of the third cleaning is 2 - 3 times, and the number of times of the third scavenging is 2 - 3 times.

[0035] Preferably, the preparation method of the carrier material includes the following steps:

[0036] Mix the ilmenite and water to obtain an ilmenite slurry; the ilmenite is a part of the first ilmenite concentrate; the solid content of the ilmenite slurry is 50 - 60%;

[0037] Mix the ilmenite slurry, the second inhibitor, and the second collector, and carry out a reaction under acidic conditions to obtain the carrier material; the second inhibitor is an organic acid-modified water glass, the second collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate, the number of carbon atoms in the alkyl group of the sodium alkyl oleate and the sodium alkyl sulfate is independently 12-18, and the mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is 3-5:1; the dosage of the second collector is 500-1000 g / t, and the dosage of the second inhibitor is 200-400 g / t;

[0038] The pH value of the reaction is 3-4; the temperature of the reaction is room temperature, the reaction is carried out under stirring conditions, the rotation speed of the stirring is 1500-1800 r / min, and the stirring time is 10-20 min.

[0039] Preferably, the mass percentage content of TiO2 in the dry matter of the first magnetic concentrate and the second magnetic concentrate is independently 5-9%;

[0040] The mass percentage content of TiO2 in the dry matter of the third magnetic concentrate is 13-17%;

[0041] The mass percentage content of TiO2 in the dry matter of the first tailing and the second tailing is <1.2%;

[0042] The mass percentage content of TiO2 in the dry matter of the third tailing is <1.5%;

[0043] The mass percentage content of TiO2 in the dry matter of the first titanium concentrate is 38-42%;

[0044] The mass percentage content of TiO2 in the dry matter of the second titanium concentrate is 42-46%;

[0045] The mass percentage content of TiO2 in the dry matter of the third titanium concentrate is 42-46%.

[0046] The present invention provides a beneficiation method for recycling titanium from ilmenite beneficiation tailings and overflow. The beneficiation method provided by the present invention classifies and concentrates the coarse-grained gravity separation tailings slurry, fine-grained gravity separation tailings slurry and classified overflow: the above two types of tailings slurry and overflow are respectively concentrated to obtain their respective sedimentation underflows and overflows; then the present invention performs magnetic waste rejection and magnetic capture on the classified and concentrated underflows through classified magnetic separation to improve the feed grade of titanium dioxide and greatly reduce the processing volume of subsequent operations; subsequently, the present invention only grinds the first magnetic concentrate obtained from the coarse-grained gravity separation tailings slurry to make it fully monomer-dissociated, and the present invention only grinds the strong magnetic separation concentrate of the coarse-grained tailings, avoiding over-crushing of brittle ilmenite, achieving the purpose of selective grinding, and the beneficiation method has remarkable energy-saving and emission-reduction effects; then the ground products are accurately classified to achieve narrow particle size classification of the materials; then the coarse particle size grade (the first classification product) and the fine particle size product (the second classification product) separated by classification are subjected to full-process physical field separation to obtain the first titanium concentrate and the second titanium concentrate; the present invention mixes the third magnetic concentrate, the carrier material, the first inhibitor and the first collector for the third time and performs back-carrying foam separation to recover the third titanium concentrate. In summary, the present invention develops a "three-part" beneficiation method to solve the problems of low titanium dioxide grade in the tailings and overflow of weathered crust lateritic ilmenite, uneven high and low tailing grades, large difference in mud content, uneven particle size distribution, complex monomer dissociation, and large difference in pulp concentration, etc. That is, it classifies, grades and separates multiple types of titanium tailings generated by the beneficiation system of a titanium sand ore beneficiation plant, realizes the transformation of complex and difficult-to-treat waste resources into optional and easy-to-treat titanium resources, and specifically develops new processes for refined gravity separation green separation and back-carrying foam separation to strengthen fine particle recovery, achieving the purpose of effectively recovering titanium dioxide in complex titanium tailings, strategically extending the service life of the mine, and substantially improving the market supply capacity of weathered crust lateritic ilmenite enterprises for titanium concentrate; the results of the examples show that the operating recovery rate of the first titanium concentrate is 70-75%, the operating recovery rate of the second titanium concentrate is 65-70%, and the operating recovery rate of the third titanium concentrate is 75-85%. Higher-quality titanium concentrate can be obtained after impurity removal. The beneficiation and separation method provided by the present invention has strong pertinence, stable process, remarkable energy-saving and emission-reduction effects, and low tail water environmental pressure.

[0047] Further, in the present invention, the magnetic field intensity during the first magnetic separation and the second magnetic separation is 0.5-1.5 T, the magnetic medium is rod medium, and the diameter of the rod medium is 3-5 mm; the magnetic field intensity during the flocculation magnetic capture is 0.7-1.8 T, the magnetic medium is rod medium, and the diameter of the rod medium is 1-3 mm. By regulating the magnetic field intensity and magnetic medium of the first magnetic separation, the second magnetic separation and the flocculation magnetic capture, the present invention accurately constructs the field strength gradient and configures the size of the rod medium during the magnetic separation process, so that the waste rejection rate of the titanium tailings is greater than 50%, reducing the processing volume of subsequent operations, and the beneficiation method has remarkable energy-saving and emission-reduction effects.

[0048] Further, in the present invention, the dosage of the second flocculant is ≤ 40 g / t. The present invention synergistically couples the magnetic capture ability of the fine particle flocculant and flocculation magnetic capture, such that the waste discharge rate of titanium tailings is greater than 50%, reducing the subsequent operation processing volume, and achieving remarkable energy conservation and emission reduction effects.

[0049] Further, in the present invention, the first re-election is carried out by using a fine sand shaking table for separation, the second rough separation of the second re-election is carried out by using a slime bed for rough separation, the second scavenging is carried out by using a grooved bed for scavenging, and the second cleaning is carried out by using a slime bed for cleaning and a rotary flow film concentrator for cleaning. Before re-election in the present invention, strict classification is carried out, and after classification, corresponding re-election equipment is adapted, so that each re-election equipment "fits its place". After classification, similar particle sizes enter the same separation process, which not only saves the site but also is easy to manage and operate. In particular, a combined equipment of "slime bed + grooved bed + rotary flow film concentrator" is used to separate the fine particle size of -0.074 to +0.02 mm. At the same time, by precisely controlling the operating parameters of the equipment and optimizing the process flow, the purpose of refined re-election is achieved. In addition, no chemical reagents need to be added during the whole process of re-election separation, and the tail water is directly recycled, reducing the tail water treatment pressure and production cost.

[0050] In the present invention, the preparation method of the carrier material includes the following steps: mixing the ilmenite and the water to obtain an ilmenite slurry; mixing the ilmenite slurry, the second inhibitor and the second collector, and reacting under acidic conditions to obtain the carrier material; the ilmenite is part of the first titanium concentrate. In the present invention, the particle size of the titanium concentrate separated by the fine sand bed matches the size of the carrier particle for back-carrying foam separation, and it can be directly used as the carrier particle, reducing the carrier preparation process and the production cost. The fine sand bed separation adopts the idea of "preserving" the recovery rate and "discarding" the grade, efficiently recovering the ilmenite. On the one hand, back-carrying foam separation obtains high-quality titanium concentrate, realizing the recovery of fine-grained ilmenite. On the other hand, it improves the grade of titanium dioxide in the carrier particles, to a certain extent solving the problem that the grade and recovery rate of titanium concentrate separated by the fine sand bed cannot be both obtained, and at the same time having good reference significance for solving the contradiction problem between grade and recovery rate commonly existing in the beneficiation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a flow chart of the beneficiation method for recycling titanium in the sand ilmenite separation tailings and overflow provided by the embodiment of the present invention;

[0052] Figure 2 It is a refined beneficiation flow chart of the first classification product, the second classification product and the second magnetic concentrate provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The present invention provides a beneficiation method for recycling titanium from ilmenite separation tailings and overflow, comprising the following steps:

[0054] First concentrate the coarse-grained gravity separation tailings slurry to obtain a first underflow and a first overflow respectively, wherein the particle size of the solid particles in the coarse-grained gravity separation tailings slurry is +0.074 to -0.20 mm;

[0055] Second concentrate the fine-grained gravity separation tailings slurry to obtain a second underflow and a second overflow respectively, wherein the particle size of the solid particles in the fine-grained gravity separation tailings slurry is +0.020 to -0.074 mm;

[0056] Mix the classified overflow and a first flocculant for the first time and then perform third concentration to obtain a third underflow and a third overflow respectively, wherein the particle size of the solid particles in the classified overflow is -0.020 mm;

[0057] Perform first magnetic separation on the first underflow to obtain a first magnetic concentrate and a first tailing respectively;

[0058] Perform second magnetic separation on the second underflow to obtain a second magnetic concentrate and a second tailing respectively;

[0059] Mix the third underflow and a second flocculant and then perform flocculation magnetic capture to obtain a third magnetic concentrate and a third tailing respectively;

[0060] Perform grinding and screening on the first magnetic concentrate to obtain an oversize product and an undersize product respectively;

[0061] Classify the undersize product to obtain a first classified product, a second classified product and a third classified product respectively; the particle size of the solid particles in the first classified product is +0.074 to -0.10 mm, the particle size of the solid particles in the second classified product is +0.02 to -0.074 mm, and the particle size of the solid particles in the third classified product is -0.02 mm;

[0062] Perform first gravity separation on the first classified product to obtain a first titanium concentrate and a fourth tailing respectively;

[0063] Mix the second classified product and the second magnetic concentrate for the second time and then perform second gravity separation to obtain a second titanium concentrate and a fifth tailing respectively;

[0064] Mix the third magnetic concentrate, a carrier material, a first inhibitor and a first collector for the third time and then perform back-carrying foam separation to obtain a third titanium concentrate and a sixth tailing; the carrier material is obtained by reacting ilmenite, a second inhibitor and a second collector.

[0065] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well-known to those skilled in the art.

[0066] Based on the problems existing in the existing titanium separation process of weathered crust lateritic sand ilmenite, such as the low titanium dioxide grade of tailings and overflow generated in each operation, the uneven high and low content of tailings grade, the large difference in mud content, the uneven particle size distribution, the complex monomer dissociation situation, and the large difference in pulp concentration, the present invention provides a beneficiation method of "three parts" for recovering titanium from complex titanium tailings. The method provided by the present invention first classifies and concentrates the tailings in the original classification and gravity separation process, then accurately classifies them according to the process mineralogy characteristics of the tailings, and finally conducts fine separation based on the differences in the physical and chemical properties of the minerals, thus constructing a "classification, grading, and separation" three-part method. At the same time, according to the different properties of the tailings, a targeted beneficiation process is designed, which has advantages that cannot be compared with traditional beneficiation recovery methods.

[0067] The present invention first concentrates the coarse-grained gravity separation tailings slurry to obtain a first underflow and a first overflow. The particle size of the solid particles in the coarse-grained gravity separation tailings slurry is +0.074~-0.20mm; the fine-grained gravity separation tailings slurry is secondarily concentrated to obtain a second underflow and a second overflow. The particle size of the solid particles in the fine-grained gravity separation tailings slurry is +0.020~-0.074mm; the classified overflow and a first flocculant are first mixed and then thirdly concentrated to obtain a third underflow and a third overflow. The particle size of the solid particles in the classified overflow is -0.020mm.

[0068] In the present invention, the coarse-grained gravity separation tailings slurry, the fine-grained gravity separation tailings slurry, and the classified overflow preferably come from the titanium separation process of weathered crust lateritic sand ilmenite.

[0069] In the present invention, the first overflow and the third overflow are returned to the titanium separation process of the weathered crust lateritic sand ilmenite and used as industrial clear water.

[0070] In the present invention, the second overflow is preferably mixed with the classified overflow and then subjected to the third concentration.

[0071] In the present invention, the mass percentage content of TiO2 in the dry-based materials of the coarse-grained gravity separation tailings slurry, the fine-grained gravity separation tailings slurry, and the classified overflow is independently preferably 2~4%.

[0072] In the present invention, the solid content of the first underflow is preferably 50~75%, more preferably 52~73%.

[0073] In the present invention, the solid content of the second underflow is preferably 25~45%, more preferably 26.5~43%.

[0074] In the present invention, the solid content of the third underflow is preferably 45~65%, more preferably 48~63%.

[0075] In the present invention, the raw materials for the first mixing preferably further include the second overflow and / or the third classified product, and more preferably further include the second overflow and the third classified product.

[0076] In the present invention, the first flocculant is preferably a linear high molecular organic polymer, and the basic unit of the linear high molecular organic polymer is preferably (C3H5NO) x ; in the (C3H5NO) x , the value range of x is preferably (1.5 - 15)×10 4 .

[0077] In the present invention, the dosage of the first flocculant is preferably 50 - 120 g / t, and more preferably 55 - 115 g / t.

[0078] In the present invention, classification and concentration are achieved by re - concentration after shunting in industrial production. For the thick - particle gravity separation tailings slurry concentration equipment, a conical thickener is preferably selected in industrial production; for the fine - particle gravity separation tailings slurry concentration equipment, an inclined - plate thickener is preferably selected in industry; for the classification overflow concentration equipment, a rake thickener with added inclined plates is preferably selected in industrial production.

[0079] After obtaining the first underflow, the second underflow and the third underflow, in the present invention, the first underflow is subjected to the first magnetic separation to obtain the first magnetic concentrate and the first tailings; the second underflow is subjected to the second magnetic separation to obtain the second magnetic concentrate and the second tailings; the third underflow is mixed with the second flocculant and then subjected to flocculation magnetic capture to obtain the third magnetic concentrate and the third tailings.

[0080] In the present invention, the magnetic field intensity during the first magnetic separation is preferably 0.5 - 1.5 T, and more preferably 0.6 - 1.2 T. The magnetic medium is preferably rod - shaped medium, and the diameter of the rod - shaped medium is preferably 3 - 5 mm, and more preferably 3.5 - 4.5 mm.

[0081] In the present invention, the magnetic field intensity during the second magnetic separation is preferably 0.5 - 1.5 T, and more preferably 0.6 - 1.2 T. The magnetic medium is preferably rod - shaped medium, and the diameter of the rod - shaped medium is preferably 3 - 5 mm, and more preferably 3.5 - 4.5 mm.

[0082] In the present invention, the second flocculant is preferably a linear high molecular organic polymer, and the basic unit of the linear high molecular organic polymer is preferably (C3H5NO) x ; in the (C3H5NO) x , the value range of x is preferably (1.5 - 15)×10 4 . The dosage of the second flocculant is preferably ≤40 g / t, more preferably 1 - 40 g / t, and further preferably 5 - 35 g / t.

[0083] In the present invention, the magnetic field strength during flocculation magnetic capture is preferably 0.7 - 1.8 T, more preferably 0.8 - 1.5 T. The magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 1 - 3 mm, more preferably 1.5 - 2.5 mm.

[0084] In the present invention, the working process of the first magnetic separation is preferably as follows: the first underflow is subjected to first magnetic roughing to obtain first roughing magnetic concentrate and first roughing magnetic tailings; the first roughing magnetic concentrate is subjected to first magnetic cleaning to obtain the first magnetic concentrate; the first roughing magnetic tailings are subjected to first magnetic scavenging to obtain the first magnetic tailings. In the present invention, the number of times of the first magnetic roughing is 1 - 2 times, the number of times of the first magnetic cleaning is 1 - 2 times, and the number of times of the first magnetic scavenging is 1 - 2 times. In the present invention, the magnetic field strength of the first magnetic roughing is preferably greater than that of the first magnetic cleaning. During the first magnetic roughing: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm; during the first magnetic cleaning: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm; during the first magnetic scavenging: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm.

[0085] In the present invention, the working process of the second magnetic separation is preferably as follows: the second underflow is subjected to second magnetic roughing to obtain second roughing magnetic concentrate and second roughing magnetic tailings; the second roughing magnetic concentrate is subjected to second magnetic cleaning to obtain the second magnetic concentrate; the second roughing magnetic tailings are subjected to second magnetic scavenging to obtain the second magnetic tailings. In the present invention, the number of times of the second magnetic roughing is 1 - 2 times, the number of times of the second magnetic cleaning is 1 - 2 times, and the number of times of the second magnetic scavenging is 1 - 2 times. In the present invention, the magnetic field strength of the second magnetic roughing is preferably greater than that of the second magnetic cleaning. During the second magnetic roughing: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm; during the second magnetic cleaning: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm; during the second magnetic scavenging: the magnetic field strength is preferably 0.5 - 1.5 T, the magnetic medium is preferably rod-shaped medium, and the diameter of the rod-shaped medium is preferably 3 - 5 mm.

[0086] In the present invention, the working process of the flocculation magnetic capture is preferably as follows: the third underflow and the second flocculant are mixed and then subjected to the third magnetic rough separation to obtain the third rough separation magnetic concentrate and the third rough separation magnetic tailings; the third rough separation magnetic concentrate is subjected to the third magnetic cleaning to obtain the third magnetic concentrate; the third rough separation magnetic tailings are subjected to the third magnetic scavenging to obtain the third magnetic tailings. In the present invention, the number of times of the third magnetic rough separation is 1 to 2 times, the number of times of the third magnetic cleaning is 1 to 2 times, and the number of times of the third magnetic scavenging is 1 to 2 times. In the present invention, the magnetic field intensity of the third magnetic rough separation is preferably greater than that of the second magnetic cleaning. During the second magnetic rough separation: the magnetic field intensity is preferably 0.7 to 1.8 T, the magnetic medium is preferably rod medium, and the diameter of the rod medium is preferably 1 to 3 mm; during the third magnetic cleaning: the magnetic field intensity is preferably 0.7 to 1.8 T, the magnetic medium is preferably rod medium, and the diameter of the rod medium is preferably 1 to 3 mm; during the second magnetic scavenging: the magnetic field intensity is preferably 0.7 to 1.8 T, the magnetic medium is preferably rod medium, and the diameter of the rod medium is preferably 1 to 3 mm.

[0087] In the present invention, the number of separation times is preferably increased or decreased specifically according to the requirements of the concentrate grade and recovery rate of separation.

[0088] In the present invention, in the processes of the first magnetic separation, the second magnetic separation and the flocculation magnetic capture, it is necessary to accurately construct the field strength gradient, configure the size of the rod medium, and the working process, so as to obtain the first magnetic concentrate, the second magnetic concentrate and the third magnetic concentrate with high recovery rates.

[0089] In the present invention, the mass percentage content of TiO2 in the first magnetic concentrate is preferably 5 to 9%, more preferably 5.5 to 8.5%.

[0090] In the present invention, the recovery rate of the first magnetic concentrate is 75 to 85%.

[0091] In the present invention, the mass percentage content of TiO2 in the first tailings is preferably <1.2%.

[0092] In the present invention, the first tailings are directly discarded as tailings.

[0093] In the present invention, the mass percentage content of TiO2 in the second magnetic concentrate is preferably 5 to 9%, more preferably 5.5 to 8.5%.

[0094] In the present invention, the recovery rate of the second magnetic concentrate is 75 to 85%.

[0095] In the present invention, the mass percentage content of TiO2 in the second tailings is preferably <1.2%.

[0096] In the present invention, the second tailings are directly discarded as tailings.

[0097] In the present invention, the mass percentage content of TiO2 in the third magnetic concentrate is preferably 13-17%, more preferably 13.5-16%.

[0098] In the present invention, the recovery rate of the third magnetic concentrate is 50-65%.

[0099] In the present invention, the mass percentage content of TiO2 in the third tailings is preferably <1.5%.

[0100] In the present invention, the third tailings are directly discarded as tailings.

[0101] In the present invention, the main functions of the first magnetic separation and the second magnetic separation are to remove a large amount of low-grade gangue. The function of the flocculation magnetic capture is, on the one hand, to selectively flocculate the target minerals by adding flocculants, increasing the apparent particle size of the fine-grained minerals to facilitate capture by the magnetic field force, and on the other hand, to remove a large amount of fine-grained gangue minerals.

[0102] After obtaining the first magnetic concentrate, in the present invention, the first magnetic concentrate is ground and then screened to obtain an oversize product and an undersize product; the undersize product is classified to obtain a first classified product, a second classified product, and a third classified product; the particle size of the solid particles of the first classified product is +0.074 to -0.10 mm, the particle size of the solid particles of the second classified product is +0.02 to -0.074 mm, and the particle size of the solid particles of the third classified product is -0.02 mm.

[0103] In the present invention, the solid content of the first magnetic concentrate during grinding is preferably 55-70%, more preferably 56-68%.

[0104] In the present invention, the oversize product is preferably mixed with the first magnetic concentrate and used as the raw material for grinding.

[0105] In the present invention, the grinding is preferably carried out in a grinding mill, and the grinding mill is preferably a rod mill.

[0106] In the present invention, the screen hole size during screening is preferably 0.10 mm. In the present invention, the fine screen used for screening is preferably a high-frequency vibrating screen or a Derrick high-frequency vibrating screen from the United States.

[0107] In the present invention, the second magnetic concentrate and the third magnetic concentrate do not need to be ground.

[0108] In the present invention, the equipment for classification preferably selects a classifier box or a hydrocyclone in industrial production.

[0109] In the present invention, the third classified product is preferably mixed with the classified overflow and then subjected to the third thickening.

[0110] In the present invention, the second magnetic concentrate and the third magnetic concentrate do not need to be subjected to the classification.

[0111] After obtaining the first classified product, the present invention subjects the first classified product to first stage gravity separation to obtain first titanium concentrate and fourth tailings.

[0112] In the present invention, the first stage gravity separation is preferably carried out by using a fine sand shaking table. The working parameters of the fine sand shaking table preferably include: the feed concentration is preferably 16-22%, more preferably 17-21%; the working slope is preferably 3-6°, more preferably 3.5-5°; the stroke is preferably 14-22 mm, more preferably 15-20 mm; the stroke frequency is preferably 240-270 times / minute, more preferably 245-265 times / minute. The working process of the first stage gravity separation is preferably: first roughing, first scavenging and first cleaning. The number of times of the first roughing is preferably 1 time, the number of times of the first scavenging is preferably 1-2 times, and the number of times of the first cleaning is preferably 2-3 times.

[0113] In the present invention, the mass percentage content of TiO2 in the first titanium concentrate is 38-42%; the operation recovery rate of the first titanium concentrate is 70-75%. In the present invention, the first titanium concentrate is preferably subjected to weak magnetic separation to remove titanium magnetite with stronger magnetism.

[0114] In the present invention, the fourth tailings are directly discarded as waste.

[0115] After obtaining the second classified product and the second magnetic concentrate, the present invention mixes the second classified product and the second magnetic concentrate for the second time and then subjects them to second stage gravity separation to obtain second titanium concentrate and fifth tailings.

[0116] In the present invention, the working process of the second stage gravity separation is preferably: second roughing, second scavenging and second cleaning. The second roughing is preferably carried out by using a slime bed for roughing. The number of times of the second roughing is preferably 1 time. The second scavenging is preferably carried out by using a grooved bed for scavenging. The number of times of the second scavenging is preferably 1-2 times. The second cleaning is preferably carried out by using a slime bed for cleaning and a rotary current film concentrator for cleaning. The number of times of the second cleaning is preferably 2-3 times.

[0117] In the present invention, the working parameters of the slime bed for roughing preferably include: the feed concentration is 14-18%, preferably 15-17%; the working slope is preferably 0-3°, more preferably 0.5-2.5°; the stroke is preferably 10-14 mm, more preferably 11-13 mm; the stroke frequency is preferably 340-380 times / minute, more preferably 345-370 times / minute.

[0118] In the present invention, the working parameters of the grooved table scavenging preferably include: the feed concentration is 14-18%, preferably 15-17%, the working slope is preferably 0-3°, more preferably 0.5-2.5°, the stroke is preferably 10-14 mm, more preferably 11-13 mm, and the stroke frequency is preferably 340-380 times / minute, more preferably 345-370 times / minute. In the present invention, the working parameters of the slime bed beneficiation preferably include: the feed concentration is 14-18%, preferably 15-17%, the working slope is preferably 0-3°, more preferably 0.5-2.5°, the stroke is preferably 10-14 mm, more preferably 11-13 mm, and the stroke frequency is preferably 340-380 times / minute, more preferably 345-370 times / minute.

[0119] In the present invention, the beneficiation of the rotary film concentrator is preferably carried out in a rotary film concentrator, and the rotary film concentrator is preferably a spherical vibration and rotation concentrator or a spherical vibration and rotation concentrator with an optimized separation surface.

[0120] In the present invention, the working parameters of the beneficiation of the rotary film concentrator preferably include: the vibration frequency is preferably 36-40 Hz, and the rotation frequency is preferably 8-12 Hz.

[0121] In the present invention, the mass percentage content of TiO2 in the second titanium concentrate is 42-46%; the operation recovery rate of the second titanium concentrate is 65-70%. In the present invention, the second titanium concentrate is preferably subjected to weak magnetic separation to remove strongly magnetic ilmenite.

[0122] In the present invention, the fifth tailings are directly discarded as waste.

[0123] After obtaining the third magnetic concentrate, the present invention mixes the third magnetic concentrate, the carrier material, the first collector and the first inhibitor for the third time and then performs back-carrying foam separation to obtain the third titanium concentrate and the sixth tailings; the carrier material is obtained by reacting ilmenite, the second collector and the second inhibitor.

[0124] In the present invention, the preparation method of the carrier material preferably includes the following steps:

[0125] Mix the ilmenite and the water to obtain an ilmenite slurry; mix the ilmenite slurry, the second collector and the second inhibitor, and react under acidic conditions to obtain the carrier material.

[0126] The present invention mixes the ilmenite and the water to obtain an ilmenite slurry. In the present invention, the ilmenite is specifically preferably part of the first titanium concentrate. In the present invention, the solid content of the ilmenite slurry is preferably 50-60%, more preferably 52-58%.

[0127] After obtaining the ilmenite slurry, the present invention mixes the ilmenite slurry, the second organic collector, the second inhibitor, and the second collector, and reacts under acidic conditions to obtain the carrier material. In the present invention, the second inhibitor is preferably an organic acid-modified water glass. In the present invention, the organic acid-modified water glass is preferably one or more of citric acid-modified water glass, oxalic acid-modified water glass, and malic acid-modified water glass. In the present invention, the second collector is preferably a mixture of sodium alkyl oleate and sodium alkyl sulfate. The number of carbon atoms in the alkyl group of the sodium alkyl oleate is preferably 12 to 18, more preferably 13 to 17. The number of carbon atoms in the alkyl group of the sodium alkyl sulfate is preferably 12 to 18, more preferably 13 to 17. In the present invention, the mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is preferably 3 to 5:1, more preferably 3.5 to 4.5:1.

[0128] In the present invention, the preparation method of the organic acid-modified water glass preferably includes the following steps: stirring and mixing water glass and the organic acid to obtain the organic acid-modified water glass. In the present invention, the modulus of the water glass is preferably 1 to 2.5.

[0129] In the present invention, the sodium alkyl oleate has good selectivity for ilmenite but weak collecting ability, and the sodium alkyl sulfate has strong collecting ability for ilmenite but poor selectivity. The present invention uses the sodium alkyl oleate and the sodium alkyl sulfate synergistically to improve the selectivity and collecting ability of ilmenite.

[0130] In the present invention, the pH value of the mixed reaction is preferably 3 to 4, more preferably 3.2 to 3.5. In the present invention, the dosage of the second inhibitor is preferably 200 to 400 g / t, and the dosage of the second collector is preferably 500 to 1000 g / t. In the present invention, the temperature of the mixed reaction is preferably room temperature. The mixed reaction is preferably carried out under stirring conditions. The rotation speed of the stirring is preferably 1500 to 1800 r / min, and the stirring time is preferably 10 to 20 min.

[0131] In the present invention, when mixing for the third time, the mass ratio of the carrier material to the third magnetic concentrate is preferably 1:3 to 8, more preferably 1:3.5 to 7.

[0132] In the present invention, the first inhibitor is preferably an organic acid-modified sodium silicate. In the present invention, the organic acid-modified sodium silicate is preferably one or more of citric acid-modified sodium silicate, oxalic acid-modified sodium silicate, and malic acid-modified sodium silicate. In the present invention, the first collector is preferably a mixture of sodium alkyl oleate and sodium alkyl sulfate. The number of carbon atoms in the alkyl group of the sodium alkyl oleate is preferably 12-18, more preferably 13-17; the number of carbon atoms in the alkyl group of the sodium alkyl sulfate is preferably 12-18, more preferably 13-17. In the present invention, the mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is preferably 3-5:1, more preferably 3.5-4.5:1.

[0133] In the present invention, the sodium alkyl oleate has good selectivity for ilmenite but weak collecting ability, while the sodium alkyl sulfate has strong collecting ability for ilmenite but poor selectivity. In the present invention, the sodium alkyl oleate and the sodium alkyl sulfate are used synergistically to improve the selectivity and collecting ability of ilmenite.

[0134] In the present invention, the dosage of the first inhibitor is preferably 300-600 g / t, and the dosage of the first collector is preferably 800-1500 g / t;

[0135] In the present invention, the third mixing is preferably carried out under stirring. The rotation speed of the stirring is preferably 1800-2900 r / min, and the stirring time is preferably 30-60 min.

[0136] In the present invention, the pH value of the back foam sorting is preferably 3-6.

[0137] In the present invention, the working process of the back foam sorting is preferably: carrying out third roughing, third cleaning, and third scavenging. The number of times of the third roughing is preferably 1-2 times, the number of times of the third cleaning is preferably 2-3 times, and the number of times of the third scavenging is preferably 2-3 times.

[0138] In the present invention, the mass percentage content of TiO2 in the third titanium concentrate is 42-46%. The operation recovery rate of the third titanium concentrate is 75-85%. The third titanium concentrate is preferably subjected to weak magnetic separation for deep impurity removal.

[0139] In the present invention, the sixth tailings are directly discarded as waste.

[0140] In order to solve the problems of low titanium dioxide grade in the tailings and overflow of weathered crust lateritic sand ilmenite separation, uneven high and low tailings grades, large difference in mud content, uneven particle size distribution, complex monomer dissociation, and large difference in pulp concentration, etc., the beneficiation method provided by the present invention is as follows: 1) Classification and concentration: Concentrate various types of tailings slurry and overflow respectively to obtain their respective sedimentation underflow and overflow; 2) Medium and strong magnetic separation to discard waste: Perform medium and strong magnetic separation to discard waste on the underflow after classification and concentration to improve the titanium dioxide grade for beneficiation and greatly reduce the subsequent operation processing volume; 3) Grinding: Only grind the strong magnetic separation concentrate of coarse-grained tailings to make its monomers fully dissociated; 4) Classification: Accurately classify the grinding products to achieve narrow particle size classification for feeding; 5) Fine gravity separation: Perform full-process physical field separation on the classified coarse-grained (>74μm) and fine-grained products (>20μm) to obtain the first titanium concentrate with TiO2: 38 - 42% and an operation recovery rate of 70 - 75% and the second titanium concentrate with TiO2: 42 - 46% and an operation recovery rate of 65 - 70%. After subsequent impurity removal, higher-quality titanium concentrate is obtained; 6) Back-carrying foam separation: After the first titanium concentrate is pretreated to obtain hydrophobic carrier particles, add them to the flocculated magnetic separation concentrate for back-carrying flotation to obtain the third titanium concentrate Ⅲ with TiO2: 42 - 46% and an operation recovery rate of 75 - 85%. After impurity removal, higher-quality titanium concentrate is obtained. The beneficiation system of the present invention has strong pertinence, stable process, remarkable energy-saving and emission-reduction effects, and low tail water environmental pressure.

[0141] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with the drawings and embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0142] Example 1

[0143] After stage grinding and stage magnetic separation of a weathered ilmenite, a gravity separation feed is obtained. Before feeding, classification is first performed to obtain a coarse-grained gravity separation feed, a fine-grained gravity separation feed, and classification overflow A. The first two are subjected to spiral chute gravity separation to obtain coarse-grained tailings and fine-grained tailings respectively. Part of the classification overflow A is used as the flushing water for the current gravity separation operation, and part is concentrated. Among them: the particle size of the coarse-grained tailings is +0.074 - -0.15mm, and the dry basis TiO2 is 3.25%; the particle size of the fine-grained tailings is +0.020 - -0.074mm, and the dry basis TiO2 is 3.48%; the particle size of the solid particles in the classification overflow A is -0.020mm, and the dry basis TiO2 is 3.31%.

[0144] (1) Classification and concentration

[0145] The thick tailings slurry is concentrated to obtain underflow I with a pulp concentration of 65% and overflow I. The overflow I is returned to the gravity separation system for reuse; the fine tailings slurry is concentrated to obtain underflow II with a pulp concentration of 35% and overflow II. The particle size of the solid particles in the underflow II is +0.037~-0.074mm, and the particle size of the solid particles in the overflow II is -0.037mm. The overflow II is incorporated into the classified overflow A; during the concentration process of the classified overflow A, a flocculant (linear high-molecular organic polymer, the basic unit of the linear high-molecular organic polymer is (C3H5NO) x ) is added at 75g / t. After concentration, underflow III with a pulp concentration of 48% and overflow III are obtained. The overflow III is returned to the system for reuse;

[0146] (2) Medium-intensity magnetic separation for waste rejection

[0147] The underflow I is fed into a medium-intensity magnetic separator. The roughing magnetic field intensity is set at 1.4T, the diameter of the rod medium is 3.5mm (performed once), the cleaning magnetic field intensity is set at 0.7T, the diameter of the rod medium is 3.5mm (performed once), and the scavenging magnetic field intensity is set at 1.5T, the diameter of the rod medium is 3.5mm (performed once); magnetic separation for waste rejection is carried out to obtain medium-intensity magnetic concentrate I with TiO2: 6.5% and an operating recovery rate of 82.29% and tailings I with TiO2: 0.98%. The tailings I are directly discarded; the underflow II is fed into a medium-intensity magnetic separator for separation. The roughing magnetic field intensity is set at 1.5T, the diameter of the rod medium is 3mm (performed one-time magnetic roughing), the cleaning magnetic field intensity is set at 0.8T, the diameter of the rod medium is 3.5mm (performed once), to obtain medium-intensity magnetic concentrate II with TiO2: 6.76% and an operating recovery rate of 84.56% and tailings II with TiO2: 0.95%. The tailings II are directly discarded; before the underflow III is fed into the medium-intensity magnetic separator, 20g / t of flocculant (linear high-molecular organic polymer, the basic unit of the linear high-molecular organic polymer is (C3H5NO) x ) is added to further flocculate the fine-grained ilmenite, thereby increasing the apparent particle size of the particles. Then, magnetic capture roughing is carried out under the conditions of a magnetic field intensity of 1.8T and a rod medium diameter of 1.5mm. The roughing concentrate and tailings are respectively subjected to two magnetic capture cleanings and one magnetic capture scavenging. The magnetic field intensity for magnetic capture cleaning is reduced to 0.8T and 0.7T respectively, and the magnetic field intensity for magnetic capture scavenging is 1.8T, to obtain magnetic capture concentrate III with TiO2: 15.8% and a recovery rate of 61% and tailings III with TiO2: 0.98%. The tailings III are directly discarded.

[0148] (3) Grinding

[0149] The medium-intensity magnetic concentrate I is ground in a rod mill. The grinding concentration is 60%. The grinding product enters a high-frequency vibrating fine screen for screening. The screen hole size is 0.10mm. The product under the screen is the selected raw material with uniform particle size.

[0150] (4) Classification

[0151] The undersize products obtained from the high-frequency vibrating fine screen are classified to obtain classified product A with a solid particle size of +0.074 to -0.10 mm, classified product B with a solid particle size of +0.02 to -0.074 mm, and classified product C with a solid particle size of -0.02 mm. The medium-intensity magnetic concentrate II and the flocculated magnetic scavenger concentrate III are not classified.

[0152] (5) Refined gravity separation

[0153] Gravity separation is performed on classified product A, classified product B, and medium-intensity magnetic concentrate II, where classified product B and medium-intensity magnetic concentrate II are combined and subjected to gravity separation in the same process. For classified product A, a fine sand shaking table is used for separation, with the feed concentration controlled at 20%, the working slope at 4°, the stroke at 21 mm, and the stroke frequency at 245 times / min. The separation process is: 1 rough selection, 1 scavenging selection, and 2 cleaning selections, obtaining titanium concentrate I with TiO2: 40.5% and a recovery rate of 75% and fine sand bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate I is increased to 42.2%, and the fine sand bed tailings are directly discarded. For the combined classified product B and medium-intensity magnetic concentrate II, a combined equipment of a slime bed, a grooved bed, and a rotary film dressing machine is used for separation. The rough selection uses a slime bed, the scavenging selection uses a grooved bed, and the cleaning selection uses a slime bed and a rotary film dressing machine. The feed concentration is controlled at 16%, the working slope at 1°, the stroke at 11 mm, and the stroke frequency at 370 times / min. The vibration frequency of the spherical vibration and rotation dressing machine is 38 Hz, and the rotation frequency is 9 Hz. The separation process is: 1 rough selection, 2 scavenging selections, and 2 cleaning selections, obtaining titanium concentrate II with TiO2: 43.5% and a recovery rate of 68.5% and grooved bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate II is increased to 45.3%, and the fine sand bed tailings are directly discarded.

[0154] (6) Back-foam separation

[0155] Using titanium concentrate Ⅰ as a carrier, the pulp is adjusted to a concentration of 55%, the pH value is adjusted to 3.5, and then 250 g / t of oxalic acid modified sodium silicate and 600 g / t of polyalkyl mixed collector (the polyalkyl mixed collector is a mixture of sodium alkyl acrylate and sodium alkyl sulfate, and the mass ratio of sodium alkyl acrylate to sodium alkyl sulfate is 3:1. The number of carbon atoms in the alkyl group of sodium alkyl acrylate is 16, and the number of carbon atoms in the alkyl group of sodium alkyl sulfate is 12) are added. It acts for 15 min under the condition of a rotation speed of 1700 r / min to obtain hydrophobic carrier particles. The carrier is added to the flocculated magnetic concentrate Ⅲ, the addition weight ratio is 1:5.5, the pH value of the pulp is adjusted to 5.2, and then 550 g / t of inhibitor (modified sodium silicate) and 900 g / t of collector (the polyalkyl mixed collector is a mixture of sodium alkyl acrylate and sodium alkyl sulfate, and the mass ratio of sodium alkyl acrylate to sodium alkyl sulfate is 3:1. The number of carbon atoms in the alkyl group of sodium alkyl acrylate is 16, and the number of carbon atoms in the alkyl group of sodium alkyl sulfate is 12) are added. It is stirred for 45 min under the condition of a stirring speed of 2500 r / min, and finally back foam separation is carried out to obtain titanium concentrate Ⅲ with TiO₂: 43.5% and a recovery rate of 81.2% and flotation tailings. After weak magnetic separation of titanium concentrate Ⅲ, the titanium dioxide grade is increased to 46.1%, and the flotation tailings are directly discarded as waste.

[0156] Example 2

[0157] A semi-weathered ilmenite is subjected to tailing removal by high-intensity magnetic separation to obtain high-intensity magnetic concentrate and tailings. After the high-intensity magnetic concentrate is classified by a classification device, +0.074 mm particle size fraction, -0.074 mm particle size fraction and classified overflow A are obtained. The +0.074 mm particle size fraction and -0.074 mm particle size fraction are respectively separated by different models of spiral chutes to obtain coarse-grained tailings and fine-grained tailings. Part of classified overflow A is used as the flushing water for the current gravity separation operation, and part is concentrated. Among them: the particle size of the coarse-grained tailings is +0.074~-0.15 mm, and the dry basis TiO₂ is 2.64%; the particle size of the fine-grained tailings is +0.020~-0.074 mm, and the dry basis TiO₂ is 2.85%; the particle size of the solid particles in classified overflow A is -0.020 mm, and the dry basis TiO₂ is 2.94%.

[0158] (1) Classification and concentration

[0159] The coarse-grained tailings pulp is concentrated to obtain underflow Ⅰ with a pulp concentration of 55% and overflow Ⅰ. Overflow Ⅰ is returned to the gravity separation system for repeated use; the fine-grained tailings pulp is concentrated to obtain underflow Ⅱ with a pulp concentration of 40% and overflow Ⅱ. Among them, the particle size of the solid particles in underflow Ⅱ is +0.020~-0.074 mm, the particle size of the solid particles in overflow Ⅱ is -0.02 mm, and overflow Ⅱ is incorporated into classified overflow A; a flocculant (linear high-molecular organic polymer, and the basic unit of the linear high-molecular organic polymer is (C₃H₅NO) is added during the concentration process of classified overflow A x) 85 g / t. After concentration, underflow III with a pulp concentration of 52% and overflow III are obtained. Overflow III is returned to the gravity separation system for reuse.

[0160] (2) Medium-intensity magnetic separation for waste rejection

[0161] Feed the underflow I into a medium-intensity magnetic separator. The magnetic field intensity is 1.5 T, the rod medium diameter is 4 mm (conducted once), the selected magnetic field intensity is set to 0.7 T, the rod medium diameter is 4 mm (conducted once), and the scavenging magnetic field intensity is set to 1.5 T, the rod medium diameter is 4 mm (conducted once); perform magnetic waste rejection to obtain medium-intensity magnetic concentrate I with TiO2: 5.37% and an operating recovery rate of 78.66% and tailings I with TiO2: 0.92%. Tailings I are directly rejected as waste; Feed the underflow II into a medium-intensity magnetic separator. Conduct waste rejection under the conditions of a magnetic field intensity of 1.5 T, a rod medium diameter of 3 mm (conducted once for magnetic roughing), a selected magnetic field intensity of 0.8 T, and a rod medium diameter of 3.5 mm (conducted once) to obtain medium-intensity magnetic concentrate II with TiO2: 5.83% and an operating recovery rate of 77.3% and tailings II with TiO2: 1.04%. Tailings II are directly rejected as waste; Feed the underflow III into a medium-intensity magnetic separator, add 26 g / t of flocculant (linear high-molecular organic polymer, the basic unit of the linear high-molecular organic polymer is (C3H5NO) x ), and then conduct magnetic capture roughing under the conditions of a magnetic field intensity of 1.8 T and a rod medium diameter of 1 mm. Conduct two magnetic selections and one magnetic capture scavenging on the roughing concentrate and tailings respectively. The magnetic field intensities for the selections are reduced to 1.0 T and 0.75 T respectively, and the magnetic field intensity for the magnetic capture scavenging is 1.8 T to obtain magnetic capture concentrate III with TiO2: 14.63% and a recovery rate of 52.5% and tailings III with TiO2: 1.24%. Tailings III are directly rejected as waste.

[0162] (3) Grinding

[0163] Grind the medium-intensity magnetic concentrate I in a rod mill. The grinding concentration is 58%. The grinding product enters a high-frequency vibrating fine screen for screening. The screen hole size is 0.10 mm. The product under the screen is the feedstock with uniform particle size for beneficiation.

[0164] (4) Classification

[0165] Classify the product under the screen obtained from the high-frequency vibrating fine screen to obtain classification product A with a solid particle size of +0.074 - -0.10 mm, classification product B with a solid particle size of +0.02 - -0.074 mm, and classification product C with a solid particle size of -0.02 mm. Do not classify the medium-intensity magnetic concentrate II and the flocculated magnetic capture concentrate III.

[0166] (5) Fine gravity separation

[0167] The classification product A is separated by a fine sand shaking table, controlling the feed concentration at 18%, the working slope at 4.5°, the stroke at 20 mm, the stroke frequency at 242 times / min. The separation process is: 1 roughing, 2 scavenging, and 2 cleaning, obtaining titanium concentrate I with TiO2: 39.5% and a recovery rate of 71% and fine sand bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate I is increased to 42.5%, and the fine sand bed tailings are directly discarded as waste; The classification product B and medium-strong magnetic concentrate II are combined, and then separated by a combined device of a slime bed, a grooved bed, and a rotary fluidized film separator. The roughing is carried out by a slime bed, the scavenging is carried out by a grooved bed, and the cleaning is carried out by a slime bed and a rotary fluidized film separator. Control the feed concentration at 15%, the working slope at 1.5°, the stroke at 12 mm, the stroke frequency at 380 times / min, the vibration frequency of the spherical vibration rotary separator at 37 Hz, and the rotation frequency at 8.5 Hz. The separation process is: 1 roughing, 2 scavenging, and 3 cleaning, obtaining titanium concentrate II with TiO2: 43.4% and an operating recovery rate of 66.8% and grooved bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate II is increased to 44.1%, and the fine sand bed tailings are directly discarded as waste.

[0168] (6) Back-loaded foam separation

[0169] Using titanium concentrate I as a carrier, the pulp is adjusted to a concentration of 58%, the pH value is adjusted to 3.2, then 350 g / t of citric acid-modified sodium silicate and 820 g / t of multi-alkyl mixed collector are added (the multi-alkyl mixed collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate, and the mass ratio of sodium alkyl oleate to sodium alkyl sulfate is 5:1. The number of carbon atoms in the alkyl group of sodium alkyl oleate is 18, and the number of carbon atoms in the alkyl group of sodium alkyl sulfate is 12). It acts for 18 min under the condition of a rotation speed of 1800 r / min to obtain hydrophobic carrier particles. The carrier is added to the flocculated magnetic concentrate III, the addition weight ratio is 1:3.5, the pulp pH value is adjusted to 5.4, then 620 g / t of inhibitor and 1100 g / t of collector are added, and it is stirred for 50 min under the condition of a stirring speed of 2750 r / min. Finally, back-loaded foam separation is carried out to obtain titanium concentrate III with TiO2: 43.8% and a recovery rate of 78.2% and flotation tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate III is increased to 45.7%, and the flotation tailings are directly discarded as waste.

[0170] Example 3

[0171] After a weathered ilmenite ore goes through the process of "grinding - high-intensity magnetic separation - classification - gravity separation by spiral chute - magnetic impurity removal", ilmenite concentrate with TiO₂ > 45% and a recovery rate of 42% is obtained. A large amount of ilmenite enters the gravity separation ilmenite tailings and classification overflow A. The gravity separation ilmenite tailings include coarse tailings with a particle size of +0.074 to -0.15 mm and fine tailings with a particle size of +0.020 to -0.074 mm. The dry basis TiO₂ of the coarse tailings is 3.59%, the dry basis TiO₂ of the fine tailings is 3.64%, and the dry basis TiO₂ in classification overflow A is 3.75%.

[0172] (1) Classification and thickening

[0173] The coarse tailings slurry is thickened to obtain underflow I with a slurry concentration of 70% and overflow I. Overflow I is returned to the gravity separation system for reuse; the fine tailings slurry is thickened to obtain underflow II with a slurry concentration of 36% and overflow II. The solid particle size in underflow II is +0.037 to -0.074 mm, and the solid particle size in overflow II is -0.037 mm. Overflow II is merged into classification overflow A; 72 g / t of flocculant is added during the thickening process of classification overflow A. After thickening, underflow III with a slurry concentration of 54% and overflow III are obtained. Overflow III is returned to the gravity separation system for reuse;

[0174] (2) Medium-intensity magnetic separation for waste rejection

[0175] The underflow I is fed into a medium-intensity magnetic separator. The roughing magnetic field intensity is set at 1.3 T, the rod medium diameter is 4 mm (for 1 time), the cleaning magnetic field intensity is set at 0.7 T, the rod medium diameter is 4 mm (for 1 time), and the scavenging magnetic field intensity is set at 1.4 T, the rod medium diameter is 4 mm (for 1 time); after separation, medium-intensity magnetic concentrate I with TiO₂ of 7.12% and an operation recovery rate of 81.01% and tailings I with TiO₂ of 1.15% are obtained. Tailings I are directly rejected as waste; the underflow II is fed into a medium-intensity magnetic separator for separation. The roughing magnetic field intensity is set at 1.5 T, the rod medium diameter is 3 mm (for 1 magnetic roughing), the cleaning magnetic field intensity is set at 0.8 T, the rod medium diameter is 3.5 mm (for 1 time). After separation, medium-intensity magnetic concentrate II with TiO₂ of 7.53% and an operation recovery rate of 80.53% and tailings II with TiO₂ of 1.16% are obtained. Tailings II are directly rejected as waste; the underflow III is fed into a medium-intensity magnetic separator, and 30 g / t of flocculant (linear high-molecular organic polymer, the basic unit of the linear high-molecular organic polymer is (C₃H₅NO) x) Then, under the conditions of a magnetic field strength of 1.8 T and a rod medium diameter of 1 mm, rough magnetic separation is carried out. The rough concentrate and tailings are respectively subjected to two times of fine magnetic separation and one time of magnetic scavenging. The magnetic field strength for fine magnetic separation is reduced to 0.95 T and 0.7 T respectively, and the magnetic field strength for magnetic scavenging is 1.8 T, obtaining magnetic concentrate Ⅲ with TiO2: 16.8% and a recovery rate of 58.57% and tailings Ⅲ with TiO2: 1.36%. The tailings Ⅲ are directly discarded as waste.

[0176] (3) Grinding

[0177] The medium-intensity magnetic concentrate Ⅰ is ground in a rod mill with a grinding concentration of 68%. The grinding product enters a high-frequency vibrating fine screen for screening with a screen hole size of 0.10 mm. The product under the screen is the feedstock with uniform particle size for beneficiation.

[0178] (4) Classification

[0179] The product under the screen obtained from the high-frequency vibrating fine screen is classified to obtain classification product A with a solid particle size of +0.074~-0.10 mm, classification product B with a solid particle size of +0.02~-0.074 mm, and classification product C with a solid particle size of -0.02 mm. The medium-intensity magnetic concentrate Ⅱ and the flocculated magnetic concentrate Ⅲ are not classified.

[0180] (5) Fine gravity separation

[0181] The classification product A is separated by a fine sand shaking table, controlling the feed concentration at 21%, the working slope at 3.5°, the stroke at 20 mm, and the stroke frequency at 255 times / min. The separation process is: 1 rough separation, 2 scavenging separations, and 2 fine separations, obtaining titanium concentrate Ⅰ with TiO2: 42.4% and a recovery rate of 76.5% and the fine sand bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate Ⅰ is increased to 44.6%, and the fine sand bed tailings are directly discarded as waste; for the combined classification product B and the medium-intensity magnetic concentrate Ⅱ, a combined equipment of a slime bed, a grooved bed, and a rotary film dressing machine is used for separation. The rough separation uses the slime bed, the scavenging separation uses the grooved bed, and the fine separation uses the slime bed and the rotary film dressing machine, controlling the feed concentration at 15%, the working slope at 2°, the stroke at 10 mm, and the stroke frequency at 375 times / min. The vibration frequency of the spherical vibration rotary dressing machine is 36 Hz, and the rotation frequency is 10 Hz. The separation process is: 1 rough separation, 2 scavenging separations, and 2 fine separations, obtaining titanium concentrate Ⅱ with TiO2: 45.6% and a recovery rate of 69.5% and the grooved bed tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate Ⅱ is increased to 46.4%, and the fine sand bed tailings are directly discarded as waste.

[0182] (6) Back-mounted foam separation

[0183] Using titanium concentrate Ⅰ as a carrier, the pulp is adjusted to a concentration of 58%, the pH value is adjusted to 4, and then 200 g / t of malic acid-modified sodium silicate and 750 g / t of multi-alkyl mixed collector are added (the multi-alkyl mixed collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate, and the mass ratio of sodium alkyl oleate to sodium alkyl sulfate is 4:1. The number of carbon atoms in the alkyl group of sodium alkyl oleate is 14, and the number of carbon atoms in the alkyl group of sodium alkyl sulfate is 18). It acts for 20 min under the condition of a rotation speed of 1750 r / min to obtain hydrophobic carrier particles. The carrier is added to the flocculated magnetic concentrate Ⅲ, and the addition weight ratio is 1:5.5. The pH value of the pulp is adjusted to 4.8, and then 580 g / t of inhibitor and 1200 g / t of collector are added. It is stirred for 55 min under the condition of a stirring speed of 2700 r / min. Finally, back-carrying foam separation is carried out to obtain titanium concentrate Ⅲ with TiO₂: 46.7% and a recovery rate of 83.2% and flotation tailings. After weak magnetic separation, the titanium dioxide grade of titanium concentrate Ⅲ is increased to 47.9%, and the flotation tailings are directly discarded as waste.

[0184] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all embodiments. Other embodiments can also be obtained according to this embodiment without creative efforts, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A beneficiation method for recycling titanium from ilmenite beneficiation tailings and overflow, characterized in that, It includes the following steps: The coarse-grained gravity separation tailings slurry is first concentrated to obtain a first underflow and a first overflow respectively. The particle size of the solid particles in the coarse-grained gravity separation tailings slurry is +0.074 to -0.20 mm; The fine-grained gravity separation tailings slurry is second concentrated to obtain a second underflow and a second overflow respectively. The particle size of the solid particles in the fine-grained gravity separation tailings slurry is +0.020 to -0.074 mm; The classified overflow and a first flocculant are first mixed and then third concentrated to obtain a third underflow and a third overflow respectively. The particle size of the solid particles in the classified overflow is -0.020 mm; The first underflow is first magnetic separated to obtain a first magnetic concentrate and a first tailing respectively; The second underflow is second magnetic separated to obtain a second magnetic concentrate and a second tailing respectively; The third underflow and a second flocculant are mixed and then subjected to flocculation magnetic capture to obtain a third magnetic concentrate and a third tailing respectively; The first magnetic concentrate is ground and then screened to obtain an oversize product and an undersize product respectively; The undersize product is classified to obtain a first classified product, a second classified product and a third classified product respectively. The particle size of the solid particles in the first classified product is +0.074 to -0.10 mm, the particle size of the solid particles in the second classified product is +0.02 to -0.074 mm, and the particle size of the solid particles in the third classified product is -0.02 mm; The first classified product is first gravity separated to obtain a first titanium concentrate and a fourth tailing respectively; The second classified product and the second magnetic concentrate are second mixed and then second gravity separated to obtain a second titanium concentrate and a fifth tailing respectively; The third magnetic concentrate, a carrier material, a first inhibitor and a first collector are third mixed and then subjected to back-carrying foam separation to obtain a third titanium concentrate and a sixth tailing. The carrier material is obtained by the reaction of ilmenite, a second inhibitor and a second collector; 2. The ore dressing method according to claim 1, wherein, The mass percentage content of TiO2 in the dry basis materials of the coarse-grained gravity separation tailings slurry, the fine-grained gravity separation tailings slurry and the classified overflow is independently 2 to 4%; The solid content of the first underflow is 50 to 75%; The solid content of the second underflow is 25 to 45%; The solid content of the third underflow is 45 to 65%; 3. The ore dressing method according to claim 1, wherein The raw materials for the first mixing further include the second overflow and / or the third classified product; The dosage of the first flocculant is 50 to 120 g / t; 4. The ore dressing method according to claim 1, wherein The dosage of the second flocculant is ≤40 g / t; 5. The ore dressing method according to claim 1, characterized in that, The conditions for the first magnetic separation and the second magnetic separation include: the magnetic field intensity is 0.5 to 1.5 T, the magnetic medium is rod medium, and the diameter of the rod medium is 3 to 5 mm; The conditions for the flocculation magnetic capture include: the magnetic field intensity is 0.7 to 1.8 T, the magnetic medium is rod medium, and the diameter of the rod medium is 1 to 3 mm; 6. The ore dressing method according to claim 1, characterized in that, The solid content of the first magnetic concentrate is 55 to 70%; the size of the sieve hole for screening is 0.10 mm.

7. The ore dressing method according to claim 1, characterized in that, The first stage of gravity separation is selected to be carried out by a fine sand shaking table. The operating parameters of the fine sand shaking table separation include: the feed concentration is 16 - 22%, the working slope is 3 - 6°, the stroke is 14 - 22 mm, and the stroke frequency is 240 - 270 times per minute. The working process of the first stage of gravity separation is: first roughing, first scavenging, and first cleaning. The number of times of the first roughing is 1, the number of times of the first scavenging is 1 - 2, and the number of times of the first cleaning is 2 - 3. The working process of the second stage of gravity separation is: second roughing, second scavenging, and second cleaning. The second roughing is carried out by a slime bed roughing. The number of times of the second roughing is 1. The second scavenging is carried out by a grooved bed scavenging. The number of times of the second scavenging is 1 - 2. The second cleaning is carried out by a slime bed cleaning and a rotary film concentrator cleaning. The number of times of the second cleaning is 2 - 3. The operating parameters of the slime bed roughing, the grooved bed scavenging, and the slime bed cleaning independently include: the feed concentration is 14 - 18%, the working slope is 0 - 3°, the stroke is 10 - 14 mm, and the stroke frequency is 340 - 380 times per minute. The operating parameters of the rotary film concentrator cleaning include: the vibration frequency is 36 - 40 Hz, and the rotation frequency is 8 - 12 Hz.

8. The ore dressing method according to claim 1, wherein When the third mixing is carried out, the mass ratio of the carrier material to the third magnetic concentrate is 1:3 - 8. The first inhibitor is an organic acid modified sodium silicate. The first collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate. The number of carbon atoms in the alkyl group of the sodium alkyl oleate and the sodium alkyl sulfate is independently 12 - 18. The mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is 3 - 5:

1. The dosage of the first inhibitor is 300 - 600 g / t, and the dosage of the first collector is 800 - 1500 g / t. The third mixing is carried out under stirring conditions. The rotation speed of the stirring is 1800 - 2900 r / min, and the stirring time is 30 - 60 min. The pH value of the back-mounted foam separation is 3 - 6. The working process of the back-mounted foam separation is: third roughing, third cleaning, and third scavenging. The number of times of the third roughing is 1 - 2, the number of times of the third cleaning is 2 - 3, and the number of times of the third scavenging is 2 - 3.

9. The ore dressing method according to claim 1 or 8, characterized in that, The preparation method of the carrier material includes the following steps: Mix the ilmenite and water to obtain an ilmenite slurry. The ilmenite is part of the first ilmenite concentrate. The solid content of the ilmenite slurry is 50 - 60%. Mix the ilmenite slurry, the second inhibitor, and the second collector, and react under acidic conditions to obtain the carrier material. The second inhibitor is an organic acid modified sodium silicate. The second collector is a mixture of sodium alkyl oleate and sodium alkyl sulfate. The number of carbon atoms in the alkyl group of the sodium alkyl oleate and the sodium alkyl sulfate is independently 12 - 18. The mass ratio of the sodium alkyl oleate to the sodium alkyl sulfate is 3 - 5:

1. The dosage of the second inhibitor is 200 - 400 g / t, and the dosage of the second collector is 500 - 1000 g / t. The pH value of the reaction is 3 to 4; the temperature of the reaction is room temperature, the reaction is carried out under stirring conditions, the rotation speed of the stirring is 1500 to 1800 r / min, and the stirring time is 10 to 20 min.

10. The ore dressing method according to claim 1, characterized in that, The mass percentage content of TiO2 in the dry matter of the first magnetic concentrate and the second magnetic concentrate is independently 5 to 9%; The mass percentage content of TiO2 in the dry matter of the third magnetic concentrate is 13 to 17%; The mass percentage content of TiO2 in the dry matter of the first tailing and the second tailing is both < 1.2%; The mass percentage content of TiO2 in the dry matter of the third tailing is < 1.5%; The mass percentage content of TiO2 in the dry matter of the first titanium concentrate is 38 to 42%; The mass percentage content of TiO2 in the dry matter of the second titanium concentrate is 42 to 46%; The mass percentage content of TiO2 in the dry matter of the third titanium concentrate is 42 to 46%.

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