Ore dressing method and device for iron ore rich in barite

Abstract

The present invention provides a beneficiation method and a beneficiation device for iron ore rich in barite, comprising the following steps: using a high-pressure roller mill to grind the crushed ore, and using a double-layer dry screening device to screen the discharge of the high-pressure roller mill, screening it into a first screened ore material larger than a first preset particle size, a second screened ore material larger than or equal to a second preset particle size and less than or equal to the first preset particle size, and a third screened ore material smaller than the second preset particle size; respectively performing re-grinding treatment on the first screened ore material by returning it to the high-pressure roller mill, performing dry separation treatment on the second screened ore material, and performing magnetic separation treatment on the third screened ore material after adding water to adjust the pulp. By using the present invention, when beneficiating refractory oxidized iron ore by using a conventional beneficiation process, problems such as low metal recovery rate and low iron concentrate grade, and due to poor quality and high moisture content of the iron concentrate, resulting in blockage of subsequent sintering and pelletizing operations, high energy consumption, and low operation rate can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of ore dressing, and more specifically, to a method for dressing iron ore rich in barite and an ore dressing device. Background Art

[0002] The Jingtieshan iron ore deposit belongs to the Sinian metamorphic sedimentary iron ore deposit and is the earliest large iron ore deposit discovered and explored in the northwest region of China. This type of iron ore belongs to typical complex and difficult-to-dress oxidized iron ore, with low iron grade in the raw ore, many types of iron-containing minerals and complex symbiotic relationships, high impurity content and serious slimeification. However, it has a large geological reserve, and there are also minerals such as copper ore and barite, showing great potential for comprehensive development and utilization.

[0003] Barite is an important non-metallic mineral and is widely used in industrial sectors such as petroleum, chemical industry, light industry, and medicine. However, at present, few processes can effectively recover resources from difficult-to-dress oxidized iron ore, and it is often discharged into the tailings pond with iron tailings, resulting in resource losses. At the same time, due to the extremely complex and difficult dressing of this type of ore, using conventional metal recovery processes, both the metal recovery rate and the iron concentrate grade are at a relatively low level in the industry. Moreover, due to the poor quality and high moisture content of the iron concentrate, problems such as blockage of subsequent sintering and pelletizing operations, high energy consumption, and low operation rate occur. Summary of the Invention

[0004] In view of the above problems, the purpose of the present invention is to provide a method for dressing iron ore rich in barite and an ore dressing device to solve the problems of low metal recovery rate and iron concentrate grade when using conventional ore dressing processes to dress difficult-to-dress oxidized iron ore, and problems such as blockage of subsequent sintering and pelletizing operations, high energy consumption, and low operation rate due to poor quality and high moisture content of the iron concentrate.

[0005] The present invention provides a method for dressing iron ore rich in barite, comprising the following steps:

[0006] Grind the crushed ore using a high-pressure roller mill, and screen the discharge of the high-pressure roller mill using a double-layer dry screening device, and screen the discharge into a first screened ore material larger than the first preset particle size, a second screened ore material larger than or equal to the second preset particle size and smaller than or equal to the first preset particle size, and a third screened ore material smaller than the second preset particle size; wherein, the first preset particle size is larger than the second preset particle size;

[0007] Respectively perform re-grinding treatment on the first screened ore material by returning it to the high-pressure roller mill, perform dry separation treatment on the second screened ore material, and perform magnetic separation treatment on the third screened ore material after adding water to adjust the pulp;

[0008] According to the first preset concentrate particle size condition, the dry concentrate obtained by the dry separation treatment and the magnetic separation concentrate obtained by the magnetic separation treatment are mixed and then subjected to grinding treatment, and the obtained first mixed concentrate is subjected to combined gravity separation of iron minerals and barite to obtain a combined concentrate of iron and barite;

[0009] According to the second preset concentrate particle size condition, the combined concentrate of iron and barite is subjected to grinding treatment, and the obtained second mixed concentrate is subjected to direct flotation of barite to obtain barite concentrate and tailings containing coarse iron respectively;

[0010] The tailings containing coarse iron are subjected to magnetic separation and upgrading roasting treatment of iron minerals to obtain iron concentrate.

[0011] In addition, a preferred solution is that before the crushed ore is ground by a high-pressure roller mill, it also includes:

[0012] The original stone is crushed to obtain crushed ore of a preset size;

[0013] The crushed ore of the preset size is subjected to ore washing treatment to obtain washed crushed ore;

[0014] The washed crushed ore is ground by a crusher, and the ground ore is screened by a screening device. The oversize material is returned to the crusher, and the undersize material is fed into the high-pressure roller mill as the crushed ore to be ground; wherein, the particle size of the undersize material is less than 50 mm.

[0015] In addition, a preferred solution is that in the process of subjecting the crushed ore of the preset size to ore washing treatment to obtain washed crushed ore, a cylindrical ore washer is used to wash the crushed ore of the preset size.

[0016] In addition, a preferred solution is that in the process of respectively returning the first screened ore to the high-pressure roller mill for re-grinding treatment, subjecting the second screened ore to dry separation treatment, and subjecting the third screened ore to magnetic separation treatment after adding water to adjust the pulp density,

[0017] A dry intelligent separator is used to perform dry separation treatment on the second screened ore;

[0018] After adding water to adjust the pulp density of the third screened ore to 30%, a large-particle high-intensity magnetic separator is used for magnetic separation treatment. Among them, during the magnetic separation treatment, the magnetic field strength is at least 8000 GS.

[0019] In addition, a preferred solution is that the first preset concentrate particle size condition is: in the first mixed concentrate, 60% of the ore has a particle size less than 0.074 mm; and / or,

[0020] The second preset concentrate particle size condition is: in the second mixed concentrate, the particle size of 90% of the ore material is less than 0.044 mm.

[0021] In addition, a preferred solution is that in the process of subjecting the obtained first mixed concentrate to combined gravity separation of iron minerals and barite to obtain a combined concentrate of iron and barite,

[0022] a spiral chute is used to perform combined gravity separation of iron minerals and barite on the first mixed concentrate through two-stage gravity separation processes of roughing and cleaning.

[0023] In addition, a preferred solution is that in the process of subjecting the obtained second mixed concentrate to positive flotation of barite to separately obtain barite concentrate and tailings containing crude iron,

[0024] a vertical stirring mill is used to perform positive flotation of barite on the second mixed concentrate through one-stage roughing and three-stage cleaning flotation processes.

[0025] In addition, a preferred solution is that the treatment of the tailings containing crude iron by magnetic separation of iron minerals and quality-improving roasting to obtain iron concentrate includes:

[0026] The tailings containing crude iron are subjected to magnetic separation by a weak magnetic-strong magnetic system to obtain crude iron concentrate; among them, the magnetic field intensity of the strong magnetic in the magnetic separation treatment is 10,000 GS;

[0027] The crude iron concentrate is concentrated and filtered to make the moisture content of the crude iron concentrate less than 12% to obtain concentrated crude iron concentrate;

[0028] The concentrated crude iron concentrate is roasted by a quality-improving roasting process to remove hydroxide ions and carbonate ions in the iron ore structure of the concentrated crude iron concentrate to obtain iron concentrate; among them, the temperature of the quality-improving roasting process is at least 700 °C, and the roasting treatment is carried out by a suspension oxidation roasting method.

[0029] The beneficiation device for the beneficiation method of iron ore rich in barite described above provided by the present invention includes: a high-pressure roller mill, a double-layer dry screening device, a separation device, a grinding device, a flotation device, an iron mineral magnetic separation device, and a quality-improving roasting device; among them,

[0030] The double-layer dry screening device includes a feed inlet, a first screened ore material outlet, a second screened ore material outlet, and a third screened ore material outlet;

[0031] The separation device includes a dry separation device and a magnetic separation device;

[0032] The flotation device includes a barite concentrate outlet and a tailings outlet;

[0033] The discharge port of the high-pressure roller mill is connected to the feed port of the double-layer dry screening device, the first screened material outlet is connected to the feed port of the high-pressure roller mill, the second screened material outlet is connected to the dry separation device, and the third screened material outlet is connected to a slurry mixing device, which is connected to the magnetic separation device;

[0034] The concentrate outlet of the dry separation device and the concentrate outlet of the magnetic separation device are both connected to the grinding device, the discharge port of the grinding device is connected to the flotation device, the tailings outlet of the flotation device is connected to the iron ore magnetic separation device, and the iron ore magnetic separation device is connected to the quality upgrading and roasting device.

[0035] In addition, a preferred solution is that the feed port of the high pressure roller mill is connected to a raw ore pretreatment device;

[0036] The raw ore pretreatment device includes a crushing device, an ore washing device and a screening device; wherein,

[0037] The discharge port of the crushing device is connected to the feed port of the ore washing device, the discharge port of the ore washing device is connected to the feed port of the screening device, the outlet of the above-screen material of the screening device is connected to the feed port of the crushing device, and the outlet of the below-screen material of the screening device is connected to the feed port of the high-pressure roller mill.

[0038] From the above technical scheme, it can be seen that the beneficiation method and beneficiation device of the iron ore rich in barite provided by the present invention, by adopting a double-layer dry screening device to screen the discharge of the high-pressure roller mill, the three kinds of ore materials with different particle sizes are targetedly treated, and the gangue minerals are removed by pre-selection, and then the stage grinding stage selection is carried out. The first stage selection utilizes the characteristics of barite and iron minerals with similar specific gravity and small specific gravity for gravity selection, and the second stage selection utilizes the different flotation performance of barite and iron minerals to adopt the combined selection process of first floating and then magnetic separation to separate barite and iron ore. Finally, the iron ore concentrate mainly composed of siderite and limonite is subjected to quality improvement oxidative roasting. Different from traditional reduction roasting, the role of quality improvement oxidative roasting is to remove the hydroxide ions and carbonate ions in the iron ore structure, while removing moisture and increasing the grade of the iron ore concentrate to more than 60%.

[0039] In order to achieve the above and related purposes, one or more aspects of the present invention include the features that will be described in detail later. The following description and the accompanying drawings describe some exemplary aspects of the present invention in detail. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] By referring to the following description in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand. In the drawings:

[0041] Figure 1 is a flowchart of a beneficiation method for barite-rich iron ore according to an embodiment of the present invention;

[0042] Figure 2 is a schematic structural diagram of a beneficiation device for barite-rich iron ore according to an embodiment of the present invention.

[0043] In the drawings, 1 - high-pressure roller mill, 2 - double-deck dry screening device, 31 - dry separation device, 32 - magnetic separation device, 4 - flotation device, 41 - barite beneficiation device, 51 - crushing device, 52 - ore washing device, 53 - screening device, 61 - ball mill, 62 - cyclone, 63 - rough gravity separation device, 64 - fine gravity separation device, 65 - vertical grinder, 71 - tailing weak magnetic separator, 72 - tailing weak magnetic separator, 81 - thickening device, 82 - filtering device, 83 - roasting device.

[0044] In all the drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Embodiments

[0045] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is obvious that these embodiments can also be implemented without these specific details.

[0046] Aiming at the problems that occur when the current conventional beneficiation process is used to beneficiate refractory oxidized iron ore, such as low metal recovery rate and iron concentrate grade, and due to poor quality and high moisture content of the iron concentrate, resulting in problems such as blockage of subsequent sintering and pelletizing operations, high energy consumption, and low operation rate, a beneficiation method and a beneficiation device for barite-rich iron ore are proposed.

[0047] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0048] In order to illustrate the beneficiation method and the beneficiation device for barite-rich iron ore provided by the present invention, Figure 1 shows the flow of the beneficiation method for barite-rich iron ore according to an embodiment of the present invention; Figure 2 shows the structure of the beneficiation device for barite-rich iron ore according to an embodiment of the present invention.

[0049] As Figure 1 shown in conjunction with Figure 2 collectively, the beneficiation method for barite-rich iron ore provided by the present invention includes the following steps:

[0050] S1, using a high pressure roller mill 1 to grind the crushed ore, and using a double-layer dry screening device 2 to screen the discharge of the high pressure roller mill 1, and screening the discharge into a first screened ore material larger than the first preset particle size, a second screened ore material larger than or equal to the second preset particle size and less than or equal to the first preset particle size, and a third screened ore material smaller than the second preset particle size according to a first preset particle size and a second preset particle size; wherein the first preset particle size is larger than the second preset particle size;

[0051] S2, respectively returning the first screened ore to the high pressure roller mill 1 for re-grinding, performing dry separation on the second screened ore, and performing magnetic separation on the third screened ore after water replenishment and slurry adjustment;

[0052] S3, according to the first preset concentrate particle size condition, the dry concentrate obtained by dry sorting treatment and the magnetic concentrate obtained by magnetic separation treatment are mixed and then subjected to grinding treatment, and the obtained first mixed concentrate is subjected to mixed re-selection treatment of iron minerals and barite to obtain a mixed concentrate of iron and barite;

[0053] S4, grinding the iron and barite mixed concentrate according to the second preset concentrate particle size condition, and performing barite positive flotation treatment on the obtained second mixed concentrate to obtain barite concentrate and tailings containing crude iron respectively;

[0054] S5. The tailings containing crude iron are subjected to magnetic separation of iron ore and quality-enhancing roasting to obtain iron concentrate.

[0055] Among them, the first preset particle size is preferably 12 mm, and the second preset particle size is preferably 2 mm.

[0056] The discharge of the high-pressure roller mill 1 is screened by using a double-layer dry screening device 2, and the three different particle sizes of the obtained ore materials are processed in a targeted manner. The gangue minerals are removed by pre-selection, and then the stage grinding and stage selection are carried out. The first stage selection uses the characteristics of barite and iron minerals with similar specific gravity and small specific gravity for gravity selection. The second stage selection uses the different flotation properties of barite and iron minerals to separate barite and iron ore by using a combined flotation and then magnetic separation process. Finally, the iron ore concentrate mainly composed of siderite and limonite is subjected to quality-enhancing oxidative roasting. Different from traditional reduction roasting, the role of quality-enhancing oxidative roasting is to remove hydroxide ions and carbonate ions in the iron ore structure, while removing moisture and increasing the grade of the iron ore concentrate to more than 60%.

[0057] As a preferred embodiment of the present invention, before the high pressure roller mill 1 is used to grind the crushed ore, the method further includes:

[0058] The raw stone is crushed to obtain crushed ore of preset size;

[0059] Wash the crushed ore of preset size to obtain the washed crushed ore;

[0060] Use a crusher to grind the washed crushed ore, and use a screening device to screen the ground ore material. Return the oversize material to the crusher, and feed the undersize material as the crushed ore to be ground into the high-pressure roller mill; wherein, the particle size of the undersize material is less than 50 mm.

[0061] The raw ore is crushed to less than or equal to 80 mm, then washed and fed into a closed-circuit screening operation. The undersize product is fed into the high-pressure roller mill closed-circuit system, and the oversize product is returned to the crusher. The closed-circuit screening particle size is controlled below 50 mm to avoid damaging the high-pressure roller mill 1.

[0062] As a preferred embodiment of the present invention, in the process of washing the crushed ore of preset size to obtain the washed crushed ore,

[0063] Use a cylindrical ore washer to wash the crushed ore of preset size. The cylindrical ore washer is suitable for various large and difficult-to-wash ores.

[0064] As a preferred embodiment of the present invention, in the processes of respectively re-grinding the first screened ore material by returning it to the high-pressure roller mill, dry separating the second screened ore material, and magnetic separating the third screened ore material after adding water to adjust the pulp concentration,

[0065] Use a dry intelligent separator to dry separate the second screened ore material;

[0066] After adding water to adjust the pulp concentration of the third screened ore material to 30%, use a large-particle-size high-intensity magnetic separator for magnetic separation. Among them, during the magnetic separation process, the magnetic field intensity is at least 8000 GS.

[0067] The dry intelligent separator detects the ore grade through a dual-spectrum fusion mode and separates the ore and waste rock with a high-speed air ejection gun. The medium box of the high-intensity magnetic separator is intensively designed for large-particle-size raw ore, and the flushing water pressure is increased to prevent material blockage.

[0068] As a preferred embodiment of the present invention, the first preset concentrate particle size condition is: in the first mixed concentrate, 60% of the ore material has a particle size less than 0.074 mm; and / or the second preset concentrate particle size condition is: in the second mixed concentrate, 90% of the ore material has a particle size less than 0.044 mm. It is convenient for flotation and magnetic separation.

[0069] As a preferred embodiment of the present invention, in the process of performing combined gravity separation on iron minerals and barite in the obtained first mixed concentrate to obtain a combined concentrate of iron and barite,

[0070] A spiral chute is adopted to carry out the combined gravity separation of iron minerals and barite on the first mixed concentrate through two-stage gravity separation processes of roughing and cleaning. It is preferably to use a spiral chute with a large diameter of 2m, and the spiral chute is designed according to the specific gravity differences of useful minerals such as siderite, limonite, barite, and minerals such as quartz and jasper.

[0071] As a preferred embodiment of the present invention, during the process of carrying out the positive flotation of barite on the obtained second mixed concentrate to obtain barite concentrate and tailings containing crude iron respectively,

[0072] A vertical agitation mill is adopted to carry out the positive flotation of barite on the second mixed concentrate through a one-roughing and three-cleaning flotation process. After reground to make 90% of the materials less than 0.044mm, a vertical agitation mill is used, and the positive flotation one-roughing and three-cleaning process is adopted for barite.

[0073] As a preferred embodiment of the present invention, the tailings containing crude iron are subjected to magnetic separation and quality-improving roasting treatment of iron minerals to obtain iron concentrate, including:

[0074] The tailings containing crude iron are subjected to magnetic separation treatment through a weak magnetic-strong magnetic system to obtain crude iron concentrate; wherein, the magnetic field intensity of the strong magnetic in the magnetic separation treatment is 10000GS;

[0075] The crude iron concentrate is subjected to concentration and filtration treatment to make the moisture content of the crude iron concentrate less than 12% to obtain concentrated crude iron concentrate;

[0076] The concentrated crude iron concentrate is subjected to roasting treatment by using a quality-improving roasting process to remove the hydroxide ions and carbonate ions in the iron ore structure of the concentrated crude iron concentrate to obtain iron concentrate; wherein, the temperature of the quality-improving roasting process is at least 700°C, and the roasting treatment is carried out by using a suspension oxidation roasting method. Different from the traditional magnetization reduction roasting, there is no need to introduce reducing gas.

[0077] The beneficiation device for the beneficiation method of iron ore rich in barite as described above provided by the present invention includes: a high-pressure roller mill 1, a double-layer dry screening device 2, a separation device, a grinding device, a flotation device 4, an iron mineral magnetic separation device and a quality-improving roasting device; wherein,

[0078] The double-layer dry screening device 2 includes a feed inlet, a first screened ore outlet, a second screened ore outlet and a third screened ore outlet;

[0079] The separation device includes a dry separation device 31 and a magnetic separation device 32;

[0080] The flotation device 4 includes a spar concentrate outlet and a tailings outlet;

[0081] The discharge port of the high-pressure roller mill 1 is connected to the feed port of the double-layer dry screening device 2. The first screened ore outlet is connected to the feed port of the high-pressure roller mill 1. The second screened ore outlet is connected to the dry separation device 31. The third screened ore outlet is connected to a pulp adjusting device (not shown in the figure), and the pulp adjusting device is connected to the magnetic separation device 32;

[0082] The concentrate outlets of the dry separation device 31 and the magnetic separation device 32 are both connected to the grinding device. The discharge port of the grinding device is connected to the flotation device 4. The tailing outlet of the flotation device 4 is connected to the iron mineral magnetic separation device, and the iron mineral magnetic separation device is connected to the quality-improving roasting device.

[0083] As a preferred embodiment of the present invention, the feed port of the high-pressure roller mill 1 is connected to a raw ore pretreatment device; the raw ore pretreatment device includes a crushing device 51, a washing device 52, and a screening device 53; wherein,

[0084] The discharge port of the crushing device 51 is connected to the feed port of the washing device 52. The discharge port of the washing device 52 is connected to the feed port of the screening device 53. The oversize material outlet of the screening device 53 is connected to the feed port of the crushing device 51. The undersize material outlet of the screening device 53 is connected to the feed port of the high-pressure roller mill 1.

[0085] As a preferred embodiment of the present invention, the double-layer dry screening device 2 is a double-layer fine powder sieve. By setting the pore sizes of the two layers of sieves, three different particle sizes of ore can be obtained.

[0086] As a preferred embodiment of the present invention, the dry separation device 31 is a dry intelligent separator. The ore grade is detected by a dual-spectrum fusion mode, and the ore and waste rock are separated by a high-speed air ejection gun.

[0087] As a preferred embodiment of the present invention, the magnetic separation device 32 is a large-particle high-intensity magnetic separator with a magnetic field intensity of 8000 GS. The medium box of the high-intensity magnetic separator is intensively designed for large-particle raw ore, and the washing water pressure is increased to prevent blockage.

[0088] As a preferred embodiment of the present invention, the grinding device includes a ball mill 61, a hydrocyclone 62, a rough gravity separation device 63, a fine gravity separation device 64, and a vertical grinder 65; wherein, the feed inlet of the ball mill 61 is respectively connected to the concentrate outlet of the dry separation device 31 and the concentrate outlet of the magnetic separation device 32, the discharge outlet of the ball mill 61 is connected to the feed inlet of the hydrocyclone 62, the fine material outlet of the hydrocyclone 62 is connected to the rough gravity separation device 63, the rough gravity separation device 63 is connected to the fine gravity separation device 64, the fine gravity separation device 64 is connected to the vertical grinder 65, the discharge outlet of the vertical grinder 65 is connected to the flotation device 4, and the coarse material outlet of the hydrocyclone 62 is connected to the feed inlet of the ball mill 61. Through the above structural design, the closed grinding of the mixed ore of dry concentrate and magnetic separation concentrate can be realized until it meets the first preset concentrate particle size condition and the second preset concentrate particle size condition, and the mixed ore of iron minerals and barite is obtained.

[0089] As a preferred embodiment of the present invention, the flotation device 4 includes a flotation machine, and a spar concentrate selection device 41 is connected to the spar concentrate outlet of the flotation machine, and the tailings outlet of the flotation machine is connected to the iron mineral magnetic separation device. The quality of the selected spar ore can be guaranteed through the spar concentrate selection device 41.

[0090] As a preferred embodiment of the present invention, the iron mineral magnetic separation device includes a tailings weak magnetic separator 71 and a tailings strong magnetic separator 72 connected to the tailings weak magnetic separator 71; the tailings strong magnetic separator 71 is connected to the upgrading roasting device. The iron in the tailings can be better magnetically separated through the double magnetic separators.

[0091] As a preferred embodiment of the present invention, the upgrading roasting device includes a concentration device 81 connected to the iron mineral magnetic separation device, a filtration device 82 connected to the concentration device 81, and a roasting device 83 connected to the filtration device 82; wherein, the temperature of the roasting device 83 is at least 700 °C. Different from traditional magnetization reduction roasting, there is no need to introduce reducing gas.

[0092] As a preferred embodiment of the present invention, the ore washing device 52 is a cylindrical ore washer. It is suitable for various large and difficult-to-wash ores.

[0093] In order to further describe and illustrate the beneficiation method of iron ore rich in barite provided by the present invention, the following specific embodiments are provided.

[0094] Example 1

[0095] The ore sample in this example is taken from a refractory iron ore containing barite in a certain place in Gansu Province. The iron grade of the raw ore is 30%, and the BaSO4 grade is 14%. The main metal minerals in this ore are limonite, siderite, specular (hematite) iron ore, and the gangue minerals are barite, jasper, quartz, phyllite (a mixture of fine-grained quartz, chlorite, sericite and other minerals), ankerite. In addition, a small amount of sulfide minerals such as pyrite and chalcopyrite can be seen. The ore properties are complex, with many slime minerals and it is very difficult to beneficiate, as shown in Table 1. The traditional production process is that the raw ore is screened into two particle size minerals of 15mm - 100mm and 15mm - 0. The 15mm - 100mm lump ore is subjected to shaft furnace reduction magnetization roasting (with gas passed) and then magnetic separation - flotation process. The fine ore of 15mm - 0 is subjected to grinding and high-intensity magnetic separation. The concentrates obtained from the two processes are mixed and then concentrated and filtered to obtain a single product iron concentrate with a grade of 52% and a recovery rate of 70%. Due to the slime of the ore and the presence of limonite, the moisture content of the concentrate is as high as over 14%, which affects the subsequent production. Moreover, the useful mineral barite cannot be recovered by this process and is lost in the tailings. Table 1 shows the main mineral composition (%) of the raw ore

[0096]

[0097] Table 1

[0098] The raw ore entering the concentrator is fed into the crushing operation. After crushing, ore washing is carried out first to quickly wash away the slime and mud to avoid adverse effects on subsequent crushing and screening, including pre-selection equipment. The product after ore washing is fed into the closed-circuit crushing and screening operation. The undersize product of 50mm - 0 is fed into the closed-circuit dry screening operation of the high-pressure roll mill. Double-layer fine powder screens are used for the closed-circuit screening, and three products are screened out: +12mm, 2mm - 12mm, and -2mm. The +12mm product returns to the closed-circuit cycle of the high-pressure roll mill. The 2mm - 12mm product is fed into the intelligent separator for dry intelligent separation. The -2mm product is supplemented with water to adjust the pulp concentration to 30% and then enters the high-intensity magnetic separator for large particle sizes, with the magnetic field intensity controlled at 8000GS. The dry intelligent separation concentrate and the high-intensity magnetic separation concentrate are fed together into the first-stage closed-circuit grinding with a product particle size of -0.074mm at 60%, and then enter the roughing and cleaning two-stage gravity separation. Spiral chutes are used for gravity separation. The gravity separation obtains a mixed concentrate of iron and barite. After re-grinding in a vertical mill to -0.044mm at 90%, it enters the barite direct flotation operation. One roughing and three cleanings are used for flotation to obtain barite concentrate. The flotation tailings first enter the weak magnetic - high-intensity magnetic system for iron mineral separation. The high-intensity magnetic field intensity is controlled at 10000GS to obtain a rough iron concentrate, which is mainly a mixed ore of limonite, siderite, and hematite. The mixed iron concentrate is concentrated and filtered to a moisture content of 12% and then fed into the upgrading roasting operation. Oxidative roasting is carried out at a roasting temperature of about 700°C. The limonite, siderite and other iron minerals in the mixed ore are converted into iron oxide products, and the OH and CO3 root ions in the iron ore structure are removed, improving the grade of the iron concentrate. At the same time, it plays a drying role, making the moisture content of the concentrate product low, which is conducive to the subsequent pellet sintering operation. The gravity separation tailings and the high-intensity magnetic separation tailings are aggregated into the final tailings. The process of the present invention finally obtains two concentrate products, iron concentrate with a TFe grade of 55%, and barite concentrate with a BaSO4 grade of 90%. This enables the full recovery and utilization of resources. Table 2 shows the comparison of process flow indexes.

[0099]

[0100]

[0101] Table 2

[0102] It can be seen from the table that when the raw ore has an iron grade of 30% and a barite grade of 14%, the production indexes of the original process are not ideal, with both the iron grade and the recovery rate being very low, and at the same time, the barite is not recovered. Through the process flow of the present invention, it adapts to the existing ore properties. The grade of the iron concentrate is increased by more than 3%, the recovery rate is increased by 5%, and at the same time, the moisture content of the concentrate is greatly reduced, which is beneficial to the subsequent pellet sintering process. And the iron separation process finally uses oxidative roasting, without the need to use reducing gases such as gas, reducing environmental pollution and energy consumption. At the same time, the barite in the raw ore is also recovered and utilized. Therefore, the process of this invention has obvious economic benefits and practical value.

[0103] As can be seen from the above specific embodiments, the beneficiation method and device for iron ore rich in barite provided by the present invention screen the discharge of the high-pressure roll mill by using a double-layer dry screening device, and perform targeted treatment on the obtained three kinds of ore materials with different particle sizes. Through pre-selection, gangue minerals are removed, and then stage grinding and stage separation are carried out. In the first-stage separation, heavy separation is carried out by utilizing the characteristics that the specific gravity difference between barite and iron minerals is close, while the specific gravity of gangue minerals is small. In the second-stage separation, due to the different flotation properties of barite and iron minerals, a combined flotation and magnetic separation process of floating first and then magnetizing is adopted to separate barite and iron ore. Finally, quality-improving oxidation roasting is carried out on the iron concentrate ore mainly composed of siderite and limonite. Different from traditional reduction roasting, the function of quality-improving oxidation roasting is to remove hydroxyl ions and carbonate ions in the iron ore structure, remove moisture at the same time, and increase the iron concentrate grade to more than 60%.

[0104] As described above by way of example with reference to the accompanying drawings, the beneficiation method and device for iron ore rich in barite proposed according to the present invention are described. However, those skilled in the art should understand that various improvements can be made to the above-mentioned beneficiation method and device for iron ore rich in barite proposed by the present invention without departing from the content of the present invention. Therefore, the protection scope of the present invention should be determined by the content of the appended claims.

Claims

1. A beneficiation method for iron ore rich in barite, characterized in that, It includes the following steps: Use a high-pressure roller mill to grind the crushed ore, and use a double-layer dry screening device to screen the discharge of the high-pressure roller mill. Screen the discharge into a first screened ore material larger than the first preset particle size, a second screened ore material larger than or equal to the second preset particle size and smaller than or equal to the first preset particle size, and a third screened ore material smaller than the second preset particle size; wherein, the first preset particle size is larger than the second preset particle size; Respectively perform re-grinding treatment on the first screened ore material by returning it to the high-pressure roller mill, perform dry separation treatment on the second screened ore material, and perform magnetic separation treatment on the third screened ore material after adding water to adjust the pulp; According to the first preset concentrate particle size condition, grind the dry concentrate obtained by the dry separation treatment and the magnetic separation concentrate obtained by the magnetic separation treatment after mixing, and perform combined gravity separation treatment on iron minerals and barite in the obtained first mixed concentrate to obtain a combined concentrate of iron and barite; According to the second preset concentrate particle size condition, grind the combined concentrate of iron and barite, and perform positive flotation treatment on barite on the obtained second mixed concentrate to obtain barite concentrate and tailings containing coarse iron respectively; Perform magnetic separation and quality-improving roasting treatment on the tailings containing coarse iron to obtain iron concentrate.

2. The ore dressing method of barite-rich iron ore according to claim 1, characterized in that, Before using the high-pressure roller mill to grind the crushed ore, it also includes: Crush the original stone to obtain crushed ore of a preset size; Perform ore washing treatment on the crushed ore of the preset size to obtain washed crushed ore; Use a crusher to grind the washed crushed ore, and perform screening treatment on the ground ore through a screening device. Return the oversize material to the crusher, and feed the undersize material as the crushed ore to be ground into the high-pressure roller mill; wherein, the particle size of the undersize material is less than 50 mm.

3. The beneficiation method of barite-rich iron ore according to claim 2, characterized in that, During the process of performing ore washing treatment on the crushed ore of the preset size to obtain washed crushed ore, Use a cylindrical ore washer to perform ore washing treatment on the crushed ore of the preset size.

4. The beneficiation method of barite-rich iron ore according to claim 1, characterized in that, During the process of respectively performing re-grinding treatment on the first screened ore material by returning it to the high-pressure roller mill, performing dry separation treatment on the second screened ore material, and performing magnetic separation treatment on the third screened ore material after adding water to adjust the pulp, Use a dry intelligent separator to perform dry separation treatment on the second screened ore material; After adding water to adjust the pulp of the third screened ore material to a concentration of 30%, perform magnetic separation treatment using a large-particle-size high-intensity magnetic separator. Among them, during the magnetic separation treatment, the magnetic field intensity is at least 8000 GS.

5. The ore dressing method for iron ore rich in barite according to claim 1, characterized in that, The first preset concentrate particle size condition is: in the first mixed concentrate, 60% of the ore material has a particle size less than 0.074 mm; and / or The second preset concentrate particle size condition is: in the second mixed concentrate, 90% of the ore material has a particle size less than 0.044 mm.

6. The beneficiation method of iron ore rich in barite according to claim 1, characterized in that, During the process of performing combined gravity separation treatment on iron minerals and barite in the obtained first mixed concentrate to obtain a combined concentrate of iron and barite, A spiral chute is adopted to carry out combined gravity separation treatment of iron minerals and barite on the first combined concentrate through two-stage gravity separation processes of roughing and cleaning.

7. The beneficiation method of barite-rich iron ore according to claim 1, characterized in that, During the process of carrying out positive flotation treatment of barite on the obtained second combined concentrate to respectively obtain barite concentrate and tailings containing crude iron, A vertical agitation mill is adopted to carry out positive flotation treatment of barite on the second combined concentrate through a one-roughing and three-cleaning flotation process.

8. The beneficiation method of barite-rich iron ore according to claim 1, characterized in that, The magnetic separation and quality-improving roasting treatment of iron minerals on the tailings containing crude iron to obtain iron concentrate includes: Carrying out magnetic separation treatment on the tailings containing crude iron through a weak magnetic-strong magnetic system to obtain crude iron concentrate; wherein, the magnetic field intensity of the strong magnetic in the magnetic separation treatment is 10,000 GS; Carrying out concentration and filtration treatment on the crude iron concentrate to make the moisture content of the crude iron concentrate less than 12% to obtain concentrated crude iron concentrate; Adopting a quality-improving roasting process to carry out roasting treatment on the concentrated crude iron concentrate to remove hydroxide ions and carbonate ions in the iron ore structure of the concentrated crude iron concentrate to obtain iron concentrate; wherein, the temperature of the quality-improving roasting process is at least 700 °C, and the roasting treatment is carried out by means of suspension oxidation roasting.

9. A beneficiation device for the beneficiation method of iron ore rich in barite according to any one of claims 1-8, characterized in that, Including: A high-pressure roll mill, a double-layer dry screening device, a separation device, a grinding device, a flotation device, an iron mineral magnetic separation device and a quality-improving roasting device; wherein, The double-layer dry screening device includes a feed inlet, a first screened ore outlet, a second screened ore outlet and a third screened ore outlet; The separation device includes a dry separation device and a magnetic separation device; The flotation device includes a spar concentrate outlet and a tailings outlet; The discharge port of the high-pressure roll mill is connected to the feed inlet of the double-layer dry screening device, the first screened ore outlet is connected to the feed inlet of the high-pressure roll mill, the second screened ore outlet is connected to the dry separation device, the third screened ore outlet is connected to a pulp conditioning device, and the pulp conditioning device is connected to the third screened ore outlet; The concentrate outlets of the dry separation device and the magnetic separation device are both connected to the grinding device, the discharge outlet of the grinding device is connected to the flotation device, the tailings outlet of the flotation device is connected to the iron mineral magnetic separation device, and the iron mineral magnetic separation device is connected to the quality-improving roasting device; The grinding device includes a ball mill, a hydrocyclone, a rough gravity separation device, a fine gravity separation device and a vertical grinding machine; The feed inlet of the high-pressure roll mill is connected to a raw ore pretreatment device; the raw ore pretreatment device includes a crushing device, a washing device and a screening device; the washing device is a cylindrical ore washer.

10. The ore dressing device according to claim 9, wherein The discharge outlet of the crushing device is connected to the feed inlet of the washing device, the discharge outlet of the washing device is connected to the feed inlet of the screening device, the oversize material outlet of the screening device is connected to the feed inlet of the crushing device, and the undersize material outlet of the screening device is connected to the feed inlet of the high-pressure roll mill.

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