Efficient and energy-saving beneficiation process for weathered crust type magnetic hematite and brown mixed iron ore

Abstract

The invention discloses an efficient and energy-saving mineral processing technology for weathered crust type magnetic hematite and brown mixed iron ore. The efficient and energy-saving mineral processing technology comprises the following steps that (1) raw ore is subjected to crushing, dry screening, ore washing, high-pressure roller grinding and wet screening, and selected products with qualified particle sizes are obtained; 2) performing low-intensity magnetic separation on the selected product to obtain magnetic separation iron ore concentrate and low-intensity magnetic separation tailings; (3) the low-intensity magnetic separation tailings are subjected to high-intensity magnetic separation, rotational flow classification and chute gravity separation to obtain gravity separation iron ore concentrate, chute gravity separation tailings and rotational flow classification overflow and high-intensity magnetic scavenging tailings; and (4) the chute reselection tailings are subjected to ore grinding classification and strong magnetic roughing to obtain strong magnetic roughing concentrate and strong magnetic roughing tailings, and the strong magnetic roughing concentrate and the rotational flow classification overflow are combined and then subjected to reverse flotation to obtain flotation iron concentrate and reverse flotation total tailings. According to the method, more than 50% of qualified selected products can be obtained through ore washing operation before entering a high-pressure roller mill, the ore grinding amount is greatly reduced, the over-crushing phenomenon is avoided, and the comprehensive utilization rate of the type of resources is remarkably increased through a magnetic separation, reselection and flotation combined beneficiation method.

Description

Technical Field

[0001] The invention belongs to the technical field of mixed iron ore beneficiation, and specifically relates to a weathering crust type mixed iron ore beneficiation method, which is particularly suitable for processing mixed iron ore with an iron grade of 35% to 45%, coexistence of magnetic, hematite and limonite minerals, high mud content, high iron clay content, easy crushing and easy mudification. Background Art

[0002] Steel is a basic and structural material in the development of the national economy and is irreplaceable. With the rapid development of the economy, the contradiction between supply and demand of my country's iron ore resources and their products has become increasingly prominent, and the external dependence has exceeded 80% for many years, seriously endangering the country's strategic security. Complex and difficult-to-process iron ores account for a high proportion of my country's iron ore resources. The total reserves of typical difficult-to-use iron ore resources such as siderite, limonite, and fine-grained ore alone are more than 20 billion tons. Due to the fine crystal grain size, complex mineral composition, and close symbiotic relationship of such iron ore resources, it is difficult to obtain good technical and economic indicators using conventional mineral processing technology. Most resources have not yet been industrially developed and utilized. Although some resources have been developed, the mineral processing process is complex and the cost is high. The recovery rate can generally only reach 60% to 65%, or even less than 50%. It is urgent to carry out technical research on complex and difficult-to-process iron ore resources, which is very necessary to ensure the safety of my country's iron ore resources.

[0003] For the separation of mixed iron ore, the current process flow for mineral processing is to grind the mixed iron ore (crushed to -12mm) in a closed circuit until the content of -0.076mm reaches about 65%, and then undergo weak magnetic separation-strong magnetic separation, concentration, filtration and dehydration to obtain the final iron concentrate (TFe grade is about 56%). In addition to the above-mentioned single magnetic separation process, the current domestic mixed iron ore separation process also includes stage grinding-weak magnetic separation-strong magnetic separation-anion reverse flotation (process one); stage grinding, coarse and fine separation, gravity separation-magnetic separation-anion reverse flotation (process two). The advantages of the stage grinding-weak magnetic separation-strong magnetic separation-anion reverse flotation process (process one) are: (1) The use of stage grinding realizes "throw away as soon as possible", and a large amount of qualified tailings are discarded under the condition of coarser grinding particle size; (2) The weak magnetic-strong magnetic mixed coarse concentrate is regrinded, which is conducive to stabilizing the flotation feed grade and has strong adaptability to ore changes; (3) Stable production and easy operation. The disadvantages are: the concentrate cannot be refined in advance, the amount of re-grinding of the coarse concentrate is large, the siderite is brittle and easily over-grinded, and it is not conducive to energy saving and consumption reduction.

[0004] In order to solve the problem of beneficiation of mixed iron ore, the article "Research on the Ore Dressing Technology of Mixed Iron Ore" published in the 6th issue of "Mining Engineering" in 2012 conducted experimental research on mixed iron ore in a certain area. The iron minerals in the raw ore are mainly magnetic iron, hematite and iron carbonate. Through systematic research on the properties of iron ore, process structure and separation process, it was finally determined to adopt "stage grinding, coarse and fine separation, spiral chute-strong magnetic-centrifuge process flow", and the indicators obtained were: raw ore grade 30.09%, concentrate grade 62.39%, yield 33.53%, recovery rate 69.52%, tailings grade 13.80%, and the concentrate grade after burning of the process reached 64.84%. But in general, the iron concentrate obtained has a low grade, low iron recovery rate, and a large amount of iron loss in the tailings.

[0005] Weathering crust type mixed iron ore is a kind of complex and difficult to beneficiate iron ore. It has the characteristics of many types of iron minerals, high mud, high iron clay, easy to crush and easy to mud. This type of iron ore is mainly distributed in Hunan, Hubei, Jiangxi, Guangdong, Guangxi, Hainan and other places in my country. It is mainly because most of the southern part of my country is in low latitudes, tropical-subtropical, warm and humid climate, and strong weathering. The current mineral processing process has a very poor beneficiation effect on weathering crust type mixed iron ore, low resource utilization, and large iron loss.

[0006] Ore washing is an effective means of pre-treatment of high-mud iron ore. Coarse and fine grading and separate selection are important ways to improve sorting efficiency. More crushing and less grinding are key ways to reduce beneficiation costs. Magnetic gravity flotation combined sorting is an important beneficiation method for the utilization of magnetic and reddish brown mixed iron ore. Therefore, it is urgent to develop an efficient and energy-saving beneficiation process for mixed iron ore with many types of useful iron minerals, high mud, high iron clay, easy to crush, and easy to mud. Summary of the invention

[0007] The purpose of the present invention is to provide a high-efficiency and energy-saving beneficiation process for weathering crust-type magnetic red-brown mixed iron ore with good sorting effect, stable and reliable process flow, strong applicability, relatively low beneficiation energy consumption and cost, in response to the technical difficulties of the prior art in beneficiating magnetic red-brown mixed iron ore with high mud, high iron content clay, easy to crush and easy to mud, and low resource utilization.

[0008] To achieve the above-mentioned purpose of the present invention, the present invention provides a high-efficiency and energy-saving beneficiation process for weathered crust type magnetic hematite mixed iron ore, which is implemented by the following processes and steps:

[0009] S1 dry screening - crushing - ore washing - wet screening - high pressure roller grinding

[0010] The raw ore is subjected to dry screening to obtain dry screen products and dry screen undersize products. The dry screen products are fed into the crushing equipment for crushing, and the crushed products are returned to the dry screening operation; the dry screen undersize products are subjected to ore washing to obtain ore washing overflow and ore washing return sand, and the ore washing return sand is fed into the wet screening equipment for screening to obtain wet screen products and wet screen undersize products. The wet screen products are subjected to high-pressure roller grinding and returned to the wet screening operation; the ore washing overflow and the wet screen undersize products are combined into selected products;

[0011] S2 weak magnetic field - strong magnetic field

[0012] The selected products obtained in step S1 are fed into weak magnetic-strong magnetic operation, wherein the weak magnetic operation includes weak magnetic roughing and weak magnetic concentrating, and the strong magnetic operation includes strong magnetic roughing and strong magnetic scavenging, respectively obtaining weak magnetic iron concentrate, strong magnetic roughing concentrate, and strong magnetic scavenging concentrate, and the strong magnetic roughing concentrate and the strong magnetic scavenging concentrate are combined into a strong magnetic comprehensive concentrate, and the strong magnetic scavenging tailings are discharged;

[0013] S3 Cyclone Classification-Chute Gravity Selection

[0014] The strong magnetic separation comprehensive concentrate obtained in step S2 is fed into a cyclone classification operation to obtain a cyclone classification overflow and a cyclone classification sand settling, and the cyclone classification sand settling is fed into a chute gravity separation operation, wherein the chute gravity separation operation includes a chute gravity separation roughing selection and a chute gravity separation selection, and a spiral chute selected concentrate is obtained, and spiral chute roughing tailings and spiral chute selected tailings are discharged, and the spiral chute roughing tailings and the spiral chute selected tailings are combined into the chute gravity separation tailings;

[0015] S4 Pre-classification - Grinding - High-intensity magnetic separation

[0016] The chute gravity separation tailings discharged from step S3 are fed into a pre-classification operation to obtain a pre-classification overflow and pre-classification return sand, the pre-classification return sand is fed into a grinding device for grinding, and the grinding product is returned to the classification operation; the pre-classification overflow is fed into a strong magnetic roughing operation to obtain a strong magnetic roughing concentrate, and the strong magnetic roughing tailings are discharged;

[0017] S5 Concentration - Reverse Flotation

[0018] The strong magnetic roughing concentrate obtained in step S4 and the pre-classification overflow are combined and fed into the concentration operation to obtain the concentration operation underflow, and the concentration operation underflow is fed into the reverse flotation operation to obtain the reverse flotation concentrate and the reverse flotation tailings. The reverse flotation concentrate and the weak magnetic iron concentrate obtained in step S2 and the spiral chute concentrate obtained in step S3 are combined into the final iron concentrate; the reverse flotation tailings and the strong magnetic sweeping tailings discharged in step S2 and the strong magnetic roughing tailings discharged in step S4 are combined into the final total tailings; the reverse flotation operation adopts one roughing and one concentrating, and the amount of reagents for each operation is calculated according to the dry ore amount fed to the reverse flotation operation:

[0019] Reverse flotation roughing: the dosage of slurry pH adjuster sodium hydroxide is 1000g / t~2000g / t, the dosage of dispersant sodium hexametaphosphate is 20g / t~40g / t, the dosage of inhibitor starch is 300g / t~500g / t, the dosage of collector dodecylamine is 600g / t~900g / t; reverse flotation selection: the dosage of collector dodecylamine is 300g / t~500g / t.

[0020] Preferably, in step S1, the dry screening operation adopts a linear vibrating screen with a mesh size of 20mm to 40mm; the crushing equipment adopts a jaw crusher; the ore washing operation adopts a single spiral trough ore washer, the spiral lifting angle is 20° to 30°, the ore washing concentration is 10% to 20%, the spiral speed is 12 rpm to 20 rpm, and the overflow particle size of the ore washing is controlled to be -200 mesh, accounting for 50% to 60%; the wet screening equipment adopts an arc vibrating screen with a mesh size of 1mm to 2mm, and the particle size of the product under the screen is -200 mesh, accounting for 50% to 60%; the high-pressure roller mill operation adopts a pin-type high-pressure roller mill, the roller surface linear speed is 0.5m / s to 0.8m / s, and the hydraulic pressure is 8Mpa to 10Mpa.

[0021] Preferably, in step S2, the magnetic field strength of the weak magnetic roughing operation is 199.04 kA / m to 318.47 kA / m, and the magnetic field strength of the weak magnetic concentrating operation is 95.54 kA / m to 159.24 kA / m; the strong magnetic roughing and strong magnetic sweeping selection both adopt Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strengths are 636.94 kA / m to 796.18 kA / m and 955.41 kA / m to 1194.27 kA / m respectively.

[0022] Preferably, in step S3, the cyclone classification operation adopts a small cone angle hydrocyclone, the cone angle of the hydrocyclone is 5° to 10°, and the feed pressure is 0.05MPa to 0.10MPa; the overflow particle size of the cyclone classification is controlled to be -325 mesh, accounting for 85% to 95%; the feed concentration of the rough selection of the chute gravity separation is controlled to be 20% to 30%, and the feed concentration of the fine selection of the chute gravity separation is controlled to be 25% to 35%.

[0023] Preferably, in step S4, the pre-grading operation adopts a high-frequency vibrating fine screen / hydrocyclone, and the underscreen product / overflow particle size is controlled to be -200 mesh, accounting for 90% to 95%; the grinding equipment adopts a vertical stirred mill, and the grinding concentration is 45% to 55%; the strong magnetic roughing operation adopts a Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is controlled to be 636.94kA / m to 796.18kA / m.

[0024] Preferably, in step S5, the underflow concentration of the concentration operation is controlled to be 25% to 35%.

[0025] Further; In step S2, the magnetic field strength of the weak magnetic roughing operation is 199.04kA / m~318.47kA / m, the magnetic field strength of the weak magnetic concentrating operation is 95.54kA / m~159.24kA / m, and the strong magnetic roughing and strong magnetic sweeping selection both use Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strengths are 636.94kA / m~796.18kA / m and 955.41kA / m~1194.27kA / m respectively; In step S3, the cyclone classification operation uses a small cone angle hydrocyclone, the cone angle of the hydrocyclone is 5°~10°, the feed pressure is 0.05MPa~0.10MPa, and the overflow particle size of the cyclone classification is controlled to -325 mesh, accounting for 85%~ 95%; in step S3, the feed concentration of the chute gravity separation roughing is controlled to be 20%-30%, and the feed concentration of the chute gravity separation fine selection is controlled to be 25%-35%; in step S4, the pre-grading operation adopts a high-frequency vibrating fine screen / hydrocyclone, and the underscreen product / overflow particle size is controlled to be -200 mesh accounting for 90%-95%, and the grinding equipment adopts a vertical stirred mill, and the grinding concentration is 45%-55%; the strong magnetic roughing operation adopts a Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is controlled to be 636.94kA / m-796.18kA / m; in step S5, the underflow concentration of the concentration operation is controlled to be 25%-35%, and the underflow particle size of the concentration operation is controlled to be -325 mesh 80%-90%.

[0026] The specific values ​​of the above parameters such as grinding particle size, magnetic field strength, flotation times, and reagent dosage can be determined based on the properties of the ore and the results of laboratory tests. The concentrations here are all mass concentrations, and the particle size ratio of the undersize product also refers to the mass ratio of a certain particle size in the undersize product.

[0027] Compared with the prior art, the high-efficiency and energy-saving beneficiation process of weathered crust type magnetic hematite mixed iron ore of the present invention has the following advantages:

[0028] (1) In view of the high mud content of the selected ore, the present invention adopts a combination of ore washing and wet screening before the ore is fed into the high-pressure roller mill, so as to separate more than 50% of the qualified selected products with particle size. This not only creates conditions for the high-pressure roller mill operation (the material is loose, without mud and agglomeration), greatly improves the crushing efficiency of the high-pressure roller mill, but also avoids over-crushing of the ore.

[0029] (2) The present invention adopts a single spiral trough ore washer for ore washing operations and an arc vibrating screen for wet screening operations, thereby improving the comprehensive efficiency of ore washing and screening, and has advanced technology and reliable operation.

[0030] (3) The present invention aims at selecting a variety of useful iron minerals in the ore. According to the principles of "easy to collect and early to collect" and "staged tailings discarding", the magnetic separation, gravity separation and flotation methods are used in sequence to recover magnetite, hematite and limonite in the ore. The separation effect is good, the process flow is stable and reliable, and the applicability is strong.

[0031] (4) The present invention has obtained most of the iron concentrate before reverse flotation, discarded most of the tailings, the amount of flotation ore is small, the consumption of flotation reagents is low, and has the advantages of relatively simple process flow, minimal environmental pollution, low cost, and high economic benefits.

[0032] (5) The ore dressing process provided by the present invention can make full use of a large amount of similar mixed iron ores in my country, which is of great significance to alleviating the shortage of iron ore resources in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention is a process flow chart of the principle of a high-efficiency and energy-saving mineral processing process for weathering crust type magnetic hematite mixed iron ore.

[0034] Figure 2 The figure is a principle flow chart of the ore crushing-ore washing-roller grinding-screening process adopted in the present invention.

[0035] Figure 3 It is a principle flow chart of the magnetic-gravity-flotation combined beneficiation process for selected products adopted in the present invention.

[0036] Figure 4 It is a numerical and qualitative flow chart of the ore crushing-ore washing-roller mill-screening process adopted in the embodiment of the present invention.

[0037] Figure 5 It is a quality flow chart of the magnetic-gravity-flotation combined beneficiation process for the selected products adopted in the embodiment of the present invention. DETAILED DESCRIPTION

[0038] To further describe the present invention, a high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0039] It should be noted that any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present invention should be included in the protection scope of the present invention. In addition, the embodiments described below are exemplary and cannot be understood as limiting the present invention.

[0040] The ore sample used in this embodiment comes from a high-mud, high-iron clay, easy-to-crush, easy-to-mudify magnetic and reddish-brown mixed iron ore from an iron mine in China. The main chemical composition analysis results of the ore are shown in Table 1, the iron phase analysis results of the ore are shown in Table 2, the main mineral composition results of the ore are shown in Table 3, and the wet screening particle size composition analysis results of the raw ore are shown in Table 4.

[0041] Table 1 Analysis results of main chemical components of ore

[0042] Element TFe <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO MgO <![CDATA[K2O]]> <![CDATA[Na2O]]> content / % 43.60 24.89 5.64 0.18 0.39 0.07 0.10 Element MnO <![CDATA[TiO2]]> Cl <![CDATA[Cr2O3]]> S P Burning content / % 0.73 0.25 0.01 0.02 0.07 0.06 6.38

[0043] Table 2 Ore iron phase analysis results

[0044]

[0045] Table 3 Main mineral composition results

[0046] Mineral Name Hematite Goethite False hematite magnetite Pyrite, pyrrhotite content / % 21.65 18.00 14.70 7.64 0.15 Mineral Name quartz clay Iron-containing clay Mica Diametre content / % 19.92 6.53 4.22 1.70 1.71 Mineral Name Pyroxene Chlorite Carbonate other total content / % 0.80 1.42 0.60 0.96 100.00

[0047] Table 4 Analysis results of particle size composition of raw ore wet screening

[0048]

[0049]

[0050] The analysis results in Tables 1 to 4 show that the TFe grade in the ore is 43.60%, and the main useful minerals are magnetite, pseudo-hematite, hematite and limonite. Limonite is easy to become muddy during the grinding process; there is a certain amount of iron-containing clay in the gangue minerals, and the iron-containing clay has weak magnetism and can easily deteriorate the recovery index of weak magnetic minerals; the yield of the original ore -1mm particle size accounts for 55.48%, indicating that more than 50% of the ore can be directly selected after screening without crushing, and the yield of the original ore -0.030mm particle size accounts for 16.23%, indicating that the ore has a high mud content.

[0051] Depend on Figure 1 The process flow chart of the invention is a high-efficiency and energy-saving mineral processing process for weathered crust type magnetic hematite mixed iron ore. Figure 2 , Figure 3 , Figure 4 , Figure 5 It can be seen that the specific process steps and parameters used in the embodiment of the present invention are as follows:

[0052] S1 dry screening - crushing - ore washing - wet screening - high pressure roller grinding

[0053] The raw ore is subjected to dry screening operation to obtain dry screen upper products and dry screen lower products. The dry screen upper products are fed into the crushing equipment for crushing, and the crushed products are returned to the dry screening operation; the dry screen lower products are subjected to ore washing operation to obtain ore washing overflow and ore washing return sand, and the ore washing return sand is fed into the wet screening equipment for screening to obtain wet screen upper products and wet screen lower products. The wet screen upper products are returned to the wet screening operation after high-pressure roller grinding operation; the ore washing overflow and the wet screen lower products are combined into the selected products, and the particle size of the selected products is -200 mesh 57%. The dry screening operation adopts a linear vibrating screen with a mesh size of 30mm; the crushing equipment adopts a jaw crusher; the ore washing operation adopts a single spiral trough ore washer, the spiral lifting angle is 25°, the ore washing concentration is 15%, the spiral speed is 16 rpm, and the overflow particle size of the ore washing is controlled to -200 mesh, accounting for 55%; the wet screening equipment adopts an arc vibrating screen with a mesh size of 1mm, and the particle size of the product under the screen is -200 mesh, accounting for 59%; the high-pressure roller mill operation adopts a pin-type high-pressure roller mill, the roller surface linear speed is 0.6m / s, and the hydraulic pressure is 9Mpa.

[0054] S2 weak magnetic field - strong magnetic field

[0055] The selected products obtained in step S1 are fed into the weak magnetic-strong magnetic operation, wherein the weak magnetic operation includes weak magnetic roughing and weak magnetic concentrating, and the strong magnetic operation includes strong magnetic roughing and strong magnetic scavenging, respectively obtaining weak magnetic iron concentrate, strong magnetic roughing concentrate, and strong magnetic scavenging concentrate, and the strong magnetic roughing concentrate and strong magnetic scavenging concentrate are combined into strong magnetic comprehensive concentrate, and the strong magnetic scavenging tailings are discharged. The magnetic field strength of the weak magnetic roughing operation is 278.66 kA / m, and the magnetic field strength of the weak magnetic concentrating operation is 159.24 kA / m; the strong magnetic roughing and strong magnetic scavenging both use Slon vertical ring pulsating high gradient strong magnetic separators, and the magnetic field strengths are 796.18 kA / m and 955.41 kA / m, respectively.

[0056] S3 Cyclone Classification-Chute Gravity Selection

[0057] The strong magnetic separation comprehensive concentrate obtained in step S2 is fed into the cyclone classification operation to obtain cyclone classification overflow and cyclone classification sand settling, and the cyclone classification sand settling is fed into the chute gravity separation operation, and the chute gravity separation operation includes chute gravity separation roughing and chute gravity separation concentrating, and the spiral chute concentrating concentrate is obtained, and the spiral chute roughing tailings and spiral chute concentrating tailings are discharged, and the spiral chute roughing tailings and spiral chute concentrating tailings are combined into the chute gravity separation tailings. The cyclone classification operation adopts a small cone angle hydrocyclone, the cone angle of the hydrocyclone is 8°, and the feeding pressure is 0.06MPa; the cyclone classification overflow particle size is controlled to -325 mesh accounting for 90%; the feed concentration of the chute gravity separation roughing is controlled to 25%, and the feed concentration of the chute gravity separation concentrating is controlled to 30%.

[0058] S4 Pre-classification - Grinding - High-intensity magnetic separation

[0059] The chute gravity tailings discharged from step S3 are fed into the pre-classification operation to obtain pre-classification overflow and pre-classification return sand, and the pre-classification return sand is fed into the grinding equipment for grinding, and the grinding product is returned to the classification operation; the pre-classification overflow is fed into the strong magnetic roughing operation to obtain the strong magnetic roughing concentrate, and the strong magnetic roughing tailings are discharged. The pre-classification operation adopts a high-frequency vibrating fine screen, and the underscreen product / overflow particle size is controlled to -200 mesh, accounting for 92%; the grinding equipment adopts a vertical stirred mill, and the grinding concentration is 50%; the strong magnetic roughing operation adopts a Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is controlled to 796.18kA / m.

[0060] S5 Concentration - Reverse Flotation

[0061] The strong magnetic roughing concentrate obtained in step S4 and the pre-classification overflow are combined and fed into the concentration operation to obtain the concentration operation bottom flow, the concentration operation bottom flow concentration is controlled to be 30%, and the particle size is -325 mesh 85%; the concentration operation bottom flow is fed into the reverse flotation operation to obtain the reverse flotation concentrate and the reverse flotation tailings, the reverse flotation concentrate and the weak magnetic iron concentrate obtained in step S2 and the spiral chute concentrate obtained in step S3 are combined into the final iron concentrate; the reverse flotation tailings and the strong magnetic sweeping tailings discharged in step S2 and the strong magnetic roughing tailings discharged in step S4 are combined into the final total tailings; the reverse flotation operation adopts one roughing and one concentrating, and the amount of reagents for each operation is calculated according to the dry ore amount fed to the reverse flotation operation:

[0062] Reverse flotation roughing: the amount of slurry pH adjuster sodium hydroxide is 1600g / t, the amount of dispersant sodium hexametaphosphate is 25g / t, the amount of inhibitor starch is 400g / t, the amount of collector dodecylamine is 800g / t; reverse flotation cleaning: the amount of collector dodecylamine is 400g / t.

[0063] After being treated by the above process, the weathering crust-type magnetic reddish-brown mixed iron ore can obtain magnetic iron concentrate with a yield of 19.80% and an iron grade of 63.61%, gravity-separated iron concentrate with a yield of 23.33% and an iron grade of 62.15%, and flotation iron concentrate with a yield of 9.28% and an iron grade of 60.74%. The above three can be combined to obtain a comprehensive iron concentrate with a yield of 52.41%, an iron grade of 62.45% and an iron recovery rate of 75.08%.

[0064] The above are embodiments of the present invention, but the above examples are only used to help understand the method and core ideas of the present invention, and are not equivalent to the specific embodiments described above. For those skilled in the art, making some improvements, modifications or changes to the present invention, and combining the above technical features in an appropriate manner, these improvements, modifications, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore, characterized in that This is done using the following steps: S1 dry screening - crushing - ore washing - wet screening - high pressure roller grinding The raw ore is subjected to dry screening to obtain dry screen products and dry screen undersize products. The dry screen products are fed into the crushing equipment for crushing, and the crushed products are returned to the dry screening operation; the dry screen undersize products are subjected to ore washing to obtain ore washing overflow and ore washing return sand, and the ore washing return sand is fed into the wet screening equipment for screening to obtain wet screen products and wet screen undersize products. The wet screen products are subjected to high-pressure roller grinding and returned to the wet screening operation; the ore washing overflow and the wet screen undersize products are combined into selected products; S2 weak magnetic field - strong magnetic field The selected products obtained in step S1 are fed into weak magnetic-strong magnetic operation, wherein the weak magnetic operation includes weak magnetic roughing and weak magnetic concentrating, and the strong magnetic operation includes strong magnetic roughing and strong magnetic scavenging, respectively obtaining weak magnetic iron concentrate, strong magnetic roughing concentrate, and strong magnetic scavenging concentrate, and the strong magnetic roughing concentrate and the strong magnetic scavenging concentrate are combined into a strong magnetic comprehensive concentrate, and the strong magnetic scavenging tailings are discharged; S3 Cyclone Classification-Chute Gravity Selection The strong magnetic separation comprehensive concentrate obtained in step S2 is fed into a cyclone classification operation to obtain a cyclone classification overflow and a cyclone classification sand settling, and the cyclone classification sand settling is fed into a chute gravity separation operation, wherein the chute gravity separation operation includes a chute gravity separation roughing selection and a chute gravity separation selection, and a spiral chute selected concentrate is obtained, and spiral chute roughing tailings and spiral chute selected tailings are discharged, and the spiral chute roughing tailings and the spiral chute selected tailings are combined into the chute gravity separation tailings; S4 Pre-classification - Grinding - High-intensity magnetic separation Feeding the chute gravity separation tailings discharged from step S3 into the pre-classification operation to obtain pre-classification overflow and pre-classification return sand, the pre-classification return sand is fed into the grinding equipment for grinding, and the grinding product is returned to the classification operation; The pre-classified overflow is fed into the strong magnetic roughing operation to obtain the strong magnetic roughing concentrate, and the strong magnetic roughing tailings are discharged; S5 Concentration - Reverse Flotation The strong magnetic roughing concentrate obtained in step S4 and the pre-classification overflow are combined and fed into the concentration operation to obtain the concentration operation underflow, and the concentration operation underflow is fed into the reverse flotation operation to obtain the reverse flotation concentrate and the reverse flotation tailings. The reverse flotation concentrate and the weak magnetic iron concentrate obtained in step S2 and the spiral chute concentrate obtained in step S3 are combined into the final iron concentrate; the reverse flotation tailings and the strong magnetic sweeping tailings discharged in step S2 and the strong magnetic roughing tailings discharged in step S4 are combined into the final total tailings; the reverse flotation operation adopts one roughing and one concentrating, and the amount of reagents for each operation is calculated according to the dry ore amount fed to the reverse flotation operation: Reverse flotation roughing: the dosage of slurry pH adjuster sodium hydroxide is 1000g / t~2000g / t, the dosage of dispersant sodium hexametaphosphate is 20g / t~40g / t, the dosage of inhibitor starch is 300g / t~500g / t, the dosage of collector dodecylamine is 600g / t~900g / t; reverse flotation selection: the dosage of collector dodecylamine is 300g / t~500g / t.

2. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore according to claim 1, characterized in that: In step S1, the dry screening operation adopts a linear vibrating screen with a mesh size of 20 mm to 40 mm; the crushing equipment adopts a jaw crusher; the ore washing operation adopts a single spiral trough ore washer, the spiral lifting angle is 20° to 30°, the ore washing concentration is 10% to 20%, the spiral speed is 12 rpm to 20 rpm, and the overflow particle size of the ore washing is controlled to -200 mesh accounting for 50% to 60%.

3. A high-efficiency and energy-saving beneficiation process for weathering shell type magnetic hematite mixed iron ore as claimed in claim 2, characterized in that: In step S1, the wet screening equipment adopts an arc-shaped vibrating screen with a mesh size of 1mm to 2mm, and the particle size of the product under the screen is -200 mesh, accounting for 50% to 60%; the high-pressure roller mill operation adopts a pin-type high-pressure roller mill, the surface linear speed of the roller is 0.5m / s to 0.8m / s, and the hydraulic pressure is 8Mpa to 10Mpa.

4. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore according to claim 1, characterized in that: In step S2, the magnetic field strength of the weak magnetic roughing operation is 199.04 kA / m to 318.47 kA / m, and the magnetic field strength of the weak magnetic concentrating operation is 95.54 kA / m to 159.24 kA / m.

5. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore as claimed in claim 4, characterized in that: In step S2, the strong magnetic roughing separation and strong magnetic sweeping separation both use Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is 636.94kA / m~796.18kA / m and 955.41kA / m~1194.27kA / m respectively.

6. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore according to claim 1, characterized in that: In step S3, the cyclone classification operation adopts a small cone angle hydrocyclone, the cone angle of the hydrocyclone is 5° to 10°, and the feed pressure is 0.05MPa to 0.10MPa; the overflow particle size of the cyclone classification is controlled to -325 mesh, accounting for 85% to 95%.

7. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore as claimed in claim 6, characterized in that: In step S3, the feed concentration of the roughing chute gravity separation is controlled to be 20% to 30%, and the feed concentration of the fine chute gravity separation is controlled to be 25% to 35%.

8. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore as claimed in claim 1, characterized in that: In step S4, the pre-grading operation adopts a high-frequency vibrating fine screen / hydrocyclone, and the underscreen product / overflow particle size is controlled to be -200 mesh, accounting for 90% to 95%; the grinding equipment adopts a vertical stirred mill, and the grinding concentration is 45% to 55%; the strong magnetic roughing operation adopts a Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is controlled to be 636.94kA / m to 796.18kA / m.

9. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore according to claim 1, characterized in that: In step S5, the underflow concentration of the concentration operation is controlled to be 25% to 35%.

10. A high-efficiency and energy-saving beneficiation process for weathering crust type magnetic hematite mixed iron ore as claimed in claim 3, characterized in that: In step S2, the magnetic field strength of the weak magnetic roughing operation is 199.04kA / m~318.47kA / m, and the magnetic field strength of the weak magnetic concentrating operation is 95.54kA / m~159.24kA / m; the strong magnetic roughing and strong magnetic sweeping both use Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is 636.94kA / m~796.18kA / m and 955.41kA / m~1194.27kA / m respectively; In step S3, the cyclone classification operation adopts a small cone angle hydrocyclone, the cone angle of the hydrocyclone is 5° to 10°, and the feed pressure is 0.05MPa to 0.10MPa; the overflow particle size of the cyclone classification is controlled to be -325 mesh, accounting for 85% to 95%; in step S3, the feed concentration of the chute gravity selection roughing is controlled to be 20% to 30%, and the feed concentration of the chute gravity selection fine selection is controlled to be 25% to 35%; In step S4, the pre-grading operation adopts a high-frequency vibrating fine screen / hydrocyclone, and the underscreen product / overflow particle size is controlled to be -200 mesh, accounting for 90% to 95%; the grinding equipment adopts a vertical stirred mill, and the grinding concentration is 45% to 55%; the strong magnetic roughing operation adopts a Slon vertical ring pulsating high gradient strong magnetic separator, and the magnetic field strength is controlled to be 636.94kA / m to 796.18kA / m; In step S5, the concentration of the underflow of the concentration operation is controlled to be 25% to 35%, and the particle size of the underflow of the concentration operation is controlled to be -325 mesh 80% to 90%.

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