Combined beneficiation process for weathering crust type high-mud-content magnetic, red and brown mixed iron ore

Abstract

The invention discloses a combined beneficiation process for weathering crust type high-mud-content magnetic, red and brown mixed iron ore, which comprises the following steps: carrying out crushing, dry screening, ore washing, high-pressure roller milling and wet screening on raw ore to obtain selected products with qualified granularity, and carrying out low-intensity magnetic separation on the selected products to obtain magnetic separation iron ore concentrate and low-intensity magnetic separation tailings; 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 the chute gravity separation tailings are subjected to ore grinding classification and high-intensity magnetic roughing to obtain high-intensity magnetic roughing concentrate and high-intensity magnetic roughing tailings; the strong magnetic roughing concentrate and the rotational flow grading overflow are combined and then subjected to reverse flotation, flotation iron concentrate and reverse flotation total tailings are obtained, and a reverse flotation collecting agent MX is a mixture of ether amine, ether diamine and quaternary ammonium salt according to the molar ratio of 1: (1.2-2.0): (1.5-2.5). The method has the advantages of being good in separation effect, stable and reliable in technological process, high in applicability, relatively low in mineral separation energy consumption and cost, extremely small in environmental pollution and high in comprehensive economic benefit.

Description

Technical Field

[0001] The invention belongs to the technical field of mixed iron ore beneficiation, and specifically relates to a high-mud mixed iron ore beneficiation process, which is used for the separation of mixed iron ore with high mud content and paragenesis of magnetic, hematite and limonite minerals, with an iron grade of 35% to 45% and a -0.030mm particle size content of ≥15.0%. Background Art

[0002] With the rapid development of the steel industry, magnetite and hematite resources with good geological conditions, coarse crystals and good selectivity are becoming increasingly scarce, while iron ore resources with fine particle size, coexistence of multiple iron minerals, high mud content and poor selectivity will become the focus of mineral processing technology research.

[0003] 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 amount to more than 20 billion tons. Due to the fine crystal 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 developed and utilized on an industrial scale. 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.

[0004] In order to solve the problem of beneficiation of mixed iron ore, Chinese patent application 201910014741.8 discloses a beneficiation process for treating mixed iron ore containing multiple iron minerals that are difficult to be selected. The raw ore with an iron grade of 21% to 23% and a particle size of 250mm-0mm is fed into a self-grinding mill to obtain a self-grinding product with a particle size of 30mm-0mm. The self-grinding product is fed into a double-layer linear vibrating screen to obtain three screening products with particle sizes of +10mm, 10mm-1mm and 1mm-0mm. The three screening products are subjected to targeted different grinding classification, dry magnetic separation, wet magnetic separation and reverse flotation operations to obtain a final concentrate grade of more than 64.5%. However, studies have shown that this beneficiation process is difficult to be used for the separation of mixed iron ores with high mud content and coexistence of magnetic hematite and limonite minerals.

[0005] In order to solve the technical problems of beneficiation of fine-grained mixed iron ore, "Gansu Metallurgy" published the "Experimental Study on the Beneficiation of Fine-grained Strong and Weak Magnetic Mixed Iron Ore in Subei, Gansu" in the 4th issue of 2024. The original ore treated in the experiment contained 30% magnetic iron minerals, 19% red (brown) iron, and 3% iron carbonate. The experiment subjected the concentrate products after pre-selection to three-stage grinding-magnetic separation, and obtained the beneficiation technical indicators of 64.32% TFe of the concentrate and 60.92% metal recovery. Obviously, the process did not fully consider the efficient recovery of red (brown) iron and iron carbonate in the ore, resulting in low iron recovery rate and high iron loss rate in tailings.

[0006] 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.

[0007] 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

[0008] In order to solve the problems existing in the prior art of poor beneficiation effect and low resource utilization rate for difficult-to-be-selected magnetic red-brown mixed iron ore with high mud, high iron content clay, easy to crush and easy to mud, the present invention provides a combined beneficiation process for weathering crust type high mud content magnetic, red and brown mixed iron ore with good sorting effect, stable and reliable process flow, strong applicability, relatively low beneficiation energy consumption and cost.

[0009] In order to achieve the above-mentioned object of the present invention, the combined beneficiation process of weathering crust type high-content mud magnetic, red and brown mixed iron ore of the present invention is implemented by the following process and steps:

[0010] S1 dry screening - crushing - ore washing - wet screening - high pressure roller grinding

[0011] The raw ore is screened by dry method to obtain dry screen products and dry screen under-screen 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 under-screen products are washed by 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 under-screen products. The wet screen products are returned to the wet screening operation after the high-pressure roller mill operation; the ore washing overflow and the wet screen under-screen products are combined into the selected products. Dry pre-screening is used before crushing to reduce the amount of ore fed into the crusher and reduce the energy consumption of the crushing operation; washing and wet screening operations are used before the high-pressure roller mill, which not only reduces the amount of ore fed into the high-pressure roller mill and reduces the energy consumption of the high-pressure roller mill operation, but more importantly, eliminates the adverse effects of mud and agglomeration on the high-pressure roller mill operation.

[0012] S2 weak magnetic field - strong magnetic field

[0013] 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 concentration, 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. In this step, a high-grade iron concentrate with an iron grade of >63.0% is obtained in advance through weak magnetic concentration, and qualified tailings are discarded in advance through strong magnetic scavenging, thereby reducing the amount of ore fed into subsequent chute re-selection, strong magnetic roughing, grinding and reverse flotation operations, and significantly reducing grinding energy consumption.

[0014] S3 Cyclone Classification-Chute Gravity Selection

[0015] 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, and the cyclone classification sand is fed into the chute gravity selection operation, and the chute gravity selection operation includes chute gravity selection roughing and chute gravity selection 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 chute gravity selection tailings. In this step, the cyclone classification sand (coarse particle size) of the cyclone classification operation is further obtained through chute gravity selection roughing and chute gravity selection concentrating, and a high-grade iron concentrate with an iron grade of> 62.5% is obtained, and the subsequent grinding operation is reduced, and the grinding energy consumption is reduced.

[0016] S4 Pre-classification - Grinding - High-intensity magnetic separation

[0017] The chute gravity separation 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. In this step, the cyclone classification overflow is subjected to strong magnetic roughing to discard qualified tailings again, and the iron grade fed to the subsequent reverse flotation operation is improved.

[0018] S5 Concentration - Reverse Flotation

[0019] 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, 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, the strong magnetic scavenging tailings discharged in step S2, and the strong magnetic roughing tailings discharged in step S4 are combined into the final total tailings, and the final total tailings are used as the raw material of the iron corrector for the iron-containing silicate cement plant; the reverse flotation operation adopts one roughing, one For the secondary concentration, the dosage of each operation reagent is calculated according to the amount of dry ore fed to the reverse flotation operation: 500g / t~1000g / t of sodium hydroxide as the slurry pH adjuster, 10g / t~30g / t of sodium hexametaphosphate as the dispersant, 200g / t~400g / t of starch as the inhibitor, and 500g / t~1000g / t of collector MX; for reverse flotation concentration: 200g / t~600g / t of collector MX; the collector MX is a mixture of etheramine, etherdiamine and quaternary ammonium salt, and the molar ratio thereof is 1:(1.2~2.0):(1.5~2.5). In this step, the collector MX uses a mixture of etheramine, etherdiamine, and quaternary ammonium salt, giving full play to the combination and synergistic effect of the three agents. For example, etheramine is easy to disperse in the slurry, the amount of agent used is low, and the flotation effect is good; etherdiamine has strong collecting performance, but when used alone, the dispersibility is poor and the agent consumption is large. When mixed with etheramine, the dispersibility in the slurry is significantly improved; quaternary ammonium salt has good selectivity under the appropriate dosage, but the collecting performance is not ideal when used alone. Studies have shown that the combination of the three agents in a suitable ratio can achieve the highest iron concentrate grade and iron recovery rate under the appropriate dosage.

[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 combined beneficiation process of weathered crust type high-content mud-magnetic, hematite and brown 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, realizing "segmented fine separation" of weak magnetic separation, spiral chute gravity separation, and reverse flotation, and "segmented tailings discarding" of strong magnetic separation and reverse flotation. The magnetite, hematite, and limonite in the ore are recovered by magnetic separation, gravity separation, and flotation in sequence, with good separation effect, stable and reliable process flow, and strong applicability.

[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 reverse flotation operation of the present invention adopts a mixture of etheramine, etherdiamine and quaternary ammonium salt MX as a combined collector. The combined collector gives full play to the combined and synergistic effect of the three reagents. Compared with the use of a single reagent, the iron recovery rate is increased by more than 2 percentage points when the iron concentrate grade is similar, and the iron concentrate grade is increased by 0.8 to 1.2 percentage points when the iron recovery rate remains unchanged, and the amount of collector used is reduced by more than 20%.

[0033] (6) Through the ore dressing process provided by the present invention, a comprehensive iron concentrate with TFe>62.3% and an iron recovery rate greater than 77.0% can be obtained, and the final total tailings discharged can be used as a raw material for iron correction agent in an iron-containing silicate cement plant, thus finally achieving full quantitative utilization and tail-free discharge of such resources. After popularization and application, a large amount of similar difficult-to-select mixed iron ores in my country can be fully utilized, which is of great significance to alleviating the shortage of iron ore resources in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a process flow chart of the combined beneficiation process principle of weathering crust type high-content mud magnetic, hematite and brown mixed iron ore.

[0035] Figure 2 The figure is a principle flow chart of the ore crushing-ore washing-roller grinding-screening process adopted in the present invention.

[0036] Figure 3 It is a principle flow chart of the magnetic-gravity-flotation combined beneficiation process for selected products adopted in the present invention.

[0037] 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.

[0038] 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

[0039] To further describe the present invention, the combined beneficiation process of weathering crust type high-content mud-magnetic, hematite and brown mixed iron ore of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0040] 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.

[0041] 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.

[0042] Table 1 Analysis results of main chemical components of ore

[0043] 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

[0044] Table 2 Ore iron phase analysis results

[0045]

[0046] Table 3 Main mineral composition results

[0047] 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

[0048] Table 4 Analysis results of particle size composition of raw ore wet screening

[0049]

[0050]

[0051] 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.

[0052] Depend on Figure 1 The process flow chart of the combined ore dressing process principle of the weathered crust type high-content magnetic, red and brown mixed iron ore of the present invention is shown in combination with 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:

[0053] S1 dry screening - crushing - ore washing - wet screening - high pressure roller grinding

[0054] 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.

[0055] S2 weak magnetic field - strong magnetic field

[0056] 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.

[0057] S3 Cyclone Classification-Chute Gravity Selection

[0058] 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%.

[0059] S4 Pre-classification - Grinding - High-intensity magnetic separation

[0060] 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.

[0061] S5 Concentration - Reverse Flotation

[0062] 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:

[0063] Reverse flotation roughing: 800g / t of sodium hydroxide as pulp pH adjuster, 20g / t of sodium hexametaphosphate as dispersant, 300g / t of starch inhibitor, and 700g / t of collector MX; reverse flotation selection: 300g / t of collector MX; the collector MX is a mixture of etheramine, etherdiamine and quaternary ammonium salt, and the molar ratio is 1.5:2:2.5.

[0064] 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%, re-selection iron concentrate with a yield of 23.33% and an iron grade of 62.15%, and flotation iron concentrate with a yield of 10.94% and an iron grade of 60.84%. The above three are combined to obtain a comprehensive iron concentrate with a total yield of 54.07%, an iron grade of 62.42% and an iron recovery rate of 77.42%.

[0065] Experimental studies have shown that the iron grade of the final total tailings discharged by the embodiment of the present invention is 21.44%, which is still relatively high, but the iron lost in the tailings cannot be recovered by the current beneficiation method to obtain a higher grade (such as TFe ≥ 56.0%) iron concentrate, and the beneficiation cost is very high. However, the main components of the final total tailings are quartz, clay, iron-containing clay and lost iron minerals, which are high-quality raw materials for iron-containing silicate cement and can be sold to iron-containing silicate cement plants for use as iron correctors.

[0066] Comparative example: dodecylamine was used instead of MX as a collector, and the reverse flotation process was the same as other reagents. The dosage of dodecylamine as a roughing collector of reverse flotation was 800g / t, and the dosage of dodecylamine as a fine collector of reverse flotation was 400g / t. Reverse flotation obtained a flotation iron concentrate with a yield of 9.28% and an iron grade of 60.74%. The combined yield of the flotation iron concentrate, the magnetic separation iron concentrate, and the gravity separation iron concentrate was 52.41%, the iron grade was 62.45%, and the iron recovery rate was 75.08%.

[0067] That is to say, the present invention adopts MX as the collector, and the iron recovery rate is increased by 2.34 percentage points under the condition that the comprehensive iron concentrate grade is basically the same.

[0068] 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 combined beneficiation process for weathering crust type high mud content magnetic, hematite and limonite mixed iron ore, used for processing iron ore with high mud content and paragenesis of magnetic, hematite and limonite minerals, with an iron grade of 35% to 45% and a particle size content of ﹣0.030 mm or more than 15.0%, 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, and the final total tailings are used as the raw material of the iron corrector of the iron-containing silicate cement plant; 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 amount of slurry pH adjuster sodium hydroxide is 500g / t~1000g / t, the amount of dispersant sodium hexametaphosphate is 10g / t~30g / t, the amount of inhibitor starch is 200g / t~400g / t, and the amount of collector MX is 500g / t~1000g / t; reverse flotation selection: the amount of collector MX is 200g / t~600g / t; the collector MX is a mixture of etheramine, etherdiamine and quaternary ammonium salt, and the molar ratio is 1:(1.2~2.0):(1.5~2.5).

2. The combined beneficiation process for weathering crust type high-content iron ore containing iron, red and brown mixed iron as claimed in 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. The combined beneficiation process for weathering crust type high-content iron ore containing iron, red and brown mixed iron 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. The combined ore dressing process of weathering crust type high-content muddy iron, red and brown mixed iron ore as claimed in 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. The combined beneficiation process for weathering crust type high-content iron ore containing iron, red and brown mixed iron 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. The combined beneficiation process for weathering crust type high-content iron ore containing iron, red and brown mixed iron as claimed in 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. The combined beneficiation process for weathering crust type high-content argillaceous, hematite and brown 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. The combined beneficiation process for weathering crust type high-content iron ore containing iron, red and brown mixed iron 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. The combined beneficiation process for weathering crust type high-content argillaceous, hematite and brown mixed iron ore as claimed in claim 1, characterized in that: In step S5, the underflow concentration of the concentration operation is controlled to be 25% to 35%.

10. The combined beneficiation process of weathering crust type high-content mud iron, red iron and brown iron mixed 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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