Novel beneficiation combination process for preparing super iron ore concentrate from magnetite concentrate

Abstract

The invention discloses a novel beneficiation combination process for preparing super iron ore concentrate by utilizing magnetite concentrate, which comprises the following steps of: pre-checking and grading, controlling and grading, tower grinding, weak magnetic roughing, weak magnetic concentration, elutriation, reverse flotation roughing, reverse flotation scavenging I, reverse flotation scavenging II, concentration magnetic separation I, concentration magnetic separation II and filtering and dewatering. The TFe grade of the super iron ore concentrate is larger than or equal to 72.1%, the SiO2 content of the super iron ore concentrate is smaller than or equal to 0.1%, and the super iron ore concentrate is subjected to concentration magnetic separation, filter pressing, drying and packaging to form a final product. Tailings of the coarse and fine magnetic separation operation, tailings of the elutriation operation and tailings of the reverse flotation are combined together to serve as common iron ore concentrate to be sold. Closed-circuit ore grinding is formed through pre-inspection and control combined classification and tower grinding, so that magnetite and gangue minerals are fully dissociated, and then the super iron ore concentrate is obtained through one-rough-one-fine magnetic separation operation, elutriation operation and one-rough-two-scavenging reverse flotation operation. The method has the advantages of uniform granularity of ground products, simple process flow, stable product quality, low comprehensive energy consumption and the like.

Description

Technical Field

[0001] The present invention relates to a re-selection process of magnetite concentrate, and in particular to a ore dressing and separation process for producing super iron concentrate using magnetite concentrate, which is particularly suitable for TFe grade 66%.

[0002] -68.5%, gangue minerals are SiO 2 Preparation of magnetite concentrate with TFe grade ≥ 72.0%, SiO 2 Super iron concentrate with grade ≤0.1%. Background Art

[0003] Super iron concentrate generally refers to high-grade iron concentrate with an iron content higher than 71.5%, an acid-insoluble content of less than 1%, and a silicon dioxide content of less than 0.4%. Super iron concentrate is the basic material for the production of powder metallurgy, magnetic materials, direct reduced iron and other products. It is widely used in the production of iron powder for powder metallurgy, the production of ferrite magnetic materials, direct reduced iron, sponge iron pellets directly rolled steel, synthetic ammonia catalysts and other fields. With the smooth progress of the national dual carbon plan, there will be huge market potential and application prospects in new materials, new energy and other fields in the future.

[0004] At present, domestic production of magnetic materials mostly uses red iron oxide as raw material. Due to changes in the steel industry, the strong implementation of national environmental protection policies, and the growth in demand for magnetic materials driven by new infrastructure, red iron oxide resources are in short supply and prices have soared. As the raw material with the largest demand in the ferrite industry, red iron oxide is likely to be in a state of tight supply to varying degrees for a long time. Therefore, China urgently needs to develop new raw materials as a substitute or supplement for red iron. Magnetite is processed into super iron concentrate, which can replace red iron oxide as a basic raw material for magnetic materials. At present, the preparation processes of super iron concentrate generally include single magnetic separation process, magnetic separation-flotation process, gravity separation process, fine screening-magnetic separation column process, and magnetic separation-flotation-leaching process. But in general, although the existing super iron concentrate preparation process can obtain iron concentrate with an iron grade of about 71.5%, the silicon dioxide content is still as high as 0.3%-0.5%. The silica content in the super iron ore concentrate obtained by the magnetic separation-flotation-leaching process can be reduced to about 0.2%, but chemical leaching is costly and will also have a certain impact on the environment, so large-scale production is difficult.

[0005] In order to obtain super iron concentrate with high iron grade and low content of impurities such as silicon dioxide, the article "Experimental Study on Deep Purification of Super Iron Concentrate" published in "Metal Mines" No. 4, 2024, respectively adopted sulfuric acid-sodium fluoride joint treatment and sulfuric acid-sodium hydroxide joint treatment to obtain ultra-pure iron concentrate with an iron grade of 72.14% and an iron recovery rate of 99.67%, and the silicon dioxide content was 0.24% and 0.22%, respectively. However, these two processes also have the problems of high leaching cost and great impact on environmental pollution, making them difficult to be applied on a large scale in industry.

[0006] Some magnetite mines in Huoqiu area of ​​Anhui Province have good resource endowment. The raw ore has simple mineral composition, low content of harmful elements such as sulfur, phosphorus and silicon, and good ore selectivity. Ordinary magnetite concentrate with TFe 66-68% can be obtained by grinding and single magnetic separation. If it is prepared into super iron concentrate by ordinary physical beneficiation methods, it will provide new development for the production process of super iron concentrate.

[0007] Therefore, it is necessary to study an economical, reliable, environmentally friendly, and high-quality mineral processing combined process for preparing ordinary magnetite concentrate into super iron concentrate. Summary of the invention

[0008] The purpose of the present invention is to provide a new beneficiation process for preparing super iron concentrate from magnetite concentrate, aiming at the technical problems that the silicon dioxide content of ultra-pure iron concentrate obtained by the current physical beneficiation method is still as high as 0.3%-0.5%, and the chemical leaching method has high cost and great impact on environmental pollution, etc., and to obtain a TFe grade ≥72%, SiO 2 Super iron concentrate with grade ≤0.1% and moisture ≤0.5%.

[0009] To achieve the above-mentioned object of the present invention, a new combined beneficiation process for preparing super iron concentrate from magnetite concentrate is implemented by the following steps:

[0010] S1 Pre-inspection classification - controlled classification - tower mill: feed the magnetite concentrate slurry with a particle size of -0.075mm accounting for 60%-75% and a TFe grade of 66%-68.5% into the pre-inspection classification - controlled classification operation, and the discharged controlled classification operation overflows; the pre-inspection classification and controlled classification both use hydrocyclones, and the sand settling of the pre-inspection classification and controlled classification is fed to the tower mill for fine grinding, and the slurry discharged from the fine grinding returns to the pre-inspection classification operation; through the pre-inspection classification - controlled classification, the fine-grained material that has been monomerically dissociated is directly fed into the next process, which reduces the amount of material fed into the tower mill and avoids the occurrence of over-grinding and mudification. The present invention uses a tower mill for fine grinding. Compared with a horizontal ball mill, the tower mill saves more than half of energy and has higher efficiency. The product particle size can be adjusted, and intermittent, cyclic, and continuous production can be achieved. The tower mill also has the characteristics of low noise, low vibration, and small footprint.

[0011] S2 weak magnetic roughing - weak magnetic concentrating - washing: The overflow of the controlled classification operation discharged from step S1 is fed into the weak magnetic roughing - weak magnetic concentrating - washing operation, and weak magnetic roughing tailings, weak magnetic concentrating tailings and washing tailings are discharged respectively to obtain the washed concentrate;

[0012] S3 reverse flotation roughing - reverse flotation scavenging I - reverse flotation scavenging II: the washed concentrate obtained in step S2 is fed into reverse flotation roughing - reverse flotation scavenging I - reverse flotation scavenging II, the bottom flow of reverse flotation scavenging II is reverse flotation concentrate, and the foam of reverse flotation roughing, reverse flotation scavenging I and reverse flotation scavenging II is reverse flotation tailings;

[0013] S4 Concentrated Magnetic Separation I: The weak magnetic rougher tailings, weak magnetic concentrate tailings, panning tailings discharged from step S2 and the reverse flotation tailings discharged from step S3 are combined and fed into concentrated magnetic separation I, and concentrated magnetic separation I tailings are discharged to obtain concentrated magnetic separation I concentrate, which is returned to the concentrator as middlings for filtration and then sold as ordinary magnetite concentrate;

[0014] S5 Concentration Magnetic Separation II - Filtration and Dehydration: The reverse flotation concentrate obtained in step S3 is fed into the concentration magnetic separation II, and the concentrated magnetic separation II tailings are discharged; the concentrated magnetic separation II concentrate is fed into the filtration and dehydration operation, and finally the TFe grade ≥72.1%, SiO 2 Super iron concentrate with content ≤0.1%.

[0015] Concentrated magnetic separation I and concentrated magnetic separation II have dual effects, which not only improve the concentrate grade and discard the gangue tailings, but also greatly increase the concentrate concentration, creating conditions for subsequent filtration operations.

[0016] Preferably, in step S1, the overflow particle size of the pre-checked grading hydrocyclone is preferably in the range of 80% to 85% by mass of the -0.075 mm particle size, and the overflow particle size of the grading hydrocyclone is preferably controlled to be ≥90% by mass of -0.075 mm, so as to facilitate subsequent sorting and impurity removal.

[0017] Preferably, the mass concentration of the magnetite concentrate slurry fed into the pre-inspection classification operation in step S1 is 35%-45%. At this mass concentration, the classification efficiency of the hydrocyclone is relatively high.

[0018] Preferably, in step S2, the weak magnetic roughing-weak magnetic concentrating operation adopts a semi-countercurrent double-drum permanent magnetic separator, the roughing magnetic field strength is 0.16-0.20T, and the concentrating field strength is 0.10-0.14T; the washing operation adopts a fully automatic washing magnetic separator. The semi-countercurrent double-drum permanent magnetic separator is a sorting equipment with the integrated functions of roughing and concentrating, which is suitable for the roughing and concentrating operations of fine-grained (less than 0.2 mm) strong magnetic ores, with good sorting effect, and can obtain higher concentrate quality and metal recovery rate. A fully automatic washing magnetic separator is a device that uses water to wash out iron ore and tailings and separate them, thereby achieving the purpose of improving the grade. The present invention adopts a semi-countercurrent double-drum permanent magnetic separator for roughing and concentrating, respectively, and then further purifies through a fully automatic washing magnetic separator, which can effectively throw out the mixed gangue minerals and significantly improve the concentrate grade.

[0019] Preferably, in step S2, the washing operation is controlled at 0.6-1.2 m3 of rising water according to the amount of slurry fed and the specifications of the selected automatic washing magnetic separator. 3 / h, by controlling the amount of rising water, the rising water flow rate can be controlled, thereby controlling the tailings discharge amount and concentrate grade.

[0020] Preferably, in step S3, dodecylamine is used as a collector in the reverse flotation operation, the amount of the reverse flotation roughing collector is 50-70 g / t, the amount of the reverse flotation scavenging collector I is 20-28 g / t, and the amount of the reverse flotation scavenging collector II is 7-13 g / t. The amounts of all the above reagents added are converted into the amount of dry ore for flotation feed; the mass concentration of the reverse flotation roughing operation is 25%-40%.

[0021] Preferably, in step S4, the concentrated magnetic separation operation uses a permanent magnetic drum magnetic separator with a magnetic field strength of 0.25-0.30T.

[0022] Preferably, in step S5, the concentrated magnetic separation II uses a permanent magnetic drum magnetic separator with a magnetic field strength of 0.20-0.25 T; the filtration and dehydration operation uses a high-pressure membrane filter press with an operation cycle time of 50-70 min. The high-pressure membrane filter press is an intermittent pressurized filtration device with good filtration effect and low moisture content of the filter cake.

[0023] Preferably, it also includes a drying process. The super iron concentrate obtained after filtering and dehydration in step S5 is fed into the drying process. The drying process uses a JAHG series drum dryer to reduce the moisture content of the super iron concentrate to below 0.5%, so as to facilitate transportation and use by downstream application manufacturers.

[0024] Compared with the existing technology, the present invention is a new combined beneficiation process for preparing super iron concentrate from magnetite concentrate. Through pre-inspection + control combined classification and tower mill to form closed-circuit grinding, magnetite and gangue minerals are fully dissociated, and then through one coarse and one fine magnetic separation operation, washing operation, one coarse and two sweep reverse flotation operation to obtain super iron concentrate, which has the advantages of uniform grinding product particle size, simple process flow, stable product quality, and low comprehensive energy consumption. It has the following innovative and beneficial effects:

[0025] (1) The invented new combined ore dressing process is aimed at the regrinding of ordinary magnetite concentrate. It adopts a combined grading process of pre-inspection grading and control grading. The classified sediment is returned to the tower mill for regrinding. This process not only achieves efficient grinding operation, but also takes into account accurate grading operation, and the grinding efficiency is significantly improved.

[0026] (2) The invented new combined beneficiation process aims at the characteristics of this type of magnetite concentrate with fine particle size and high grade. It adopts weak magnetic separation, washing and reverse flotation to form a combined process flow for gradually improving the grade of iron ore concentrate. It uses three different physical beneficiation methods to prepare TFe grade ≥72%, SiO 2 Super iron concentrate with grade ≤0.1%.

[0027] (3) The invented new combined beneficiation process is aimed at the dehydration process of the super iron ore concentrate produced by reverse flotation. It adopts the process flow of concentrated magnetic separation, filter pressing and drying to reduce the moisture content in a step-by-step manner, making full use of the characteristics of different dehydration processes to achieve efficient dehydration of the product;

[0028] (4) The present invention combines conventional physical mineral processing technology with ordinary magnetite concentrate to prepare super iron concentrate, and high-quality super iron concentrate can be obtained without chemical leaching, which greatly reduces the mineral processing cost and the impact on the environment. The selected middlings are returned to the concentrator for filtration and sold as ordinary magnetite concentrate, thus achieving efficient utilization of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a new process flow chart of a ore dressing combination for preparing super iron concentrate using magnetite concentrate. DETAILED DESCRIPTION

[0030] To further describe the present invention, a new combined beneficiation process for preparing super iron concentrate from magnetite concentrate is further described in detail below in conjunction with the accompanying drawings and embodiments. 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.

[0031] In this embodiment, the ordinary magnetite concentrate is produced by a mining company in Huoqiu, Anhui. The particle size screening results of the ordinary magnetite concentrate are shown in Table 1, the chemical multi-element analysis results of the ordinary magnetite concentrate are shown in Table 2, and the iron phase analysis results of the ordinary magnetite concentrate are shown in Table 3.

[0032] Table 1 Ordinary magnetite concentrate particle size screening results

[0033]

[0034] Table 1 The results of particle size screening show that the coarse particles of the original ore + 0.1 mm account for 17.66%, the coarse particle size has low dissociation degree, low iron grade, low SiO 2 High content; -0.030mm fine-grained grade has the highest iron grade, but only 71.06% and SiO 2 The content is still as high as 1.32%, which means that in order to obtain high-quality ultra-pure iron concentrate, fine grinding and deep selection are necessary.

[0035] Table 2 Chemical multi-element analysis results of common magnetite concentrate (%)

[0036] Element Name TFe <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> CaO MgO MnO S P content 68.60 4.45 0.189 0.282 0.305 0.052 0.024 0.001 Element Name CuO <![CDATA[K 2 The]]> <![CDATA[Na 2 The]]> <![CDATA[Cr 2 THE 3 ]]> <![CDATA[V 2 THE 5 ]]> ZnO NiO <![CDATA[TiO 2 ]]> content <0.005 0.011 0.119 <0.005 0.006 0.006 <0.005 0.034

[0037] The results of multi-element analysis in Table 2 show that the total iron grade of the ore is 68.60%, the alkali ratio is 0.127, and it is an acidic iron concentrate. The main impurities are SiO 2 , the content is 4.45%, and the content of other impurities is low.

[0038] Table 3 Iron phase analysis results of common magnetite concentrate (%)

[0039] Phase Name magnetite Hematite Pyrite Pyrrhotite Iron silicate Siderite Total Iron Iron Grade 67.68 0.59 0.038 0.036 0.19 0.16 68.69 Iron distribution rate 98.52 0.86 0.06 0.05 0.28 0.23 100.00

[0040] The results of iron phase analysis in Table 3 show that the main iron mineral in the ore is magnetite, with a content of up to 98.52%, and about 0.86% of hematite, while the content of other iron minerals is very small.

[0041] In the embodiment, the new combined beneficiation process for preparing super iron concentrate from ordinary magnetite concentrate specifically includes the following processes and steps:

[0042] (1) Ordinary magnetite concentrate uses a tower mill and two-stage hydrocyclones for pre-inspection classification and control classification to form a closed-loop operation. The overflow of the control classification hydrocyclone enters the next stage of weak magnetic roughing operation. The sand settling of the pre-inspection classification and control classification hydrocyclones is returned to the tower mill. The fineness of the pre-selection inspection classification overflow is controlled at -0.038mm 80%, and the particle size of the control classification overflow is controlled at -0.038mm 90%;

[0043] (2) The finely ground ore pulp enters a double-drum permanent magnetic separator for magnetic separation, one for roughing and one for fine separation. The field strength of the weak magnetic roughing separation is controlled at 0.16T, and the field strength of the weak magnetic fine separation is controlled at 0.12T;

[0044] (3) The concentrate from the weak magnetic concentration operation enters the washing machine for washing. The rising water consumption for the washing operation is 0.8m 3 / h;

[0045] (4) The underflow concentrate after washing enters the stirring tank and is fully mixed with the reverse flotation reagent before entering the flotation operation. The roughing reverse flotation mass concentration is 30%, the roughing reverse flotation time is 4 minutes, and the two sweeping reverse flotation times are both 3 minutes;

[0046] (5) The flotation concentrate enters into concentrated magnetic separation, filter pressing, drying and packaging to become super iron concentrate. The field strength of concentrated magnetic separation is 0.2T, the filter pressing cycle time is 60min, and the moisture content after drying is ≤0.5%;

[0047] (6) The tailings from the coarse and fine magnetic separation operation, the tailings from the washing operation, and the tailings from the reverse flotation operation are combined and concentrated in the magnetic separation operation using a permanent magnetic drum magnetic separator as the separation equipment with a magnetic field strength of 0.25T.

[0048] According to the above process and steps, the ordinary magnetite concentrate can be processed into super iron concentrate and by-product middlings by performing a combined beneficiation process. The super iron concentrate has a TFe grade of ≥72.1%, a SiO2 grade of ≤0.1%, a yield of 33.06%, and a moisture content of ≤0.5%.

[0049] The production line scale is calculated based on processing 151,200 t / a of raw ore, and can produce 50,000 t of super iron ore concentrate each year. The middling ore is returned to the beneficiation plant. The new process adopts physical beneficiation technology, which has the characteristics of simple process, convenient operation and stable products. It increases the company's annual after-tax profit by 8.47 million yuan each year.

Claims

1. A new combined beneficiation process for preparing super iron concentrate from magnetite concentrate, characterized in that This is done using the following steps: S1 Pre-inspection classification - controlled classification - tower mill: feed the magnetite concentrate slurry with a particle size of -0.075mm, a mass proportion of 60%-75%, and a TFe grade of 66%-68.5% into the pre-inspection classification - controlled classification operation, and discharge the overflow of the controlled classification operation; both the pre-inspection classification and the controlled classification use hydrocyclones, and the sand from the pre-inspection classification and the controlled classification is fed to the tower mill for fine grinding, and the slurry discharged from the fine grinding returns to the pre-inspection classification operation; S2 weak magnetic roughing - weak magnetic concentrating - washing: The overflow of the controlled classification operation discharged from step S1 is fed into the weak magnetic roughing - weak magnetic concentrating - washing operation, and weak magnetic roughing tailings, weak magnetic concentrating tailings and washing tailings are discharged respectively to obtain the washed concentrate; S3 reverse flotation roughing - reverse flotation scavenging I - reverse flotation scavenging II: the washed concentrate obtained in step S2 is fed into reverse flotation roughing - reverse flotation scavenging I - reverse flotation scavenging II, the bottom flow of reverse flotation scavenging II is reverse flotation concentrate, and the foam of reverse flotation roughing, reverse flotation scavenging I and reverse flotation scavenging II is reverse flotation tailings; S4 Concentrated Magnetic Separation I: The weak magnetic rougher tailings, weak magnetic concentrate tailings, panning tailings discharged from step S2 and the reverse flotation tailings discharged from step S3 are combined and fed into concentrated magnetic separation I, and concentrated magnetic separation I tailings are discharged to obtain concentrated magnetic separation I concentrate, which is returned to the concentrator as middlings for filtration and then sold as ordinary magnetite concentrate; S5 Concentrated Magnetic Separation II - Filtration and Dehydration: The reverse flotation concentrate obtained in step S3 is fed into concentrated magnetic separation II, and concentrated magnetic separation II tailings are discharged; the concentrated magnetic separation II concentrate is fed into filtration and dehydration operation, and finally a super iron concentrate with TFe grade ≥72.1% and SiO2 content ≤0.1% is obtained.

2. The new combined beneficiation process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: In step S1, the overflow particle size of the grading hydrocyclone is pre-checked to be in the range of 80% to 85% by mass of the -0.075 mm particle size, and the overflow particle size of the grading hydrocyclone is controlled to be in the range of ≥90% by mass of the -0.075 mm particle size.

3. The new combined beneficiation process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: The mass concentration of the magnetite concentrate slurry fed into the pre-inspection classification operation in step S1 is 35%-45%.

4. The new combined ore dressing process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: In step S2, the weak magnetic roughing and weak magnetic concentrating operations adopt a semi-countercurrent double-drum permanent magnetic separator, the roughing magnetic field strength is 0.16-0.20T, and the concentrating field strength is 0.10-0.14T; the washing operation adopts a fully automatic washing magnetic separator.

5. The new combined beneficiation process for preparing super iron concentrate from magnetite concentrate as claimed in claim 4, characterized in that: In step S2, the washing operation is controlled at 0.6-1.2 m3 of rising water according to the amount of slurry fed and the specifications of the selected automatic washing magnetic separator. 3 / h.

6. The new combined ore dressing process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: In step S3, dodecylamine is used as a collector in the reverse flotation operation, the amount of the collector used in the reverse flotation roughing is 50-70 g / t, the amount of the collector used in the reverse flotation scavenging I is 20-28 g / t, and the amount of the collector used in the reverse flotation scavenging II is 7-13 g / t. The addition amounts of all the above reagents are converted into the amount of dry ore for flotation feed; the mass concentration of the reverse flotation roughing operation is 25%-40%.

7. The new combined ore dressing process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: In step S4, the concentrated magnetic separation operation uses a permanent magnetic drum magnetic separator with a magnetic field strength of 0.25-0.30T.

8. The new combined ore dressing process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: In step S5, the concentrated magnetic separation II uses a permanent magnetic drum magnetic separator with a magnetic field strength of 0.20-0.25 T; the filtration and dehydration operation uses a high-pressure diaphragm filter press with an operation cycle time of 50-70 min.

9. The new combined beneficiation process for preparing super iron concentrate from magnetite concentrate as claimed in claim 1, characterized in that: The method also includes a drying process. The super iron concentrate obtained after filtering and dehydration in step S5 is fed into the drying process to reduce the moisture content of the super iron concentrate to below 0.5%.

10. The new combined beneficiation process for preparing super iron concentrate from magnetite concentrate as claimed in claim 9, characterized in that: The drying process uses JAHG series drum dryer.

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