Novel process for improving beneficiation index of mixed magnetite-hematite-siderite

Abstract

The invention relates to a novel process for improving the beneficiation index of mixed magnetite-hematite-siderite, which comprises the following steps: (1) grinding a belt sample of the mixed magnetite-hematite-siderite by a first-section ball mill to obtain first ball-milling discharged ore, and performing first-section magnetic separation on the first ball-milling discharged ore to obtain first concentrate and first tailings; (2) the first tailings are subjected to first-stage screening, first oversize materials and first screened materials are obtained, the first oversize materials are first coarse grain tailings, the first undersize materials are first magnetic separation tailings, and the first oversize materials and the first screened materials enter a total tailings system; (3) feeding the concentrate I to first-stage classification to obtain overflow I and return sand I, returning the return sand I to a second-stage ball mill for ore grinding, performing ore grinding by the second-stage ball mill to obtain ball-milling discharged ore II, and returning the ball-milling discharged ore II to the first-stage classification; (4) the first overflow is subjected to second-section magnetic separation to obtain second concentrate and second tailings, the second concentrate is first iron ore concentrate and enters a total concentrate system, and the second tailings are subjected to third-section magnetic separation to obtain third concentrate and third tailings; according to the scheme, the problem of invalid ore grinding in the ore grinding process is solved, gangue minerals dissociated from iron minerals are thrown away in advance, and the treatment capacity of the mill is improved.

Description

Technical Field

[0001] The invention relates to a ore dressing process, in particular to a new process for improving the ore dressing index of a magnetite-hematite-siderite mixed iron ore, and belongs to the technical field of ore dressing of various iron ores such as magnetite, hematite and siderite. Background Art

[0002] The beneficiation process for the recovery of mixed iron ore resources of magnetite, hematite and siderite generally adopts stage grinding-weak magnetic-strong magnetic or adding reverse flotation process. However, the obtained iron concentrate is often of low grade or low metal recovery rate, and the sorting tailings are all fine-grained tailings. Only part of the tailings can be filled underground, and most of the tailings still need to be discharged into the tailings pond, which makes it difficult to achieve mining and filling balance. At present, the state has strict control over the approval policy of tailings ponds, and the possibility of approving the construction of tailings ponds is very small, which directly affects the normal production and operation of enterprises. At the same time, all the vein minerals in the ore enter the grinding and sorting system, resulting in ineffective grinding, increasing operating costs, and affecting the system processing capacity. Therefore, it is of great significance to seek a mixed iron ore beneficiation process that can improve beneficiation indicators and save energy and reduce consumption. Summary of the invention

[0003] The present invention is aimed at the technical problems existing in the prior art, and provides a new process for improving the beneficiation index of magnetic-hematite-siderite mixed iron ore. This solution solves the problem of ineffective grinding in the grinding process, removes the gangue minerals dissociated from the iron ore in advance, improves the processing capacity of the mill, and makes the tailings coarser, thereby reducing the fine tailings and recycling them. When sorting the ground products, the magnetic inclusions are reduced, and qualified iron concentrate products are obtained in advance during the sorting process; the undissociated iron minerals in the ground products are selectively re-grinded and re-selected, which saves energy and reduces consumption, and obtains qualified iron concentrate products.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows: a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore, the process comprising the following steps:

[0005] (1) The magnetic-hematite-siderite mixed iron ore belt sample is subjected to a first-stage ball mill grinding to obtain a ball mill discharge ore 1, and the ball mill discharge ore 1 is subjected to a first-stage magnetic separation to obtain a concentrate ore 1 and a tailing ore 1;

[0006] (2) Screening the tailings 1 to obtain an oversize material 1 and a screened material 1, wherein the oversize material 1 is coarse-grained tailings 1 and the undersize material 1 is magnetically separated tailings 1, and enters the total tailings system;

[0007] (3) Concentrate 1 is sent to the first stage classification to obtain overflow 1 and return sand 1, and the return sand 1 is returned to the second stage ball mill for grinding, and the second stage ball mill is used to grind the ore to obtain ball mill discharge 2, and the ball mill discharge 2 is returned to the first stage classification;

[0008] (4) the overflow 1 is subjected to a second-stage magnetic separation to obtain a concentrate 2 and a tailing 2, the concentrate 2 is the iron concentrate 1 entering the total concentrate system, and the tailing 2 is subjected to a third-stage magnetic separation to obtain a concentrate 3 and a tailing 3;

[0009] (5) performing two-stage screening on the tailings 3 to obtain an oversize material 2 and an undersize material 2, wherein the oversize material 2 is a coarse-grained tailings 2;

[0010] (6) subjecting the undersize material 2 to four-stage magnetic separation to obtain concentrate 4 and tailings 4, wherein concentrate 4 is iron concentrate 2 and enters the total concentrate system; subjecting the tailings 4 to five-stage magnetic separation to obtain concentrate 5 and tailings 5, wherein tailings 5 ​​is magnetically separated tailings 2 and enters the total tailings system;

[0011] (7) The concentrate 3 and the concentrate 5 are combined and sent to the second stage classification to obtain overflow 2 and return sand 2, the return sand 2 is returned to the third stage ball mill for grinding, the third stage ball mill is used to grind the ball mill discharge 3, and the ball mill discharge 3 is returned to the second stage classification;

[0012] (8) The overflow 2 is subjected to six-stage magnetic separation to obtain concentrate 6 and tailings 6, and the concentrate 6 is the iron concentrate 3, which enters the total concentrate system;

[0013] (9) Tailings 6 is subjected to seven-stage magnetic separation to obtain concentrate 7 and tailings 7. Concentrate 7 is iron concentrate 4 and enters the total concentrate system. Tailings 7 is magnetically separated tailings 3 and enters the total tailings system.

[0014] Wherein, the belt sample feed particle size is 0mm to 20mm.

[0015] Among them, the sieve hole size of the first stage screening is 0.25mm~3mm; the sieve hole size of the second stage screening is 0.1mm~0.5mm.

[0016] Among them, the magnetic field strength of the first stage magnetic separation is 5000Oe~15000Oe; the magnetic field strength of the second, third and sixth stages magnetic separation is 800Oe~5000Oe; the magnetic field strength of the fourth, fifth and seventh stages magnetic separation is 5000Oe~17000Oe.

[0017] Wherein, the content of ball mill discharge-grinding fineness-200 mesh is 10% to 40%.

[0018] Wherein, the first stage classification overflow first grinding fineness -200 mesh content is 45% to 80%; the second stage classification overflow second grinding fineness -200 mesh content is 45% to 80%.

[0019] Wherein, the concentration of the second, third and sixth stage magnetic separation is 10% to 40%.

[0020] The technical solution is to add tailings discarding operation in the continuous grinding process, adopt cascade magnetic separation technology, selectively re-grind and re-select weak magnetic scavenging concentrate and strong magnetic scavenging concentrate, and add screening operation before strong magnetic separation to isolate coarse gangue minerals. The technical features of the present invention are:

[0021] ① Solve the problem of gangue minerals that are prematurely dissociated from iron minerals during the grinding process, achieve early tailings disposal, reduce the subsequent mill input, and effectively improve the mill processing capacity. This part of the gangue minerals has a coarse particle size and can be used for construction sand.

[0022] ② For the grinding products, the cascade weak magnetic separation and strong magnetic separation processes are adopted to reduce magnetic inclusions, separate the monomer and conjoined iron minerals during the separation process, and obtain qualified iron concentrate products in advance.

[0023] ③ Selectively regrind and reselect the scavenged weak magnetic concentrate and the scavenged strong magnetic concentrate to obtain qualified iron ore concentrate products.

[0024] ④ Before the weak magnetic tailings enter the subsequent strong magnetic separation operation, increase the screening and separation to obtain coarse-grained gangue, which can be used for construction sand. At the same time, it can improve the subsequent separation feed grade, which is conducive to obtaining qualified concentrate products.

[0025] Compared with the prior art, the invention has the following beneficial effects: for the intermediate products of the two-stage grinding, the dissociated gangue minerals are discarded in advance, the processing capacity of the mill is improved, and this part of the gangue can be used for building sand; the use of the cascade magnetic separation technology can reduce the magnetic inclusion problem in the separation process, obtain qualified iron ore concentrate products in advance, and at the same time select the incompletely dissociated middling products (weak magnetic scavenging concentrate and strong magnetic scavenging concentrate); the middling products are selectively regrinded and reselected to obtain qualified iron ore concentrate products, avoid ineffective grinding, save energy and reduce consumption; the strong Screening and coarsening the magnetic ore can increase the grade of the strong magnetic separation, and the screened product can be used as construction sand; ultimately, the mixed iron ore selection indicators can be improved, including increasing the processing capacity by 9 percentage points (increasing the processing ore by 450,000 tons / year), increasing the TFe recovery rate by 1.5 percentage points while keeping the iron concentrate grade unchanged, and increasing the coarse-grained tailings content by 4 percentage points (increasing the construction sand content by 200,000 tons / year), so that the fine-grained tailings can be reduced and recycled, ultimately achieving a balance between mining and filling, reducing costs and increasing efficiency, and ensuring smooth production of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of a new process for improving the mineral processing index of magnetic-hematite-siderite mixed ore according to the present invention.

[0027] Figure 2 It is a schematic diagram of an implementation case of a new process for improving the mineral processing index of a magnetic-hematite-siderite mixed ore according to the present invention. DETAILED DESCRIPTION

[0028] In order to deepen the understanding of the present invention, the present embodiment is described in detail below with reference to the accompanying drawings.

[0029] Example 1: See Figure 1 , Figure 2 , a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore, the process comprising the following steps:

[0030] (1) The magnetic-hematite-siderite mixed iron ore belt sample is subjected to a first-stage ball mill grinding to obtain a ball mill discharge ore 1, and the ball mill discharge ore 1 is subjected to a first-stage magnetic separation to obtain a concentrate ore 1 and a tailing ore 1;

[0031] (2) Screening the tailings 1 to obtain an oversize material 1 and a screened material 1, wherein the oversize material 1 is coarse-grained tailings 1 and the undersize material 1 is magnetically separated tailings 1, and enters the total tailings system;

[0032] (3) Concentrate 1 is sent to the first stage classification to obtain overflow 1 and return sand 1, and the return sand 1 is returned to the second stage ball mill for grinding, and the second stage ball mill is used to grind the ore to obtain ball mill discharge 2, and the ball mill discharge 2 is returned to the first stage classification;

[0033] (4) the overflow 1 is subjected to a second-stage magnetic separation to obtain a concentrate 2 and a tailing 2, the concentrate 2 is the iron concentrate 1 entering the total concentrate system, and the tailing 2 is subjected to a third-stage magnetic separation to obtain a concentrate 3 and a tailing 3;

[0034] (5) performing two-stage screening on the tailings 3 to obtain an oversize material 2 and an undersize material 2, wherein the oversize material 2 is a coarse-grained tailings 2;

[0035] (6) subjecting the undersize material 2 to four-stage magnetic separation to obtain concentrate 4 and tailings 4, wherein concentrate 4 is iron concentrate 2 and enters the total concentrate system; subjecting the tailings 4 to five-stage magnetic separation to obtain concentrate 5 and tailings 5, wherein tailings 5 ​​is magnetically separated tailings 2 and enters the total tailings system;

[0036] (7) The concentrate 3 and the concentrate 5 are combined and sent to the second stage classification to obtain overflow 2 and return sand 2, the return sand 2 is returned to the third stage ball mill for grinding, the third stage ball mill is used to grind the ball mill discharge 3, and the ball mill discharge 3 is returned to the second stage classification;

[0037] (8) The overflow 2 is subjected to six-stage magnetic separation to obtain concentrate 6 and tailings 6, and the concentrate 6 is the iron concentrate 3, which enters the total concentrate system;

[0038] (9) Tailings 6 is subjected to seven-stage magnetic separation to obtain concentrate 7 and tailings 7. Concentrate 7 is iron concentrate 4 and enters the total concentrate system. Tailings 7 is magnetically separated tailings 3 and enters the total tailings system.

[0039] Wherein, the belt sample feed particle size is 0mm to 20mm.

[0040] Among them, the sieve hole size of the first stage screening is 0.25mm~3mm; the sieve hole size of the second stage screening is 0.1mm~0.5mm.

[0041] Among them, the magnetic field strength of the first stage magnetic separation is 5000Oe~15000Oe; the magnetic field strength of the second, third and sixth stages magnetic separation is 800Oe~5000Oe; the magnetic field strength of the fourth, fifth and seventh stages magnetic separation is 5000Oe~17000Oe.

[0042] Wherein, the content of ball mill discharge-grinding fineness-200 mesh is 10% to 40%.

[0043] Wherein, the first stage classification overflow first grinding fineness -200 mesh content is 45% to 80%; the second stage classification overflow second grinding fineness -200 mesh content is 45% to 80%.

[0044] Wherein, the concentration of the second, third and sixth stage magnetic separation is 10% to 40%.

[0045] Example 2: A magnetic-hematite-siderite mixed iron ore beneficiation plant in Nanjing, Jiangsu Province adopts Figure 1 and Figure 2 The ore dressing process shown above has an annual processing scale of 5 million tons of ore. The specific process is:

[0046] 1. The mixed iron ore belt sample is ground in a ball mill 1 to obtain a ball mill discharge 1, and the ball mill discharge 1 is sent to a magnetic separator 2 for a magnetic separation to obtain a concentrate 1 and a tailing 1;

[0047] 2. Send the tailings to the high-frequency fine screen 3 for a stage of screening to obtain the oversize material 1 and undersize material 1. The oversize material 1 is the coarse-grained tailings 1, and the undersize material 1 is the magnetically separated tailings 1, which enter the total tailings system;

[0048] 3. The concentrate 1 flows by gravity to the pump tank 4, and is sent to the cyclone 6 for classification by the pump 5 to obtain overflow 1 and return sand 1. The return sand 1 flows by gravity to the ball mill 2 7 for grinding to obtain the ball mill discharge 2. The ball mill discharge 2 flows by gravity to the pump tank 4 and is combined with the concentrate 1.

[0049] 4. The overflow 1 is sent to the magnetic separator 2 8 for two-stage magnetic separation to obtain concentrate 2 and tailings 2. The concentrate 2 is the iron concentrate 1 and enters the total concentrate system. The tailings 2 flows by gravity to the magnetic separator 3 9 for three-stage magnetic separation to obtain concentrate 3 and tailings 3.

[0050] 5. Send the tailings 3 to the high-frequency fine screen 2 10 for two-stage screening to obtain the screen-over material 2 and the screen-under material 2, wherein the screen-over material 2 is the coarse-grained tailings 2;

[0051] 6. The undersize material 2 flows by gravity to the pump pool 2 11, and is sent to the magnetic separator 4 13 by the pump 2 12 for four-stage magnetic separation to obtain concentrate 4 and tailings 4. The concentrate 4 is the iron concentrate 2, which enters the total concentrate system; the tailings 4 flows by gravity to the magnetic separator 5 14 for five-stage magnetic separation to obtain concentrate 5 and tailings 5. The tailings 5 ​​is the magnetically separated tailings 2, which enters the total tailings system;

[0052] 7. The concentrate 3 and the concentrate 5 are combined, flowed to the pump pool 15 by gravity, and sent to the cyclone 2 by the pump 3 16 for classification to obtain overflow 2 and return sand 2, and the return sand 2 flows by gravity to the ball mill 3 18 for three-stage ball mill grinding to obtain the ball mill discharge 3, and the ball mill discharge 3 flows by gravity to the pump pool 3;

[0053] 8. The overflow 2 is sent to the magnetic separator 6 19 for six-stage magnetic separation to obtain concentrate 6 and tailings 6. The concentrate 6 is the iron concentrate 3 and enters the total concentrate system;

[0054] 9. The tailings 6 are sent to the magnetic separator 7 20 for seven-stage magnetic separation to obtain concentrate 7 and tailings 7. The concentrate 7 is the iron concentrate 4 and enters the total concentrate system. The tailings 7 is the magnetically separated tailings 3 and enters the total tailings system.

[0055] The ball mill 1 2 and the ball mill 2 18 are MQS40×60 ball mills, and the ball mill 3 18 is MQS27×36 ball mill; the magnetic field strength of the magnetic separator 1 2 is 8000Oe; the magnetic field strength of the magnetic separator 2 8 is 1200Oe; the magnetic field strength of the magnetic separator 3 9 and the magnetic separator 6 19 is 3000Oe; the magnetic field strength of the magnetic separator 4 13 is 6000Oe; the magnetic field strength of the magnetic separator 5 14 and the magnetic separator 7 20 is 12000Oe; the sieve hole diameter of the high-frequency fine screen 1 3 is 0.25mm, and the sieve hole diameter of the high-frequency fine screen 2 10 is 0.25mm.

[0056] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore, characterized in that: The process comprises the following steps: (1) The magnetic-hematite-siderite mixed iron ore belt sample is subjected to a first-stage ball mill grinding to obtain a ball mill discharge ore 1, and the ball mill discharge ore 1 is subjected to a first-stage magnetic separation to obtain a concentrate ore 1 and a tailing ore 1; (2) Screening the tailings 1 to obtain an oversize material 1 and a screened material 1, wherein the oversize material 1 is coarse-grained tailings 1 and the undersize material 1 is magnetically separated tailings 1, and enters the total tailings system; (3) Concentrate 1 is sent to the first stage classification to obtain overflow 1 and return sand 1, and the return sand 1 is returned to the second stage ball mill for grinding, and the second stage ball mill is used to grind the ore to obtain ball mill discharge 2, and the ball mill discharge 2 is returned to the first stage classification; (4) the overflow 1 is subjected to a second-stage magnetic separation to obtain a concentrate 2 and a tailing 2, the concentrate 2 is the iron concentrate 1 entering the total concentrate system, and the tailing 2 is subjected to a third-stage magnetic separation to obtain a concentrate 3 and a tailing 3; (5) performing two-stage screening on the tailings 3 to obtain an oversize material 2 and an undersize material 2, wherein the oversize material 2 is a coarse-grained tailings 2; (6) subjecting the undersize material 2 to four-stage magnetic separation to obtain concentrate 4 and tailings 4, wherein concentrate 4 is iron concentrate 2 and enters the total concentrate system; subjecting the tailings 4 to five-stage magnetic separation to obtain concentrate 5 and tailings 5, wherein tailings 5 ​​is magnetically separated tailings 2 and enters the total tailings system; (7) The concentrate 3 and the concentrate 5 are combined and sent to the second stage classification to obtain overflow 2 and return sand 2, the return sand 2 is returned to the third stage ball mill for grinding, the third stage ball mill is used to grind the ball mill discharge 3, and the ball mill discharge 3 is returned to the second stage classification; (8) The overflow 2 is subjected to six-stage magnetic separation to obtain concentrate 6 and tailings 6, and the concentrate 6 is iron concentrate 3, which enters the total concentrate system; (9) Tailings 6 is subjected to seven-stage magnetic separation to obtain concentrate 7 and tailings 7. Concentrate 7 is iron concentrate 4 and enters the total concentrate system. Tailings 7 is magnetically separated tailings 3 and enters the total tailings system.

2. According to claim 1, a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore, characterized in that: The belt sample feed particle size is 0 mm to 20 mm.

3. According to claim 2, a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore, characterized in that: The sieve hole size of the first stage screening is 0.25 mm to 3 mm; the sieve hole size of the second stage screening is 0.1 mm to 0.5 mm.

4. According to claim 3, a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore is characterized in that: The magnetic field strength of the first stage magnetic separation is 5000Oe to 15000Oe; the magnetic field strength of the second, third and sixth stages magnetic separation is 800Oe to 5000Oe; the magnetic field strength of the fourth, fifth and seventh stages magnetic separation is 5000Oe to 17000Oe.

5. According to claim 4, a new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore is characterized in that: The ball mill discharge-grinding fineness-200 mesh content is 10% to 40%.

6. The new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore according to claim 5 is characterized in that: The first stage classification overflow first grinding fineness-200 mesh content is 45% to 80%; the second stage classification overflow second grinding fineness-200 mesh content is 45% to 80%.

7. A new process for improving the beneficiation index of magnetic-hematite-siderite mixed ore according to claim 6, characterized in that: The concentration of the second, third and sixth stage magnetic separation is 10% to 40%.

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