Combined beneficiation method for laterite-nickel ore

Abstract

The invention provides a combined beneficiation method for laterite-nickel ore, which comprises the following steps: separating chromite in the laterite-nickel ore through a combined process of one-stage cyclone separation, spiral chute, multi-stage table classification, multiple low-intensity magnetic separation and multiple spiral classification to obtain first chromium concentrate, chromium middling, low-intensity magnetic separation middling and mixed light mineral aggregate; the chromium in the limonite and the chromite subjected to leakage treatment in the mixed light mineral aggregate, the low-intensity magnetic separation middling and the high-intensity magnetic separation magnetic substance is further enriched and separated by combining a combined process of subsequent multiple ball milling, two-stage rotational flow, low-intensity magnetic separation and high-intensity magnetic separation, so that more second chromium concentrate is screened out, the content of the chromium in the subsequent high-pressure leaching stock solution is reduced, and the yield of the high-pressure leaching stock solution is improved. The comprehensive utilization of the chromium element is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of ore dressing and relates to a combined ore dressing method for laterite nickel ore. Background Art

[0002] Laterite nickel ore often contains nickel and cobalt. The industry often uses hydrometallurgical technology to develop laterite nickel ore. Since laterite nickel ore often contains about 2% chromium, the chromium will be converted into Cr in the process of nickel and cobalt leaching. 6+ If it contains Cr 6+ If the waste liquid is discharged directly, it will cause serious environmental problems. Therefore, after nickel and cobalt leaching, chromium removal operation needs to be added, which increases production costs.

[0003] The limonite layer with a lower nickel grade in laterite nickel ore cannot be used in the pyrometallurgical process and can only be processed by hydrometallurgy. Hydrometallurgy, especially high-pressure acid leaching, will cause corrosion to the equipment used. In addition, the associated spinel-type chromite in laterite nickel ore also has a strong abrasive effect on the equipment. Therefore, expensive corrosion-resistant equipment is required when hydrometallurgical processing is used for laterite nickel ore, which increases the equipment cost and brings unpredictable safety risks. For the separation of chromium in laterite nickel ore, the prior art generally adopts a single gravity separation or magnetic separation method, and a single separation method often loses a large part of the chromium, and the grade of the obtained chromium concentrate is also low.

[0004] Therefore, it is necessary to provide a combined beneficiation method for laterite-nickel ore that can improve the grade and recovery rate of chromium concentrate and reduce the chromium content in subsequent high-pressure leaching solution. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a combined beneficiation method for laterite nickel ore, which separates the chromite in the laterite nickel ore, and the obtained chromium concentrate and chromium middlings have high grade and recovery rate, and are beneficial to reducing the chromium removal pressure in the hydrometallurgical smelting process of laterite nickel ore, thereby realizing the comprehensive utilization of chromium element.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] The present invention provides a combined beneficiation method for laterite nickel ore, the combined beneficiation method comprising the following steps:

[0008] (1) washing the laterite nickel ore and subjecting it to a first cyclone separation in sequence to obtain a first cyclone overflow and a first cyclone underflow, and then subjecting the first cyclone underflow to spiral chute classification, multi-stage shaking table classification, several weak magnetic separations and several spiral classifications in sequence to obtain a first chromium concentrate, a chromium middling, a weak magnetic separation middling and a mixed light ore;

[0009] (2) subjecting the mixed light ore of step (1) to first ball milling and second cyclone separation in sequence to obtain second cyclone overflow and second cyclone underflow, and then subjecting the second cyclone underflow to third weak magnetic separation to obtain third weak magnetic separation non-magnetic material and third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to shaking table classification and spiral classification in sequence to obtain a second chromium concentrate;

[0010] The third weak magnetic separation non-magnetic material in step (2) is subjected to strong magnetic separation to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then the weak magnetic separation ore and the strong magnetic separation magnetic material in step (1) are mixed, subjected to a second ball milling, and then reused in the first ball milling of step (2); at the same time, the first stage cyclone overflow of step (1), the second stage cyclone overflow of step (2) and the strong magnetic separation non-magnetic material are post-processed to obtain a high-pressure leaching stock solution.

[0011] In the present invention, the purpose of the mineral processing in step (1) is to remove gravels of different particle size ranges, so as to reduce the interference of gravels in subsequent mineral processing and improve the grade and quality of the concentrate; for example, a drum ore washer can be used to remove gravels with a particle size greater than 5 mm, and then a double-helix scrubber and a linear vibrating screen can be used to remove gravels with a particle size of 2-5 mm to obtain a gravel-free ore.

[0012] The combined ore dressing method provided by the present invention separates chromite in laterite nickel ore through a combined process of a cyclone separation, a spiral chute, a multi-stage shaking table classification, a plurality of weak magnetic separations and a plurality of spiral classifications, so as to obtain a first chromium concentrate, a chromium middling, a weak magnetic separation middling and a mixed light ore material. The obtained first chromium concentrate has a high grade, and the recovery rates of the first chromium concentrate and the chromium middling are also high. The present invention further performs post-processing on the obtained weak magnetic separation middling and the mixed light ore material to obtain a second chromium concentrate with high grade and high recovery rate, which is also beneficial to reducing the chromium removal pressure in the laterite nickel ore wet smelting process, greatly reducing the difficulty of subsequent operations, and realizing the comprehensive utilization of the chromium element.

[0013] It is worth noting that, since the mixed light ore and the weak magnetic separation ore contain limonite and chromite wrapped in limonite, and both limonite and chromite contain chromium, the mixed light ore is subjected to a first ball milling treatment to improve the monomer dissociation degree of chromite wrapped in limonite, so that the chromite and limonite in the mixed light ore are separated, and then the second chromium concentrate is obtained after the second stage cyclone separation and the third weak magnetic separation treatment. In addition, in order to further improve the recovery rate and grade of the second chromium concentrate, the inventor carried out a strong magnetic separation on the third weak magnetic separation non-magnetic material, and the strong magnetic separation magnetic material obtained by the strong magnetic separation was mixed with the weak magnetic separation ore and then reused in the first ball milling process. In summary, by combining multiple ball milling, two-stage cyclone, weak magnetic separation and strong magnetic separation, the chromium in the limonite and chromite leaked in the mixed light ore, weak magnetic separation ore and strong magnetic separation magnetic material is further enriched and separated to screen out more second chromium concentrate.

[0014] It is worth noting that by post-processing the overflow of each section of cyclone and the non-magnetic materials of strong magnetic separation, the pressure of chromium removal in high-pressure leaching solution is reduced, and the subsequent processing costs are reduced.

[0015] As a preferred technical solution of the present invention, the particle size of the ore particles in the cyclone bottom flow in step (1) is 74μm to 2mm, for example, it can be 74μm, 100μm, 300μm, 500μm, 800μm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm, etc.

[0016] In the present invention, since Ni and Cr 2 O 3 The grade does not change synchronously with the particle size. Therefore, by controlling the particle size of the ore in the bottom flow of a cyclone separation within the range of 74μm to 2mm, most of the chromium-containing impurities can be separated in the bottom flow of a cyclone, ensuring the full recovery of useful minerals while improving the efficiency and effect of subsequent spiral chute classification, further improving the grade of chrome concentrate.

[0017] Preferably, the spiral chute classification in step (1) comprises: allowing a section of cyclone underflow to enter the spiral chute for classification to obtain chute light ore and chute heavy ore; the chute light ore is one of the components of the mixed light ore.

[0018] In the present invention, although most of the chromium-containing ore phase is separated in the heavy ore material in the chute, the light ore material in the chute still contains a small amount of chromium ore phase.

[0019] Preferably, the multi-stage shaking table classification in step (1) includes a first shaking table classification and a second shaking table classification performed sequentially.

[0020] Preferably, when the first shaking table is graded, the stroke of the shaking table is 8 to 16 mm, for example, it can be 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or 16 mm, and the stroke rate is 245 to 380 times / min, for example, it can be 245 times / min, 250 times / min, 260 times / min, 280 times / min, 300 times / min, 320 times / min, 350 times / min, 360 times / min or 380 times / min, etc.

[0021] Preferably, the first shaking table classification includes: the heavy ore obtained after spiral chute classification enters the first shaking table for screening to obtain the first shaking table light ore and the first shaking table heavy ore; the first shaking table light ore is one of the components of the mixed light ore.

[0022] Preferably, when the second shaking table is graded, the stroke of the shaking table is 8 to 12 mm, for example, it can be 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm or 12 mm, and the stroke rate is 320 to 380 times / min, for example, it can be 320 times / min, 325 times / min, 330 times / min, 335 times / min, 340 times / min, 345 times / min, 350 times / min, 360 times / min or 380 times / min, etc.

[0023] In the present invention, by controlling the working parameters of the first shaking table and the second shaking table, ores of different grades can be separated, and the grades of the intermediate ore and tailings obtained by the shaking table separation can be reduced to a certain extent, and the recovery rate of the heavy ore containing chromium element can be increased, thereby improving the grade and recovery rate of the first chromium concentrate and the chromium intermediate ore.

[0024] Preferably, the second shaking table classification includes: the heavy ore obtained after the first shaking table classification is put into the second shaking table for re-screening to obtain the second shaking table light ore, the second shaking table medium ore and the second shaking table heavy ore; the second shaking table light ore is one of the components of the mixed light ore.

[0025] In the present invention, both the light ore material of the first shaking table and the light ore material of the second shaking table contain a small amount of chromium ore phase.

[0026] As a preferred technical solution of the present invention, the several weak magnetic separations in step (1) include a first weak magnetic separation and a second weak magnetic separation which are performed independently.

[0027] Preferably, the magnetic field strength of the first weak magnetic separation is 1000-1600 Gs, for example, it can be 1050 Gs, 1100 Gs, 1150 Gs, 1200 Gs, 1250 Gs, 1300 Gs, 1350 Gs, 1400 Gs, 1450 Gs, 1500 Gs or 1600 Gs.

[0028] Preferably, the first weak magnetic separation comprises: subjecting the heavy ore obtained after classification on the second shaking table to a first weak magnetic separation to obtain a first weak magnetic separation concentrate and a first weak magnetic separation ore.

[0029] Preferably, the first weak magnetic separation concentrate is spirally classified to obtain a first chromium concentrate.

[0030] In the present invention, the second shaking table heavy ore material can be separated into strongly magnetic chromium-containing minerals by the first weak magnetic separator under a specific magnetic field strength, and a high-grade first chromium concentrate can be obtained after spiral classification.

[0031] Preferably, the magnetic field strength of the second weak magnetic separation is 1400-2000 Gs, for example, it can be 1400 Gs, 1450 Gs, 1500 Gs, 1550 Gs, 1600 Gs, 1650 Gs, 1700 Gs, 1750 Gs, 1800 Gs, 1850 Gs, 1900 Gs, 1950 Gs or 2000 Gs.

[0032] Preferably, the second weak magnetic separation comprises: subjecting the middlings obtained after the second shaking table classification to a second weak magnetic separation to obtain a second weak magnetic separation concentrate and a second weak magnetic separation ore.

[0033] In the present invention, the ore in the second shaking table is continuously screened by the second weak magnetic separator under a specific magnetic field strength to select chromium-containing minerals with relatively strong magnetism for recovering the chromium middlings.

[0034] Preferably, the middlings obtained by the first weak magnetic separation and the concentrates obtained by the second weak magnetic separation are mixed and subjected to spiral classification to obtain the chromium middlings.

[0035] As a preferred technical solution of the present invention, in step (1), the chromium grade of the first chromium concentrate is ≥40%, for example, it can be 40%, 40.2%, 40.5%, 40.8%, 41%, 41.2%, 41.5%, 41.8%, 42% or 43%, etc.

[0036] Preferably, the chromium grade of the chromium ore in step (1) is ≥24%, for example, it can be 24%, 24.2%, 24.5%, 24.8%, 25%, 24.2%, 24.5%, 24.8%, 25%, 26% or 27%, etc.

[0037] As a preferred technical solution of the present invention, the rotation speed of the first ball mill in step (2) is 15 to 20 r / min, for example, it can be 15 r / min, 16 r / min, 17 r / min, 18 r / min, 19 r / min or 20 r / min.

[0038] Preferably, in step (2), the mineral particles with a particle size of -200 mesh after the first ball milling account for more than 65%, and preferably the mineral particles with a particle size of -200 mesh account for more than 70%.

[0039] In the present invention, the output particle size -200 mesh means that after the material is ball-milled, the particle size can pass through a 200-mesh sieve.

[0040] It is worth noting that by controlling the rotation speed of the first ball mill and the range of the discharge particle size, the monomer dissociation of chromite ore encapsulated in limonite in the mixed light ore is achieved, further improving the grade and recovery rate of the second chromium concentrate.

[0041] As a preferred technical solution of the present invention, the magnetic field strength of the third weak magnetic separation in step (2) is 1000-2000 Gs, for example, it can be 1000 Gs, 1100 Gs, 1200 Gs, 1300 Gs, 1400 Gs, 1500 Gs, 1600 Gs, 1700 Gs, 1800 Gs, 1900 Gs or 2000 Gs, etc.

[0042] It is worth noting that the second-stage cyclone bottom flow can be separated into strongly magnetic chromium-containing minerals by the third weak magnetic separator under a specific magnetic field strength, and then a high-grade second chromium concentrate can be obtained after shaking table classification and spiral classification.

[0043] As a preferred technical solution of the present invention, the magnetic field strength of the strong magnetic separation in step (3) is 10000-20000 Gs, for example, it can be 10000 Gs, 11000 Gs, 12000 Gs, 13000 Gs, 14000 Gs, 15000 Gs, 16000 Gs, 17000 Gs, 18000 Gs, 19000 Gs or 20000 Gs, etc.

[0044] In the present invention, the strong magnetic separator with increased magnetic field strength is used to magnetically select chromium-containing minerals with relatively strong magnetism, thereby further improving the grade and recovery rate of the second chromium concentrate.

[0045] Preferably, the rotation speed of the second ball mill in step (3) is 15 to 20 r / min, for example, it can be 15 r / min, 16 r / min, 17 r / min, 18 r / min, 19 r / min or 20 r / min.

[0046] Preferably, in step (3), the mineral particles with a particle size of -200 mesh after the second ball milling account for more than 60%.

[0047] As a preferred technical solution of the present invention, the post-treatment in step (3) includes: subjecting the first-stage cyclone overflow to a first-stage impurity removal to obtain a first-stage impurity-removed solution; mixing the second-stage cyclone overflow with a strong magnetic separation non-magnetic material to a second-stage impurity removal to obtain a second-stage impurity-removed solution; and then mixing a flocculant, the first-stage impurity-removed solution and the second-stage impurity-removed solution to solid-liquid separation to obtain a high-pressure leaching stock solution.

[0048] As a preferred technical solution of the present invention, the chromium grade of the second chromium concentrate in step (2) is ≥35%, for example, it can be 35%, 35.2%, 35.5%, 35.8%, 36%, 36.2%, 36.5%, 36.8%, 37%, 37.5%, 38%, 39% or 40%, etc.

[0049] Preferably, the recovery rate of the second chromium concentrate in step (2) is ≥15%, for example, it can be 15%, 15.2%, 15.5%, 15.8%, 16%, 16.2%, 16.5%, 16.8%, 17%, 18%, 19% or 20%, etc.

[0050] Preferably, the chromium content in the high-pressure leaching solution of step (3) is ≤0.2%, for example, it can be 0.18%, 0.15%, 0.12%, 0.1%, 0.08%, 0.05%, 0.02%, 0.01% or 0.005%, etc., preferably ≤0.05%.

[0051] As a preferred technical solution of the present invention, the combined mineral processing method comprises the following steps:

[0052] (1) washing the laterite nickel ore and performing a cyclone separation in sequence to obtain a cyclone overflow and a cyclone underflow, wherein the particle size of the cyclone underflow is 74 μm to 2 mm; then the cyclone underflow is subjected to spiral chute classification to obtain a chute light ore material and a chute heavy ore material, and then the chute heavy ore material is subjected to a first shaking table classification at a shaking table stroke of 8 to 16 mm and a stroke of 245 to 380 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material, and then the first shaking table heavy ore material is subjected to a second shaking table classification at a shaking table stroke of 8 to 12 mm and a stroke of 320 to 380 times / min to obtain a second shaking table light ore material, a second shaking table medium ore material and a second shaking table heavy ore material;

[0053] The heavy ore material of the second shaking table is subjected to first weak magnetic separation at a magnetic field strength of 1000-1600 Gs to obtain a first weak magnetic separation concentrate and a first weak magnetic separation ore, and then the first weak magnetic separation concentrate is subjected to spiral classification to obtain a first chromium concentrate with a chromium grade of ≥40%;

[0054] The ore in the second shaking table is subjected to a second weak magnetic separation at a magnetic field strength of 1400-2000 Gs to obtain a second weak magnetic separation concentrate and a second weak magnetic separation middling, and then the first weak magnetic separation middling and the second weak magnetic separation concentrate are mixed, and after spiral classification, a chromium middling with a chromium grade of ≥24% is obtained;

[0055] The obtained chute light ore material, the first shaking table light ore material and the second shaking table light ore material constitute a mixed light ore material;

[0056] (2) subjecting the mixed light ore of step (1) to first ball milling and second cyclone separation at a rotation speed of 15 to 20 r / min, to obtain a second cyclone overflow and a second cyclone underflow, and then subjecting the second cyclone underflow to a third weak magnetic separation at a magnetic field strength of 1000 to 2000 Gs, to obtain a third weak magnetic separation non-magnetic material and a third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to shaking table classification and spiral classification, to obtain a second chromium concentrate with a chromium grade of ≥35% and a recovery rate of ≥15%;

[0057] The mineral particles with a particle size of -200 mesh after the first ball milling account for more than 65%;

[0058] (3) subjecting the non-magnetic material of the third weak magnetic separation of step (2) to strong magnetic separation at a magnetic field strength of 10000-20000 Gs to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then mixing the ore from the second weak magnetic separation and the magnetic material from the strong magnetic separation in step (1), subjecting the ore to a second ball mill at a rotation speed of 15-20 r / min, and then reusing the ore to the first ball mill in step (2); the ore particles with a particle size of -200 mesh account for more than 60% of the output after the second ball mill;

[0059] The first stage cyclone overflow of step (1) is subjected to a first stage of impurity removal to obtain a first stage of impurity-removed solution; the second stage cyclone overflow of step (2) is mixed with the strong magnetic separation non-magnetic material to carry out a second stage of impurity removal to obtain a second stage of impurity-removed solution; and then the flocculant, the first stage of impurity-removed solution and the second stage of impurity-removed solution are mixed to carry out solid-liquid separation to obtain a high-pressure leaching stock solution with a chromium content of ≤0.2%.

[0060] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] (1) The combined beneficiation method provided by the present invention separates chromite from laterite nickel ore through a combined process of a first cyclone separation, a spiral chute, a multi-stage shaking table classification, a plurality of weak magnetic separations and a plurality of spiral classifications, thereby obtaining a first chromium concentrate, a chromium middling, a weak magnetic separation middling and a mixed light ore; wherein the chromium grade of the first chromium concentrate is ≥40%, the chromium grade of the chromium middling is ≥24%, and the recovery rates of the first chromium concentrate and the chromium middling are both ≥10%;

[0063] (2) The combined beneficiation method provided by the present invention further enriches and separates the chromium in the mixed light ore, the weak magnetic separation ore and the chromite ore that has been missed in the strong magnetic separation magnetic material through the combined process of multiple ball milling, two-stage cyclone, weak magnetic separation and strong magnetic separation, so as to screen more second chromium concentrate, and is conducive to reducing the chromium content in the subsequent high-pressure leaching solution, thereby realizing the comprehensive utilization of the chromium element; wherein the chromium grade of the second chromium concentrate is ≥35%, the recovery rate is ≥15%, and the chromium content in the high-pressure leaching solution is ≤0.2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a flow chart of the combined beneficiation method of laterite nickel ore provided in Example 1. DETAILED DESCRIPTION

[0065] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0066] The raw materials in the specific implementation of the present invention are all laterite nickel ore from a tropical rainforest climate island near the equator in Indonesia. The main valuable metal elements of the laterite nickel ore are Ni, Fe and Co, and there are also valuable metal elements such as Ca, Mg, Cr 2 O 3 and SiO 2 And other impurities.

[0067] In the following embodiments and comparative examples, the laterite nickel ore was washed before chromium selection, and the washing was carried out by the following method: the laterite nickel ore was transported to the drum washing machine by a heavy plate feeder to remove gravel with a particle size of ≥35 mm, and then the double spiral scrubber and linear vibrating screen were used to remove gravel with a particle size of ≥2 mm, and then the ore was successively input into the mixing tank and the slurry pump to obtain the gravel-free ore, and the content of the gravel-free ore was measured. Among them, the Cr in the gravel-free ore 2 O 3 The grade is 3.39% and the recovery rate is 97.4%.

[0068] Example 1

[0069] This embodiment provides a combined beneficiation method for laterite nickel ore, the flow chart is as follows: Figure 1 As shown, the combined mineral processing method comprises the following steps:

[0070] (1) introducing the ore material except gravel into a cyclone for a cyclone separation to obtain a cyclone overflow and a cyclone underflow, wherein the particle size of the cyclone underflow is 74 to 200 μm; then subjecting the cyclone underflow to spiral chute classification to obtain chute light ore material and chute heavy ore material, and then subjecting the chute heavy ore material to a first shaking table classification at a shaking table stroke of 12 mm and a stroke of 280 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material, and then subjecting the first shaking table heavy ore material to a second shaking table classification at a shaking table stroke of 10 mm and a stroke of 320 times / min to obtain a second shaking table light ore material, a second shaking table medium ore material and a second shaking table heavy ore material;

[0071] The heavy ore material of the second shaking table is subjected to the first weak magnetic separation at a magnetic field strength of 1500 Gs to obtain the first weak magnetic separation concentrate and the first weak magnetic separation ore, and then the first weak magnetic separation concentrate is subjected to spiral classification to obtain the first chromium concentrate;

[0072] The ore in the second shaking table is subjected to a second weak magnetic separation at a magnetic field strength of 1700 Gs to obtain a second weak magnetic separation concentrate and a second weak magnetic separation middling, and then the first weak magnetic separation middling and the second weak magnetic separation concentrate are mixed to obtain a chromium middling after spiral classification;

[0073] The obtained chute light ore material, the first shaking table light ore material and the second shaking table light ore material constitute a mixed light ore material;

[0074] (2) subjecting the mixed light ore of step (1) to a first ball mill and a second cyclone separation at a rotation speed of 18 r / min, to obtain a second cyclone overflow and a second cyclone underflow, and then subjecting the second cyclone underflow to a third weak magnetic separation at a magnetic field strength of 1800 Gs, to obtain a third weak magnetic separation non-magnetic material and a third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to a third shaking table classification and a spiral classification, to obtain a second chromium concentrate;

[0075] The output particle size of the first ball mill is -200 mesh, and the mineral particles account for more than 70%;

[0076] (3) subjecting the non-magnetic material of the third weak magnetic separation of step (2) to strong magnetic separation at a magnetic field strength of 10000 Gs to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then mixing the ore from the second weak magnetic separation and the magnetic material from the strong magnetic separation of step (1), subjecting the ore to a second ball mill at a rotation speed of 17.3 r / min, and then reusing the ore to the first ball mill of step (2); the ore particles with a particle size of -200 mesh account for more than 60% of the output after the second ball mill;

[0077] At the same time, the first-stage cyclone overflow of step (1) is subjected to a stage of impurity removal to obtain a stage of impurity-removed solution, and then the first-stage impurity-removed solution is sequentially transported to the finished product tank and the raw ore slurry storage tank, and the second-stage cyclone overflow of step (2) is mixed with the strong magnetic separation non-magnetic material to perform a second-stage impurity removal, and the second-stage impurity-removed solution is transported to the raw ore slurry storage tank; then the mixture in the raw ore slurry storage tank is introduced into a thickener containing a flocculant for solid-liquid separation to obtain a high-pressure leaching stock solution;

[0078] In this embodiment, the Cr in the second chromium concentrate 2 O 3 If the grade and recovery rate remain stable, the laterite-nickel ore combined beneficiation method of this embodiment is completed.

[0079] Example 2

[0080] The present embodiment provides a combined beneficiation method for laterite nickel ore, the combined beneficiation method comprising the following steps:

[0081] (1) introducing the ore material except gravel into a cyclone for a cyclone separation to obtain a cyclone overflow and a cyclone underflow, wherein the particle size of the cyclone underflow is 74 to 200 μm; then subjecting the cyclone underflow to spiral chute classification to obtain chute light ore material and chute heavy ore material, and then subjecting the chute heavy ore material to a first shaking table classification at a shaking table stroke of 14 mm and a stroke of 245 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material, and then subjecting the first shaking table heavy ore material to a second shaking table classification at a shaking table stroke of 9 mm and a stroke of 360 times / min to obtain a second shaking table light ore material, a second shaking table medium ore material and a second shaking table heavy ore material;

[0082] The heavy ore material of the second shaking table is subjected to a first weak magnetic separation at a magnetic field strength of 1200 Gs to obtain a first weak magnetic separation concentrate and a first weak magnetic separation ore, and then the first weak magnetic separation concentrate is subjected to spiral classification to obtain a first chromium concentrate;

[0083] The ore in the second shaking table is subjected to a second weak magnetic separation at a magnetic field strength of 1500 Gs to obtain a second weak magnetic separation concentrate and a second weak magnetic separation middling, and then the first weak magnetic separation middling and the second weak magnetic separation concentrate are mixed to obtain a chromium middling after spiral classification;

[0084] The obtained chute light ore material, the first shaking table light ore material and the second shaking table light ore material constitute a mixed light ore material;

[0085] (2) subjecting the mixed light ore of step (1) to a first ball mill and a second cyclone separation at a rotation speed of 20 r / min, to obtain a second cyclone overflow and a second cyclone underflow, and then subjecting the second cyclone underflow to a third weak magnetic separation at a magnetic field strength of 1900 Gs, to obtain a third weak magnetic separation non-magnetic material and a third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to a third shaking table classification and a spiral classification, to obtain a second chromium concentrate;

[0086] The output particle size of the first ball mill is -200 mesh, and the mineral particles account for more than 70%;

[0087] (3) subjecting the non-magnetic material of the third weak magnetic separation of step (2) to strong magnetic separation at a magnetic field strength of 12000 Gs to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then mixing the ore from the second weak magnetic separation and the magnetic material from the strong magnetic separation of step (1), subjecting the ore to a second ball mill at a rotation speed of 18 r / min, and then reusing the ore to the first ball mill of step (2); the ore particles with a particle size of -200 mesh after the second ball milling account for more than 60%;

[0088] At the same time, the first-stage cyclone overflow of step (1) is subjected to a stage of impurity removal to obtain a stage of impurity-removed solution, and then the first-stage impurity-removed solution is sequentially transported to the finished product tank and the raw ore slurry storage tank, and the second-stage cyclone overflow of step (2) is mixed with the strong magnetic separation non-magnetic material to perform a second-stage impurity removal, and the second-stage impurity-removed solution is transported to the raw ore slurry storage tank; then the mixture in the raw ore slurry storage tank is introduced into a thickener containing a flocculant for solid-liquid separation to obtain a high-pressure leaching stock solution;

[0089] In this embodiment, the Cr in the second chromium concentrate 2 O 3 If the grade and recovery rate remain stable, the laterite-nickel ore combined beneficiation method of this embodiment is completed.

[0090] Example 3

[0091] This embodiment provides a combined beneficiation method for laterite nickel ore. Except that in step (2), the ore particles with a particle size of -200 mesh after the first ball milling account for more than 50%, other conditions are the same as those in embodiment 1.

[0092] Example 4

[0093] This embodiment provides a combined beneficiation method for laterite nickel ore. Except that the magnetic field intensity of the third weak magnetic separation in step (2) is 800 Gs, other conditions are the same as those in Example 1.

[0094] Example 5

[0095] This embodiment provides a combined beneficiation method for laterite nickel ore. Except that the magnetic field intensity of the third weak magnetic separation in step (2) is 2500 Gs, other conditions are the same as those in Example 1.

[0096] Example 6

[0097] This embodiment provides a combined beneficiation method for laterite nickel ore. Except that the ore particles with a particle size of -200 mesh in the second ball mill in step (3) account for more than 50%, other conditions are the same as those in Example 1.

[0098] Comparative Example 1

[0099] This comparative example provides a combined beneficiation method for laterite nickel ore, except that the first ball milling is not performed in step (2), that is, the mixed light ore is directly subjected to the second-stage cyclone separation, and other conditions are the same as those in Example 1.

[0100] Comparative Example 2

[0101] This comparative example provides a combined beneficiation method for laterite nickel ore. Except that step (2) does not perform the second-stage cyclone separation, that is, the ore after the first ball milling is directly subjected to the third weak magnetic separation, other conditions are the same as those in Example 1.

[0102] Comparative Example 3

[0103] This comparative example provides a combined beneficiation method for laterite nickel ore, except that in step (2), the third shaking table classification is not performed, that is, the third weak magnetic separation non-magnetic material is directly subjected to spiral classification, and other conditions are the same as those in Example 1.

[0104] Comparative Example 4

[0105] This comparative example provides a combined beneficiation method for laterite nickel ore, except that step (3) does not perform the second ball milling, i.e., the ore from the second weak magnetic separation and the magnetic material from the strong magnetic separation are used as slag instead of being ball milled for recycling, and other conditions are the same as those in Example 1.

[0106] Comparative Example 5

[0107] This comparative example provides a combined beneficiation method for laterite nickel ore, except that step (3) does not perform strong magnetic separation and second ball milling, that is, the first-stage cyclone overflow of step (1) and the second-stage cyclone overflow of step (2) are directly post-treated to obtain a high-pressure leaching stock solution, and other conditions are the same as those of Example 1.

[0108] Comparative Example 6

[0109] This comparative example provides a combined beneficiation method for laterite nickel ore, which comprises the following steps:

[0110] (1) introducing the ore except gravel into a cyclone for a cyclone separation to obtain a cyclone overflow and a cyclone underflow, wherein the particle size of the cyclone underflow is 74-200 μm; then subjecting the cyclone underflow to a first weak magnetic separation at a magnetic field strength of 1500 Gs to obtain a first weak magnetic separation magnetic material and a first weak magnetic separation non-magnetic material, and then collecting the first weak magnetic separation magnetic material into a weak magnetic pump pool for spiral classification to obtain a first chromium middling; at the same time, subjecting the first weak magnetic separation non-magnetic material to a first strong magnetic separation at a magnetic field strength of 10000 Gs to obtain a first strong magnetic separation non-magnetic material and a first strong magnetic separation magnetic material;

[0111] (2) The first strong magnetic separation magnetic material of step (1) is introduced into a spiral chute for spiral chute classification to obtain chute light ore and chute heavy ore, and then the chute heavy ore is subjected to first shaking table classification to obtain first shaking table light ore and first shaking table heavy ore, and then the first shaking table heavy ore is subjected to second shaking table classification to obtain second shaking table light ore, second shaking table medium ore and second shaking table heavy ore;

[0112] The heavy ore material of the second shaking table is subjected to second weak magnetic separation at a magnetic field strength of 1500 Gs to obtain second weak magnetic separation concentrate and second weak magnetic separation ore, and then the second weak magnetic separation concentrate is subjected to spiral classification to obtain chromium concentrate;

[0113] The ore in the second shaking table is subjected to third weak magnetic separation at a magnetic field strength of 1100 Gs to obtain third weak magnetic separation concentrate and third weak magnetic separation middling, and then the middling obtained by the second weak magnetic separation is mixed with the concentrate obtained by the third weak magnetic separation, and a second chromium middling is obtained after spiral classification;

[0114] The obtained chute light ore material, the first stage shaking table light ore material and the second stage shaking table light ore material constitute the mixed light ore material;

[0115] (3) mixing the first strong magnetic separation non-magnetic material of step (1) and the mixed light mineral material of step (2), and sequentially subjecting the mixture to first ball milling and second-stage cyclone separation to obtain second-stage cyclone overflow and second-stage cyclone underflow;

[0116] The output particle size of the first ball mill is -200 mesh, and the mineral particles account for more than 70%;

[0117] The overflow of the second-stage cyclone is transported to the raw ore slurry storage tank after being removed by the second-stage impurity removal screen. At the same time, the overflow of the first-stage cyclone in step (1) is first transported to the finished product tank and then to the raw ore slurry storage tank after being removed by the first-stage impurity removal screen. The mixture in the raw ore slurry storage tank is introduced into a thickener containing a flocculant for solid-liquid separation to obtain a high-pressure leaching stock solution.

[0118] The second-stage cyclone underflow and the ore separated in the third weak magnetic separation in step (2) are mixed, subjected to a second ball mill, and then reused in the first strong magnetic separation in step (1);

[0119] After the second ball milling, the mineral particles with a particle size of -200 mesh account for more than 60%.

[0120] In this comparative example, the chromium grade of the first chromium middling was 17.3% and the recovery rate was 30.5%; the chromium grade of the chromium concentrate was 37.38% and the recovery rate was 15.44%; the chromium grade of the second chromium middling was 21.01% and the recovery rate was 8.93%; the chromium content in the high-pressure leaching stock solution was 0.03%.

[0121] By comparing this comparative example with Example 1, it can be seen that if the weak magnetic separation and strong magnetic separation steps after the second-stage cyclone separation are adjusted to after the first-stage cyclone separation, it is not conducive to improving the grade and recovery rate of the chromium concentrate.

[0122] In the above embodiments and comparative examples, the chromium contents in the chromium concentrate, chromium middlings and high-pressure leaching stock solution obtained in the above embodiments and comparative examples were determined by titration, and the corresponding recovery rates were calculated. The specific results are shown in Table 1.

[0123] Table 1

[0124]

[0125]

[0126] From Table 1, we can see that:

[0127] (1) The combined beneficiation method provided in Examples 1-2 of the present invention separates chromite from laterite nickel ore through a combined process of a first cyclone separation, a spiral chute, a multi-stage shaking table classification, a plurality of weak magnetic separations and a plurality of spiral classifications, thereby obtaining a first chromium concentrate with a chromium grade of ≥40% and a chromium middling with a chromium grade of ≥24%; and further enriches and separates the chromium in the mixed light ore, the weak magnetic separation middling and the chromite ore that has been missed in the strong magnetic separation magnetic material through a combined process of multiple ball milling, a second cyclone, a weak magnetic separation and a strong magnetic separation, so as to screen more second chromium concentrate, and is conducive to reducing the chromium content in the subsequent high-pressure leaching stock solution, thereby realizing the comprehensive utilization of the chromium element; wherein the chromium grade of the second chromium concentrate is ≥35%, the recovery rate is ≥15%, and the chromium content in the high-pressure leaching stock solution is ≤0.02%;

[0128] (2) By comparing Example 1 with Example 3 and Example 6, it can be seen that when the proportion of the ore particles with a particle size of -200 mesh in the first ball mill or the second ball mill is too small, the chromite monomers that are encapsulated cannot be fully dissociated, resulting in a decrease in the chromium grade and recovery rate of the second chromium concentrate;

[0129] (3) By comparing Example 1 with Examples 4-5, it can be seen that when the magnetic field strength of the third weak magnetic separation is low, part of the chromium middlings enter the chromium concentrate tank due to the low magnetic field strength, resulting in a decrease in the grade of the second chromium concentrate; when the magnetic field strength of the third weak magnetic separation is high, the chromium concentrate enters the chromium middlings tank due to the high magnetic field strength, resulting in a decrease in the recovery rate of the second chromium concentrate;

[0130] (4) From the comparison between Example 1 and Comparative Example 1, it can be seen that if the first ball milling is not performed, the chromite and limonite in the mixed light ore cannot be separated, resulting in a decrease in the grade and recovery rate of the second chromium concentrate; from the comparison between Example 1 and Comparative Example 2, it can be seen that since the second-stage cyclone separation is not performed, most of the chromium-containing impurities cannot be separated in the second-stage cyclone bottom flow, and the useful minerals cannot be fully recovered, resulting in a decrease in the grade and recovery rate of the second chromium concentrate;

[0131] (5) By comparing Example 1 with Comparative Example 3, it can be seen that if the third shaking table classification is not performed, but the third weak magnetic separation non-magnetic material is directly subjected to spiral classification, the chrome concentrate and the middlings cannot be separated, resulting in a decrease in the grade and recovery rate of the second chrome concentrate;

[0132] (6) By comparing Example 1 with Comparative Examples 4-5, it can be seen that if the second ball milling or strong magnetic separation is not performed, the chromium in the limonite and chromite ore that are missed in the weak magnetic separation and the third weak magnetic separation non-magnetic material cannot be further enriched and separated, resulting in a decrease in the grade and recovery rate of the second chromium concentrate.

[0133] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A combined beneficiation method for laterite nickel ore, characterized in that: The combined mineral processing method comprises the following steps: (1) washing the laterite nickel ore and subjecting it to a first cyclone separation in sequence to obtain a first cyclone overflow and a first cyclone underflow, and then subjecting the first cyclone underflow to spiral chute classification, multi-stage shaking table classification, several weak magnetic separations and several spiral classifications in sequence to obtain a first chromium concentrate, a chromium middling, a weak magnetic separation middling and a mixed light ore; (2) subjecting the mixed light ore of step (1) to first ball milling and second cyclone separation in sequence to obtain second cyclone overflow and second cyclone underflow, and then subjecting the second cyclone underflow to third weak magnetic separation to obtain third weak magnetic separation non-magnetic material and third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to shaking table classification and spiral classification in sequence to obtain a second chromium concentrate; (3) subjecting the third weak magnetic separation non-magnetic material of step (2) to strong magnetic separation to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then mixing the weak magnetic separation ore and the strong magnetic separation magnetic material of step (1), subjecting them to a second ball milling and then recycling them to the first ball milling of step (2); at the same time, post-treating the first stage cyclone overflow of step (1), the second stage cyclone overflow of step (2) and the strong magnetic separation non-magnetic material to obtain a high-pressure leaching stock solution.

2. The combined mineral processing method according to claim 1, characterized in that: The particle size of the ore particles in the cyclone bottom flow in step (1) is 74 μm to 2 mm; Preferably, the spiral chute classification in step (1) comprises: allowing a section of cyclone underflow to enter the spiral chute for classification to obtain a chute light ore material and a chute heavy ore material; the chute light ore material is one of the components of the mixed light ore material; Preferably, the multi-stage shaking table classification in step (1) includes a first shaking table classification and a second shaking table classification performed sequentially; Preferably, when the first shaking table is used for classification, the stroke of the shaking table is 8 to 16 mm and the stroke frequency is 245 to 380 times / min; Preferably, the first shaking table classification comprises: the heavy ore obtained after the spiral chute classification enters the first shaking table for screening to obtain the first shaking table light ore and the first shaking table heavy ore; the first shaking table light ore is one of the components of the mixed light ore; Preferably, when the second shaking table is used for classification, the stroke of the shaking table is 8 to 12 mm and the stroke frequency is 320 to 380 times / min; Preferably, the second shaking table classification includes: the heavy ore obtained after the first shaking table classification is put into the second shaking table for re-screening to obtain the second shaking table light ore, the second shaking table medium ore and the second shaking table heavy ore; the second shaking table light ore is one of the components of the mixed light ore.

3. The combined mineral processing method according to claim 1 or 2, characterized in that: The plurality of weak magnetic separations in step (1) include a first weak magnetic separation and a second weak magnetic separation which are performed independently; Preferably, the magnetic field strength of the first weak magnetic separation is 1000-1600 Gs; Preferably, the first weak magnetic separation comprises: subjecting the heavy ore obtained after the second shaking table classification to the first weak magnetic separation to obtain the first weak magnetic separation concentrate and the first weak magnetic separation ore; Preferably, the first weak magnetic separation concentrate is subjected to spiral classification to obtain a first chromium concentrate; Preferably, the magnetic field strength of the second weak magnetic separation is 1400-2000 Gs; Preferably, the second weak magnetic separation comprises: subjecting the middlings obtained after the second shaking table classification to second weak magnetic separation to obtain second weak magnetic separation concentrate and second weak magnetic separation ore; Preferably, the middlings obtained by the first weak magnetic separation and the concentrates obtained by the second weak magnetic separation are mixed and subjected to spiral classification to obtain the chromium middlings.

4. The combined mineral processing method according to any one of claims 1 to 3, characterized in that: Step (1) the chromium grade of the first chromium concentrate is ≥40%; Preferably, the chromium grade of the chromium ore in step (1) is ≥24%.

5. The combined mineral processing method according to any one of claims 1 to 4, characterized in that: Step (2) The rotation speed of the first ball mill is 15 to 20 r / min; Preferably, in step (2), the mineral particles with a particle size of -200 mesh after the first ball milling account for more than 65%, and preferably the mineral particles with a particle size of -200 mesh account for more than 70%.

6. The combined mineral processing method according to any one of claims 1 to 5, characterized in that: The magnetic field strength of the third weak magnetic separation in step (2) is 1000-2000 Gs.

7. The combined mineral processing method according to any one of claims 1 to 6, characterized in that: The magnetic field strength of the strong magnetic separation in step (3) is 10000-20000Gs; Preferably, the rotation speed of the second ball mill in step (3) is 15 to 20 r / min; Preferably, in step (3), the mineral particles with a particle size of -200 mesh after the second ball milling account for more than 60%.

8. The combined mineral processing method according to any one of claims 1 to 7, characterized in that: The post-treatment in step (3) includes: subjecting the first-stage cyclone overflow to a first-stage impurity removal to obtain a first-stage impurity-removed solution; mixing the second-stage cyclone overflow with a strong magnetic separation non-magnetic material to a second-stage impurity removal to obtain a second-stage impurity-removed solution; and then mixing a flocculant, the first-stage impurity-removed solution and the second-stage impurity-removed solution to solid-liquid separation to obtain a high-pressure leaching stock solution.

9. The combined mineral processing method according to any one of claims 1 to 8, characterized in that: Step (2) the chromium grade of the second chromium concentrate is ≥35%; Preferably, the recovery rate of the second chromium concentrate in step (2) is ≥15%; Preferably, the chromium content in the high-pressure leaching solution in step (3) is ≤0.2%, preferably ≤0.05%.

10. The combined mineral processing method according to any one of claims 1 to 9, characterized in that: The combined mineral processing method comprises the following steps: (1) washing the laterite nickel ore and performing a cyclone separation in sequence to obtain a cyclone overflow and a cyclone underflow, wherein the particle size of the cyclone underflow is 74 μm to 2 mm; then the cyclone underflow is subjected to spiral chute classification to obtain a chute light ore material and a chute heavy ore material, and then the chute heavy ore material is subjected to a first shaking table classification at a shaking table stroke of 8 to 16 mm and a stroke of 245 to 380 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material, and then the first shaking table heavy ore material is subjected to a second shaking table classification at a shaking table stroke of 8 to 12 mm and a stroke of 320 to 380 times / min to obtain a second shaking table light ore material, a second shaking table medium ore material and a second shaking table heavy ore material; The heavy ore material of the second shaking table is subjected to first weak magnetic separation at a magnetic field strength of 1000-1600 Gs to obtain a first weak magnetic separation concentrate and a first weak magnetic separation ore, and then the first weak magnetic separation concentrate is subjected to spiral classification to obtain a first chromium concentrate with a chromium grade of ≥40%; The ore in the second shaking table is subjected to a second weak magnetic separation at a magnetic field strength of 1400-2000 Gs to obtain a second weak magnetic separation concentrate and a second weak magnetic separation middling, and then the first weak magnetic separation middling and the second weak magnetic separation concentrate are mixed, and after spiral classification, a chromium middling with a chromium grade of ≥24% is obtained; The obtained chute light ore material, the first shaking table light ore material and the second shaking table light ore material constitute a mixed light ore material; (2) subjecting the mixed light ore of step (1) to first ball milling and second cyclone separation at a rotation speed of 15 to 20 r / min, to obtain a second cyclone overflow and a second cyclone underflow, and then subjecting the second cyclone underflow to a third weak magnetic separation at a magnetic field strength of 1000 to 2000 Gs, to obtain a third weak magnetic separation non-magnetic material and a third weak magnetic separation magnetic material, and then subjecting the third weak magnetic separation non-magnetic material to shaking table classification and spiral classification, to obtain a second chromium concentrate with a chromium grade of ≥35% and a recovery rate of ≥15%; The mineral particles with a particle size of -200 mesh after the first ball milling account for more than 65%; (3) subjecting the non-magnetic material of the third weak magnetic separation of step (2) to strong magnetic separation at a magnetic field strength of 10000-20000 Gs to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then mixing the ore from the second weak magnetic separation and the magnetic material from the strong magnetic separation in step (1), subjecting the ore to a second ball mill at a rotation speed of 15-20 r / min, and then reusing the ore to the first ball mill in step (2); the ore particles with a particle size of -200 mesh account for more than 60% of the output after the second ball mill; At the same time, the first stage cyclone overflow of step (1) is subjected to a first stage of impurity removal to obtain a first stage of impurity-removed solution; the second stage cyclone overflow of step (2) is mixed with the strong magnetic separation non-magnetic material to carry out a second stage of impurity removal to obtain a second stage of impurity-removed solution; and then the flocculant, the first stage of impurity-removed solution and the second stage of impurity-removed solution are mixed to carry out solid-liquid separation to obtain a high-pressure leaching stock solution with a chromium content of ≤0.2%.

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