A combined beneficiation method for laterite nickel ore

Abstract

The present invention provides a combined beneficiation method for laterite nickel ore. The method comprises the following steps: 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, so as to separate chromite from the laterite nickel ore, thereby obtaining a first chromium concentrate, a chromium middling, a weak magnetic separation middling and a mixed light ore; and a subsequent combined process of multiple ball millings, a second cyclone, a weak magnetic separation and a strong magnetic separation is used to further enrich and separate chromium from the mixed light ore, the weak magnetic separation middling and the limonite and chromite that have been missed in the strong magnetic separation magnetic material, thereby screening out more second chromium concentrate, facilitating a reduction in the chromium content in a subsequent high-pressure leaching stock solution, thereby achieving comprehensive utilization of the chromium element.

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. In industry, hydrometallurgical process is often used 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 needs to be added, which increases production costs.

[0003] The limonite layer with a lower nickel grade in laterite nickel ore cannot be utilized in the pyrometallurgical process and can only be processed through 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 needs to be used when hydrometallurgical smelting laterite nickel ore, which increases the equipment cost and brings unpredictable safety risks. For the separation of chromium in laterite nickel ore, the existing technology 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 present invention aims to provide a combined beneficiation method for laterite nickel ore, which separates chromite from the laterite nickel ore. The obtained chromium concentrate and chromium middlings have high grade and recovery rate, and are conducive to reducing the chromium removal pressure during 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, which comprises the following steps:

[0008] (1) washing the laterite nickel ore and subjecting it to a first cyclone separation 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 to obtain a first chromium concentrate, chromium middlings, weak magnetic separation ore, and mixed light ore;

[0009] (2) subjecting the mixed light ore of step (1) to first ball milling and second-stage cyclone separation in sequence to obtain second-stage cyclone overflow and second-stage cyclone underflow, and then subjecting the second-stage 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 in step (1), the second stage cyclone overflow in 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 gravel of different particle size ranges to reduce the interference of gravel in subsequent mineral processing and improve the grade and quality of the concentrate; for example, a drum ore washer can be used to remove gravel with a particle size greater than 5 mm, and then the gravel with a particle size of 2-5 mm can be removed by a double-helix scrubber and a linear vibrating screen to obtain a gravel-free ore.

[0012] The combined mineral processing method provided by the present invention separates chromite from laterite nickel ore through a combined process of a first-stage cyclone separation, a spiral chute, a multi-stage shaking table classification, several weak magnetic separations and several spiral classifications, thereby obtaining a first chromium concentrate, a chromium middling, a weak magnetic separation ore and a mixed light ore. 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 post-processes the obtained weak magnetic separation ore and the mixed light ore to obtain a second chromium concentrate with high grade and high recovery rate. This method is also beneficial to reducing the chromium removal pressure in the wet smelting process of laterite nickel ore, 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 the 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 the 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 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 inventors 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 ball-milled and reused to the first ball milling process. In summary, by combining the process of multiple ball milling, two-stage cyclone, weak magnetic separation and strong magnetic separation, the chromium in the limonite and chromite that were leaked from 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 through strong magnetic separation, the pressure of chromium removal in the 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 mineral 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 the grades of Ni and Cr2O3 do not change synchronously with the particle size, most of the chromium-containing impurities can be separated in the first cyclone underflow by controlling the particle size of the ore particles in the underflow of the first cyclone separation to be within the range of 74 μm to 2 mm. This ensures the full recovery of useful minerals while improving the efficiency and effect of subsequent spiral chute classification, thereby further improving the grade of the chromium concentrate.

[0017] Preferably, the spiral chute classification in step (1) includes: entering a section of cyclone underflow into 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 into 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, etc., 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 first shaking table light ore and 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 grade of the middlings and tailings obtained by the shaking table separation can be reduced to a certain extent, and the recovery rate of heavy ore containing chromium elements can be increased, thereby improving the grade and recovery rate of the first chromium concentrate and the chromium middlings.

[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 1000-1600Gs, for example, it can be 1050Gs, 1100Gs, 1150Gs, 1200Gs, 1250Gs, 1300Gs, 1350Gs, 1400Gs, 1450Gs, 1500Gs or 1600Gs.

[0028] Preferably, the first weak magnetic separation comprises: subjecting the heavy ore obtained after classification on the second shaking table to first weak magnetic separation to obtain first weak magnetic separation concentrate and 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 is subjected to a first weak magnetic separator under a specific magnetic field strength to separate the strongly magnetic chromium-containing minerals, and a high-grade first chromium concentrate is obtained after spiral classification.

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

[0032] Preferably, the second weak magnetic separation comprises: subjecting the middlings obtained after classification on the second shaking table 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 further screened by the second weak magnetic separator under a specific magnetic field strength to select chromium-containing minerals with relatively strong magnetism for recovering chromium middlings.

[0034] Preferably, the middlings obtained by the first weak magnetic separation and the concentrate 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, the chromium grade of the first chromium concentrate in step (1) 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 and the particle size range of the first ball mill, the monomer dissociation of chromite wrapped 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 1000-2000Gs, for example, it can be 1000Gs, 1100Gs, 1200Gs, 1300Gs, 1400Gs, 1500Gs, 1600Gs, 1700Gs, 1800Gs, 1900Gs or 2000Gs, 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 10000~20000Gs, for example, it can be 10000Gs, 11000Gs, 12000Gs, 13000Gs, 14000Gs, 15000Gs, 16000Gs, 17000Gs, 18000Gs, 19000Gs or 20000Gs, etc.

[0044] In the present invention, the high-magnetic field strength of the strong magnetic separator is used to magnetically separate out 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: performing a first-stage impurity removal on the overflow of the first cyclone to obtain a first-stage impurity-removed solution; mixing the overflow of the second cyclone with a strong magnetic separation non-magnetic material to perform a second-stage impurity removal to obtain a second-stage impurity-removed solution; and then mixing the flocculant, the first-stage impurity-removed solution and the second-stage impurity-removed solution to perform 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 in 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) The laterite nickel ore is sequentially subjected to ore washing and a first-stage cyclone separation to obtain a first-stage cyclone overflow and a first-stage cyclone underflow, wherein the particle size of the ore particles of the first-stage cyclone underflow is 74 μm to 2 mm; the first-stage cyclone underflow is then subjected to spiral chute classification to obtain a chute light ore material and a chute heavy ore material; the chute heavy ore material is then subjected to a first shaking table classification at a shaking table stroke of 8 to 16 mm and a stroke frequency of 245 to 380 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material; the first shaking table heavy ore material is then subjected to a second shaking table classification at a shaking table stroke of 8 to 12 mm and a stroke frequency 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 to 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 spirally classified to obtain a chromium middling with a chromium grade of ≥24%;

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

[0056] (2) subjecting the mixed light ore of step (1) to a first ball mill and a 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 a shaking table classification and a spiral classification, to obtain a second chromium concentrate with a chromium grade of ≥35% and a recovery rate of ≥15%;

[0057] After the first ball milling, the output particle size of the mineral particles is -200 mesh, accounting for more than 65%;

[0058] (3) subjecting the non-magnetic material from the third weak magnetic separation in step (2) to strong magnetic separation at a magnetic field strength of 10,000 to 20,000 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 in step (1) and the magnetic material from the strong magnetic separation, subjecting the ore to a second ball milling at a rotation speed of 15 to 20 r / min and then recycling the ore to the first ball milling in step (2); the ore particles with a particle size of -200 mesh after the second ball milling account for more than 60%;

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

[0060] The numerical range described in the present invention includes not only the point values ​​listed above, but also 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, several weak magnetic separations, and several spiral classifications, thereby obtaining a first chromium concentrate, chromium middlings, weak magnetic separation middlings, and a mixed light ore; wherein the chromium grade of the first chromium concentrate is ≥40%, the chromium grade of the chromium middlings is ≥24%, and the recovery rates of the first chromium concentrate and the chromium middlings 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 ore extracted by weak magnetic separation and the chromium in the limonite and chromite that have been missed in the magnetic material of strong magnetic separation by combining the processes 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 for laterite nickel ore provided in Example 1. DETAILED DESCRIPTION

[0065] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely 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 embodiment 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 impurities such as Ca, Mg, Cr2O3 and SiO2 are also present.

[0067] In the following examples and comparative examples, the laterite nickel ore was washed before chromium separation. The washing process was as follows: the raw laterite nickel ore was conveyed by a heavy-duty plate feeder to a drum ore washer to remove gravel with a particle size of 35 mm or greater. The ore was then processed by a double-screw scrubber and a linear vibrating screen to remove gravel with a particle size of 2 mm or greater. The ore was then fed sequentially into a mixing tank and a slurry pump to obtain a de-graveled ore material, which was then assayed for chromium content. The de-graveled ore material had a Cr2O3 grade of 3.39% and a Cr2O3 recovery of 97.4%.

[0068] Example 1

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

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

[0071] The heavy ore material in the second shaking table is subjected to first weak magnetic separation at a magnetic field strength of 1500 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;

[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 and spirally classified to obtain a chromium middling;

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

[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] After the first ball milling, the output particle size of the mineral particles is -200 mesh, accounting for more than 70%;

[0076] (3) subjecting the non-magnetic material from the third weak magnetic separation in step (2) to strong magnetic separation at a magnetic field strength of 10,000 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 in step (1) and the magnetic material from the strong magnetic separation, subjecting the mixture to a second ball milling at a rotation speed of 17.3 r / min and then recycling the mixture to the first ball milling in step (2); the ore particles after the second ball milling having a particle size of -200 mesh account for more than 60%;

[0077] At the same time, the first-stage cyclone overflow of step (1) is subjected to a first-stage impurity removal to obtain a first-stage impurity-removed solution, and then the first-stage impurity-removed solution is sequentially transported to a finished product tank and a 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 to obtain a second-stage impurity-removed solution and transported to a 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 laterite-nickel ore combined beneficiation method of this embodiment is completed when the Cr2O3 grade and recovery rate in the second chromium concentrate remain stable.

[0079] Example 2

[0080] This embodiment provides a combined beneficiation method for laterite nickel ore, which comprises the following steps:

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

[0082] The heavy ore material in the second shaking table is subjected to 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 and spirally classified to obtain a chromium middling;

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

[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] After the first ball milling, the output particle size of the mineral particles is -200 mesh, accounting for more than 70%;

[0087] (3) subjecting the non-magnetic material from the third weak magnetic separation in 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 in step (1) and the magnetic material from the strong magnetic separation, subjecting the mixture to a second ball milling at a rotation speed of 18 r / min and then recycling the mixture to the first ball milling in step (2); the ore particles after the second ball milling having a particle size of -200 mesh account for more than 60%;

[0088] At the same time, the first-stage cyclone overflow of step (1) is subjected to a first-stage impurity removal to obtain a first-stage impurity-removed solution, and then the first-stage impurity-removed solution is sequentially transported to a finished product tank and a 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 to obtain a second-stage impurity-removed solution and transported to a 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 laterite-nickel ore combined beneficiation method of this embodiment is completed when the Cr2O3 grade and recovery rate in the second chromium concentrate remain stable.

[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 discharge particle size of -200 mesh after the first ball milling account for more than 50%, other conditions are the same as those in Example 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, 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 the second-stage cyclone separation is not performed in step (2), 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 the third shaking table classification is not performed in step (2), that is, the non-magnetic materials separated by the third weak magnetic separation are directly subjected to spiral classification, 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 the second ball milling is not performed in step (3), that is, the ore removed by the second weak magnetic separation and the magnetic material separated by the strong magnetic separation are used as slag instead of ball milling 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, wherein the conditions are the same as those in Example 1 except that the strong magnetic separation and the second ball milling are not performed in step (3), that is, the overflow of the first stage cyclone in step (1) and the overflow of the second stage cyclone in step (2) are directly post-treated to obtain a high-pressure leaching solution.

[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 to 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 and performing 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 a first strong magnetic separation 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 collected 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 a first shaking table classification to obtain a first shaking table light ore and a first shaking table heavy ore, and then the first shaking table heavy ore is subjected to a second shaking table classification to obtain a second shaking table light ore, a second shaking table medium ore, and a second shaking table heavy ore;

[0112] The heavy ore material 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 ore, and then the second weak magnetic separation concentrate is subjected to spiral classification to obtain a chromium concentrate;

[0113] The ore from 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 from the second weak magnetic separation is mixed with the concentrate obtained from the third weak magnetic separation, and spirally classified to obtain the second chromium middling;

[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 them to first ball milling and second-stage cyclone separation to obtain second-stage cyclone overflow and second-stage cyclone underflow;

[0116] After the first ball milling, the output particle size of the mineral particles is -200 mesh, accounting for more than 70%;

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

[0118] The second-stage cyclone bottom flow and the ore separated in the third weak magnetic separation in step (2) are mixed, subjected to a second ball milling, 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%; and the chromium content in the high-pressure leaching 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 will be detrimental to improving the grade and recovery rate of the chromium concentrate.

[0122] In the above examples and comparative examples, the chromium contents in the chromium concentrate, chromium middlings and high-pressure leaching stock solution obtained in the above examples and comparative examples were determined by titration, and the corresponding recoveries 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-stage cyclone separation, a spiral chute, a multi-stage shaking table classification, several weak magnetic separations and several spiral classifications, thereby obtaining a first chromium concentrate with a chromium grade of ≥40% and a chromium middling with a chromium grade of ≥24%. The combined process of multiple ball milling, a second-stage cyclone, a weak magnetic separation and a strong magnetic separation is used to further enrich and separate the chromium in the mixed light ore, the weak magnetic separation middling and the limonite and chromite that have been missed in the strong magnetic separation magnetic material, 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. 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 ≤0.02%.

[0128] (2) From the comparison between Example 1, 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 encapsulated chromite monomers cannot be fully dissociated, resulting in a decrease in the chromium grade and recovery rate of the second chromium concentrate;

[0129] (3) From the comparison between Example 1 and 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 enters 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 underflow, 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) From the comparison between Example 1 and Comparative Example 3, it can be seen that if the third shaking table classification is not performed and the non-magnetic material of the third weak magnetic separation is directly subjected to spiral classification, the chromium concentrate and the middlings cannot be separated, resulting in a decrease in the grade and recovery rate of the second chromium concentrate;

[0132] (6) From the comparison between Example 1 and 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 that have been missed in the weak magnetic separation and the non-magnetic materials in the third weak magnetic separation 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 embodiment of the present invention, but the scope of protection 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 fall within the scope of protection and disclosure 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) The laterite nickel ore is sequentially subjected to ore washing and a first-stage cyclone separation to obtain a first-stage cyclone overflow and a first-stage cyclone underflow, and then the first-stage cyclone underflow is sequentially subjected to spiral chute classification, multi-stage shaking table classification, several weak magnetic separations and several spiral classifications to obtain a first chromium concentrate, chromium middlings, weak magnetic separation ore and mixed light ore; (2) subjecting the mixed light ore of step (1) to first ball milling and second-stage cyclone separation in sequence to obtain second-stage cyclone overflow and second-stage cyclone underflow, and then subjecting the second-stage 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) The third weak magnetic separation non-magnetic material of 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 ore from the weak magnetic separation and the strong magnetic separation magnetic material 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.

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~2 mm.

3. The combined mineral processing method according to claim 1, characterized in that: The spiral chute classification in step (1) includes: feeding a section of cyclone underflow into 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.

4. The combined mineral processing method according to claim 1, characterized in that: The multi-stage shaking table classification in step (1) includes a first shaking table classification and a second shaking table classification performed in sequence.

5. The combined mineral processing method according to claim 4, characterized in that: When the first shaking table is used for classification, the stroke of the shaking table is 8-16 mm and the stroke frequency is 245-380 times / min.

6. The combined mineral processing method according to claim 4, characterized in that: 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.

7. The combined mineral processing method according to claim 4, characterized in that: When the second shaking table is used for classification, the stroke of the shaking table is 8-12 mm and the stroke frequency is 320-380 times / min.

8. The combined mineral processing method according to claim 4, characterized in that: 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.

9. The combined mineral processing method according to claim 1, characterized in that: The several weak magnetic separations in step (1) include a first weak magnetic separation and a second weak magnetic separation which are performed independently.

10. The combined mineral processing method according to claim 9, characterized in that: The magnetic field strength of the first weak magnetic separation is 1000~1600Gs.

11. The combined mineral processing method according to claim 9, characterized in that: The first weak magnetic separation includes: performing first weak magnetic separation on the heavy ore obtained after classification on the second shaking table to obtain first weak magnetic separation concentrate and first weak magnetic separation ore.

12. The combined mineral processing method according to claim 11, characterized in that: The first weak magnetic separation concentrate is spirally classified to obtain a first chromium concentrate.

13. The combined mineral processing method according to claim 9, characterized in that: The magnetic field strength of the second weak magnetic separation is 1400~2000Gs.

14. The combined mineral processing method according to claim 9, characterized in that: The second weak magnetic separation includes: performing second weak magnetic separation on the middling material obtained after classification on the second shaking table to obtain second weak magnetic separation concentrate and second weak magnetic separation ore.

15. The combined mineral processing method according to claim 9, characterized in that: The middlings obtained from the first weak magnetic separation and the concentrates obtained from the second weak magnetic separation are mixed and subjected to spiral classification to obtain the chromium middlings.

16. The combined mineral processing method according to claim 1, characterized in that: Step (1) The chromium grade of the first chromium concentrate is ≥40%.

17. The combined mineral processing method according to claim 1, characterized in that: The chromium grade of the chromium ore in step (1) is ≥24%.

18. The combined mineral processing method according to claim 1, characterized in that: In step (2), the rotation speed of the first ball mill is 15-20 r / min.

19. The combined mineral processing method according to claim 1, characterized in that: In step (2), the output particle size of the first ball milling is -200 mesh mineral particles accounting for more than 65%.

20. The combined mineral processing method according to claim 19, characterized in that: In step (2), the output particle size of the first ball milling is -200 mesh mineral particles accounting for more than 70%.

21. The combined mineral processing method according to claim 1, characterized in that: The magnetic field strength of the third weak magnetic separation in step (2) is 1000~2000Gs.

22. The combined mineral processing method according to claim 1, characterized in that: The magnetic field strength of the strong magnetic separation in step (3) is 10000~20000Gs.

23. The combined mineral processing method according to claim 1, characterized in that: In step (3), the rotation speed of the second ball mill is 15-20 r / min.

24. The combined mineral processing method according to claim 1, characterized in that: In step (3), the output particle size of the second ball milling is -200 mesh, accounting for more than 60%.

25. The combined mineral processing method according to claim 1, characterized in that: The post-treatment in step (3) includes: performing a first-stage impurity removal on the first-stage cyclone overflow to obtain a first-stage impurity-removed solution; mixing the second-stage cyclone overflow with a strong magnetic separation non-magnetic material to perform 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 perform solid-liquid separation to obtain a high-pressure leaching stock solution.

26. The combined mineral processing method according to claim 1, characterized in that: In step (2), the chromium grade of the second chromium concentrate is ≥35%.

27. The combined mineral processing method according to claim 1, characterized in that: The recovery rate of the second chromium concentrate in step (2) is ≥15%.

28. The combined mineral processing method according to claim 1, characterized in that: The chromium content in the high-pressure leaching solution in step (3) is ≤0.2%.

29. The combined mineral processing method according to claim 28, characterized in that: The chromium content in the high-pressure leaching solution in step (3) is ≤0.05%.

30. The combined mineral processing method according to claim 1, characterized in that: The combined mineral processing method comprises the following steps: (1) The laterite nickel ore is sequentially subjected to ore washing and a first-stage cyclone separation to obtain a first-stage cyclone overflow and a first-stage cyclone underflow, wherein the particle size of the cyclone underflow is 74 μm to 2 mm; the first-stage cyclone underflow is then subjected to spiral chute classification to obtain a chute light ore material and a chute heavy ore material; the chute heavy ore material is then subjected to a first shaking table classification at a shaking table stroke of 8 to 16 mm and a stroke frequency of 245 to 380 times / min to obtain a first shaking table light ore material and a first shaking table heavy ore material; the first shaking table heavy ore material is then subjected to a second shaking table classification at a shaking table stroke of 8 to 12 mm and a stroke frequency 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 spirally classified to obtain a chromium middling with a chromium grade of ≥24%; The obtained chute light ore, the first shaking table light ore and the second shaking table light ore constitute a mixed light ore; (2) subjecting the mixed light ore of step (1) to a first ball mill and a second cyclone separation at a rotation speed of 15-20 r / min in sequence 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 1000-2000 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 a shaking table classification and a spiral classification in sequence to obtain a second chromium concentrate with a chromium grade of ≥35% and a recovery rate of ≥15%; After the first ball milling, the output particle size of the mineral particles is -200 mesh, accounting for more than 65%; (3) The non-magnetic material of the third weak magnetic separation in step (2) is subjected to strong magnetic separation at a magnetic field strength of 10,000 to 20,000 Gs to obtain strong magnetic separation non-magnetic material and strong magnetic separation magnetic material, and then the ore extracted from the second weak magnetic separation in step (1) and the strong magnetic separation magnetic material are mixed, and the ore is subjected to a second ball milling at a rotation speed of 15 to 20 r / min and then reused in the first ball milling in step (2); the ore particles with a particle size of -200 mesh after the second ball milling account for more than 60%; At the same time, the first-stage cyclone overflow of step (1) is subjected to a first-stage impurity removal to obtain a first-stage impurity-removed solution; 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 to obtain a second-stage impurity-removed solution; and then the flocculant, the first-stage impurity-removed solution and the second-stage impurity-removed solution are mixed and solid-liquid separation is performed to obtain a high-pressure leaching stock solution with a chromium content of ≤0.2%.

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