A method for efficient recovery of nickel and cobalt from gravels
By classifying and refining the gravel by particle size, the problem of ineffective utilization of nickel and cobalt resources in gravel has been solved, achieving efficient recycling and environmentally friendly resource utilization, improving the nickel and cobalt recovery rate and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- FUJIAN HENGZHUO EQUIPMENT MANUFACTURING CO LTD
- Filing Date
- 2024-12-25
- Publication Date
- 2026-06-26
AI Technical Summary
In existing technologies, nickel and cobalt resources in gravel are not effectively utilized, resulting in waste of metal resources, low recovery rates, high transportation costs, and environmental pollution risks. Furthermore, traditional processing methods are inefficient.
Gravel is separated into different particle size grades by two-stage screening, and appropriate smelting methods are adopted according to the particle size grades, such as hydrometallurgy, post-grinding smelting, and pyrometallurgy. Combined with overflow ball mill and hydrocyclone classification, fine processing is carried out, including washing and impurity removal steps. Reasonable processing methods are selected to improve recovery efficiency.
This approach maximizes the utilization of nickel and cobalt resources, improves recycling efficiency and purity, reduces energy consumption and environmental pollution risks, broadens the utilization pathways of low-grade mineral resources, and aligns with the concept of green development.
Smart Images
Figure CN122279255A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of laterite nickel ore beneficiation technology, specifically relating to a method for efficiently recovering nickel and cobalt from gravel. Background Technology
[0002] Lateritic nickel deposits are mainly divided into an upper limonite layer, a middle transition layer, and a lower residual layer. The limonite layer is mainly composed of limonite-type lateritic nickel ore, which is suitable for hydrometallurgical processes. The residual layer is mainly composed of magnesium nickel silicate ore, which is suitable for pyrometallurgical processes. The middle transition layer is suitable for both processes. In nickel recovery processes, the proportion of hydrometallurgical processes is about twice that of pyrometallurgical processes. In the wet high pressure acid leaching (HPAL) process for laterite nickel ore, a large amount of gravel is produced during the washing stage. This gravel is incompletely weathered ferrosilicon nickel ore, which is an intermediate transitional form in the formation of laterite nickel ore. It contains valuable components such as nickel, cobalt, chromium, and manganese. Due to the technical limitations of the washing process, a layer of fine laterite nickel ore mud adheres to the surface of the gravel. The fine mud has a high nickel and cobalt grade, while the nickel and cobalt grade of the gravel itself is mostly lower than the average grade of laterite nickel ore. Because the economic benefits of gravel production are low, it has not been effectively utilized. In actual production, it is generally treated by paving roads, backfilling in mining areas, or transporting it to tailings storage. This treatment method has the following defects: (1) it causes a great waste of nickel and cobalt metal resources; (2) it causes a loss of the comprehensive recovery rate of nickel and cobalt in the wet process; (3) it increases vehicle transportation, maintenance, fuel consumption and labor costs, and shortens the storage period of tailings storage; (4) it poses an environmental pollution risk. Summary of the Invention
[0003] To address the problems existing in the prior art, this invention provides a method for efficiently recovering nickel and cobalt from gravel. The gravel mentioned in this invention refers to the gravel produced during the washing stage of the wet high-pressure acid leaching (HPAL) process for laterite nickel ore. Specifically, this invention includes the following:
[0004] The gravel is subjected to two-stage sieving to obtain first-size gravel, second-size gravel, and third-size gravel with successively decreasing particle size;
[0005] The third-sized gravel is subjected to hydrometallurgical processing to recover nickel and cobalt.
[0006] The second-sized gravel is ground and classified before being fed into a smelting neutralization system for smelting to recover nickel and cobalt.
[0007] The first-sized gravel is smelted using pyrometallurgy to recover nickel and cobalt.
[0008] Alternatively, the first-sized gravel may be subjected to harmless treatment.
[0009] Furthermore, the particle size of the first grade gravel is 10-50 mm; and / or, the particle size of the second grade gravel is 3-10 mm; and / or, the particle size of the third grade gravel is <3 mm.
[0010] Furthermore, the third-sized gravel is washed before hydrometallurgical processing.
[0011] Furthermore, the second-sized gravel is ground using an overflow ball mill to obtain a secondary slurry; then the secondary slurry is classified by a hydrocyclone to obtain underflow and overflow; the underflow is returned to the overflow ball mill for grinding, and the overflow is fed into the smelting neutralization system for smelting.
[0012] Furthermore, the overflow is screened through a sieve to remove impurities before being introduced into the smelting neutralization system for smelting.
[0013] Furthermore, the gravel contains ≤0.93wt% nickel and ≤0.08wt% cobalt.
[0014] Furthermore, the third-grade gravel contains ≥1.25wt% nickel and ≥0.15wt% cobalt.
[0015] Furthermore, the second-sized gravel contains ≥1.02wt% nickel and ≥0.08wt% cobalt.
[0016] Furthermore, the first-sized gravel contains less than 0.90 wt% nickel and less than 0.075 wt% cobalt.
[0017] The beneficial effects of this invention are:
[0018] (1) This invention separates gravel into different particle size grades through two-stage screening and adopts appropriate smelting methods (hydrometallurgical smelting, post-grinding smelting, and pyrometallurgical smelting) according to the characteristics of different gravel grades. For example, the smaller third-grade gravel is directly subjected to hydrometallurgical smelting, while the slightly larger second-grade gravel is smelted after grinding and classification. This not only adapts to the different material properties but also maximizes resource utilization, avoiding the resource waste that may be caused by traditional single processing methods. Moreover, it can process materials of each particle size more precisely, effectively improving the recovery efficiency and purity of nickel and cobalt. In particular, for the third-grade and second-grade gravel rich in nickel and cobalt, the resource utilization rate is significantly improved through fine processing.
[0019] (2) This invention reduces unnecessary energy consumption and material loss through precise particle size control and a reasonable smelting process design. Using an overflow ball mill for grinding, combined with hydrocyclone classification, improves grinding efficiency and effectively separates fine particles, reducing energy consumption and the difficulty of subsequent processing. Simultaneously, the choice to treat the first-stage gravel in a harmless manner reflects both environmental and economic considerations. Washing the third-stage gravel before hydrometallurgical processing, and subsequent impurity removal steps before smelting, effectively reduce the impact of impurities on the smelting process and lower the risk of environmental pollution. Furthermore, the flexible selection of treatment methods based on the different nickel and cobalt contents in the gravel not only improves recovery efficiency but also aligns with the concept of green and sustainable development.
[0020] (3) The method described in this invention is applicable to the processing of gravel resources with low nickel and cobalt content (nickel ≤ 0.93 wt%, cobalt ≤ 0.08 wt%). Through fine processing, valuable metal elements can be extracted from low-grade raw materials, which broadens the source of raw materials and provides a new way for the effective utilization of low-grade mineral resources. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the process flow of the method disclosed in this invention. Detailed Implementation
[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments shown below do not limit the scope of the invention as described in the claims. Furthermore, the complete contents of the configurations illustrated in the following embodiments are not limited to those necessary for the solution of the invention as described in the claims.
[0023] A method for efficiently recovering nickel and cobalt from gravel with low nickel and cobalt grades, wherein nickel ≤ 0.93 wt% and cobalt ≤ 0.08 wt%, the method comprising:
[0024] The gravel is subjected to two-stage sieving to obtain a first-size gravel with a particle size of 10-25 mm, a second-size gravel with a particle size of 3-10 mm, and a third-size gravel with a particle size of <3 mm. Classifying the gravel according to particle size allows for the enrichment of nickel and cobalt in the second and third-size gravel. Specifically, the third-size gravel contains ≥1.25 wt% nickel and ≥0.15 wt% cobalt, the second-size gravel contains ≥1.02 wt% nickel and ≥0.08 wt% cobalt, and the first-size gravel contains <0.90 wt% nickel and <0.075 wt% cobalt.
[0025] The third-sized gravel is washed and then subjected to hydrometallurgical processing to recover nickel and cobalt.
[0026] The second-sized gravel is ground using an overflow ball mill to obtain a secondary slurry; the secondary slurry is then classified by a hydrocyclone to obtain underflow and overflow; the underflow is returned to the overflow ball mill for grinding, screened for impurity removal, and then fed into a smelting neutralization system for smelting to recover nickel and cobalt.
[0027] The first-sized gravel can be smelted using pyrometallurgy to recover nickel and cobalt; or the first-sized gravel can be treated to render it harmless.
[0028] Example 1
[0029] A certain project's concentrator has an annual processing capacity of 9 million tons of dry limonite-type laterite nickel ore. On-site investigation revealed a small gravel yield of 9.79%, equivalent to an annual output of 881,100 tons. However, the designed grinding capacity for small gravel is 600,000 tons per year. To reduce the grinding load, the small gravel is screened before entering the mill. As shown in Table 1, the average yield of +10mm gravel reaches 50.95%, but its valuable element content is low, so it is stockpiled. The average yield of gravel smaller than 10mm is 49.05%.
[0030] Table 1. Screening and analysis results of small gravel at a mineral processing plant in a certain project.
[0031]
[0032] To address the industrialization issues associated with small gravel, a process improvement was implemented. The optimized scheme involves adding a double-layer screening system (using wet screening with 3mm and 10mm apertures) to separate the small gravel into three particle sizes: 10-25mm, 3-10mm, and -3mm. The -3mm material is returned to the washing system for further classification before entering the slurry storage tank for use as raw material slurry in the wet process for nickel and cobalt production. The 3-10mm material enters the small gravel grinding system for grinding and classification, subsequently entering the smelting neutralization system to recover some nickel and cobalt. The 10-25mm material is stored separately as a supplement to the designed grinding volume difference, and can be used for supplementary recovery of nickel and cobalt from pyrometallurgical raw materials, or for road paving, landfill, and other harmless treatment. Table 2 shows a comparison of the elemental contents of the small gravel entering the mill after the process improvement.
[0033] Table 2 Comparison of elemental content of small gravel entering the mill after process improvement.
[0034]
[0035] As shown in Table 2, the improved process increases the chromium, nickel, cobalt, and manganese content in the small gravel entering the mill, thereby increasing the utilization rate of the small gravel, reducing the amount of small gravel discharged, and reducing the tailings transportation costs.
[0036] Example 2
[0037] A method for efficiently recovering nickel and cobalt from gravel, including
[0038] The gravel is subjected to two-stage sieving to obtain first-grade gravel with a particle size of 10-25 mm, second-grade gravel with a particle size of 3-10 mm, and third-grade gravel with a particle size of <3 mm.
[0039] The third-sized gravel is washed and then subjected to hydrometallurgical processing to recover nickel and cobalt.
[0040] The second-sized gravel is ground using an overflow ball mill to obtain a secondary slurry; the secondary slurry is then classified by a hydrocyclone to obtain underflow and overflow; the underflow is returned to the overflow ball mill for grinding, screened for impurity removal, and then fed into a smelting neutralization system for smelting to recover nickel and cobalt.
[0041] The first-sized gravel can be smelted using pyrometallurgy to recover nickel and cobalt; or the first-sized gravel can be treated to render it harmless.
[0042] The composition of the gravel raw material and gravel of each size fraction in this embodiment is shown in Table 3.
[0043] Table 3. Composition of gravel raw materials and gravel of various sizes
[0044]
[0045] As shown in Table 3, the method disclosed in this invention can effectively enrich valuable elements in gravel and improve the recovery rate.
[0046] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for efficiently recovering nickel and cobalt from gravel, characterized in that, include The gravel is subjected to two-stage sieving to obtain first-size gravel, second-size gravel, and third-size gravel with successively decreasing particle size; The third-sized gravel is subjected to hydrometallurgical processing to recover nickel and cobalt. The second-sized gravel is ground and classified before being fed into a smelting neutralization system for smelting to recover nickel and cobalt. The first-sized gravel is smelted using pyrometallurgy to recover nickel and cobalt. Alternatively, the first-sized gravel may be subjected to harmless treatment.
2. The method for efficiently recovering nickel and cobalt from gravel according to claim 1, characterized in that, The first grade of gravel has a particle size of 10-50 mm; and / or, the second grade of gravel has a particle size of 3-10 mm; and / or, the third grade of gravel has a particle size of <3 mm.
3. The method for efficiently recovering nickel and cobalt from gravel according to claim 1, characterized in that, The third-sized gravel is washed before hydrometallurgical processing.
4. The method for efficiently recovering nickel and cobalt from gravel according to claim 1, characterized in that, The second-sized gravel is ground using a ball mill to obtain a secondary slurry; the secondary slurry is then classified by a classifying device to obtain underfill and overflow; the underfill is returned to the ball mill for grinding, and the overflow is flowed into the smelting neutralization system for smelting.
5. The method for efficiently recovering nickel and cobalt from gravel according to claim 4, characterized in that, The overflow is screened and impurities are removed before being fed into the smelting neutralization system for smelting.
6. The method for efficiently recovering nickel and cobalt from gravel according to any one of claims 1-5, characterized in that, The gravel contains ≤0.93wt% nickel and ≤0.08wt% cobalt.
7. A method for efficiently recovering nickel and cobalt from gravel according to claim 6, characterized in that, The third-grade gravel contains ≥1.25wt% nickel and ≥0.15wt% cobalt.
8. A method for efficiently recovering nickel and cobalt from gravel according to claim 6, characterized in that, The second-sized gravel contains ≥1.02wt% nickel and ≥0.08wt% cobalt.
9. A method for efficiently recovering nickel and cobalt from gravel according to claim 6, characterized in that, The first-sized gravel contains <0.90 wt% nickel and <0.075 wt% cobalt.