Method for recovering valuable metals in laterite-nickel ore gravels
Through the method of circulating leaching and supplementing leaching liquid, the problem of low recovery efficiency of valuable metals in laterite nickel ore gravel is solved, and efficient resource recycling and utilization is achieved.
Patent Information
- Application Number
- CN202411559370.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-02-14
AI Technical Summary
The resource utilization rate of existing laterite nickel ore is low, especially the valuable metals in gravel cannot be effectively recycled, resulting in waste of resources.
By stacking the laterite nickel ore gravel in the leaching pond, using sulfuric acid as the leaching solution for circulating leaching, the initial leaching solution is replenished before each leaching, and repeated leaching times to recover the valuable metal.
Maximize the recycling of valuable metals in gravel, improve the resource utilization rate of laterite nickel ore, is easy to operate, has low energy consumption, large processing volume and low cost.
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of laterite nickel ore resource recovery, and in particular to a method for recovering valuable metals in laterite nickel ore gravel. Background Art
[0002] Laterite nickel ore contains rich valuable metals such as nickel and cobalt. At present, pyrometallurgy or hydrometallurgy is mainly used to extract nickel and cobalt from laterite nickel ore. The hydrometallurgy process usually includes ore dressing, high-pressure acid leaching, leaching solution impurity removal, metal precipitation and other steps. Among them, ore dressing refers to the separation of valuable minerals by physical methods. Some by-products will be produced during the ore dressing process, such as gravel (also known as laterite nickel ore gravel). Due to the low content of valuable metals such as nickel and cobalt in gravel and the high magnesium content, it cannot enter the subsequent high-pressure acid leaching stage. This part of gravel is generally used as waste rock or as a filler pile in the goaf. Therefore, it is necessary to provide a method for recycling valuable metals in gravel to improve the resource utilization rate of laterite nickel ore. Summary of the invention
[0003] The main purpose of the present application is to provide a method for recovering valuable metals in laterite nickel ore gravel to solve the problem of low utilization rate of existing laterite nickel ore resources.
[0004] In order to achieve the above object, one aspect of the present application provides a method for recovering valuable metals in laterite nickel ore gravel, comprising:
[0005] S1, stacking the laterite nickel ore gravel in the leaching tank to form a gravel layer;
[0006] S2, adding the leaching solution into the leaching tank so that the liquid level of the leaching solution is above the gravel layer, and after the initial leaching, discharging the initial leaching solution;
[0007] S3, returning the initial leachate to the leaching tank, collecting the leachate after N cycles of leaching; wherein N ≥ 1, and before each cycle of leaching, adding supplementary leachate to the leachate produced by the previous cycle of leaching, and then returning the leachate to the leaching tank to complete the cycle of leaching.
[0008] Furthermore, S2 and S3 are one leaching cycle, and the recovery method further comprises:
[0009] S4, repeat S2 and S3 with fresh leaching solution to complete M leaching cycles, and collect the leaching solution generated after each leaching cycle; wherein M≥1.
[0010] Further, in one leaching cycle, except for the Nth cyclic leaching, the liquid level in the leaching pool is kept above the gravel layer; and / or, N is 1-50, and M is 1-10.
[0011] Furthermore, S1 includes:
[0012] S11, crushing and screening the laterite nickel ore gravel to obtain gravel to be processed; the particle diameter of the gravel to be processed is ≤25 mm;
[0013] S12, piling the gravel to be treated in a leaching tank to form a gravel layer.
[0014] Further, in S2, the leaching solution is sulfuric acid, and preferably the concentration of H2SO4 in the leaching solution is 10 to 100 g / L;
[0015] Preferably, the concentration of H2SO4 in the extract is 50-80 g / L.
[0016] Furthermore, in S3, before each leaching cycle, a supplementary leaching solution is added to the leaching solution produced by the previous leaching cycle to maintain the H2SO4 concentration therein at 10-100 g / L, and then returned to the leaching tank;
[0017] Preferably, before each leaching cycle, supplementary leaching solution is added to the leaching solution produced by the previous leaching cycle to maintain the H2SO4 concentration therein at 50-80 g / L, and then returned to the leaching tank.
[0018] Furthermore, in S2, the ratio of the volume of the extract to the dry basis mass of the gravel layer is 0.1 to 10 m 3 / t.
[0019] Further, each leaching cycle is 1 to 120 hours; and / or, the time of each cyclic leaching is 0.5 to 24 hours;
[0020] Preferably, each leaching cycle is 12 to 48 hours; preferably, the time for each cyclic leaching is 1 to 12 hours.
[0021] Furthermore, it also includes:
[0022] S5, after completing M leaching cycles, washing water is sprayed or poured into the leaching tank to wash and soak the leached residue until the pH value of the washing solution reaches 6 to 9;
[0023] Preferably, the washing times are 1 to 5 times, and the soaking time for each time is 1 to 6 hours.
[0024] Furthermore, the nickel mass content in the laterite nickel ore gravel is 0.3% to 1.5%, the cobalt mass content is 0.01% to 0.1%, the iron mass content is 1% to 30%, the manganese mass content is 0.01% to 2%, the chromium mass content is 0.01% to 2%, the magnesium mass content is 1% to 40%, the aluminum mass content is 0.01% to 10%, and the silicon mass content is 1% to 40%.
[0025] By applying the technical solution of the present application, valuable metals in gravel can be recovered to the maximum extent through cyclic leaching with leaching solution and replenishing the leaching solution before each cyclic leaching, thereby improving the resource utilization rate of laterite nickel ore. The operation is simple and has the advantages of low energy consumption, large processing volume and low cost. DETAILED DESCRIPTION
[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below in conjunction with the embodiments.
[0027] As described in the background technology, the existing gravel has the problem of low resource utilization. In order to solve the above technical problems, the present application provides a method for recovering valuable metals in laterite nickel ore gravel, comprising:
[0028] S1, stacking the laterite nickel ore gravel in the leaching tank to form a gravel layer;
[0029] S2, adding the leaching solution into the leaching tank so that the liquid level of the leaching solution is above the gravel layer, and after the initial leaching, discharging the initial leaching solution;
[0030] S3, returning the initial leachate to the leaching tank, collecting the leachate after N cycles of leaching; wherein N ≥ 1, and before each cycle of leaching, adding supplementary leachate to the leachate produced by the previous cycle of leaching, and then returning the leachate to the leaching tank to complete the cycle of leaching.
[0031] The laterite nickel ore gravel of the present application is the gravel produced in the ore dressing stage of the laterite nickel ore hydrometallurgy process. Specifically, the laterite nickel ore hydrometallurgy process is a process method for extracting nickel from laterite nickel ore, and the hydrometallurgy process mainly includes the steps of ore dressing, leaching, purification, and precipitation. The ore dressing stage usually includes ore washing, screening, ore dressing and other treatments. Due to the complex ore properties of laterite nickel ore, it usually contains gravels of varying particle sizes. These gravels are separated by ore washing and screening, that is, laterite nickel ore gravels. These laterite nickel ore gravels usually contain a small amount of valuable metals nickel and cobalt, and are generally used as waste rock or backfilled in goafs.
[0032] In S1, laterite nickel ore gravel is used as a pool leaching raw material and piled in a leaching pool. Specifically, the surface of the gravel can be flattened to form a gravel layer.
[0033] In S2, the leachate can be fed into the leaching pool by spraying so that the leachate covers the surface of the gravel layer to ensure the uniformity of the leachate fed to the entire pool surface and promote the dissolution of the target component. The process of using the leachate for leaching for the first time is the primary leaching, and the leachate produced by the primary leaching is obtained, that is, the primary leachate. In the present application, the leachate can be prepared by mixing the lean solution (or water) with concentrated sulfuric acid to prevent the concentrated sulfuric acid from being over-acidified locally and causing excessive leaching of the impurity Mg.
[0034] In S3, the initial leachate is used for leaching again to extract the remaining target components. This process can be repeated N times. After the N cycles of leaching are completed, the leachate produced by the last cycle of leaching is collected, that is, the leachate, which can be directly used to recover valuable metals. Specifically, the leachate can be sent to the neutralization and impurity removal process of the laterite nickel ore hydrometallurgy process for impurity removal and subsequent processes.
[0035] Wherein, N≥1, before each cycle leaching, supplementary leaching solution is added to the leaching solution produced by the previous cycle leaching, and then returned to the leaching tank to complete the cycle leaching. Specifically, after the first leaching is completed, the initial leachate is mixed with the supplementary leachate, and then returned to the leaching tank for the first cycle leaching; after the first cycle leaching is completed, the leachate generated by the first cycle leaching is mixed with the supplementary leachate, and then returned to the leaching tank for the second cycle leaching; after the second cycle leaching is completed, the leachate generated by the second cycle leaching is mixed with the supplementary leachate, and then returned to the leaching tank for the third cycle leaching, and so on, until the N-1th cycle leaching is completed, the leachate generated by the N-1th cycle leaching is mixed with the supplementary leachate, and then returned to the leaching tank for the Nth cycle leaching. After the Nth cycle leaching is completed, the final leachate is obtained. In this way, through the cyclic leaching of the leachate and the supplementary leachate before each cycle leaching, the valuable metals in the gravel can be recovered to the maximum extent, the resource utilization rate of the laterite nickel ore gravel is improved, and the operation is simple, and it has the advantages of low energy consumption, large processing capacity, low cost, etc. In some embodiments, a circulation tank can be used to collect the leachate produced by the initial leaching and each cyclic leaching, and then return it to the leaching tank. At this time, the leaching tank is connected to the circulation tank, the liquid outlet of the leaching tank is connected to the liquid inlet of the circulation tank, and the liquid outlet of the circulation tank is connected to the liquid inlet of the leaching tank; the liquid inlet of the leaching tank is located at the top, and the liquid outlet of the leaching tank is located at the bottom. The circulation tank is also provided with an acidity monitoring unit. During the cyclic leaching process, the acid is continuously added to the circulation tank by monitoring the pH value or sampling to detect the acidity. After the cyclic leaching cycle of a single leaching solution is completed, the leachate in the leaching tank and the circulation tank is emptied and recovered.
[0036] In the above embodiment, the leaching solution can be prepared in the circulation tank, for example, the lean solution (water) and concentrated sulfuric acid (industrial sulfuric acid with a concentration of 98%) are simultaneously introduced into the circulation tank to form the leaching solution; then the leaching solution in the circulation tank is sprayed onto the gravel layer in the leaching tank. When the leaching solution in the leaching tank is above the gravel layer, the lean solution (water) is no longer introduced into the circulation tank, and concentrated sulfuric acid is continuously introduced (i.e., the leaching solution is replenished). At the same time, the drain valve at the bottom of the leaching tank is opened to circulate the leached leaching solution to the circulation tank, and the leaching solution enters from the top of the gravel layer and is discharged from the bottom of the gravel layer, forming a continuous cycle of "circulation tank-leaching tank-circulation tank" and continuous acid leaching. In this way, during the circulation leaching process, the liquid level in the leaching tank is kept above the gravel layer. The N cycles of each leaching cycle actually means that all the leaching liquid (the sum of the liquid in the circulation tank and the leaching pool) in each leaching cycle has circulated N times as a whole. At this time, N is the total circulation volume of the leaching liquid in one leaching cycle / the volume of the initial leaching liquid. Similarly, N is the time of one leaching cycle / the time for all the leaching liquid (the sum of the liquid in the circulation tank and the leaching pool) to circulate once as a whole.
[0037] In order to further improve the resource utilization rate of laterite nickel ore gravel, multiple leaching cycles can be performed on the gravel layer. In some embodiments, S2 and S3 are one leaching cycle, and the recovery method further includes:
[0038] S4, repeat S2 and S3 with fresh leaching solution to complete M leaching cycles, and collect the leaching solution generated after each leaching cycle; wherein M≥1.
[0039] Specifically, each leaching cycle includes an initial leaching and N cycles of leaching. After the leaching cycle of each leaching solution ends, the leachates produced in the last cycle of each leaching cycle are collected respectively. These leachates contain target component valuable metals and can be directly used to recover valuable metals.
[0040] Wherein, M≥1, and M is a natural integer. Specifically, the first leachate is added to the leaching pool, and the initial leaching and N-cycle leaching are carried out in sequence to complete the first leaching cycle, and the leachate produced after the first leaching cycle is obtained; the second leachate is continuously added to the leaching pool, and the initial leaching and N-cycle leaching are carried out in sequence to complete the second leaching cycle, and the leachate produced after the second leaching cycle is obtained. By analogy, the Mth leachate is continuously added to the leaching pool, and the initial leaching and N-cycle leaching are carried out in sequence to complete the leaching cycle of the Mth leachate, and the leachate produced after the Mth leaching cycle is obtained. The leaching cycles of the Mth leachate are completed, and the leachate produced after the first leaching cycle and the leachate produced after the second leaching cycle are collected, and by analogy, the leachate produced after the Mth leaching cycle is collected, which are the leachates produced after each leaching cycle. Wherein, the first leachate, the second leachate, and so on, the Mth leachate are different.
[0041] In some embodiments, in one leaching cycle, except for the Nth cyclic leaching, the liquid level in the leaching pool is kept above the gravel layer. In this way, continuous circulation and continuous acid leaching are ensured, further improving the leaching rate.
[0042] In some preferred embodiments, N is 1 to 50, for example, N is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40 or 50; M is 1 to 10, for example, M is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.
[0043] It should be noted that in S2 and S3, the present application can determine the number of cyclic leaching times according to the nickel concentration in the leachate, and can determine the number of leaching cycles according to the nickel leaching rate. The specific number can be determined according to actual conditions, and the present application does not make too many restrictions here.
[0044] In order to further improve the leaching rate of valuable metals, the laterite nickel ore gravel needs to be crushed and screened to ensure sufficient contact area. In some embodiments, S1 includes:
[0045] S11, crushing and screening the laterite nickel ore gravel to obtain gravel to be processed; the particle diameter of the gravel to be processed is ≤25 mm;
[0046] S12, piling the gravel to be treated in a leaching tank to form a gravel layer.
[0047] Specifically, the laterite nickel ore gravel is crushed and screened to a particle size of ≤25 mm, and then piled in a leaching tank as a pool leaching raw material to form a gravel layer.
[0048] The leaching solution of the present application may be sulfuric acid solution, which may be prepared by using the overflow solution of the second-stage nickel-cobalt thickener in the laterite nickel ore hydrometallurgy process and industrial sulfuric acid. In some embodiments, in S2, the concentration of H2SO4 in the leaching solution is 10-100 g / L, in some preferred embodiments, the concentration of H2SO4 in the leaching solution is 50-80 g / L, and in S3, the supplementary leaching solution may be industrial sulfuric acid with a concentration of 98%. By limiting the concentration of H2SO4 in the leaching solution, the leaching efficiency can be further improved.
[0049] Specifically, the concentration of H2SO4 in the extract is 10 to 100 g / L, for example, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 80 g / L, 100 g / L or a range consisting of any two of them.
[0050] The supplementary leaching solution of the present application can be industrial sulfuric acid. By adding the supplementary leaching solution to the leachate produced by the previous leaching, the leaching efficiency of each cyclic leaching is ensured. In some embodiments, in S3, before each cyclic leaching, the supplementary leaching solution is added to the leachate produced by the previous cyclic leaching, so that the H2SO4 concentration therein is maintained at 10-100 g / L, and then returned to the leaching tank. In some preferred embodiments, before each cyclic leaching, the supplementary leaching solution is added to the leachate produced by the previous cyclic leaching, so that the H2SO4 concentration therein is maintained at 50-80 g / L, and then returned to the leaching tank.
[0051] Specifically, before each leaching cycle, supplementary leaching solution is added to the leaching solution produced by the previous leaching cycle to maintain the H2SO4 concentration therein at 10 to 100 g / L, for example, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 80 g / L, 100 g / L or any two thereof.
[0052] In order to ensure that the leaching solution is in full contact with the gravel layer, in some embodiments, in S2, the ratio of the volume of the leaching solution to the dry basis mass of the gravel layer is 0.1 to 10 m 3 / t. That is, the volume of leaching solution added to each ton of gravel layer is 0.1~10m 3 , for example 0.1m 3 , 1m 3 、5m 3 、10m 3 Or a range consisting of any two of them.
[0053] The present application does not limit the time and speed of leaching, which can be adjusted according to actual needs. For example, in some embodiments, each leaching cycle is 1 to 120 hours; and / or, the time of each cyclic leaching is 0.5 to 24 hours. Preferably, each leaching cycle is 12 to 48 hours; preferably, the time of each cyclic leaching is 1 to 12 hours.
[0054] The time of each leaching cycle refers to the sum of the initial leaching time of a single leaching solution and the N-cycle leaching time.
[0055] The extraction time for each cycle refers to the duration of each cycle of extraction of the extract in one extraction cycle, and may also refer to the duration of the initial extraction of the extract in one extraction cycle.
[0056] By collecting the leaching liquid generated after each leaching cycle, the valuable metals in the gravel can be recovered. At this time, the leaching pool contains a residual gravel layer (also called leaching residue). By further processing the leaching residue, environmentally friendly discharge can be achieved and used as a filling material for reclamation of goaf areas. In some embodiments, it also includes:
[0057] S5, after completing the leaching cycles of M leaching solutions, washing water is sprayed or poured into the leaching tank to wash and soak the leached residue until the pH value of the washing solution reaches 6-9.
[0058] Specifically, the overflow of the second-stage nickel-cobalt thickener in the laterite nickel ore hydrometallurgy process can be fed into the leaching tank as washing water, and the soaking time starts after the washing water submerges the leaching residue, and the soaking time is 1 to 6 hours. The washing water after washing in the leaching tank is emptied and recovered, and the single washing is completed. In some preferred embodiments, the number of washings is 1 to 5 times. The washing liquid produced after washing is selected as a leaching liquid for recovery treatment or as a preparation of leaching liquid according to the valuable metal content. When the leaching residue is washed for the last time, lime milk and washing water are added to the leaching tank separately, or the washing water and lime milk are first mixed in the circulation tank and then fed into the leaching tank, so that the pH value of the last washing liquid reaches 6 to 9. Specifically, the washing water used for the first few washings (except the washing water used for the last washing) can be sprayed through the circulation tank, or can be directly fed into the leaching tank, or both methods can be used at the same time to save water intake time. The washing liquid produced after washing can be recovered together with the leaching liquid, preferably pumped to the laterite nickel ore hydrometallurgy process. During the last washing, the lime milk can be added by spraying it into the leaching tank through the circulation tank, or it can be added directly into the leaching tank. The washing liquid produced in the last washing is circulated to other leaching tanks through the circulation tank for preparing the leaching liquid.
[0059] After the leaching residue is washed, it is taken out from the leaching pool and stored, and can be used as filling material for reclamation of goaf areas later.
[0060] In some embodiments, the laterite nickel ore gravel is gravel produced in the beneficiation stage of the laterite nickel ore hydrometallurgical process; in some preferred embodiments, the nickel mass content of the laterite nickel ore gravel is 0.3% to 1.5%, the cobalt mass content is 0.01% to 0.1%, the iron mass content is 1% to 30%, the manganese mass content is 0.01% to 2%, the chromium mass content is 0.01% to 2%, the magnesium mass content is 1% to 40%, the aluminum mass content is 0.01% to 10%, and the silicon mass content is 1% to 40%.
[0061] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.
[0062] Example 1
[0063] In this embodiment, the laterite nickel ore gravel is the gravel produced in the beneficiation stage of the laterite nickel ore hydrometallurgical process, and the nickel mass content of the gravel is 0.93%, the cobalt mass content is 0.076%, the iron mass content is 16.18%, the manganese mass content is 0.79%, the chromium mass content is 0.57%, the magnesium mass content is 13.08%, the aluminum mass content is 1.77%, and the silicon mass content is 15.16%;
[0064] The sulfuric acid solution prepared by the overflow liquid of the second-stage nickel-cobalt thickener and concentrated sulfuric acid in the laterite nickel ore hydrometallurgy process is used as the leaching solution.
[0065] The method for recovering valuable metals from laterite nickel ore gravel in this embodiment comprises:
[0066] S1, crushing and screening the laterite nickel ore gravel to obtain the gravel to be processed with a particle diameter of less than 25 mm; piling the gravel in a leaching tank to form a gravel layer;
[0067] S2, add the leaching solution with H2SO4 concentration of 50g / L into the leaching tank, so that the liquid surface of the leaching solution is above the gravel layer. After the initial leaching, discharge the initial leaching solution; the ratio of the volume of the leaching solution to the dry basis mass of the gravel layer is 0.5m 3 / t;
[0068] S3, returning the initial leachate to the leaching tank, and collecting the leachate after 5 cycles of leaching, each cycle of leaching lasting 4 hours. Before each cycle of leaching, industrial sulfuric acid is added to the leachate produced by the previous cycle of leaching to make the H2SO4 concentration therein 50g / L, and then returning it to the leaching tank to complete the cycle of leaching.
[0069] S4, S2 and S3 are one leaching cycle, one leaching cycle is 24 hours, and S2 and S3 are repeated with fresh leaching solution to complete 7 leaching cycles, and the leaching solution produced after each leaching cycle is collected; wherein, the total leaching time is 168 hours.
[0070] Example 2
[0071] The difference from Example 1 is that in S2, the concentration of H2SO4 in the leaching solution is 60g / L.
[0072] Example 3
[0073] The difference from Example 1 is that in S2, the concentration of H2SO4 in the leaching solution is 70g / L.
[0074] Example 4
[0075] The difference from Example 1 is that in S2, the concentration of H2SO4 in the leaching solution is 80g / L.
[0076] Example 5
[0077] The difference from Example 1 is that in S2, the H2SO4 concentration in the leaching solution is 60g / L, and in S3, the initial leaching solution is returned to the leaching tank and leached twice, with each leaching time being 8h.
[0078] Example 6
[0079] The difference from Example 1 is that in S2, the H2SO4 concentration in the leaching solution is 80 g / L, and in S3, the initial leaching solution is returned to the leaching tank and leached twice, with each leaching time being 8 hours.
[0080] Example 7
[0081] The difference from Example 1 is that in S1, the laterite nickel ore gravel is crushed and sieved to obtain the gravel to be processed with a particle diameter of less than 10 mm.
[0082] Example 8
[0083] The difference from Example 1 is that in S1, the laterite nickel ore gravel is crushed and sieved to obtain the gravel to be treated with a particle diameter of less than 10 mm, and in S2, the H2SO4 concentration in the leaching solution is 60 g / L.
[0084] Example 9
[0085] The difference from Example 1 is that in S1, the laterite nickel ore gravel is crushed and sieved to obtain the gravel to be treated with a particle diameter of less than 10 mm, and in S2, the H2SO4 concentration in the leaching solution is 70 g / L.
[0086] Example 10
[0087] The difference from Example 1 is that in S1, the laterite nickel ore gravel is crushed and sieved to obtain the gravel to be treated with a particle diameter of less than 10 mm, and in S2, the H2SO4 concentration in the leaching solution is 80 g / L.
[0088] Embodiment 11
[0089] The difference from Example 1 is that in S2, the H2SO4 concentration in the leaching solution is 60 g / L, and in S4, the first leaching cycle is 30 h, the second leaching cycle is 42 h, the third leaching cycle is 60 h, and the fourth leaching cycle is 36 h, completing 4 leaching cycles.
[0090] Comparative Example 1
[0091] The difference from Example 1 is that in S3, no additional industrial sulfuric acid is added in each leaching cycle, the leaching solution is directly returned to the leaching tank, and S4 is omitted.
[0092] Comparative Example 2
[0093] The difference from Example 1 is that in S3, no additional industrial sulfuric acid is added in each leaching cycle, and the leaching solution is directly returned to the leaching tank.
[0094] The nickel leaching rate and cobalt leaching rate were calculated according to the following formula:
[0095] Nickel leaching rate = (1-(mass of nickel in leached residue / mass of nickel in initial gravel)) × 100%; cobalt leaching rate = (1-(mass of cobalt in leached residue / mass of cobalt in initial gravel)) × 100%. The results are shown in Table 1.
[0096] Table 1
[0097] serial number Nickel leaching rate Cobalt leaching rate Example 1 66.31％ 43.93％ Example 2 69.80％ 47.03％ Example 3 73.90％ 50.08％ Example 4 74.21％ 51.48％ Example 5 68.21％ 45.38％ Example 6 71.99％ 50.47％ Example 7 67.63％ 44.89％ Example 8 70.88％ 48.41％ Example 9 75.03％ 50.93％ Example 10 75.31％ 52.24％ Embodiment 11 68.30％ 45.91％ Comparative Example 1 9.8％ 7.3％ Comparative Example 2 32.6％ 24.8％
[0098] According to Table 1, the present invention can maximize the recovery of valuable metals in gravel and improve the resource utilization rate of laterite nickel ore gravel by circulating leaching with leaching solution and replenishing the leaching solution before each leaching cycle. The process is simple to operate and has the advantages of low energy consumption, large processing volume and low cost.
[0099] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.
[0100] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for recovering valuable metals from laterite nickel ore gravel, characterized in that: include: S1, stacking the laterite nickel ore gravel in the leaching tank to form a gravel layer; S2, adding the leaching solution into the leaching tank so that the liquid level of the leaching solution is above the gravel layer, and after the initial leaching, discharging the initial leaching solution; S3, returning the initial leachate to the leaching tank, collecting the leachate after N cycles of leaching; wherein N ≥ 1, and before each cycle of leaching, adding supplementary leachate to the leachate produced by the previous cycle of leaching, and then returning the initial leachate to the leaching tank to complete the cycle of leaching.
2. The recycling method according to claim 1, characterized in that: The S2 and S3 are one leaching cycle, and the recovery method further comprises: S4, repeating S2 and S3 with fresh leaching solution to complete M leaching cycles, and collecting the leaching solution generated after each leaching cycle; wherein M≥1.
3. The recycling method according to claim 2, characterized in that: In one leaching cycle, except for the Nth leaching cycle, the liquid level in the leaching tank is kept above the gravel layer; and / or, N is 1 to 50, and M is 1 to 10.
4. The recycling method according to claim 1 or 2, characterized in that: The S1 includes: S11, crushing and screening the laterite nickel ore gravel to obtain gravel to be processed; the particle diameter of the gravel to be processed is ≤25 mm; S12, piling the gravel to be treated in a leaching tank to form the gravel layer.
5. The recycling method according to claim 1 or 2, characterized in that: In S2, the leaching solution is sulfuric acid solution, and preferably the concentration of H2SO4 in the leaching solution is 10-100 g / L; More preferably, the concentration of H2SO4 in the extract is 50-80 g / L.
6. The recycling method according to claim 5, characterized in that: In S3, before each cycle leaching, a supplementary leaching solution is added to the leaching solution produced by the previous cycle leaching to maintain the H2SO4 concentration therein at 10-100 g / L, and then returned to the leaching tank; Preferably, before each of the cyclic leaching, supplementary leaching solution is added to the leaching solution produced by the previous cyclic leaching to maintain the H2SO4 concentration therein at 50-80 g / L, and then returned to the leaching tank.
7. The recycling method according to claim 1 or 2, characterized in that: In S2, the ratio of the volume of the extract to the dry basis mass of the gravel layer is 0.1 to 10 m 3 / t.
8. The recycling method according to claim 2, characterized in that: Each of the leaching cycles is 1 to 120 hours; and / or, each of the cyclic leaching times is 0.5 to 24 hours; Preferably, each of the leaching cycles is 12 to 48 hours; preferably, each of the cyclic leaching times is 1 to 12 hours.
9. The recycling method according to claim 2, characterized in that: Also includes: S5, after completing M leaching cycles, spraying and / or pouring washing water into the leaching tank to soak and wash the leached residue until the pH value of the washing liquid reaches 6 to 9; Preferably, the washing is performed 1 to 5 times, and the soaking time for each time is 1 to 6 hours.
10. The recovery method according to any one of claims 1 to 3, characterized in that: The laterite nickel ore gravel has a nickel content of 0.3% to 1.5% by mass, a cobalt content of 0.01% to 0.1% by mass, an iron content of 1% to 30% by mass, a manganese content of 0.01% to 2% by mass, a chromium content of 0.01% to 2% by mass, a magnesium content of 1% to 40% by mass, an aluminum content of 0.01% to 10% by mass, and a silicon content of 1% to 40% by mass.