A method for synergism precipitation of iron-aluminum SLAG and tailings

Abstract

The present invention discloses a method for the synergism precipitation of iron-aluminum slag and tailings. The synergism precipitation method comprises the following steps: taking a laterite nickel ore high-pressure leaching slurry and sequentially performing a cyclic leaching treatment and a pre-neutralization treatment to obtain a pre-neutralized slurry, and then performing a multi-stage CCD washing to obtain a CCD overflow liquid; sequentially performing a first-stage iron-aluminum removal and a second-stage iron-aluminum removal treatment on the CCD overflow liquid, and the first-stage iron-aluminum removal underflow is recycled to the multi-stage CCD washing process, and is precipitated together with the pre-neutralized slurry to obtain a CCD underflow, and the CCD underflow is discharged after being subjected to tailings neutralization and filter pressing treatment in sequence. The present invention directly reuses the first-stage iron-aluminum removal underflow to the multi-stage CCD washing process, and dilutes it with water, so that the iron-aluminum slag in the original first-stage iron-aluminum removal underflow and the tailings in the pre-neutralized slurry are synergistically precipitated, which not only omits the filter pressing-washing cycle treatment of the first-stage iron-aluminum removal underflow in the prior art, but also effectively washes the two slag materials, reducing the content of nickel, cobalt and manganese in the final tailings.

Description

[0001] Description

[0002] A METHOD FOR SYNERGISM PRECIPITATION OF IRON-ALUMINUM SLAG AND TAILINGS

[0003] Field Of Disclosure

[0004] The invention belongs to the field of hydrometallurgy, and in particular relates to a synergism precipitation method of iron-aluminum slag and tailings .

[0005] Background

[0006] Nickel laterite is a type of ore rich in nickel and cobalt that is formed primarily in warm and humid climates when ultramafic rocks are weathered and leached at or near the surface to form nickel-rich laterite layers . The mining and processing of nickel laterite is critical to the global supply of nickel , especially for its growing use in the stainless steel and battery manufacturing industries .

[0007] Hydrometallurgy is a technology for extracting metals from ores , especially for processing ores with high water content and loose structure such as laterite nickel ore . The method mainly dissolves the metals in the ore into a solution through a series of chemical reactions , and then recovers the metals from the solution through steps such as precipitation, extraction or ion exchange . When processing laterite nickel ore , hydrometallurgical technology mainly includes high pressure acid leaching (HPAL ) , atmospheric acid leaching (ATM) and atmospheric sul furic acid leaching ( LSX ) .

[0008] Since laterite nickel ore not only contains rich nickel , cobalt , and manganese , but also contains other impurities such as iron, aluminum, chromium, etc . , impurity removal is a crucial processing step in the existing laterite nickel ore hydrometallurgical process , which directly affects the subsequent metal recovery ef ficiency and product quality . Furthermore , in the process of removing iron and aluminum, the iron and aluminum in the underflow often exist in the leachate in the form of colloids , which makes them di f ficult to separate by simple filtering methods . The current treatment method is to discharge it in the form of slag phase after multi-stage washing and pressure filtration . Due to the presence of iron-aluminum slag colloids , the above process is prone to blockage , and the treatment process is time-consuming and labor- intensive . It is urgent to propose a new process method to solve the above problems .

[0009] Summary

[0010] In the prior art , the first stage of iron and aluminum removal underflow is usually discharged after multiple cycles of treatment in the form of filter pressing and washing . Due to the presence of iron and aluminum slag colloid in the first stage of iron and aluminum removal underflow, the above process is prone to blockage , and the treatment process is time-consuming and labor-intensive . The purpose of the present invention is to provide a synergi sm precipitation method for iron and aluminum slag and tailings to solve the above problems .

[0011] The present invention is speci fically implemented through the following technical solutions :

[0012] A method for synergism precipitation of iron-aluminum slag and tailings comprises the following steps :

[0013] S I . Taking a laterite nickel ore high pressure leaching slurry and sequentially performing a cyclic leaching treatment and a pre-neutrali zation treatment to obtain a pre-neutrali zed slurry, and then performing a multi-stage CCD washing to obtain a CCD overflow liquid;

[0014] S2 The CCD overflow liquid is sequentially subj ected to first-stage iron and aluminum removal and second-stage iron and aluminum removal treatments . The first-stage iron and aluminum removal underflow is recycled to the multi-stage CCD washing process and precipitated together with the pre-neutrali zed slurry to obtain the CCD underflow . The CCD underflow is sequentially subj ected to tailings neutrali zation and filter press treatment before the tailings are discharged .

[0015] Preferably, in step S I , the process conditions for the cyclic leaching treatment are : controlling the pH<1 . 5 . Preferably, in step SI, the process conditions for the pre-neutralization treatment are: controlling the pH to be 1.8-2.2.

[0016] Preferably, the pre-neutralization treatment is performed by adding limestone to adjust the pH to 1.8-2.2.

[0017] Preferably, in step SI, the number of stages of multi-stage CCD washing is 2-6.

[0018] Preferably, in step SI, the process conditions for multi-stage CCD washing are: controlling pH=2.2-4.7.

[0019] Preferably, in step S2, the process conditions for the first stage of iron and aluminum removal treatment are: controlling the pH to be 3.5-3.8.

[0020] Preferably, in step S2, the process conditions for the second-stage iron and aluminum removal treatment are: controlling the pH to be 4.8-5.0.

[0021] Preferably, in step S2, the specific steps of recycling the first stage of iron and aluminum removal underflow to the multi-stage CCD washing process include: recycling the first stage of iron and aluminum removal underflow to the secondary CCD washing section in the multi-stage CCD washing process, and adding water to dilute it in the secondary CCD washing section, and the ratio of the volume of the added water to the volume of the first stage of iron and aluminum removal underflow is greater than 1.2.

[0022] Preferably, the concentration of the first stage iron removal aluminum underflow is less than 30%.

[0023] Preferably, in step S2, the specific step of neutralizing the tailings comprises: adding lime milk to make the system pH=7.

[0024] Preferably, the above-mentioned synergism precipitation method of iron-aluminum slag and tailings also includes: in step S2, after the second-stage iron-aluminum removal treatment, a second-stage iron-aluminum removal underflow and a second-stage iron-aluminum removal overflow are obtained, the second-stage iron-aluminum removal underflow is reused and sub ected to a cyclic leaching treatment again, and the second-stage iron-aluminum removal overflow is subjected to precipitation MHP treatment.

[0025] Compared with the prior art, the beneficial effects of the present invention include: It is directly recycled to the multi-stage CCD washing process and diluted with water, so that the iron and aluminum slag in the original underflow from the first stage of iron and aluminum removal and the tailings in the pre-neutrali zed slurry are synergistically settled, which not only eliminates the process of circulating the underflow from the first stage of iron and aluminum removal by filter pressing and washing in the prior art , but also can e f fectively wash the two slag materials , thereby reducing the nickel , cobalt and manganese content in the final tailings .

[0026] Brief Description Of The Drawings

[0027] FIG . l is a schematic flow diagram of a method for co-precipitating iron-aluminum slag and tailings according to the present invention;

[0028] FIG . 2 is a schematic flow diagram of the multi-stage CCD washing process of the present invention .

[0029] Detailed Description Of Preferred Embodiments

[0030] In order to make the purpose , technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conj unction with the embodiments . It should be understood that the speci fic embodiments described herein are only used to explain the present invention and are not used to limit the present invention .

[0031] The present invention provides a method for the synergism precipitation of iron-aluminum slag and tailings , comprising the following steps :

[0032] S I . A high-pressure leaching slurry of laterite nickel ore is subj ected to a cyclic leaching treatment and a pre-neutrali zation treatment in sequence to obtain a pre-neutrali zed slurry, which is then subj ected to a multi-stage CCD washing to obtain a CCD overflow liquid .

[0033] In some speci fic embodiments , in step S I , the process conditions of the cyclic leaching treatment are : controlling the pH value to be less than 1 . 5 ; the process conditions of the pre-neutrali zation treatment are : adj usting the pH value to 1 . 8~2 . 2 by adding limestone ; and the process conditions of the multi-stage CCD washing are: the number of stages of the multi-stage CCD washing is 2 to 6, and the pH value is controlled to be 2.2~4.7.

[0034] S2. The CCD overflow liquid is sequentially subjected to first-stage iron and aluminum removal and second-stage iron and aluminum removal treatments. The first-stage iron and aluminum removal underflow is recycled to the multi-stage CCD washing process and precipitated together with the pre-neutralized slurry to obtain the CCD underflow. The CCD underflow is sequentially subjected to tailings neutralization and filter press treatment before the tailings are discharged.

[0035] In some specific embodiments, in step S2, the process conditions for the first stage of iron and aluminum removal are: controlling the pH to be 3.5~3.8, and the process conditions for the second stage of iron and aluminum removal are: controlling the pH to be 4.8~5.0.

[0036] In some specific embodiments, as shown in FIG.2, the specific steps of recycling a first stage of iron removal and aluminum underflow to a multi-stage CCD washing process include: recycling a first stage of iron removal and aluminum underflow to a secondary CCD washing stage in a multi-stage CCD washing process, and diluting with water in the secondary CCD washing stage, wherein the ratio of the volume of the added water to the volume of the first stage of iron removal and aluminum underflow is >1.2.

[0037] More specifically, the overflow liquid from the next stage CCD washing is used as added water for reuse to dilute a section of the iron removal and aluminum underflow, and is settled in the previous stage CCD washing section; for example, the overflow liquid from the third stage CCD washing can be reused as added water to dilute a section of the iron removal and aluminum underflow, and is introduced into the second stage CCD washing section for precipitation; in other embodiments, similar overflow reuse methods or other water addition methods can also be used, which are not limited here.

[0038] In this process, the concentration of the first section of the de-ironing and aluminum underflow needs to be controlled to be less than 30%. If the concentration of the first section of the de-ironing and aluminum underflow is too high, it will be difficult to transport to the secondary CCD washing section and affect the effect of joint precipitation . At the same time , the ratio of the volume of added water to the volume of the first section of the de-ironing and aluminum underflow also needs to be controlled . I f the volume of added water is too small , it will be di f ficult to fully dilute the first section of the de-ironing and aluminum underflow, and it wi ll also cause the mixed solution concentration to be too high and di fficult to settle in the secondary CCD washing section .

[0039] In some speci fic embodiments , the speci fic step of tailings neutrali zation treatment includes : adding lime milk to make the system pH=7 .

[0040] S3 . After the second stage iron removal and aluminum treatment , the second stage iron removal aluminum underflow and the second stage iron removal aluminum overflow are obtained . The second stage iron removal aluminum underflow is recycled and subj ected to the cyclic leaching treatment again, and the second stage iron removal aluminum overflow is subj ected to the MHP treatment . Speci fically, the second stage iron removal aluminum underflow is recycled to the cyclic leaching process , and the residual temperature and residual acid of the high-pressure acid leaching slurry are used to carry out cyclic leaching with the reflowing second stage iron removal aluminum underflow, and the metal elements such as Ni and Co remaining in the second stage iron removal aluminum underflow re-enter the reaction system, thereby improving the subsequent extraction rate of metal elements such as Ni and Co .

[0041] The mass percentage of each element in the laterite nickel ore used in the following embodiments and comparative examples is shown in Table 1 . The ore is prepared into a slurry and then subj ected to high-pressure acid leaching to obtain a laterite nickel ore high-pressure acid leaching slurry; wherein the conditions of the high-pressure acid leaching are : 250 °C . , pressure 4 . 5 MPa, and acid consumption 15 25 tons / ton of nickel ; the multi-stage CCD washing process speci fically includes 6 stages of countercurrent washing . Table 1 Composition of laterite nickel ore

[0042] Example 1

[0043] A method for synergism precipitation of iron-aluminum slag and tailings , comprising the following steps :

[0044] 51 . The high-pressure leaching slurry of laterite nickel ore is subj ected to a cyclic leaching treatment and a pre-neutrali zation treatment in sequence to obtain a pre-neutrali zed slurry, wherein the cyclic leaching treatment controls the pH<l . 5 , pre-neutrali zation treatment controls pH=l . 8~2 . 2 ; then 6-stage CCD washing is performed to obtain CCD overflow liquid, wherein the first-stage CCD washing section of the multi-stage CCD washing controls pH=2 . 2~2 . 5 , and the sixth-stage CCD washing section controls pH=4 . 5~4 . 7 .

[0045] S2 . The CCD overflow is sub ected to a first-stage iron and aluminum removal treatment ( controlling pH=3 . 5~3 . 8 ) and a second-stage iron and aluminum removal treatment ( controlling pH=4 . 8~5 . 0 ) in sequence , wherein the concentration of the first-stage iron and aluminum removal underflow is less than 30% ; the third-stage CCD washing overflow liquid is reused as water to dilute the first-stage iron and aluminum removal underflow, and then reused to the second-stage CCD washing section and co-sedimented with the pre-neutrali zed slurry, and the volume ratio of the added water to the first-stage iron and aluminum removal underflow is 1 . 3 ; after co-precipitation, the CCD underflow is derived from the sixth-stage CCD washing section, and the CCD underflow is subj ected to tailings neutrali zation treatment ( adj usting pH=7 by adding lime milk) , and then subj ected to filter press treatment , and finally the tailings are discharged .

[0046] 52 . After the second-stage iron removal and aluminum treatment , the second-stage iron removal aluminum underflow and the second-stage iron removal aluminum overflow are obtained . The second-stage iron removal aluminum underflow is reused and the cyclic leaching process is carried out again . The residual temperature and residual acid of the high-pressure acid leaching slurry and the refluxed second-stage iron removal aluminum underflow are used for cyclic leaching . The second-stage iron removal aluminum overflow is subj ected to MHP treatment .

[0047] Example 2

[0048] A method for synergism precipitation of iron-aluminum slag and tailings , comprising the following steps :

[0049] S I . The high-pressure leaching slurry of laterite nickel ore is subj ected to a cyclic leaching treatment and a pre-neutrali zation treatment in sequence to obtain a pre-neutrali zed slurry, wherein the cyclic leaching treatment controls the pH<l . 5 , pre-neutrali zation treatment to control pH=l . 8~2 . 2 ; then 6-stage CCD washing to obtain CCD overflow liquid, wherein the f irst-stage CCD washing section of multi-stage CCD washing controls pH=2 . 2~2 . 5 , and the sixth-stage CCD washing section controls pH=4 . 5~4 . 7 ;

[0050] S2 . The CCD overflow is subj ected to a first-stage iron and aluminum removal treatment ( controlling pH=3 . 5~3 . 8 ) and a second-stage iron and aluminum removal treatment ( controlling pH=4 . 8~5 . 0 ) in sequence , wherein the concentration of the first-stage iron and aluminum removal underflow is less than 30% ; the fourth-stage CCD washing overflow liquid is reused as water to dilute the first-stage iron and aluminum removal underflow, and then reused to the third-stage CCD washing section and co-sedimented with the pre-neutrali zed slurry . Water needs to be added at this stage , and the volume ratio of the added water to the volume of the first-stage iron and aluminum removal underflow is 1 . 3 ; after co -precipitation, the CCD underflow is derived from the sixth-stage CCD washing section . After the tailings are neutrali zed ( adj usting pH=7 by adding lime milk) , the CCD underflow is subj ected to filter press treatment , and finally the tailings are discharged .

[0051] S3 . After the second-stage iron removal and aluminum treatment , the second-stage iron removal aluminum underflow and the second-stage iron removal aluminum overflow are obtained . The second-stage iron removal aluminum underflow is reused and the cyclic leaching process is carried out again . The residual temperature and residual acid of the high-pressure acid leaching slurry and the refluxed second-stage iron removal aluminum underflow are used for cyclic leaching . The second-stage iron removal aluminum overflow is subj ected to MHP treatment . Example 3

[0052] A method for synergism precipitation of iron-aluminum slag and tailings , comprising the following steps :

[0053] S I . The high-pressure leaching slurry of laterite nickel ore is subj ected to a cyclic leaching treatment and a pre-neutrali zation treatment in sequence to obtain a pre-neutrali zed slurry, wherein the cyclic leaching treatment controls the pH<l . 5 , pre-neutrali zation treatment to control pH=l . 8~2 . 2 ; then 6-stage CCD washing to obtain CCD overflow liquid, wherein the f irst-stage CCD washing section of multi-stage CCD washing controls pH=2 . 2~2 . 5 , and the sixth-stage CCD washing section controls pH=4 . 5~4 . 7 ;

[0054] S2 . The CCD overflow is sub ected to a first-stage iron and aluminum removal treatment ( controlling pH=3 . 5~3 . 8 ) and a second-stage iron and aluminum removal treatment ( controlling pH=4 . 8~5 . 0 ) in sequence , wherein the concentration of the first-stage iron and aluminum removal underflow is less than 30% ; the fi fth-stage CCD washing overflow liquid is reused as water to dilute the first-stage iron and aluminum removal underflow, and then reused to the fourth-stage CCD washing section and co-sedimented with the pre-neutrali zed slurry . Water needs to be added at this stage , and the volume ratio of the added water to the volume of the first-stage iron and aluminum removal underflow is 1 . 3 ; after co -precipitation, the CCD underflow is derived from the sixth-stage CCD washing section . After the tailings are neutrali zed ( adj usting pH=7 by adding lime milk) , the CCD underflow is subj ected to filter press treatment , and finally the tailings are discharged .

[0055] S3 . After the second-stage iron removal and aluminum treatment , the second-stage iron removal aluminum underflow and the second-stage iron removal aluminum overflow are obtained . The second-stage iron removal aluminum underflow is reused and the cyclic leaching process is carried out again . The residual temperature and residual acid of the high-pressure acid leaching slurry and the refluxed second-stage iron removal aluminum underflow are used for cyclic leaching . The second-stage iron removal aluminum overflow is subj ected to MHP treatment .

[0056] The nickel and cobalt contents in the tailings obtained by the filter press treatment in step S2 of Examples 1 to 3 were tested . The test results are shown in Table 1 .

[0057] Table 1 Statistical table of nickel and cobalt content in tailings obtained in Examples 1 to 3

[0058] From the statistical results in Table 1 , we can see that in Examples 1 to 3 , after the iron-aluminum slag in a first-stage iron-aluminum removal underflow and the tailings in the pre-neutrali zation slurry are synergistically settled by the aforementioned method, the nickel and cobalt content in the discharged tailings is signi ficantly reduced; at the same time , in the process of recycling a first-stage iron-aluminum underflow for multi-stage CCD washing treatment , the earlier the bottom flow is reused, the better of washing ef fect , and the lower of nickel ion content in the resulting tailings ,

[0059] The speci fic implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention . Any other corresponding changes and modi fications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention .

Claims

What Is Claimed Is1. A method for the synergism precipitation of iron-aluminum slag and tailings, characterized in that it comprises the following steps:

51. Taking a laterite nickel ore high pressure leaching slurry and sequentially performing a cyclic leaching treatment and a pre-neutralization treatment to obtain a pre-neutralized slurry, and then performing a multi-stage CCD washing to obtain a CCD overflow liquid;52. The CCD overflow liquid is sequentially subjected to first-stage iron and aluminum removal and second-stage iron and aluminum removal treatments, and the first-stage iron and aluminum removal underflow is recycled to the multi-stage CCD washing process and precipitated together with the pre-neutralized slurry to obtain a CCD underflow, which is sequentially subjected to tailings neutralization and filter press treatment to discharge the tailings.

2. The method for synergism precipitation of iron-aluminum slag and tailings according to claim 1, characterized in that in step SI, the process conditions for the cyclic leaching treatment are: controlling the pH<l .5 ;In step SI, the process conditions for the pre-neutralization treatment are: controlling pH=l .8~2.2.

3. The method for synergism precipitation of iron-aluminum slag and tailings according to claim 2, characterized in that the pre-neutralization treatment is performed by adding limestone to adjust the pH to 1.8-2.2.

4. The method for synergism precipitation of iron-aluminum slag and tailings according to claim 1, characterized in that the number of stages of the multi-stage CCD washing in step SI is 2 to 6.

5. The method for synergism precipitation of iron-aluminum slag and tailings according to claim 1, characterized in that the process conditions of the multi-stage CCD washing in step SI are: controlling pH=2.2-4 .7.6 . The method for the synergism precipitation of iron-aluminum slag and tailings according to claim 1 , characteri zed in that the process conditions for the one-stage iron and aluminum removal treatment in step S2 are : controlling the pH to be 3 . 5~3 . 8 .7 . The method for synergism precipitation of iron-aluminum slag and tailings according to claim 1 , characteri zed in that the process conditions of the two-stage iron and aluminum removal treatment in step S2 are : controlling the pH=4 . 8~5 . 0 .8 . The method for synergism precipitation of iron-aluminum slag and tailings according to claim 4 is characteri zed in that the speci fic step of recycling the first-stage iron-aluminum removal underflow to the multi-stage CCD washing process in step S2 includes : recycling the first-stage iron-aluminum removal underflow to the secondary CCD washing section in the multi-stage CCD washing process , and diluting it with water in the secondary CCD washing section, and the ratio of the volume of the added water to the volume of the first-stage iron-aluminum removal underflow is greater than 1 . 2 .9 . The synergism precipitation method of iron-aluminum slag and tailings according to claim 8 , characteri zed in that the concentration of the first stage of iron-aluminum removal underflow is less than 30% ;The speci fic steps of the tailings neutrali zation treatment in step S2 include : adding lime milk to make the system pH=7 .10 . The method for synergism precipitation of iron-aluminum slag and tailings according to claim 1 , characteri zed in that it also comprises :After the second-stage iron removal and aluminum treatment in step S2 , a second-stage iron removal and aluminum underflow and a second-stage iron removal and aluminum overflow are obtained . The second-stage iron removal and aluminum underflow is reused and subj ected to a cyclic leaching treatment again, and the second-stage iron removal and aluminum overflow is subj ected to a precipitation and MHP treatment .

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