Method for enriching precious metals in nickel concentrate pressurized acid leach tailings

Abstract

The application discloses a method for enriching noble metals in nickel concentrate pressurized acid leaching tailings, which comprises the following steps: firstly, performing pressurized full leaching on the nickel concentrate pressurized acid leaching tailings; recovering base metals such as nickel, copper and cobalt from leaching liquid; secondly, performing chlorination leaching on the acid leaching tailings A again; recovering base metals such as copper and iron from chlorination leaching liquid; thirdly, performing alkali leaching desilication on the chlorination leaching tailings B after slurry; and fourthly, using the desilication tailings C to extract noble metals such as gold, palladium and platinum. The method realizes effective separation of base metals and noble metals, has high base metal leaching rate, and can be used as raw material to enter a noble metal production system after noble metal enrichment. The process is simple, convenient to operate and avoids waste of the nickel concentrate pressurized acid leaching tailings.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal hydrometallurgy technology, specifically a method for enriching precious metals in the tailings of pressurized acid leaching of nickel concentrate. Background Technology

[0002] The existing nickel refining pressure leaching process involves leaching nickel concentrate, which requires the removal of metals such as nickel and cobalt as much as possible. A large amount of precious metals and base metals such as copper and iron are enriched in the pressure leaching tailings. The total precious metal content in the pressure leaching tailings is about 280 g / t, including 84.35 g / t of Au, 55.38 g / t of Pt, and 143.00 g / t of Pd.

[0003] Currently, some of the pressure leaching tailings are stockpiled, while others are processed in the pyrometallurgical system. Valuable metals such as precious metals and copper in the pressure leaching tailings are constantly circulating in the production system without being opened up or realized, resulting in a waste of precious metals. Summary of the Invention

[0004] The purpose of this invention is to provide a method for enriching precious metals in the tailings of pressurized acid leaching of nickel concentrate, thereby re-enriching the precious metals in the tailings and avoiding waste.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate includes the following steps:

[0007] Step 1: Pressure leaching: Prepare the pre-pressure leaching solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. Mix the pre-pressure leaching solution with the pressure acid leaching tailings to be treated at a liquid-to-solid ratio of 4-15:1, stir, and slurry for 0.5-3 hours. Add the slurry to the pressure leaching reactor, introduce industrial oxygen, maintain a reaction temperature of 130-200℃, a reactor pressure of 0.5-1.5 MPa, and a reaction time of 3-8 hours. After the reaction, perform solid-liquid separation on the slurry, collect the leaching solution for the recovery of nickel, copper, and cobalt base metals, and collect tailings A.

[0008] Step 2: Chlorination leaching: Prepare the iron leaching pre-liquid with appropriate amounts of fresh water, hydrochloric acid, and copper chloride. Mix the iron leaching pre-liquid with the tailings A collected in Step 1 at a liquid-to-solid mass ratio of 4-15:1, stir, and slurry for 0.5-3 hours. Add the slurry to the leaching reactor, introduce chlorine gas, maintain a reaction temperature of 60-100℃, a leaching reaction potential of 300-500mV, a reaction time of 3-8 hours, and an endpoint pH of 0.5-1.5. After the reaction, perform solid-liquid separation on the slurry, collect the leaching liquid for the recovery of copper and iron base metals, and collect the tailings B.

[0009] Step 3: Alkali leaching desilication: Add fresh water and liquid alkali to the tailings B collected in Step 2, so that the mass percentage of liquid alkali in the slurry is 5-30%, and maintain the liquid-solid mass ratio of the slurry at 4-15:1. Mix, stir, and slurry for 0.5-3 hours. Add the slurry to a pressure leaching reactor, with a reaction temperature of 140-200℃, a leaching pressure of 0.5-1.5 MPa, and a reaction time of 3-6 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The desilication tailings C are used to extract gold, palladium, and platinum precious metals.

[0010] Preferably, the liquid alkali in step three is a NaOH solution.

[0011] Preferably, the Cu in the pressurized full immersion pre-liquid prepared in step one is... 2+ The content is 5-20g / L, and the sulfuric acid content is 5-50g / L.

[0012] Preferably, the Cu in the iron leaching pre-solution prepared in step two is... 2+ The content is 20-40g / L, and the hydrochloric acid content is 5-30g / L.

[0013] This invention involves first subjecting the tailings from a pressurized acid leaching process of nickel concentrate to a pressurized full leaching process, recovering base metals such as nickel, copper, and cobalt from the leaching solution. The tailings A are then subjected to a second chlorination leaching, recovering base metals such as copper and iron from the chlorinated leaching solution. Tailings B are then pulped and subjected to alkaline leaching for desilication. Tailings C are used to extract gold, palladium, and platinum. This leaching process achieves effective separation of base metals and precious metals, resulting in a high base metal leaching rate. The enriched precious metals can then be used as raw materials in precious metal production systems.

[0014] In step two of this invention, chlorine gas is introduced into the leaching reactor, the reaction temperature is 60-100℃, the leaching reaction potential is 300-500mv, the endpoint pH value is 0.5-1.5, and the reaction time is 3-8h. It has been verified that under the above process conditions, the leaching amount of metallic iron and copper in tailings A is optimal, and precious metals will not be leached out, which facilitates subsequent processing.

[0015] The process described in this invention is simple and easy to operate, avoiding the waste of nickel concentrate tailings from pressurized acid leaching. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the method. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments.

[0018] Example 1

[0019] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, wherein the mass percentage content of each element in the pressure acid leaching tailings is: Ni 12.48%, Cu 15.42%, Co 0.22%, Fe 20.19%, Si 3.25%, and the content of precious metals Au, Pd, and Pt is approximately 280 g / t; the method includes the following steps:

[0020] Step 1: Pressure Immersion: Prepare the pre-pressure immersion solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. The Cu in the pre-pressure immersion solution... 2+ The content is 10 g / L, and the sulfuric acid content is 20 g / L. The pre-pressurized full leaching solution and the pressurized acid leaching tailings to be treated are mixed at a liquid-to-solid ratio of 8:1, stirred, and slurried for 1 hour. The slurry is then added to a pressurized leaching reactor, industrial oxygen is introduced, the reaction temperature is 160℃, the leaching reaction pressure is 0.9 MPa, and the reaction time is 6 hours. After the reaction, the slurry is subjected to solid-liquid separation, and tailings A are collected. The leaching solution is collected for the recovery of nickel, copper, and cobalt base metals. The leaching solution contains 14.29 g / L Ni, 16.73 g / L Cu, and 0.20 g / L Co.

[0021] Step 2: Chlorination leaching: Prepare the pre-leaching solution for iron by adding appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The Cu in the pre-leaching solution... 2+ The content is 30 g / L, and the hydrochloric acid content is 10 g / L. The iron leaching liquid before leaching is mixed with the tailings A collected in step one at a liquid-solid mass ratio of 6:1, stirred, and slurried for 0.5 h. The slurry is then added to the leaching reactor, chlorine gas is introduced, the reaction temperature is 90℃, the leaching reaction potential is 400 mV, the reaction time is 5 h, and the final pH is 1.0. After the reaction, the slurry is separated into solid and liquid components, and tailings B are collected. The leaching liquid is collected for the recovery of copper and iron base metals. The leaching liquid contains 86.29 g / L Fe and 34.36 g / L Cu.

[0022] Step 3: Alkali leaching desilication: Add fresh water and NaOH solution to the tailings B collected in Step 2, so that the NaOH content in the slurry is 20% by mass, and maintain the liquid-solid mass ratio of the slurry at 8:1. Mix, stir, and slurry for 1 hour. Add the slurry to a pressure leaching reactor, with a reaction temperature of 160℃, a leaching pressure of 0.9 MPa, and a reaction time of 5 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The mass percentage content of each component in the desilication tailings C is Ni 0.96%, Cu 1.24%, Fe 2.37%, Co 0.033%, and the precious metals Au, Pd, and Pt are approximately 20741 g / t.

[0023] In this embodiment, the leaching rates of base metals Ni, Cu, and Co were 99.3%; the direct recovery rate of precious metals was 97.38%; and the slag rate was 1.35%.

[0024] Example 2

[0025] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, wherein the mass percentage content of each element in the pressure acid leaching tailings is: Ni 15.37%, Cu 14.28%, Co 0.22%, Fe 29.24%, Si 4.12%, and the content of precious metals Au, Pd, and Pt is approximately 320 g / t; the method includes the following steps:

[0026] Step 1: Pressure Immersion: Prepare the pre-pressure immersion solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. The Cu in the pre-pressure immersion solution... 2+ The content is 10 g / L, and the sulfuric acid content is 10 g / L. The pre-pressurized full leaching solution and the pressurized acid leaching tailings to be treated are mixed at a liquid-solid ratio of 10:1, stirred, and slurried for 1 hour. The slurry is then added to a pressurized leaching reactor, industrial oxygen is introduced, the reaction temperature is 180℃, the leaching reaction pressure is 1.2 MPa, and the reaction time is 4 hours. After the reaction, the slurry is subjected to solid-liquid separation, and tailings A are collected. The leaching solution is collected for the recovery of base metals such as nickel, copper, and cobalt. The leaching solution contains 16.84 g / L of Ni, 17.35 g / L of Cu, and 0.22 g / L of Co.

[0027] Step 2: Chlorination Leaching: Prepare the pre-leaching solution with appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The pre-leaching solution contains 40 g / L Cu2+ and 10 g / L hydrochloric acid. Mix the pre-leaching solution with the tailings A collected in Step 1 at a liquid-to-solid mass ratio of 8:1, stir, and slurry for 1 hour. Add the slurry to the leaching reactor, introduce chlorine gas, maintain a reaction temperature of 90℃, a leaching reaction potential of 400 mV, and a reaction time of 4 hours. The final pH is 0.8. After the reaction, perform solid-liquid separation on the slurry, collect tailings B, and collect the leaching solution for the recovery of copper and iron base metals. The leaching solution contains 74.58 g / L Fe and 43.85 g / L Cu.

[0028] Step 3: Alkali leaching desilication: Add fresh water and NaOH solution to the tailings B collected in Step 2, so that the NaOH content in the slurry is 10% by mass, and maintain the liquid-solid mass ratio of the slurry at 10:1. Mix, stir, and slurry for 1 hour. Add the slurry to a pressure leaching reactor, with a reaction temperature of 180℃, a leaching pressure of 1.1 MPa, and a reaction time of 5 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The mass percentage content of each component in the desilication tailings C is Ni 1.22%, Cu 1.12%, Fe 2.76%, Co 0.027%, and the precious metals Au, Pd, and Pt are approximately 21581 g / t.

[0029] In this embodiment, the leaching rates of base metals Ni, Cu, and Co were 98.7%; the direct recovery rate of precious metals was 96.27%; and the slag rate was 1.48%.

[0030] Example 3

[0031] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, wherein the mass percentage content of each element in the pressure acid leaching tailings is: Ni 11.86%, Cu 14.67%, Co 0.25%, Fe 21.03%, Si 3.52%, and the content of precious metals Au, Pd, and Pt is approximately 295 g / t; the method includes the following steps:

[0032] Step 1: Pressure Immersion: Prepare the pre-pressure immersion solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. The Cu in the pre-pressure immersion solution... 2+ The content of the leaching solution is 5 g / L, and the sulfuric acid content is 5 g / L. The pre-leaching solution under pressure and the tailings from the pressure acid leaching process to be treated are mixed at a liquid-to-solid ratio of 4:1, stirred, and slurried for 0.5 h. The slurry is then added to a pressure leaching reactor, industrial oxygen is introduced, the reaction temperature is 130℃, the leaching reaction pressure is 0.5 MPa, and the reaction time is 3 h. After the reaction, the slurry is subjected to solid-liquid separation, and tailings A are collected. The leaching solution is collected for the recovery of base metals such as nickel, copper, and cobalt. The leaching solution contains 13.72 g / L of Ni, 17.23 g / L of Cu, and 0.25 g / L of Co.

[0033] Step 2, Chlorination Leaching: Prepare the pre-leaching solution for iron by adding appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The Cu in the pre-leaching solution... 2+ The content is 20 g / L, and the hydrochloric acid content is 5 g / L. The pre-leaching liquid and the tailings A collected in step one are mixed at a liquid-solid mass ratio of 4:1, stirred, and slurried for 2 hours. The slurry is then added to the leaching reactor, chlorine gas is introduced, the reaction temperature is 60℃, the leaching reaction potential is 300 mV, the reaction time is 3 hours, and the final pH is 0.5. After the reaction, the slurry is separated into solid and liquid components, and tailings B are collected. The leaching liquid is collected for the recovery of copper and iron base metals. The leaching liquid contains 87.52 g / L Fe and 36.61 g / L Cu.

[0034] Step 3: Alkali leaching desilication: Add fresh water and NaOH solution to the tailings B collected in Step 2, so that the NaOH content in the slurry is 5% by mass, and maintain the liquid-solid mass ratio of the slurry at 4:1. Mix, stir, and slurry for 0.5 hours. Add the slurry to a pressure leaching reactor, with a reaction temperature of 140℃, a leaching pressure of 1.5 MPa, and a reaction time of 3 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The mass percentage content of each component in the desilication tailings C is Ni 0.92%, Cu 1.13%, Fe 2.72%, Co 0.031%, and the precious metals Au, Pd, and Pt are approximately 20630 g / t.

[0035] In this embodiment, the leaching rates of base metals Ni, Cu, and Co were 98.93%; the direct recovery rate of precious metals was 98.03%; and the slag rate was 1.43%.

[0036] Example 4

[0037] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, wherein the mass percentage content of each element in the pressure acid leaching tailings is: Ni 13.21%, Cu 15.67%, Co 0.32%, Fe 19.95%, Si 3.47%, and the content of precious metals Au, Pd, and Pt is approximately 295 g / t; the method includes the following steps:

[0038] Step 1: Pressure Immersion: Prepare the pre-pressure immersion solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. The Cu in the pre-pressure immersion solution... 2+ The content is 20 g / L, and the sulfuric acid content is 25 g / L. The pre-pressurized full leaching solution and the pressurized acid leaching tailings to be treated are mixed at a liquid-to-solid ratio of 12:1, stirred, and slurried for 2.5 h. The slurry is then added to a pressurized leaching reactor, industrial oxygen is introduced, the reaction temperature is 150℃, the leaching reaction pressure is 1.5 MPa, and the reaction time is 5 h. After the reaction, the slurry is separated into solid and liquid components, and tailings A are collected. The leaching solution is collected for the recovery of base metals such as nickel, copper, and cobalt. The leaching solution contains 15.02 g / L Ni, 16.15 g / L Cu, and 0.19 g / L Co.

[0039] Step 2: Chlorination leaching: Prepare the pre-leaching solution for iron by adding appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The Cu in the pre-leaching solution... 2+ The content of Fe is 25 g / L, and the hydrochloric acid content is 25 g / L. The pre-leaching liquid and the tailings A collected in step one are mixed at a liquid-to-solid mass ratio of 12:1, stirred, and slurried for 2.5 h. The slurry is then added to the leaching reactor, chlorine gas is introduced, the reaction temperature is 100℃, the leaching reaction potential is 500 mV, the reaction time is 6 h, and the final pH is 1.2. After the reaction, the slurry is separated into solid and liquid components, and tailings B are collected. The leaching liquid is collected for the recovery of copper and iron base metals. The leaching liquid contains 89.03 g / L Fe and 35.29 g / L Cu.

[0040] Step 3: Alkali leaching desilication: Add fresh water and NaOH solution to the tailings B collected in Step 2, so that the NaOH content in the slurry is 30% by mass, and maintain the liquid-solid mass ratio of the slurry at 12:1. Mix, stir, and slurry for 2.5 hours. Add the slurry to a pressure leaching reactor, with a reaction temperature of 150℃, a leaching pressure of 0.5 MPa, and a reaction time of 6 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The mass percentage content of each component in the desilication tailings C is Ni 0.89%, Cu 1.31%, Fe 2.65%, Co 0.029%, and the precious metals Au, Pd, and Pt are approximately 19934 g / t.

[0041] In this embodiment, the leaching rates of base metals Ni, Cu, and Co were 99.5%; the direct recovery rate of precious metals was 97.32%; and the slag rate was 1.48%.

[0042] Example 5

[0043] A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, wherein the mass percentage content of each element in the pressure acid leaching tailings is: Ni 13.14%, Cu 14.63%, Co 0.26%, Fe 19.74%, Si 3.82%, and the content of precious metals Au, Pd, and Pt is approximately 305 g / t; the method includes the following steps:

[0044] Step 1: Pressure Immersion: Prepare the pre-pressure immersion solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. The Cu in the pre-pressure immersion solution... 2+ The content is 15 g / L, and the sulfuric acid content is 50 g / L. The pre-pressurized full leaching solution and the pressurized acid leaching tailings to be treated are mixed at a liquid-solid ratio of 15:1, stirred, and slurried for 3 hours. The slurry is then added to a pressurized leaching reactor, industrial oxygen is introduced, the reaction temperature is 200℃, the leaching reaction pressure is 1.2 MPa, and the reaction time is 8 hours. After the reaction, the slurry is separated into solid and liquid components, and tailings A are collected. The leaching solution is collected for the recovery of base metals such as nickel, copper, and cobalt. The leaching solution contains 15.01 g / L of Ni, 15.93 g / L of Cu, and 0.22 g / L of Co.

[0045] Step 2: Chlorination leaching: Prepare the pre-leaching solution for iron by adding appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The Cu in the pre-leaching solution... 2+ The content is 35 g / L, and the hydrochloric acid content is 30 g / L. The iron leaching liquid before leaching is mixed with the tailings A collected in step one at a liquid-solid mass ratio of 15:1, stirred, and slurried for 3 hours. The slurry is then added to the leaching reactor, chlorine gas is introduced, the reaction temperature is 80℃, the leaching reaction potential is 450 mV, the reaction time is 8 hours, and the final pH is 1.5. After the reaction, the slurry is separated into solid and liquid components, and tailings B are collected. The leaching liquid is collected for the recovery of copper and iron base metals. The leaching liquid contains 89.12 g / L of Fe and 35.09 g / L of Cu.

[0046] Step 3: Alkali leaching desilication: Add fresh water and NaOH solution to the tailings B collected in Step 2, so that the NaOH content in the slurry is 25% by mass, and maintain the liquid-solid mass ratio of the slurry at 15:1. Mix, stir, and slurry for 3 hours. Add the slurry to a pressure leaching reactor, with a reaction temperature of 200℃, a leaching pressure of 1.2 MPa, and a reaction time of 4 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The mass percentage content of each component in the desilication tailings C is Ni 1.02%, Cu 1.53%, Fe 2.78%, Co 0.029%, and the precious metals Au, Pd, and Pt are approximately 23644 g / t.

[0047] In this embodiment, the leaching rates of base metals Ni, Cu, and Co were 99.21%; the direct recovery rate of precious metals was 96.98%; and the slag rate was 1.29%.

[0048] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make other equivalent modifications and improvements based on the technical teachings provided by the present invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for enriching precious metals in pressure acid leaching tailings of nickel concentrate, characterized in that: Includes the following steps: Step 1: Pressure Full Leaching: Prepare the pre-pressure full leaching solution with appropriate amounts of fresh water, sulfuric acid, and copper sulfate. Mix the pre-pressure full leaching solution with the pressure acid leaching tailings to be treated at a liquid-to-solid ratio of 4-15:1, stir, and slurry for 0.5-3 hours. Add the slurry to the pressure leaching reactor, introduce industrial oxygen, maintain a reaction temperature of 130-200℃, a reactor pressure of 0.5-1.5 MPa, and a reaction time of 3-8 hours. After the reaction, perform solid-liquid separation on the slurry, collect the leaching liquid for the recovery of nickel, copper, and cobalt base metals, and collect tailings A. Step 2: Chlorination leaching: Prepare the pre-leaching solution for iron by adding appropriate amounts of fresh water, hydrochloric acid, and copper chloride. The Cu in the pre-leaching solution... 2+ The content is 20-40 g / L, and the hydrochloric acid content is 5-30 g / L. The iron leaching liquid before leaching is mixed with the tailings A collected in step one at a liquid-to-solid mass ratio of 4-15:1, stirred, and slurried for 0.5-3 hours. The slurry is then added to the leaching reactor, chlorine gas is introduced, the reaction temperature is 60-100℃, the leaching reaction potential is 300-500 mV, the reaction time is 3-8 hours, and the final pH is 0.5-1.

5. After the reaction, the slurry is subjected to solid-liquid separation. The leached liquid is collected for the recovery of copper and iron base metals, and tailings B are collected. Step 3: Alkali leaching desilication: Add fresh water and liquid alkali to the tailings B collected in Step 2, so that the mass percentage of liquid alkali in the slurry is 5-30%, and maintain the liquid-solid mass ratio of the slurry at 4-15:

1. Mix, stir, and slurry for 0.5-3 hours. Add the slurry to a pressure leaching reactor, with a reaction temperature of 140-200℃, a leaching pressure of 0.5-1.5 MPa, and a reaction time of 3-6 hours. After the reaction, perform solid-liquid separation on the slurry to collect the desilication tailings C. The desilication tailings C are used to extract gold, palladium, and platinum precious metals.

2. The method for enriching precious metals in pressure acid leaching tailings of nickel concentrate according to claim 1, characterized in that: The liquid alkali in step three is a NaOH solution.

3. The method for enriching precious metals in pressure acid leaching tailings of nickel concentrate according to claim 1 or 2, characterized in that: Cu in the pressurized full immersion pre-liquid prepared in step one 2+ Content 5-20g / L, sulfuric acid content 5-50g / L.

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