Method for recovering valuable metal from three-phase waste liquid heap leaching byproduct slag

Abstract

The invention discloses a method for recovering valuable metals from three-phase waste liquid heap leaching byproduct residues, and relates to the technical field of hydrometallurgy. Comprising the following steps: piling the by-product slag: piling the by-product slag to obtain by-product piling slag; three-phase waste liquid dump leaching: distributing the three-phase waste liquid on the byproduct dump slag for dump leaching, collecting the leachate and returning the leachate to the byproduct dump slag for cyclic dump leaching to obtain dump leaching slag and first dump leaching liquid; heap leaching residue cleaning: cleaning the heap leaching residue to obtain a second heap leaching solution; recycling valuable metals, removing oil from the dump leaching liquid, then filtering to obtain filtrate and residues, and recycling the valuable metals in the filtrate; wherein the heap leaching liquid comprises a first heap leaching liquid and a second heap leaching liquid. The method disclosed by the invention is simple in process, easy to operate and low in cost, and valuable metals such as nickel and cobalt in the recovered waste residues are consumed without increasing auxiliary materials while harmless treatment is carried out on the three-phase waste liquid.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for recovering valuable metals from by-product slag by heap leaching of three-phase waste liquid. Background Art

[0002] Nickel is a nonferrous metal that is widely used in petrochemical, national defense, metallurgy, machinery, electroplating, electronics, batteries, building materials and other industries. With the rapid development of new energy industries in recent years, the growing demand for nickel has led to an increase in the contradiction between nickel supply and demand. In order to alleviate the contradiction between supply and demand and improve the comprehensive utilization of resources, recovering nickel from by-product slag (nickel-containing waste) has become one of the main research directions of hydrometallurgy. The original treatment process of by-product slag is pyrometallurgy, which has a complex process flow, high energy consumption and low recovery value. Therefore, a new treatment method is needed to recycle this part of nickel-containing materials.

[0003] The hydrometallurgical extraction of valuable metals such as nickel and cobalt will indirectly produce three-phase slag and three-phase waste. These three-phase waste liquids contain a small amount of valuable metals such as nickel, cobalt, and manganese, which have certain value, but they cannot be directly recycled and treated in the production system, and cannot be discharged, otherwise they will cause great harm to the water environment. We tried to use a centrifuge to separate the three-phase waste liquid into solid and liquid, and return the separated organic phase and aqueous phase to the system, and the solid phase was transported to the slag storage as the slag phase. However, after many tests, the centrifuge failed to achieve the solid-liquid separation effect, and the three-phase waste liquid could only be stored in the storage site. Therefore, it is necessary to find a new method for harmless treatment of organic waste liquid. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] To this end, the present invention provides a method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, comprising:

[0006] Building a pile of by-product slag, building a pile of by-product slag to obtain a by-product slag pile;

[0007] Three-phase waste liquid heap leaching, distributing the three-phase waste liquid to the by-product slag for heap leaching, collecting the leachate and returning it to the by-product slag for cyclic heap leaching to obtain heap leaching slag and a first heap leaching liquid;

[0008] Heap leaching residue cleaning, cleaning the heap leaching residue to obtain a second heap leaching liquid;

[0009] Valuable metal recovery: deoiling the heap leach liquid, filtering to obtain a filtrate and residue, and recovering the valuable metals in the filtrate; wherein the heap leach liquid includes the first heap leach liquid and the second heap leach liquid.

[0010] Furthermore, the by-product slag includes: solid slag separated from the hydrometallurgical process, containing impurities and carrying valuable metals such as nickel and cobalt.

[0011] Furthermore, the three-phase waste liquid includes: a mixed phase generated during the hydrometallurgical extraction of valuable metals such as nickel and cobalt, wherein the mixed phase is an organic phase, an aqueous phase and a flocculated phase that are difficult to separate.

[0012] Furthermore, the three-phase waste liquid heap leaching specifically comprises:

[0013] The three-phase waste liquid is evenly distributed on the by-product slag, and after the leaching liquid appears in the liquid collecting pool, the flow rate of the three-phase waste liquid is reduced, and the heap leaching is carried out for 5 to 8 days; the collected leaching liquid is returned to the by-product slag for cyclic heap leaching for 5 to 8 days, and the cycle is terminated after 2 to 4 times to obtain the heap leaching slag and the first heap leaching liquid.

[0014] Furthermore, the liquid-to-solid volume ratio of the three-phase waste liquid to the by-product slag is 1:0.8 to 1:1.2.

[0015] Furthermore, the cleaning of the heap leaching residue comprises:

[0016] The cleaning liquid is sprayed evenly onto the heap leaching residue until the cleaning liquid seeps out from under the heap leaching residue, and then the spraying rate is reduced. After the spraying is completed, the cleaning liquid is allowed to stand for 5 to 8 days to obtain the second heap leaching liquid.

[0017] Furthermore, the cleaning liquid is water, and the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is 1:3 to 1:5.

[0018] Furthermore, the deoiling of the heap leachate includes: adding a deoiling agent into the heap leachate and stirring intermittently for 20 minutes to 40 minutes; wherein the deoiling agent includes but is not limited to one or more of activated carbon, diatomaceous earth and resin.

[0019] Furthermore, the deoiling agent is added in an amount of 800 g to 900 g per cubic meter of the heap leach liquid.

[0020] Furthermore, the filtrate is pumped into a return liquid tank and then enters a hydrometallurgical leaching purification and impurity removal system, the residual slag enters the by-product slag, and the valuable metals include nickel and cobalt.

[0021] The method for recovering valuable metals from by-product slag of three-phase waste liquid heap leaching provided by the present invention has at least the following beneficial effects compared with the prior art:

[0022] (1) It can carry out harmless treatment of three-phase waste liquid;

[0023] (2) Heap leaching utilizes the residual acid in the three-phase waste liquid, does not increase the consumption of other auxiliary materials, and saves the cost of acid leaching reaction;

[0024] (3) Through the replacement and acid leaching reactions in the heap leaching process, the valuable metals nickel and cobalt in the by-product slag are enriched and recovered, thereby improving the comprehensive recovery rate of valuable metals;

[0025] (4) The process is short and simple, does not require complex equipment, is low cost, pollution-free, and suitable for large-scale industrial production. DETAILED DESCRIPTION

[0026] In order to better understand the above technical solution, the technical solution of the present application is described in detail below through specific embodiments.

[0027] The embodiment of the present invention provides a method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, comprising:

[0028] Building a pile of by-product slag, building a pile of by-product slag to obtain a by-product slag pile;

[0029] Three-phase waste liquid heap leaching, distributing the three-phase waste liquid to the by-product slag for heap leaching, collecting the leaching liquid and returning it to the by-product slag for cyclic heap leaching to obtain heap leaching slag and the first heap leaching liquid;

[0030] Heap leaching residue cleaning, cleaning the heap leaching residue to obtain a second heap leaching liquid;

[0031] Valuable metal recovery: deoiling the heap leaching liquid, filtering it to obtain a filtrate and residue, and recovering the valuable metals in the filtrate; wherein the heap leaching liquid includes a first heap leaching liquid and a second heap leaching liquid.

[0032] Specifically, by-product slag includes: solid slag containing valuable metals such as nickel and cobalt, which is separated by leaching, purification, impurity removal and filtration during hydrometallurgy. Three-phase waste liquid refers to the three-phase waste produced in each stage of the extraction process, including: the organic phase + water phase + flocculation phase that is difficult to separate when mixed phases are used to extract valuable metals such as nickel and cobalt during hydrometallurgy.

[0033] The method for recovering valuable metals from by-product slag by heap leaching of three-phase waste liquid provided in the embodiment of the present invention gives full play to the synergistic treatment efficiency of the three-phase waste liquid on the by-product slag, and recovers valuable metal elements such as nickel and cobalt in the by-product slag at low cost with the advantages of short process flow, no need for complex equipment, low cost, no pollution, and the availability of three-phase waste liquid, thereby improving the comprehensive recovery rate of valuable metals.

[0034] In a feasible implementation, three-phase waste liquid heap leaching specifically includes:

[0035] The three-phase waste liquid is evenly distributed on the by-product slag. After the leaching liquid appears in the liquid collecting pool, the flow rate of the three-phase waste liquid is reduced and the heap leaching is carried out for 5 to 8 days. The collected leaching liquid is returned to the by-product slag for cyclic heap leaching for 5 to 8 days. After 2 to 5 cycles, the heap leaching residue and the first heap leaching liquid are obtained.

[0036] Specifically, we evenly distribute the three-phase waste liquid on the by-product slag, and adsorb and filter the hydrophobic organic pollutants through the bridging phenomenon of the pores of the by-product slag. The organic matter in the three-phase waste liquid remains in the by-product slag, and the residual acid in the three-phase waste liquid undergoes acid leaching reaction to remove Ni in the by-product slag during the process of the by-product slag penetrating downward. 2+ 、Co 2+ The leaching is carried out, and the collected leaching solution is returned to the by-product slag for cyclic leaching.

[0037] The specific heap leaching process is: evenly distribute the three-phase waste liquid to the by-product slag, reduce the flow rate of the three-phase waste liquid after the leachate appears in the liquid collecting pool, distribute the three-phase waste liquid to the by-product slag in a spraying manner according to the liquid-solid volume ratio of the three-phase waste liquid to the by-product slag of 1:0.8 to 1:1.2, and then heap leaching for 5 to 8 days, return the collected leachate to the by-product slag for 5 to 8 days of cyclic heap leaching, and then return the collected leachate to the by-product slag for 5 to 8 days of cyclic heap leaching, so that the leachate collected for 5 to 8 days of heap leaching is circulated 2 to 4 times, and the three-phase waste liquid heap leaching process is completed to obtain heap leaching slag and the first heap leachate. It can be understood that the leaching time of the heap leaching process in the embodiment of the present invention is 15 to 40 days, which is greatly shortened compared to the leaching time of hundreds of days in the prior art.

[0038] It can be understood that when the liquid-to-solid volume ratio of the three-phase waste liquid to the by-product slag is less than 1:1.2, the heap leaching liquid is less and the metal recovery rate is lower; when the liquid-to-solid volume ratio of the three-phase waste liquid to the by-product slag is greater than 1:0.8, the adsorption and filtration of organic pollutants reach saturation, and there are more residual organic matter in the heap leaching liquid, which increases the amount of deoiling agent used in the subsequent process flow.

[0039] In a feasible embodiment, the heap leaching residue is cleaned, including: spraying a cleaning liquid evenly onto the heap leaching residue until the cleaning liquid seeps out from below the heap leaching residue, then reducing the spraying rate, and standing for 5 to 8 days after the spraying is completed to obtain the second heap leaching liquid. The cleaning liquid is water, and the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is 1:3 to 1:5.

[0040] Specifically, the cleaning liquid is sprayed for cleaning, and the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is 1:3-1:5. During the downward penetration of the cleaning liquid, the Ni 2+ 、Co 2+ The organic metals such as Ni, etc. are brought into the cleaning solution. By standing for 5 to 8 days, the heap leaching residue can be effectively cleaned, increasing the Ni 2+ 、Co 2+ When the liquid-to-solid ratio of the cleaning solution to the heap leaching residue is less than 1:5, the cleaning is insufficient and Ni 2+ 、Co 2+When the amount of organic metals brought into the cleaning solution is reduced, the metal recovery rate is reduced; when the liquid-to-solid ratio of the cleaning solution to the heap leaching residue is greater than 1:3, too much cleaning solution is added, which will cause excessive waste of the cleaning solution and increase the Ni content in the total heap leaching solution. 2+ 、Co 2+ The content of Ni in the hydrometallurgical leaching purification and impurity removal system is reduced. 2+ 、Co 2+ The metal content is reduced, increasing the processing cost.

[0041] In a feasible embodiment, deoiling the heap leachate includes: adding a deoiling agent to the heap leachate and stirring intermittently for 20 minutes to 40 minutes; wherein the deoiling agent includes but is not limited to one or more of activated carbon, diatomaceous earth and resin, and the amount of the deoiling agent added is 800g to 900g per cubic meter of heap leachate.

[0042] Specifically, the oil in the heap leaching liquid is generally an organic extractant. When the heap leaching liquid enters the hydrometallurgical leaching purification and impurity removal system (mainly inorganic reaction), the presence of the organic extractant will produce a large amount of foam during the impurity removal process, which has the risk of bubbling and affecting the normal reaction. Therefore, deoiling operation is required before entering the hydrometallurgical leaching purification and impurity removal system. In order to ensure the production principle of not introducing other impurities, the physical adsorption deoiling method is adopted. The addition amount of deoiling agent is 800g to 900g per cubic meter of heap leaching liquid, which can effectively reduce the oil content.

[0043] In a feasible implementation, the filtrate is pumped into a return liquid tank and then into a main leaching purification and impurity removal system, and the remaining slag enters the by-product slag, and the valuable metals include nickel and cobalt.

[0044] Specifically, after filtration, the filtrate is pumped into the return tank, where it can be further precipitated and clarified to remove residual impurities and particles. The filtrate treated in the return tank is reintroduced into the hydrometallurgical leaching purification and impurity removal process system. The residual slag is collected and sent to the by-product slag accumulation area, waiting for the next step of treatment.

[0045] Example 1 A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching

[0046] A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, comprising the following steps:

[0047] (1) Take 500 g of by-product slag and put it in a beaker. The test results of by-product slag composition are shown in Table 1;

[0048] (2) three-phase waste liquid heap leaching, 500 ml of the three-phase waste liquid (the test results of the water phase composition are shown in Table 1) is evenly distributed on the by-product slag by soaking, and the heap leaching liquid is filtered out after soaking and standing for 12 hours, and the filtered heap leaching liquid is slowly returned to the heap slag again, and this cycle is repeated 3 times until no more heap leaching liquid flows out from under the heap leaching slag, and finally the heap leaching slag and the first heap leaching liquid are obtained;

[0049] (3) Heap leaching residue cleaning: 100 ml of water is sprayed evenly onto the heap leaching residue by spraying, and the heap leaching residue is filtered to obtain a second heap leaching liquid; wherein the heap leaching liquid is 400 ml in total, including the first heap leaching liquid and the second heap leaching liquid.

[0050] (4) Valuable metal recovery: deoiling the heap leaching liquid by adsorption with activated carbon. According to the calculation of 800g to 900g of activated carbon per cubic meter of liquid, 0.35g of activated carbon was added, and then the mixture was stirred intermittently for 30 minutes. Finally, the obtained mixed solution was filtered to obtain filtrate and residue, respectively, and the valuable metals were recovered. The test results are shown in Table 2. As can be seen from Table 2, after the heap leaching reaction, 4.21% of metal nickel and 0.25% of metal cobalt in the by-product heap slag were leached into the heap leaching liquid, so that the nickel content of the heap leaching liquid increased to 28.69g / l, the nickel recovery rate reached 58.43%, and the cobalt content increased to 1.83g / l, and the cobalt recovery rate reached 68.11%. The replacement and acid leaching reactions in the heap leaching process played a role in enriching and recovering the valuable metals nickel and cobalt in the by-product slag, and the purpose of improving the comprehensive recovery rate of valuable metals was achieved.

[0051] Table 1 is the analysis table of by-product slag and three-phase waste liquid-water phase composition

[0052] Analyze Project Ni Co <![CDATA[H2O]]> By-product slag / % 4.21 0.25 15.17 Three-phase waste liquid (water phase) g / l 3.56 0.029

[0053] Table 2 is the component analysis table of heap leaching results of Example 1

[0054] Analyze Project Ni Co Oil mg / l Heap leach liquid g / l 28.69 1.83 <0.5 Recovery rate / % 58.43 68.11 —

[0055] Example 2 A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching

[0056] A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, comprising the following steps:

[0057] (1) Take 500 g of by-product slag and put it in a beaker. The test results of by-product slag composition are shown in Table 1;

[0058] (2) three-phase waste liquid heap leaching, 500 ml of the three-phase waste liquid (the test results of the water phase composition are shown in Table 1) is evenly distributed on the by-product slag by soaking, and the heap leaching liquid is filtered out after soaking and standing for 8 hours, and the filtered heap leaching liquid is slowly returned to the heap slag again, and this cycle is repeated 3 times until no more heap leaching liquid flows out from under the heap leaching slag, and finally the heap leaching slag and the first heap leaching liquid are obtained;

[0059] (3) Heap leaching residue cleaning: 150 ml of water is sprayed evenly onto the heap leaching residue by spraying, and the heap leaching residue is filtered to obtain a second heap leaching liquid; wherein the heap leaching liquid is 435 ml in total, including the first heap leaching liquid and the second heap leaching liquid.

[0060] (4) Valuable metal recovery: The heap leaching liquid was deoiled. The deoiling agent was a mixture of diatomaceous earth and activated carbon in a ratio of 1:1. 800 g to 900 g of deoiling agent was added per cubic meter of liquid. 0.39 g of deoiling agent was added, and then stirred intermittently for 30 minutes. Finally, the obtained mixed liquid was filtered to obtain filtrate and residue, respectively, and the valuable metals were recovered. The test results are shown in Table 3. As can be seen from Table 3, the nickel content of the heap leaching liquid decreased when the heap leaching time was reduced, the oil content of the heap leaching liquid increased slightly when the amount of cleaning liquid was increased, and the volume of the heap leaching liquid increased, but the nickel recovery rate increased to 59.87%, and the cobalt recovery rate increased to 70.42%. Appropriately increasing the heap leaching liquid can improve the comprehensive recovery rate of valuable metals.

[0061] Table 3 is the component analysis table of heap leaching results of Example 2

[0062] Analyze Project Ni Co Oil mg / l Heap leach liquid g / l 27.03 1.74 10 Recovery rate / % 59.87 70.42 —

[0063] Example 3 A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching

[0064] A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, comprising the following steps:

[0065] (1) By-product slag is piled up in the slag pool using a crane. The volume of the by-product slag is about 350m 3 ;

[0066] (2) Three-phase waste liquid heap leaching: evenly distribute the three-phase waste liquid on the by-product slag. After the heap leaching liquid seeps out of the collecting tank at the bottom of the heap leaching slag, reduce the flow rate of the three-phase waste liquid and add a total of 360m3 of the three-phase waste liquid by spraying. 3 After standing for a week, the leaching liquid collected in the liquid collecting tank is pumped out by a pump and returned to the by-product slag. The heap leaching is repeated three times to obtain heap leaching slag.

[0067] (3) Heap leaching residue cleaning: water is sprayed evenly onto the heap leaching residue by spraying. The liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is 1:5, and the volume of the cleaning liquid-water used is 72m 3, until the washing liquid seeps out from under the heap leaching residue, then reduce the spraying rate, and let it stand for one week after the spraying is completed;

[0068] (4) Collect the heap leaching liquid. Collect 240m3 of heap leaching liquid in the collecting pool. 3 ;

[0069] (5) Valuable metal recovery, further degreasing and filtering, the obtained heap leaching liquid is pumped out for degreasing, 210 kg of activated carbon is added according to 800 g to 900 g of wood powdered activated carbon per cubic meter of liquid, intermittent stirring for 30 minutes, and finally the obtained mixed liquid is filtered through a filter press, the filtrate enters the return liquid tank through a pump and then enters the main leaching purification and impurity removal system, the test results of the filtrate are shown in Table 4, and a small amount of residual slag enters the by-product slag and waits for the next step of treatment. It can be seen from Table 4 that after the heap leaching reaction, the nickel content of the heap leaching liquid increased to 15.34 g / l, and the cobalt content increased to 1.66 g / l, and a total of 3.68 tons of nickel metal and 0.4 tons of cobalt metal were recovered, achieving the purpose of enriching and recovering the valuable metals nickel and cobalt in the by-product slag.

[0070] Table 4 is a component analysis table of the heap leaching results of Example 3

[0071] Analyze Project Ni g / l Co Oil mg / l Heap leach liquid g / l 15.34 1.66 <0.5 Recycled metal amount / t 3.68 0.40 —

[0072] Example 4

[0073] This example investigates the effect of three-phase waste liquid heap leaching time on the recovery of nickel and cobalt metals.

[0074] The difference between this embodiment and embodiment 3 is that the heap leaching time is different in step (2) of three-phase waste liquid heap leaching. The metal recovery rates at different heap leaching times are shown in Table 5. It can be seen from Table 5 that when the heap leaching time increases from 1 day to 5 days, the nickel and cobalt metal recovery rates show a significant upward trend. When the heap leaching time is 7 days to 9 days, the nickel and cobalt metal recovery rates tend to be stable, indicating that the heap leaching time exceeding 8 days does not have a good leaching effect. Therefore, the heap leaching time of the three-phase waste liquid is preferably 5 days to 8 days.

[0075] Table 5 Different heap leaching time and metal recovery rate

[0076]

[0077]

[0078] Example 5

[0079] This example investigates the effect of the liquid-to-solid volume ratio of the cleaning solution to the heap leaching residue on the recovery of nickel and cobalt metals.

[0080] The difference between this embodiment and embodiment 3 is that in step (3) of cleaning the heap leaching residue, the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is different. The different liquid-to-solid volume ratios of the cleaning liquid to the heap leaching residue and the metal recovery rates are shown in Table 6. It can be seen from Table 6 that when the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is lower than 1:5, the metal recovery rate is low, and when the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is higher than 1:3, the metal recovery rate does not increase significantly. Therefore, the liquid-to-solid ratio of the cleaning liquid to the heap leaching residue is better when it is between 1:3 and 1:5.

[0081] Table 6 Liquid-to-solid volume ratio and metal recovery rate of different cleaning and heap leaching residues

[0082]

[0083] In summary, the embodiments of the present invention provide a method for recovering valuable metals from by-product slag by heap leaching of three-phase waste liquid, which can not only perform harmless treatment on the three-phase waste liquid, but also recover the valuable metals nickel and cobalt in the by-product slag by heap leaching of residual acid in the three-phase waste liquid under the condition of simple and brief process flow and without increasing the consumption of other auxiliary materials, thereby improving the comprehensive recovery rate of valuable metals.

[0084] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above are only preferred implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching, characterized in that: include: Building a pile of by-product slag, building a pile of by-product slag to obtain a by-product slag pile; Three-phase waste liquid heap leaching, distributing the three-phase waste liquid to the by-product slag for heap leaching, collecting the leachate and returning it to the by-product slag for cyclic heap leaching to obtain heap leaching slag and a first heap leaching liquid; Heap leaching residue cleaning, cleaning the heap leaching residue to obtain a second heap leaching liquid; Valuable metal recovery: deoiling the heap leach liquid, filtering to obtain a filtrate and residue, and recovering the valuable metals in the filtrate; wherein the heap leach liquid includes the first heap leach liquid and the second heap leach liquid.

2. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 1, characterized in that: The by-product slag includes: solid slag separated in the hydrometallurgical process, containing impurities and valuable metals such as nickel and cobalt.

3. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 2, characterized in that: The three-phase waste liquid includes: a mixed phase generated during the hydrometallurgical extraction of valuable metals such as nickel and cobalt, wherein the mixed phase is an organic phase, an aqueous phase and a flocculation phase that are difficult to separate.

4. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 3, characterized in that: The three-phase waste liquid heap leaching specifically comprises: The three-phase waste liquid is evenly distributed on the by-product slag, and after the leaching liquid appears in the liquid collecting pool, the flow rate of the three-phase waste liquid is reduced, and the heap leaching is carried out for 5 to 8 days; the collected leaching liquid is returned to the by-product slag for cyclic heap leaching for 5 to 8 days, and the cycle is terminated after 2 to 4 times to obtain the heap leaching slag and the first heap leaching liquid.

5. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 4, characterized in that: The liquid-to-solid volume ratio of the three-phase waste liquid to the by-product slag is 1:0.8 to 1:1.

2.

6. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 1, characterized in that: The step of cleaning the heap leaching residue comprises: The cleaning liquid is sprayed evenly onto the heap leaching residue until the cleaning liquid seeps out from under the heap leaching residue, and then the spraying rate is reduced. After the spraying is completed, the cleaning liquid is allowed to stand for 5 to 8 days to obtain the second heap leaching liquid.

7. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 6, characterized in that: The cleaning liquid is water, and the liquid-to-solid volume ratio of the cleaning liquid to the heap leaching residue is 1:3 to 1:

5.

8. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 1, characterized in that: The deoiling of the heap leaching liquid comprises: adding a deoiling agent into the heap leaching liquid and stirring intermittently for 20 minutes to 40 minutes; wherein the deoiling agent comprises but is not limited to one or more of activated carbon, diatomaceous earth and resin.

9. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 8, characterized in that: The amount of the deoiling agent added is 800 g to 900 g per cubic meter of the heap leach liquid.

10. The method for recovering valuable metals from by-product slag by three-phase waste liquid heap leaching according to claim 1, characterized in that: The filtrate is pumped into the return liquid tank and then enters the hydrometallurgical leaching purification and impurity removal system, and the residual slag enters the by-product slag, and the valuable metals include nickel and cobalt.

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