In-situ resource extraction method of electrolytic manganese residue

Abstract

The application discloses an in-situ resource extraction method for electrolytic manganese residue, and relates to the technical field of industrial solid waste resource utilization.The method comprises water washing and filtrate treatment steps.In order to avoid secondary pollution in the manganese residue recovery process, the steps of gradient water washing and filtrate resource extraction are all transferred to the residue field, and the manganese residue storage yard is changed into a resource factory.The in-situ extraction method uses the manganese residue storage yard as the resource extraction factory, does not need to excavate a manganese residue storage, does not cause disturbance to the surrounding environment, avoids secondary pollution and uncertain factors caused by external engineering measures, reduces sewage treatment cost, realizes efficient resource utilization, realizes in-situ resource extraction of the manganese residue, integrates the manganese residue storage yard with a raw material storage factory, a resource extraction workshop and a product warehouse, saves the cost generated by raw material and product transportation, and saves land resources.The method can also be applied to the field of manganese residue storage pollution treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial solid waste resource utilization, and particularly relates to an in-situ resource extraction method for electrolytic manganese residue. BACKGROUND

[0002] The electrolytic manganese residue is a near-neutral waste residue produced after the carbon manganese ore is subjected to acid leaching, neutralization and filter pressing processes, and contains a large amount of combined leaching solution, which is 20%-30% according to the water content, and has complex chemical composition, in which the ion state manganese Mn 2+ and ammonia nitrogen NH 4+ are main pollutants; at present, most of the electrolytic manganese residues are directly stacked for treatment, and the long-term stacked electrolytic manganese residues not only occupy land resources, but also are easy to produce a large amount of leachate in the rainy season, which will cause serious environmental pollution when the leachate enters the surrounding soil and groundwater.

[0003] The manganese and ammonia nitrogen in the electrolytic manganese residue are pollutants to the surrounding environment, but are essentially resources misplaced. Extracting the manganese and ammonia nitrogen resources in the electrolytic manganese residue by an effective method can not only produce economic benefits, but also reduce the pollution load of the manganese residue. For example, a harmless treatment and ammonia recovery process resource extraction system for electrolytic manganese residue disclosed in C116274306A adopts multi-stage slurry reaction, and through multi-stage washing, filter pressing, and ammonia removal of process water, the process water can be recycled, which can effectively recover the ammonia in the manganese residue; and for example, a method for extracting manganese from electrolytic manganese residue disclosed in CN116043040A specifically is to co-mill the electrolytic manganese residue, pyrite and leaching agent to obtain a ball-milling product, and perform solid-liquid separation on the ball-milling product to obtain a manganese-containing extraction liquid, which has a high manganese leaching rate. The above two technical solutions can achieve the resource extraction target of the manganese residue, but are easy to cause environmental pollution; because whether water washing or acid leaching, the manganese residue needs to be excavated first; for the manganese residue bank that has been closed, the surface has been covered, in the process of excavating the manganese residue bank, the original impermeable system needs to be damaged, after the original impermeable system is damaged, rainwater is easy to infiltrate or surface runoff, causing pollution of surface water and groundwater.

[0004] For example, the method disclosed in CN116274306A, which is specifically to make the manganese residue reach the standard of a kind of solid waste by countercurrent water washing, and recover ammonia nitrogen resources, but in this invention, the ex-situ water washing method is adopted, that is, the manganese residue needs to be excavated first, which means that the integrity of the sealing system is destroyed, and under the action of rainfall, the pollutants in the manganese residue will pollute the surrounding environment; in addition, this method recovers the ammonia nitrogen resources in the manganese residue, but does not recover the manganese resources, resulting in waste of manganese resources; for another example, the method disclosed in CN116043040A also needs ex-situ disposal, and the problem of secondary pollution caused by excavation cannot be avoided; the electrolytic manganese residue, pyrite and leaching agent are jointly ball milled to obtain a filter liquor of the ball milled product, and the manganese resources are recovered, but the ammonia nitrogen resources are not recovered, which not only wastes the ammonia nitrogen resources, but also causes the ammonia nitrogen in the treated filter liquor to exceed the standard, and the treated filter liquor is directly discharged instead of being recycled, which increases the sewage disposal cost. SUMMARY

[0005] The purpose of the present application is to solve the above technical problems, and to provide a method for in-situ resource extraction of manganese residue, which comprises water washing and filter liquor disposal steps, in order to avoid the problem of secondary pollution during the excavation of manganese residue, the steps of manganese residue gradient water washing and filter liquor resource extraction are all transferred to the residue field, and the manganese residue storage yard is changed into a resource factory, thereby solving the problems in the background art.

[0006] To solve the above technical problems, the present application is realized by the following technical scheme:

[0007] The method for in-situ resource extraction of electrolytic manganese residue of the present application comprises two steps of in-situ cyclic leaching of manganese residue and percolate resource extraction, and specifically comprises the following process flow:

[0008] S1, installing a deep well vacuum suction system in the manganese residue storage yard, which is composed of a percolate extraction shaft, a recharge well and a gas-driven water drainage control system; the extraction well and the recharge well are arranged at intervals;

[0009] S2, improving the first percolate containing total manganese and ammonia nitrogen by the deep well vacuum suction system, and driving water pumping by gas pressure in the extraction well;

[0010] S3, the first percolate enters a primary reactor, anhydrous sodium carbonate is added to adjust the pH value to 9, 5% of clear liquid with a concentration of 30% hydrogen peroxide is added, and then 2% of PAC flocculant is added after standing for 15 min;

[0011] S4, the mixed liquid obtained in step S3 is dewatered by a plate and frame filter press to obtain a first precipitate and a second percolate, the first precipitate has a water content of 15-20% and contains manganese carbonate; the manganese carbonate is returned to the electrolytic manganese plant as a production raw material;

[0012] S5, the second filtrate obtained in step S4 is introduced into a secondary reactor, and then phosphoric acid with an ammonia nitrogen content of 1 times is added, then magnesium oxide is added to adjust the pH to about 6.5, then an appropriate amount of solid sodium hydroxide is added to adjust the pH to about 8.5, and then a PAC flocculant with a volume of 5% of the clear liquid is added;

[0013] S6, the mixed liquid obtained in step S5 is dewatered by a plate and frame filter press to obtain a second precipitate and a third filtrate, the second precipitate has a water content of 15-20% and contains ammonium magnesium phosphate, and the ammonium magnesium phosphate is used as a slow-release fertilizer;

[0014] S7, the third filtrate obtained in step S6 is pressurized and recharged into the manganese slag heap body through a recharge well to leach the manganese slag.

[0015] Further, the depth of the extraction well is 20-50 m; and the depth of the recharge well is 10-20 m.

[0016] Further, the gas pressure for driving water extraction is 1-2 MPa.

[0017] Further, the concentration of the PAC flocculant is 1.5%.

[0018] Further, the recharging pressure in step S7 is 0.15 MPa.

[0019] The present application has the following beneficial effects compared with the prior art:

[0020] (1) The present application is in-situ extraction, and the manganese slag storage yard is a resource extraction factory. Since the manganese slag library does not need to be excavated, the treatment range does not exceed the boundary of the slag yard, does not disturb the surrounding environment, avoids secondary pollution and the uncertainty brought by external engineering measures;

[0021] (2) More than 90% of MnSO4 and (NH4)2SO4 resources can be recovered and utilized at the same time, the sewage treatment cost is reduced, and resource utilization is realized;

[0022] (3) The manganese slag is in-situ resource extraction, and the manganese slag yard integrates raw material storage plant, resource extraction workshop and product warehouse, which saves the cost of raw material and product transportation and saves land resources;

[0023] (4) In the method of the present application, when the resources in the manganese slag do not need to be extracted, a solidification agent is injected through the recharge well to solidify the pollutants in the manganese slag cone. This method can also be applied to the field of manganese slag library pollution treatment.

[0024] Of course, any product implementing the present application does not necessarily need to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the description of the embodiments, obviously, the drawings in the following description are only some of the embodiments of the present application, and for the ordinary skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0026] Figure 1 A principle step diagram of a method for extracting resources from electrolytic manganese residue in situ. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application, obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the ordinary skilled in the art without creative labor are within the protection scope of the present application.

[0028] Please refer to Figure 1 As shown in the figure, the method for extracting resources from electrolytic manganese residue in situ comprises two links of manganese residue in-situ cyclic leaching and leachate resource extraction, and specifically comprises the following process flow:

[0029] S1, a deep well vacuum pumping system is installed in the manganese residue reservoir, the system is composed of a leachate extraction shaft, a recharge well and a gas-driven drainage control system; the extraction well and the recharge well are arranged at intervals; the depth of the extraction well is 20-50 m; the depth of the recharge well is 10-20 m; the deep well vacuum pumping system belongs to the prior art, and will not be described in detail in the specification;

[0030] S2, the first leachate A containing total manganese and ammonia nitrogen with high concentration is improved through the deep well vacuum pumping system, and the extraction well is driven to pump water through gas pressure; the gas pressure of the gas pressure driven pumping is 1-2 MPa;

[0031] As shown in Table 1, the detection result table of the pollutant concentration of the first leachate A of a manganese residue reservoir in Tongren, Guizhou is shown;

[0032] Indicator pH Total manganese mg / L Ammonia nitrogen mg / L Data 5.1～5.5 16000～18000 14000～16000

[0033] Table 1: Detection result table of pollutant concentration of first leachate A of a manganese residue reservoir in Tongren, Guizhou

[0034] S3, the first leachate A enters a first reactor, anhydrous sodium carbonate is added, the pH value is adjusted to 9, 5% of clear liquid with a concentration of 30% of hydrogen peroxide is added, and then 2% of PAC flocculant is added after standing for 15 min;

[0035] S4, the mixed solution obtained in step S3 is dewatered by plate and frame filter press to obtain first precipitate B and second percolate C, the first precipitate B has a water content of 15-20% and contains manganese carbonate; the manganese carbonate is returned to the electrolytic manganese plant as a raw material for production, and more than 90% of the manganese resources in the second percolate C can be extracted; as shown in Table 2, the detection results of the pollutant concentration of the second percolate C in the corresponding examples are shown;

[0036] Indicator pH Total manganese mg / L Ammonia nitrogen mg / L Data 9～10 1500～1600 13000～14000

[0037] Table 2: Detection results of the pollutant concentration of the second percolate C in the examples

[0038] S5, the second percolate C obtained in step S4 is introduced into a secondary reactor, then phosphoric acid with an ammonia nitrogen content of 1 times is added, then magnesium oxide is added to adjust the pH to about 6.5, then an appropriate amount of sodium hydroxide solid is added to adjust the pH to about 8.5, and then 5% of the volume of the clear liquid is added to PAC flocculant;

[0039] S6, the mixed solution obtained in step S5 is dewatered by plate and frame filter press to obtain second precipitate D and third percolate E, the second precipitate D has a water content of 15-20% and contains ammonium magnesium phosphate, and the ammonium magnesium phosphate is used as a slow-release fertilizer, which can reduce the ammonia nitrogen content in the percolate by more than 90%; as shown in Table 3, the detection results of the pollutant concentration of the third percolate E in the examples are shown;

[0040] Indicator pH Total manganese mg / L Ammonia nitrogen mg / L Data 8～9 800～900 1100～1300

[0041] Table 3: Detection results of the pollutant concentration of the third percolate E in the examples

[0042] S7, the third percolate E obtained in step S6 is pressurized and recharged into the manganese residue heap body through a recharge well to leach the manganese residue; the recharge pressure is 0.15 MPa.

[0043] The PAC flocculant has a concentration of 1.5%.

[0044] Through the above process, the percolate is repeatedly extracted, the percolate resources are extracted, and the percolate recharging and leaching process is repeated to extract more than 90% of the manganese and ammonia nitrogen resources;

[0045] The innovation of the technical solution lies in the manganese residue pore water extraction technology, high concentration content, ammonia nitrogen sewage resource extraction technology, and manganese residue percolate recharging technology;

[0046] (1) Manganese slag pore water extraction technology: Manganese and ammonia nitrogen resources in manganese slag exist in its pore water. Due to the large buried depth of manganese slag and poor water permeability, there is a lack of means for in-situ extraction of pore water, and traditional manganese slag resource extraction can only be forced to adopt ex-situ extraction method. In the present invention, a deep well bottom vacuum suction system is used to extract manganese slag pore water. This technology is widely used in tailings pond drainage field and can effectively control the saturation line of the heap. A deep well bottom vacuum suction system was installed in a manganese slag pond in Guizhou, and a field pumping test was conducted. It was found that the pumping flow rate of a single extraction shaft reached 1-3 m 3 / h, and when the recharge pressure was set at 0.10-0.15 MPa, the pumping and recharge volumes were balanced, meeting the needs of resource extraction process;

[0047] (2) High-concentration manganese and ammonia nitrogen-containing wastewater resource extraction technology: In traditional methods, manganese and ammonia nitrogen cannot be recovered at the same time, resulting in waste of one of the resources. In the present invention, a fractional precipitation method is used: ① First, add carbonate to the manganese slag leachate stock solution, then add flocculant, precipitate and filter. The manganese content of the filtered clear liquid (first filtrate) is reduced by more than 90%. ② Add magnesium ions and phosphate ions to the first filtrate to form ammonium magnesium phosphate, and obtain clear liquid by flocculation and filtration. The ammonia nitrogen concentration of the clear liquid is reduced by more than 95% compared with the leachate stock solution;

[0048] (3) Manganese slag leachate recharge technology. Using a deep well bottom vacuum suction system, the free pore water in the manganese slag heap can be pumped out. However, due to the large suction force of the manganese slag matrix, 20%-30% of the pore water in the manganese slag cannot be pumped out through the extraction well, resulting in incomplete recovery of manganese and ammonia nitrogen resources. In the present invention, the secondary filtrate after extraction of manganese and ammonia nitrogen is recharged into the manganese slag heap through a pressurized recharge well, replacing the high-concentration pore water and extracting resources. After multiple cycles, most of the manganese and ammonia nitrogen resources in the manganese slag are recovered.

[0049] The method of the present invention can realize in-situ resource extraction of manganese slag. The manganese slag heap site integrates raw material storage plant, resource extraction workshop, and product warehouse, which not only saves the cost of raw material and product transportation, but also saves land resources. In addition, when the resources in the manganese slag are no longer needed to be extracted, solidification agents can be injected through the recharge well to solidify the pollutants in the manganese slag heap, so the method can also be applied to the field of manganese slag pond pollution control.

[0050] The preferred embodiments of the application disclosed above are only to facilitate the elucidation of the application. The preferred embodiments do not describe all the details of the application and limit the application to the specific embodiments described. Obviously, many modifications and variations can be made in light of the teachings above. The description is chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application and get the best results from the application. The application is only limited by the claims and their full scope and equivalents.

Claims

1. A method for in-situ resource extraction from electrolytic manganese slag, characterized in that, The process includes two steps: in-situ circulating leaching of manganese slag and extraction of leachate resources. The specific process flow is as follows: S1. Install a deep well bottom vacuum suction system in the manganese slag storage. The system consists of a leachate extraction well, a reinjection well, and a gas-driven drainage control system. The extraction well and the reinjection well are arranged at intervals. The depth of the extraction well is 20-50m. The depth of the reinjection well is 10-20m. S2. The first filtrate (A) containing total manganese and ammonia nitrogen is improved by a deep well bottom vacuum pumping system, and the pumping well is driven by gas pressure; the gas pressure for the gas pressure driven pumping is 1-2 MPa. S3. The first leachate (A) enters the primary reactor, anhydrous sodium carbonate is added, the pH value is adjusted to 9, hydrogen peroxide with a concentration of 30% and a volume of 5% of the clear liquid is added, and it is allowed to stand for 15 minutes. Then, PAC flocculant with a concentration of 1.5% and a volume of 2% of the clear liquid is added. S4. The mixture obtained in step S3 is dehydrated by pressing and filtering with a plate and frame filter press to obtain the first precipitate (B) and the second leachate (C). The first precipitate (B) has a water content of 15-20% and contains manganese carbonate. The manganese carbonate is returned to the electrolytic manganese plant as a production raw material. S5. The second leachate (C) obtained in step S4 is fed into the secondary reactor. Phosphoric acid with a concentration equal to 1 times the ammonia nitrogen content of the pollutants in the second leachate (C) is added. Then, magnesium oxide is added to adjust the pH to about 6.

5. Then, an appropriate amount of sodium hydroxide solid is added to adjust the pH to about 8.

5. Finally, 5% of the volume of the clear liquid is added as PAC flocculant. S6. The mixture obtained in step S5 is dehydrated by pressing and filtering with a plate and frame filter press to obtain a second precipitate (D) and a third leachate (E). The second precipitate (D) has a water content of 15-20% and contains magnesium ammonium phosphate. Magnesium ammonium phosphate is used as a slow-release fertilizer. S7. The third permeate (E) obtained in step S6 is reinjected into the manganese slag pile under pressure through the reinjection well to wash the manganese slag; the reinjection pressure is 0.15 MPa.

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