Method for harmless treatment of electrolytic manganese residue

Abstract

The present application relates to the technical field of general solid waste harmless treatment, and particularly relates to a method for electrolytic manganese residue harmless treatment. The method for electrolytic manganese residue harmless treatment comprises the following steps: solidifying treatment of electrolytic manganese residue to be treated by using a solidifying agent; the solidifying agent comprises a first solidifying agent and / or a second solidifying agent; the first solidifying agent comprises the following components in parts by weight: 0.5-1.25 parts of sodium phosphate, 4-8 parts of quicklime, 3-12 parts of cement and 2-8 parts of fly ash; the second solidifying agent comprises the following components in parts by weight: 5-7 parts of calcium oxide, 1.5-2.5 parts of sodium hydroxide and 0.8-1.2 parts of sodium silicate. After the electrolytic manganese residue is treated by using the suitable solidifying agent, the electrolytic manganese residue can be harmlessly treated and recycled, and can be used for producing building material raw materials, and the method is simple in operation, high in product added value and low in cost.

Description

Technical Field

[0001] This invention relates to the field of general solid waste harmless treatment technology, and in particular to a method for harmless treatment of electrolytic manganese slag. Background Technology

[0002] Electrolytic manganese slag is the filtered acid residue produced during the electrolytic production of metallic manganese. It contains a large amount of soluble manganese sulfate and ammonium sulfate, as well as certain amounts of heavy metals such as zinc, copper, lead, and selenium. During outdoor storage, the leachate from electrolytic manganese slag continuously seeps into the natural environment due to rainwater leaching, polluting nearby soil and water bodies and posing a significant threat to human health. Current research on harmless treatment technologies for electrolytic manganese slag mainly focuses on methods such as cement and chemical reagent solidification, liquefaction leaching, and calcination. While chemical reagent solidification / stabilization of electrolytic manganese slag is effective and requires low dosage, it suffers from high reagent costs, and the long-term stability of the solidified products needs further evaluation. Simple liquefaction leaching cannot achieve the required removal rate of soluble pollutants to meet relevant emission standards. Calcination, while effectively reducing pollutant concentrations in electrolytic manganese slag, presents a significant challenge for many small and medium-sized electrolytic manganese enterprises due to the high requirements and costs associated with establishing dedicated production lines. The low-cost, high-efficiency, and harmless treatment of electrolytic manganese slag is a key factor restricting the large-scale disposal of electrolytic manganese slag by small and medium-sized electrolytic manganese enterprises. Therefore, providing a harmless treatment method that can improve the current efficiency of harmless treatment of electrolytic manganese slag in small and medium-sized electrolytic manganese enterprises and reduce treatment costs is of great significance for subsequent resource utilization.

[0003] In view of this, the present invention is hereby proposed. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the harmless treatment of electrolytic manganese slag, so as to solve the technical problems of high cost and low efficiency in the treatment of electrolytic manganese slag in the prior art.

[0005] To achieve the above-mentioned objectives of the present invention, one aspect of the present invention provides a method for the harmless treatment of electrolytic manganese slag, comprising the following steps:

[0006] A curing agent was used to cure the electrolytic manganese slag to be treated.

[0007] The curing agent includes a first curing agent and / or a second curing agent;

[0008] The first curing agent comprises the following components in parts by weight:

[0009] Sodium phosphate 0.5-1.25 parts, quicklime 4-8 parts, cement 3-12 parts, and fly ash 2-8 parts;

[0010] The second curing agent comprises the following components in parts by weight:

[0011] 5-7 parts calcium oxide, 1.5-2.5 parts sodium hydroxide and 0.8-1.2 parts sodium silicate.

[0012] In a specific embodiment of the present invention, the amount of the first curing agent is 2.4% to 30% of the mass of the electrolytic manganese slag to be treated. Further, the amount of sodium phosphate is 0.15% to 1.25% of the mass of the electrolytic manganese slag to be treated, the amount of quicklime is 1% to 8% of the mass of the electrolytic manganese slag to be treated, the amount of cement is 0.75% to 12% of the mass of the electrolytic manganese slag to be treated, and the amount of fly ash is 0.5% to 8% of the mass of the electrolytic manganese slag to be treated.

[0013] In a specific embodiment of the present invention, the mass ratio of the second curing agent to the electrolytic manganese slag to be treated is (3-15):100.

[0014] In a specific embodiment of the present invention, the mass ratio of sodium hydroxide to sodium silicate in the second curing agent is 2:1.

[0015] In a specific embodiment of the present invention, in the second curing agent, the mass ratio of sodium hydroxide to sodium silicate and to calcium oxide is 1:(1.5-2.5).

[0016] In a specific embodiment of the present invention, when the first curing agent is used, the curing treatment includes: mixing the curing agent, the electrolytic manganese slag to be treated, and water, stirring, and then letting it stand for 1 to 1.5 days;

[0017] The water content of the mixed system is controlled to be 25% to 29%.

[0018] In a specific embodiment of the present invention, during the stirring process, the released ammonia gas is recovered, and stirring is stopped after no more ammonia gas is released.

[0019] In a specific embodiment of the present invention, when the first curing agent is used, the method for obtaining the electrolytic manganese slag to be treated includes: air-drying the electrolytic manganese slag raw material naturally, then crushing it to obtain the electrolytic manganese slag to be treated.

[0020] In another specific embodiment of the present invention, when a first solidification agent is used, the method for obtaining the electrolytic manganese slag to be treated includes:

[0021] (a) After the electrolytic manganese slag raw material is naturally air-dried, it is crushed to obtain homogeneous electrolytic manganese slag;

[0022] (b) The homogeneous electrolytic manganese slag is mixed with water to form a slurry, and then the slurry is filtered and washed with water to obtain an electrolytic manganese slag filter cake;

[0023] (c) After drying the electrolytic manganese slag filter cake, crush it to obtain the electrolytic manganese slag to be treated.

[0024] In a specific embodiment of the present invention, in step (b), the mass ratio of the homogeneous electrolytic manganese slag to the water is 1:(1-8).

[0025] In a specific embodiment of the present invention, the pulping method includes: stirring the mixture of homogeneous electrolytic manganese slag and water at a speed of 40-100 r / min for 20-40 min.

[0026] In a specific embodiment of the present invention, the method further includes repeating step (b) 1 to 3 times with the obtained electrolytic manganese slag filter cake, and then proceeding to step (c).

[0027] In a specific embodiment of the present invention, when a second curing agent is used, the method for obtaining the electrolytic manganese slag to be treated includes: air-drying the electrolytic manganese slag raw material naturally, then crushing it to obtain homogeneous electrolytic manganese slag; and mixing the homogeneous electrolytic manganese slag with fly ash to obtain the electrolytic manganese slag to be treated.

[0028] In a specific embodiment of the present invention, the mass ratio of the homogeneous electrolytic manganese slag to the fly ash is (3-7):3.

[0029] In a specific embodiment of the present invention, when a second curing agent is used, the curing treatment includes: uniformly mixing calcium oxide in the curing agent with the electrolytic manganese slag to be treated to obtain a mixture; then dissolving sodium hydroxide and sodium silicate in the curing agent in water, and adding them to the mixture to obtain a mixed system; stirring to carry out a curing and stabilization reaction to obtain an electrolytic manganese slag-based polymer. Further, in the mixed system, the liquid-to-solid ratio is 40%–60%.

[0030] In a specific embodiment of the present invention, the temperature of the curing and stabilization reaction is 25–100°C, and the time of the curing and stabilization reaction is 70–74 h.

[0031] In a specific embodiment of the present invention, the electrolytic manganese slag-based polymer is mixed with aggregates to prepare concrete. Further, the aggregates include cement, fly ash, sand, and stone. The mass ratio of cement, fly ash, sand, and stone can be 11:3:31:55.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The present invention can solve the problem of high soluble salt content in electrolytic manganese slag when it is used for resource utilization in the building materials field by using a suitable curing agent for curing treatment, and can also solve the problems of high cost and low efficiency in the harmless treatment of electrolytic manganese slag by small and medium-sized electrolytic manganese enterprises.

[0034] (2) By using a suitable solidification agent to treat electrolytic manganese slag, the present invention can not only achieve the harmlessness of electrolytic manganese slag, but also achieve the resource recycling of electrolytic manganese slag, which can be used to produce raw materials for building materials. The operation is simple, the product added value is higher, and the cost is lower. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the apparatus for washing electrolytic manganese slag with water according to an embodiment of the present invention;

[0037] Figure 2 This is a scanning electron microscope image of the electrolytic manganese slag obtained after the harmless treatment in Example 2 of the present invention;

[0038] Figure 3 This is a scanning electron microscope image of the electrolytic manganese slag geopolymer obtained after harmless treatment in Example 15 of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0040] This invention provides a method for the harmless treatment of electrolytic manganese slag, comprising the following steps:

[0041] A curing agent was used to cure the electrolytic manganese slag to be treated.

[0042] The curing agent includes a first curing agent and / or a second curing agent;

[0043] The first curing agent comprises the following components in parts by weight:

[0044] Sodium phosphate 0.5-1.25 parts, quicklime 4-8 parts, cement 3-12 parts, and fly ash 2-8 parts;

[0045] The second curing agent comprises the following components in parts by weight:

[0046] 5-7 parts calcium oxide, 1.5-2.5 parts sodium hydroxide and 0.8-1.2 parts sodium silicate (Na2SiO3).

[0047] In different embodiments, the amounts of each component in the first curing agent, by weight, can be as follows:

[0048] The amount of sodium phosphate can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.25 parts, or any combination thereof;

[0049] The amount of quicklime used can be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any combination thereof;

[0050] The amount of cement can be 3 parts, 4 parts, 5 parts, 6 parts, 8 parts, 10 parts, 12 parts, or any combination thereof;

[0051] The amount of fly ash can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any combination thereof.

[0052] In different embodiments, the amounts of each component in the second curing agent, by weight, can be as follows:

[0053] The amount of calcium oxide can be 5 parts, 6 parts, 6.5 parts, 7 parts, or any combination thereof;

[0054] The amount of sodium hydroxide can be 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, or any combination thereof;

[0055] The amount of sodium silicate can be 0.8 parts, 0.9 parts, 1 part, 1.2 parts, or any combination thereof.

[0056] This invention significantly reduces costs and improves the efficiency of harmless treatment by using suitable solidification agents to solidify electrolytic manganese slag.

[0057] The quicklime in the first curing agent releases heat when it comes into contact with water, causing the gypsum to lose its water of crystallization and become calcined gypsum and a small amount of anhydrite; the cement hydration products undergo carbonation to produce carbonate precipitates; the manganese slag, after being harmlessly treated by the first curing agent, exhibits obvious cementing, encapsulation and adsorption effects, and the pollutants in the manganese slag can be effectively fixed in the resulting crystals.

[0058] OH - With Mn 2+ The reaction produced MnOOH and MnO2 precipitates, as shown in the following equation:

[0059] CaO + H₂O = Ca(OH)₂ → Ca 2+ +2OH -

[0060] Mn(OH)₂ + O₂ → MnOOH↓ + MnO₂↓

[0061] The second solidification agent mainly removes pollutants from electrolytic manganese slag in the following ways:

[0062] (1) Removal of characteristic pollutants:

[0063] CaO + H₂O → Ca(OH)₂

[0064] 4Mn 2+ +8OH - +O2→4MnOOH↓+2H2O

[0065] 4MnOOH + O2 → 4MnO2↓ + 2H2O

[0066] NH4 + +OH - →NH3↑+H2O

[0067] NH4 + +PO4 3- +Mg 2+ +6H₂O→MgNH₄PO₄·6H₂O↓

[0068] (2) Other reactions

[0069] M n+ +nOH - →M(OH) n ↓

[0070] Al 3+ +4OH - →[Al(OH)4] -

[0071] 3SiO2 + 5OH - →SiO3 2-+[SiO2(OH)2] 2- +[SiO(OH)3] -

[0072] 2SiO2+2Al 3+ +11OH - →[(OH)3-Al-O-SiO2(OH)] 3- +[(OH)3-Al-O-SiO(OH)2] 2- +H2O

[0073] y[Si-O-Al] m- →[Si-O-Al] y m- +(y-1)H2O

[0074] xM n+ +[Si-O-Al] y m- →M x -[Si-O-Al] y xn-m

[0075] In (2), M represents the polluting element, [Si-O-Al]. m- It is a silica-alumina gel, including [Al(OH)4]. - [SiO2(OH)2] 2- [SiO(OH)3] - [(OH)3-Al-O-SiO2(OH)] 3- [(OH)3-Al-O-SiO(OH)2] 2- wait.

[0076] Electrolytic manganese slag contains aluminosilicates. Aluminosilicate solid waste activated by alkali metal hydroxides or alkali metal silicates can generate geopolymers with silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra as the main structures. This is a multifunctional material with strong mechanical properties, as well as resistance to acids, alkalis and low temperatures. At the same time, geopolymers can also passively solidify pollutants, achieving both economic and environmental benefits.

[0077] In a specific embodiment of the present invention, the amount of the first curing agent is 2.4% to 30% of the mass of the electrolytic manganese slag to be treated. Further, the amount of sodium phosphate is 0.15% to 1.25% of the mass of the electrolytic manganese slag to be treated, the amount of quicklime is 1% to 8% of the mass of the electrolytic manganese slag to be treated, the amount of cement is 0.75% to 12% of the mass of the electrolytic manganese slag to be treated, and the amount of fly ash is 0.5% to 8% of the mass of the electrolytic manganese slag to be treated.

[0078] In different embodiments, the dosage of the first solidification agent can be 2.4%, 3%, 5%, 7.5%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30% of the mass of the electrolytic manganese slag to be treated, or any combination thereof. Experimental verification shows that when the components of the first solidification agent are compounded in a certain proportion, during the solidification treatment of water-washed manganese slag, the first solidification agent, with a relatively small dosage, can ensure that the manganese and ammonia nitrogen in the leachate meet the first-level standard for integrated wastewater discharge. For example, in the first curing agent, the amount of sodium phosphate can be 0.15%, 0.3%, 0.5%, 0.75%, 1%, 1.25% of the mass of the electrolytic manganese slag to be treated, or any combination thereof; the amount of quicklime can be 1%, 1.5%, 2%, 4%, 6%, 8% of the mass of the electrolytic manganese slag to be treated, or any combination thereof; the amount of cement can be 0.75%, 1.5%, 3%, 6%, 9%, 12% of the mass of the electrolytic manganese slag to be treated, or any combination thereof; and the amount of fly ash can be 0.5%, 1%, 2%, 4%, 6%, 8% of the mass of the electrolytic manganese slag to be treated, or any combination thereof.

[0079] In a specific embodiment of the present invention, the mass ratio of the second curing agent to the electrolytic manganese slag to be treated is (3-15):100.

[0080] In different embodiments, the mass ratio of the second curing agent to the electrolytic manganese slag to be treated can be 3:100, 6:100, 9:100, 12:100, 15:100, or any combination thereof.

[0081] In a specific embodiment of the present invention, the mass ratio of sodium hydroxide to sodium silicate in the second curing agent is 2:1.

[0082] Using the second curing agent in the above proportions further facilitates the formation of geopolymers.

[0083] In a specific embodiment of the present invention, when the first curing agent is used, the method for obtaining the electrolytic manganese slag to be treated includes: air-drying the electrolytic manganese slag raw material naturally, then crushing it to obtain the electrolytic manganese slag to be treated.

[0084] In another specific embodiment of the present invention, when a first solidification agent is used, the method for obtaining the electrolytic manganese slag to be treated includes:

[0085] (a) After the electrolytic manganese slag raw material is naturally air-dried, it is crushed to obtain homogeneous electrolytic manganese slag;

[0086] (b) The homogeneous electrolytic manganese slag is mixed with water to make a slurry, and then the slurry is filtered and washed with water to obtain an electrolytic manganese slag filter cake.

[0087] (c) After drying the electrolytic manganese slag filter cake, crush it to obtain the electrolytic manganese slag to be treated.

[0088] This invention addresses the problem of excessively high soluble salt content in electrolytic manganese slag when using only solidification treatment in the building materials industry, through a combined water washing and solidification process. It also solves the high cost and low efficiency issues faced by small and medium-sized electrolytic manganese enterprises in the harmless treatment of electrolytic manganese slag. After water washing, the electrolytic manganese slag, with a relatively small amount of the first solidification agent, can achieve manganese and ammonia nitrogen levels in the leachate that meet the first-level standard for integrated wastewater discharge.

[0089] In practice, the aforementioned electrolytic manganese slag to be treated can be processed as follows: Figure 1 The apparatus shown is prepared as follows: Specifically, the apparatus may include a slurry stirring device and a vacuum filtration device. The slurry stirring device may include an electromagnetic stirrer and a container holding homogeneous electrolytic manganese slag and water; the vacuum filtration device may include a funnel connected to a vacuum pump and a vacuum filtration flask. The mixture of homogeneous electrolytic manganese slag and water is stirred by the electromagnetic stirrer to form a slurry, and then the slurry is poured into the funnel of the vacuum filtration device for vacuum filtration and water washing to obtain the corresponding filter cake. The apparatus for obtaining the above-mentioned electrolytic manganese slag to be treated is not limited to this.

[0090] In a specific embodiment of the present invention, in step (b), the mass ratio of homogeneous electrolytic manganese slag to water is 1:(1-8), preferably 1:(1.8-2.2). In step (b), the number of water washing cycles can be 1 to 4.

[0091] In different embodiments, the mass ratio of homogeneous electrolytic manganese slag to water in step (b) can be 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, or any combination thereof.

[0092] In a specific embodiment of the present invention, the pulping method includes: stirring a mixture of homogeneous electrolytic manganese slag and water at a speed of 40-100 r / min for 20-40 min.

[0093] In different embodiments, the rotation speed can be a range of 40 r / min, 60 r / min, 80 r / min, 100 r / min or any combination thereof, and the stirring time can be a range of 20 min, 25 min, 30 min, 35 min, 40 min or any combination thereof.

[0094] In the pulping method, the rotation speed and stirring time can be adjusted according to the actual situation to ensure that the electrolytic manganese slag is fully pulped. The pulping operation can be carried out at room temperature.

[0095] In a specific embodiment of the present invention, the process further includes repeating the obtained electrolytic manganese slag filter cake according to step (b) 1 to 3 times, and then proceeding to step (c).

[0096] In another specific embodiment of the present invention, when a second curing agent is used, the method for obtaining the electrolytic manganese slag to be treated includes: air-drying the electrolytic manganese slag raw material naturally, crushing it to obtain homogeneous electrolytic manganese slag; and mixing the homogeneous electrolytic manganese slag with fly ash to obtain the electrolytic manganese slag to be treated.

[0097] The harmless treatment method of the present invention allows for the use of different solidification agents to treat electrolytic manganese slag obtained through different methods. Specifically, in the harmless treatment method of electrolytic manganese slag of the present invention, the electrolytic manganese slag can be directly solidified, or the washed electrolytic manganese slag can be combined with a solidification agent for treatment, or a base polymer for electrolytic manganese slag can be prepared by using a second solidification agent. This method ensures the efficiency of harmless treatment of electrolytic manganese slag, meets the standard concentration requirements of the leachate after treatment, and allows for the recovery and reuse of ammonia gas collected during the treatment process. The harmlessly treated electrolytic manganese slag product has high added value, the treatment process is simple, and it can better improve the efficiency and reduce the cost of electrolytic manganese slag treatment for small and medium-sized electrolytic manganese enterprises, providing a harmless treatment method for subsequent resource utilization.

[0098] In a specific embodiment of the present invention, when a first curing agent is used, the curing treatment includes: mixing the curing agent, the electrolytic manganese slag to be treated, and water, stirring, and then allowing it to stand for 1 to 1.5 days; wherein the water content of the mixed system is controlled to be 25% to 29%. Studies have found that when the first curing agent is used, if the curing agent, the electrolytic manganese slag to be treated, and water are mixed and stirred, and a leaching toxicity test is conducted immediately, the concentration of Mn in the leachate can meet the first-level standard for integrated wastewater discharge, while ammonia nitrogen can only meet the second-level standard. When the mixture is stirred and left to stand for 1 day, and then a leaching toxicity test is conducted, the concentration of Mn in the leachate is further reduced, and the ammonia nitrogen can meet the first-level standard for integrated wastewater discharge.

[0099] In different implementations, the water content of the mixed system is controlled to be within the range of 25%, 26%, 27%, 28%, 29%, or any combination thereof.

[0100] In a specific embodiment of the present invention, during the stirring process, the released ammonia gas is recovered, and stirring is stopped after no more ammonia gas is released.

[0101] In a specific embodiment of the present invention, when the second curing agent is used, the mass ratio of homogeneous electrolytic manganese slag to fly ash in the acquisition of the electrolytic manganese slag to be treated is (3-7):3.

[0102] In different implementations, the mass ratio of homogeneous electrolytic manganese slag to fly ash in obtaining the electrolytic manganese slag to be treated can be 1:1, 11:9, 3:2, 13:7, 7:3, or any combination thereof.

[0103] Electrolytic manganese slag geopolymer is formulated from electrolytic manganese slag, fly ash, and a second curing agent. Pre-mixing the homogeneous electrolytic manganese slag with fly ash ensures the uniformity of the second curing agent treatment and guarantees the performance of the geopolymer.

[0104] In a specific embodiment of the present invention, when a second curing agent is used, the curing treatment includes: uniformly mixing calcium oxide in the curing agent with the electrolytic manganese slag to be treated to obtain a mixture; then dissolving sodium hydroxide and sodium silicate in the curing agent in water, and adding them to the mixture to obtain a mixed system; stirring to carry out a curing and stabilization reaction to obtain an electrolytic manganese slag-based polymer. Further, in the mixed system, the liquid-to-solid ratio is 40%–60%.

[0105] In different implementations, the amount of water is adjusted so that the liquid-to-solid ratio in the mixture can be 40%, 45%, 50%, 55%, 60%, or any combination thereof.

[0106] In a specific embodiment of the present invention, the temperature of the curing and stabilization reaction is 25–100°C, and the time of the curing and stabilization reaction is 70–74 h.

[0107] In different embodiments, the curing and stabilization reaction temperature can be a range of 25°C, 40°C, 60°C, 80°C, 100°C or any combination thereof; the curing and stabilization reaction time can be a range of 70h, 72h, 74h or any combination thereof.

[0108] In a specific embodiment of the present invention, concrete is prepared by mixing electrolytic manganese slag-based polymer with aggregates. Further, the aggregates include cement, fly ash, sand, and stone. The mass ratio of cement, fly ash, sand, and stone can be 11:3:31:55.

[0109] The electrolytic manganese slag geopolymer obtained by the harmless treatment method of this invention can be used in the preparation of concrete blocks, which can be cured for approximately 28 days after preparation. The concrete blocks can be prepared by mixing the electrolytic manganese slag geopolymer obtained by the harmless treatment method of this invention with aggregates.

[0110] The size of the concrete blocks can be adjusted according to actual needs.

[0111] Example 1

[0112] This embodiment provides a method for the harmless treatment of electrolytic manganese slag, including the following steps:

[0113] Weigh 100g of air-dried and ground electrolytic manganese slag and place it in a clean beaker. Add the curing agent to the beaker, add water (controlling the water content of the system to 27%), stir until uniform (about 3-5 minutes), and let it stand for 1 day to react. The curing agent includes 1.25g of Na3PO4, 8g of quicklime, 9g of cement (425 ordinary Portland cement), and 4g of fly ash.

[0114] Example 2

[0115] This embodiment provides a method for the harmless treatment of electrolytic manganese slag, including the following steps:

[0116] (1) Weigh 200g of air-dried and ground electrolytic manganese slag, place it in a clean beaker, add 400mL of pure water to the beaker, stir with an electromagnetic stirrer at 50r / min for 30min at room temperature to fully slurry, filter the slurry under reduced pressure, and collect 100g of filter cake.

[0117] (2) Place 100g of filter cake in a beaker containing 200mL of pure water, repeat step (1), collect 50g of filter cake and dry it at 105℃;

[0118] (3) Add the dried filter cake from step (2) to the curing agent, add water (control the water content of the system after adding water to be 27%) and stir until uniform (about 3-5 min), then let it stand for 1 day to react; the curing agent includes Na3PO4, quicklime, cement (425 ordinary Portland cement) and fly ash, the amount of curing agent is 9.6% of the mass of the dried filter cake, and the mass ratio of Na3PO4, quicklime, cement and fly ash is 0.6:4:3:2.

[0119] Figure 2 The image shows a scanning electron microscope (SEM) image of the electrolytic manganese slag obtained after harmless treatment in Example 2 of the present invention. It can be seen from the image that the treated electrolytic manganese slag underwent obvious gelation, encapsulation and adsorption, which effectively fixed the pollutants in the electrolytic manganese slag in the generated crystals.

[0120] Example 3

[0121] This embodiment refers to the harmless treatment method of electrolytic manganese slag in Embodiment 2, the only difference being: in step (3), the amount of solidification agent is different.

[0122] In step (3) of this embodiment, the curing agent includes Na3PO4, quicklime, cement (425 ordinary silicate cement) and fly ash. The amount of curing agent is 2.4% of the mass of the dried filter cake, and the mass ratio of Na3PO4, quicklime, cement and fly ash is 0.6:4:3:2.

[0123] Example 4

[0124] This embodiment refers to the harmless treatment method of electrolytic manganese slag in Embodiment 2, the only difference being: in step (3), the amount of solidification agent is different.

[0125] In step (3) of this embodiment, the curing agent includes Na3PO4, quicklime, cement (425 ordinary silicate cement) and fly ash. The amount of curing agent is 4.8% of the mass of the dried filter cake, and the mass ratio of Na3PO4, quicklime, cement and fly ash is 0.6:4:3:2.

[0126] Examples 5-14

[0127] Examples 5-14 refer to the harmless treatment method of electrolytic manganese slag in Example 1, the only difference being the different qualities of Na3PO4, quicklime, cement and fly ash in the solidification agent.

[0128] The mass of each component in the curing agent used in Examples 5-14 is shown in Table 1.

[0129] Table 1. Mass (g) of each component in the curing agent.

[0130] serial number <![CDATA[Na3PO4]]> quicklime cement fly ash Example 5 0.5 4 6 4 Example 6 0.5 6 9 6 Example 7 0.5 8 12 8 Example 8 0.75 4 3 8 Example 9 0.75 6 12 2 Example 10 1 4 12 6 Example 11 1 6 3 4 Example 12 1 8 6 2 Example 13 1.25 4 9 2 Example 14 1.25 6 6 8

[0131] Example 15

[0132] This embodiment provides a method for the harmless treatment of electrolytic manganese slag, including the following steps:

[0133] (1) Weigh out the air-dried and ground electrolytic manganese slag, then add fly ash of the same mass as the electrolytic manganese slag and mix evenly to obtain the electrolytic manganese slag to be treated;

[0134] (2) Add calcium oxide from the curing agent to the electrolytic manganese slag to be treated, mix evenly, and then add sodium hydroxide and sodium silicate from the curing agent (sodium hydroxide and sodium silicate are pre-dissolved in water) to obtain a mixed system with a liquid-to-solid ratio of 50%. Carry out the curing and stabilization reaction at 60°C for 70-74 hours. The curing agent includes calcium oxide, sodium hydroxide and sodium silicate in a mass ratio of 6:2:1, and the amount of curing agent (calcium oxide + sodium hydroxide + sodium silicate) is 9% of the mass of the electrolytic manganese slag to be treated.

[0135] Figure 3 The image shows a scanning electron microscope (SEM) image of the electrolytic manganese slag obtained after harmless treatment in Example 15 of the present invention. It can be seen from the image that an electrolytic manganese slag-based polymer is formed in the treated electrolytic manganese slag.

[0136] The preparation of concrete by mixing the harmlessly treated electrolytic manganese slag from this embodiment with aggregates includes the following steps:

[0137] Electrolytic manganese slag (after harmless treatment) and aggregates were mixed in a specific ratio. The mixture was poured into a mold and compacted. After curing in a constant temperature and humidity curing chamber at 95% humidity and 20℃ for 24 hours, the mixture was demolded and transferred to the curing chamber for further curing for 28 days to obtain concrete test blocks. The amount of electrolytic manganese slag was 8 wt% of the total amount of concrete test blocks. The aggregates included cement, fly ash, sand, and stone in a mass ratio of 11:3:31:55. The compressive strength of the obtained concrete test blocks was 9.76 MPa.

[0138] Examples 16-18

[0139] Examples 16-18 refer to the harmless treatment method of electrolytic manganese slag in Example 15, the only difference being that in step (2), the mass ratio of calcium oxide, sodium hydroxide and sodium silicate in the solidification agent and the proportion of the solidification agent to the electrolytic manganese slag to be treated are different.

[0140] The composition and dosage of the curing agents used in Examples 16-18 are shown in Table 2.

[0141] Table 2 Composition and dosage of solidification agent (proportion of the mass of electrolytic manganese slag to be treated)

[0142]

[0143]

[0144] Example 19

[0145] Example 19 refers to the harmless treatment method of electrolytic manganese slag in Example 15, the only difference being that in step (1), the mass ratio of electrolytic manganese slag to fly ash is different.

[0146] In this embodiment, the air-dried and ground electrolytic manganese slag is weighed, and then mixed evenly with fly ash to obtain the electrolytic manganese slag to be treated; wherein, the mass ratio of fly ash to electrolytic manganese slag is 4:6.

[0147] Comparative Examples 1-4

[0148] The harmless treatment methods of Comparative Examples 1 to 4 refer to Example 1, except that the quantities of Na3PO4, quicklime, cement, and fly ash in the solidification agent are different.

[0149] The mass of each component in the curing agent used in Comparative Examples 1 to 4 is shown in Table 3.

[0150] Table 3. Mass (g) of each component in the curing agent.

[0151] serial number <![CDATA[Na3PO4]]> quicklime cement fly ash Comparative Example 1 0.5 2 3 2 Comparative Example 2 0.75 2 6 6 Comparative Example 3 1 2 9 8 Comparative Example 4 1.25 2 12 4

[0152] Comparative Examples 5-10

[0153] Comparative Examples 5 to 10 refer to the harmless treatment method of Example 15, the difference being that in step (2), the mass ratio of calcium oxide, sodium hydroxide and sodium silicate in the solidification agent and the proportion of the solidification agent to the electrolytic manganese slag to be treated are different.

[0154] The composition and dosage of the curing agents used in Comparative Examples 5 to 10 are shown in Table 4.

[0155] Table 4. Composition and dosage of solidification agent (proportion of the mass of the electrolytic manganese slag to be treated)

[0156] serial number <![CDATA[CaO﹕NaOH﹕Na2SiO3]]> Dosage Comparative Example 5 4.5﹕1﹕0.5 6 Comparative Example 6 4.5﹕4﹕2 10.5 Comparative Example 7 4.5﹕5﹕2.5 12 Comparative Example 8 6﹕3﹕1.5 10.5 Comparative Example 9 6﹕4﹕2 12 Comparative Example 10 6﹕5﹕2.5 13.5

[0157] Comparative Examples 11–15

[0158] The harmless treatment methods of Comparative Examples 11-15 refer to Example 15, the difference being that the type of solidification agent is different in step (2).

[0159] The composition and dosage of the curing agents used in Comparative Examples 11–15 are shown in Table 5.

[0160] Table 5 Composition and dosage of solidification agent (proportion of the mass of the electrolytic manganese slag to be treated)

[0161] serial number <![CDATA[Ca(OH)2﹕Na2SiO3]]> Dosage Comparative Example 11 2﹕1 2wt% Comparative Example 12 2﹕1 4wt% Comparative Example 13 2﹕1 6wt% Comparative Example 14 2﹕1 8wt% Comparative Example 15 2﹕1 10wt%

[0162] Experimental Example 1

[0163] The electrolytic manganese slag, after being rendered harmless according to the various embodiments and comparative examples, was leached using the horizontal oscillation method (HJ557-2010) for toxic leaching of solid waste. The concentrations of ammonia nitrogen, manganese ions, and pH in the leachate were tested, and the test results are shown in Table 6.

[0164] Table 6 Test Results

[0165]

[0166]

[0167]

[0168] The results above show that, using the harmless treatment method of the present invention, the electrolytic manganese slag treated by leaching with the "Horizontal Shaking Method for Leaching Toxicity of Solid Waste" (HJ557-2019) can meet the Class I discharge standard (2.0 mg / L) of the "National Integrated Wastewater Discharge Standard" (GB8978-1996), and all of them are lower than 0.1 mg / L. Through further optimization of the solidification agent and solidification method, the concentration of ammonia nitrogen in the leachate meets the Class I discharge standard (15 mg / L) of the "National Integrated Wastewater Discharge Standard" (GB8978-1996).

[0169] Comparative Examples 15 and 11-15 show that although CaO reacts with water to form Ca(OH)2, if Ca(OH)2 is used to replace CaO and NaOH for curing, the pH value of the system increases rapidly as the amount of curing agent increases. Furthermore, in the subsequent resource utilization of electrolytic manganese slag, the admixtures in concrete are mostly alkaline materials. Using Ca(OH)2 / Na2SiO3 as a curing agent makes it difficult to meet the standard of HJ 1241-2022 requiring the pH of the electrolytic manganese slag treatment product system to be controlled between 6 and 9.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for harmless treatment of electrolytic manganese slag, characterized in that, Includes the following steps: The electrolytic manganese slag to be treated is solidified using a first solidifying agent; the amount of the first solidifying agent is 2.4% to 20% of the mass of the electrolytic manganese slag to be treated. The first curing agent comprises the following components in parts by weight: Sodium phosphate 0.5-1.25 parts, quicklime 4-8 parts, cement 3-12 parts, and fly ash 2-8 parts; The method for obtaining the electrolytic manganese slag to be treated includes: (a) After the electrolytic manganese slag raw material is naturally air-dried, it is crushed to obtain homogeneous electrolytic manganese slag; (b) The homogeneous electrolytic manganese slag is mixed with water to form a slurry, and then the slurry is filtered and washed with water to obtain an electrolytic manganese slag filter cake; (c) The electrolytic manganese slag filter cake is dried and then crushed to obtain the electrolytic manganese slag to be treated.

2. The method for harmless treatment of electrolytic manganese slag according to claim 1, characterized in that, The amount of sodium phosphate used is 0.15% to 0.75% of the mass of the electrolytic manganese slag to be treated, the amount of quicklime used is 1% to 4% of the mass of the electrolytic manganese slag to be treated, the amount of cement used is 0.75% to 3% of the mass of the electrolytic manganese slag to be treated, and the amount of fly ash used is 0.5% to 2% of the mass of the electrolytic manganese slag to be treated.

3. The method for harmless treatment of electrolytic manganese slag according to claim 1, characterized in that, The curing process includes: mixing the first curing agent, the electrolytic manganese slag to be treated, and water, stirring, and then letting it stand for 1 to 1.5 days; The water content of the mixed system is controlled to be 25% to 29%.

4. The method for harmless treatment of electrolytic manganese slag according to claim 3, characterized in that, During the stirring process, the released ammonia gas is recovered, and stirring is stopped once no more ammonia gas is released.

5. The method for harmless treatment of electrolytic manganese slag according to claim 1, characterized in that, In step (b), the mass ratio of the homogeneous electrolytic manganese slag to the water is 1:(1-8).

6. The method for harmless treatment of electrolytic manganese slag according to claim 5, characterized in that, The method for preparing the slurry includes: stirring the mixture of homogeneous electrolytic manganese slag and water at a speed of 40-100 r / min for 20-40 min.

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