A method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake

Abstract

This invention discloses a method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake. The steps are as follows: pre-dispersing the water-washed electrolytic manganese slag filter cake, followed by adding alkaline materials in two stages to further disperse the filter cake and simultaneously remove residual NH4 from the water-washed electrolytic manganese slag. + The removal of soluble harmful ions and the stabilization and solidification, followed by ball milling and calcination after aging, further activate the deammonium-washed electrolytic manganese slag, which can be used to prepare mineral admixtures or cement mortar. This invention effectively reduces the particle size of the material, increases its specific surface area, and lowers the surface binding energy between elements such as Al, Si, and Ca and O in the crystal structure through mechanical activation technology, causing the silicate minerals and quartz crystals in the material to transform into an amorphous state, thereby enhancing the pozzolanic activity of the material. Thermal activation technology promotes the dehydration, dehydroxylation, decomposition reactions, or crystal transformation of the silicate minerals in the material, thereby enhancing its pozzolanic activity.

Description

Technical Field

[0001] This invention relates to the field of industrial solid waste pretreatment and resource utilization, and in particular to a method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake. Background Technology

[0002] Currently, the historical stockpile of electrolytic manganese slag exceeds 160 million tons, and continues to grow at a rate of over 10 million tons per year. This is because electrolytic manganese slag contains a large amount of harmful ions (NH4+). + Mn 2+ Cu 2+ 、Zn 2+ Cr 6+ Cd 2+ Se 4+ Pb 2+ and Ni 2+ This could cause soil and water pollution, severely damage ecosystems, and even endanger human health. Reusing electrolytic manganese slag not only realizes its resource utilization but also brings considerable economic benefits. Among these, the resource utilization in building materials has become the mainstream disposal method for electrolytic manganese slag. However, the difficulty in dispersing plate-shaped electrolytic manganese slag and the presence of NH4+ are challenges. + The high content of heavy metals and low chemical reactivity of electrolytic manganese slag greatly hinder the reuse of it in building materials.

[0003] Washing is an effective method for removing or reducing NH4 in electrolytic manganese slag. + and Mn 2+ Methods for reducing the leaching rate of harmful ions. For example, patent CN202011301655.4 uses 2-5 stages of countercurrent water washing to reduce the leaching rate of soluble NH4+ in electrolytic manganese slag. + and Mn 2+ The recycling process is described in patent CN201810582540.3, which uses anolyte to acid wash the electrolytic manganese slag and recovers NH4 from it through pressure filtration, water washing, and alkaline washing. + and Mn 2+ Studies have also shown that soluble Mn can be leached from electrolytic manganese slag using pure water. 2+ Mn 2+ The leaching rate can reach 83.35%. Under mechanochemical ball milling conditions, using water as the leaching agent, the Mn content in electrolytic manganese slag was reduced. 2+ and NH4 + The concentrations can be reduced to 1.01 mg / L and 13.65 mg / L, Mn 2+ The recovery rate exceeded 98%. A low-temperature roasting-water washing process was used to leach Mn from electrolytic manganese slag. Results showed that after roasting at 600℃ for 60 min followed by water washing for 25 min, the Mn recovery rate reached 67.12%. Although washing is an effective method for removing Mn from electrolytic manganese slag... 2+ and NH4+ However, even after washing, the electrolytic manganese slag will still retain a certain amount of Mn. 2+ and NH4 + These residual Mn 2+ and NH4 + These substances may escape or dissolve during reuse, affecting the performance of products related to water-washed electrolytic manganese slag. Furthermore, the water-washed electrolytic manganese slag after multi-stage pressure filtration and washing is plate-shaped, has a high moisture content, is difficult to disperse, and is not easily utilized as a resource. The aforementioned studies mainly focus on the stable solidification behavior and mechanism of electrolytic manganese slag, often neglecting its dispersibility.

[0004] Patent CN201010283952.0 proposes the preparation of eco-friendly cement by crushing and calcining electrolytic manganese slag, followed by ball milling with blast furnace slag and clinker. Patent CN2019108592619 proposes the preparation of a novel cementitious material using electrolytic manganese slag, fly ash, red mud, calcium-containing alkaline compounds, cement, and water. Patent CN201911151473.0 utilizes alkali to reduce NH4 in electrolytic manganese slag. + Removal of Mn 2+ The solidification process was used to prepare alkaline cementitious materials. Patents CN201810051563.1, CN201910396599.8, CN202011316136.5, and CN201910829401.0 describe the preparation of mineral admixtures, silicate cement clinker, and sulfoaluminate cement clinker through high-temperature calcination, supplemented with other siliceous and aluminous raw materials, activators, and pulverized coal. While these studies have yielded good results, they primarily focus on the desulfurization activation or calcination characteristics of electrolytic manganese slag, often neglecting the dispersibility of the slag, and failing to demonstrate a combined mechanical-thermal activation method to enhance the hydration activity of the slag. Summary of the Invention

[0005] The purpose of this invention is to provide a method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake, comprising:

[0007] (1) The water-washed electrolytic manganese slag filter cake with a moisture content of 15-30% is mechanically stirred for a period of time to achieve the pre-dispersion of the water-washed electrolytic manganese slag filter cake. Then, while stirring, 5-10% of the base mass of the filter cake of alkaline material is added in two batches.

[0008] (2) Take out the above-mentioned well-stirred sample and place it in a dry and ventilated environment for aging;

[0009] (3) Place the aged electrolytic manganese slag from step (2) into a ball mill and ball mill it;

[0010] (4) The electrolytic manganese slag after ball milling is placed in a muffle furnace for calcination;

[0011] (5) Replace the cement in the mineral admixture or cement mortar with the mechanically-thermally activated deammonium-washed electrolytic manganese slag obtained in step (4) at a rate of 5-50 wt.%.

[0012] Preferably, in step (1), the alkaline material is selected from one or more of quicklime, hydrated lime, calcined raw meal, steel slag, and carbide slag.

[0013] Preferably, in step (1), the alkaline material is added in two batches while stirring. The amount of the first addition is 10-60 wt.% of the total amount of alkaline material, preferably 20-50 wt.%, more preferably 40 wt.%. The stirring time after each addition is 5-30 min, and the time for each addition is 10-30 s.

[0014] Preferably, in step (1), the water-washed electrolytic manganese slag filter cake with a moisture content of 15-30% is mechanically stirred for 5-30 minutes to achieve pre-dispersion of the water-washed electrolytic manganese slag filter cake.

[0015] Preferably, in step (2), the aging process is carried out for more than 48 hours.

[0016] Preferably, in step (3), the ball-to-material ratio is 10:1, the rotation speed is 30 r / min, and the ball milling time is 0.5-7 h, preferably 3 h.

[0017] Preferably, in step (4), the calcination temperature is 300-900℃, more preferably 300-700℃, and the calcination time is 0.5-3h, more preferably 1h.

[0018] Compared with existing inventions on the pretreatment and resource utilization of electrolytic manganese slag, this invention has the following significant advantages:

[0019] (1) This invention utilizes a concrete twin-shaft mixer for mixing and disperses the filter cake of water-washed electrolytic manganese slag by adding alkaline materials in stages, while simultaneously eliminating residual NH4 in the water-washed electrolytic manganese slag. + Removal and soluble harmful ions (such as Mn) 2+ and Mg 2+ The stable solidification of manganese slag filter cake (etc.) is achieved through traditional processes. Traditional electrolytic manganese slag filter cake requires crushing, drying, and ball milling, while this invention greatly simplifies the process and significantly reduces costs.

[0020] (2) This invention utilizes an alkaline material treatment process for electrolytic manganese slag to activate the inert silica-alumina substances in the water-washed electrolytic manganese slag. Mechanical activation causes lattice distortion and particle size refinement, further enhancing its activity. The calcination process achieves dehydration, dehydroxylation, and decomposition reactions of silicates, carbonates, and aluminosilicates. The above process improves the activity of the water-washed electrolytic manganese slag and decomposes the clay substances within it, alleviating the decrease in cement mortar flowability when adding water-washed electrolytic manganese slag, and even improving the flowability of cement mortar. Existing technologies often employ high-temperature desulfurization calcination or direct calcination activation processes. This technology, due to the prior removal of ammonia, eliminates ammonia pollution during calcination. Compared with existing technologies, it has advantages such as simple process, low cost, and strong operability.

[0021] (3) This invention not only provides theoretical support for the new process of pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake, but also provides new research ideas for the pretreatment and resource utilization of other acidic wet metallurgical slag filter cake. Attached Figure Description

[0022] Figure 1 The effect of different treatment processes on the pH value, leaching concentration and particle size of water-washed electrolytic manganese slag is shown in the figure. (ac) represents the amount of carbide slag added and (df) represents the stepwise addition of carbide slag.

[0023] Figure 2 Particle size, specific surface area and particle size distribution of PI 42.5 cement and mechanically activated deammoniation washed electrolytic manganese slag, wherein (a) particle size and specific surface area and (b) particle size distribution.

[0024] Figure 3 SEM images of electrolytic manganese slags from different mechanically-thermally activated deammoniation washing processes are shown, with (a) BM0.5, (b) BM3, (c) BM-C4 and (d) BM-C7.

[0025] Figure 4 To determine the fluidity of cement mortar with different mechanically-thermally activated deammoniation-washed electrolytic manganese slags, the following factors were considered: (a) mechanical activation time, (b) BM3 dosage, (c) calcination time, and (d) BM-C7 dosage.

[0026] Figure 5 To assess the compressive strength of cement mortar with different mechanically and thermally activated deammoniation-washed electrolytic manganese slag, the following factors were considered: (a) different mechanical activation times, (b) different BM3 dosages, (c) different thermal activation temperatures, and (d) different BM-C7 dosages. Detailed Implementation

[0027] To better illustrate the present invention, specific embodiments are given below to describe the present invention in more detail. The scope of protection of the present invention is not limited to the examples given.

[0028] The main objective of this invention is to simplify the pretreatment process of water-washed electrolytic manganese slag filter cake and to remove residual NH4 from the water-washed electrolytic manganese slag. + Removal and soluble harmful ions (such as Mn) 2+ and Mg 2+ The process stabilizes and solidifies the manganese slag (e.g., NH4), enhances its activity, and solves its problems of poor dispersion and NH4 content. + Overcoming challenges such as high heavy metal content and low chemical reactivity, it can be used as a mineral admixture. A concrete twin-shaft mixer is used to pre-disperse the filter cake from the washed electrolytic manganese slag, while simultaneously removing residual NH4 from the slag. + Removal and soluble harmful ions (such as Mn) 2+ and Mg 2+ The process involves stabilizing and solidifying materials (such as silicate minerals and quartz crystals). Mechanical activation technology effectively reduces particle size, increases specific surface area, and lowers the surface bonding energy between elements like Al, Si, and Ca and O in the crystal structure, causing silicate minerals and quartz crystals in the material to transform into an amorphous state, thereby enhancing the pozzolanic activity of the material. Thermal activation technology promotes dehydration, dehydroxylation, decomposition reactions, or crystal transformation of silicate minerals in the material, thereby enhancing its pozzolanic activity.

[0029] A method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake, the specific steps of which are as follows:

[0030] (1) Place the water-washed electrolytic manganese slag filter cake with a moisture content of 15-30% in a concrete twin-shaft mixer and stir for 10-30 minutes to achieve pre-dispersion of the water-washed electrolytic manganese slag filter cake. Then, while stirring, add 5-10 wt.% of alkaline material, such as quicklime, hydrated lime, calcined raw meal, steel slag, or carbide slag, to the pre-dispersed water-washed electrolytic manganese slag filter cake in two batches. The first addition is carried out after the pre-dispersion of the water-washed electrolytic manganese slag filter cake, and the amount of the first addition is 10-60 wt.% of the total amount of alkaline material. After the first addition, continue stirring for 5-30 minutes, and then start the second addition. The time for each addition is 10-30 seconds. After the second addition, continue stirring for 5-30 minutes. Then, take out the above-mentioned uniformly stirred sample and place it in a dry and ventilated environment to age for 48 hours for later use. The released gas needs to be collected and recovered. The obtained sample is recorded as deammoniated water-washed electrolytic manganese slag.

[0031] (2) The deammoniation-washed electrolytic manganese slag described in step (1) is placed in a ball mill and ball-milled at a ball-to-material ratio of 10:1, a rotation speed of 30 r / min, and a milling time of 0.5-7 h. Then, the ball-milled deammoniation-washed electrolytic manganese slag is placed in a muffle furnace and calcined for 0.5-3 h at a calcination temperature of 300-900 °C. The resulting sample is recorded as mechanically-thermally activated deammoniation-washed electrolytic manganese slag.

[0032] (3) Replace PI 42.5 cement with 5-50% of the mechanically-activated deammoniation-washed electrolytic manganese slag described in step (2) as a mineral admixture or cement mortar.

[0033] Example 1

[0034] 30 kg of water-washed electrolytic manganese slag filter cake with a moisture content of 23.05% was placed in a concrete twin-shaft mixer and stirred for 15 min to achieve pre-dispersion of the water-washed electrolytic manganese slag filter cake. When adding carbide slag in one step, the carbide slag dosages of 0, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, and 8 wt.% were designated as A0, A1, A2, A3, A4, and A5, respectively. Carbide slag was added while stirring for 5 seconds, and stirring continued for 25 min. When adding 6% carbide slag in stages (in two steps), the first addition was after pre-dispersion, with a certain mass of carbide slag added while stirring for 5 seconds, and stirring continued for 10 min; the second addition was after stirring for 10 min, with the remaining carbide slag added while stirring for 5 seconds. The ratios of the two carbide slag additions were 2:8, 3:7, 4:6, and 5:5, respectively, and the corresponding groups were designated as A6, A7, A8, and A9. The effects of different treatment processes (calcium carbide slag dosage and stepwise addition of calcium carbide slag) on ​​the pH value, leaching concentration, and particle size of water-washed electrolytic manganese slag are as follows: Figure 1 As shown. Figure 1 From 'a', we can see that when the calcium carbide slag content is 6 wt.%, the pH value of the treated electrolytic manganese slag is 9.67, and the NH4+ content of the treated electrolytic manganese slag is... + The concentration decreased from 22.19 mg / L to 1.63 mg / L. Figure 1 The value of 'b' in the figure indicates that when the calcium carbide slag content increases to 8 wt.%, the Mn content of the treated electrolytic manganese slag increases. 2+ The leaching concentration decreased from 77.58 mg / L to below the detection limit, Mg 2 + The leaching concentration decreased from 50.21 mg / L to 1.37 mg / L. When the calcium carbide slag content was 4 wt.%, the Al content of the treated electrolytic manganese slag... 3+ The leaching concentration was 1.81 mg / L, which decreased to 0.42 mg / L when the amount of calcium carbide slag added was 8 wt.%. Figure 1 The value of c indicates that the average particle size of the untreated water-washed electrolytic manganese slag is 10.92 μm. When the amount of carbide slag added is 6 wt.%, the average particle size of the treated water-washed electrolytic manganese slag decreases to 9.32 μm. This indicates that the reaction of an appropriate amount of carbide slag with water-washed electrolytic manganese slag can promote the dispersion of water-washed electrolytic manganese slag agglomerates.

[0035] Depend on Figure 1 As can be seen from d, adding carbide slag in stages can further reduce NH4. + When the leaching concentration and the amount of carbide slag added are 6 wt.%, the NH4 content of all stepwise addition groups is...+ The leaching concentrations were all below the detection limit. This indicates that adding calcium carbide slag in stages is more effective than adding it only once in treating washed electrolytic manganese slag. Figure 1 As shown in e, Mn is added stepwise to the water-washed electrolytic manganese slag after treatment with carbide slag group. 2+ The leaching concentrations were all below the detection limit for Mg. 2+ The leaching concentration was not significantly affected. When the carbide slag was added in steps at the proportions described in A8, Al 3+ The leaching concentration reached the minimum value (0.33 mg / L). For example... Figure 1 As shown in f, the average particle size of the group with a single addition of 6 wt.% calcium carbide slag was 9.32 μm. When calcium carbide slag was added in proportions A8 and A9, the average particle sizes were 58.36 μm and 240.56 μm, respectively. The main reason is that the stepwise addition of calcium carbide slag promoted the reaction between the water-washed electrolytic manganese slag and the calcium carbide slag, thereby increasing the particle size of the treated water-washed electrolytic manganese slag.

[0036] Example 2

[0037] The particle size, specific surface area, and particle size distribution of mechanically activated deammoniation-removed and washed electrolytic manganese slag can, to some extent, reflect the activity of the mechanically activated deammoniation-removed and washed electrolytic manganese slag. Deammoniation-removed and washed electrolytic manganese slag from group A8 of Example 1 was used for mechanical activation. The mechanical ball milling times were selected as 0.5h, 1h, 2h, 3h, and 4h, respectively, and the samples were designated as BM0.5, BM1, BM2, BM3, and BM4. The particle size, specific surface area, and particle size distribution of the samples are shown below. Figure 2 As shown in a and b in the figure.

[0038] Depend on Figure 2 It can be seen that the d10, d50, and d90 values ​​of the mechanically activated, ammonia-removed, and water-washed electrolytic manganese slag are all lower than those of PI 42.5 cement, while its specific surface area is higher. With prolonged mechanical activation time, the d10, d50, and d90 values ​​of the mechanically activated, ammonia-removed, and water-washed electrolytic manganese slag first decrease and then increase, reaching their lowest values ​​after 3 hours of mechanical activation. The d50 of BM3 is approximately 0.25 times that of PI 42.5. The specific surface area of ​​the mechanically activated, ammonia-removed, and water-washed electrolytic manganese slag first increases and then decreases with prolonged mechanical activation time, reaching its highest value after 3 hours of mechanical activation. The specific surface area of ​​BM3 is approximately 2.55 times that of PI 42.5.

[0039] Example 3

[0040] The microstructure of the deammoniation-washed electrolytic manganese slag changes during the mechanical-thermal activation process, reflecting its activity to some extent. Mechanically activated deammoniation-washed electrolytic manganese slag BM3 from Example 2 was used for mechanical-thermal activation at temperatures of 300℃, 400℃, 500℃, 600℃, 700℃, and 800℃, with activation times of 1 hour. The samples were designated BM3-C3, BM3-C4, BM3-C5, BM3-C6, BM3-C7, and BM3-C8. SEM images of samples BM0.5, BM3, BM3-C4, and BM3-C7 were compared, and the results are as follows: Figure 3 As shown.

[0041] Depend on Figure 3 As shown in a and b, the deammoniation-removed, washed electrolytic manganese slag after 0.5 hours of mechanical activation is composed of agglomerated particles, which significantly disperse after 3 hours of mechanical activation. This is because the mechanical stress generated during the mechanical activation process reduces the particle size, which is consistent with the particle size analysis results. Figure 3 As can be seen from b and d, calcination can further refine the particle size of the deammonium-washed electrolytic manganese slag. With the increase of calcination temperature, the particle size of the deammonium-washed electrolytic manganese slag gradually decreases, and the content of flaky material in the calcined deammonium-washed electrolytic manganese slag increases.

[0042] Example 4

[0043] The fluidity of cement mortar reflects the workability of cement-based materials and, to some extent, predicts the workability of concrete with the same cementitious material mix. The mechanical and thermal activation process, including the dehydration, dehydroxylation, and decomposition reactions of clay substances in the electrolytic manganese slag after ammonia removal washing, affects the fluidity of the corresponding cement mortar. The basic formula for traditional cement mortar is: 450g cement, 1350g standard sand, and 225g water. The fluidity of cement mortar with different amounts of electrolytic manganese slag added is as follows: Figure 4 As shown, the compressive strength of the corresponding cement mortar is shown in the figure. Figure 5 .

[0044] Depend on Figure 4 As shown in section a, the cement mortar in this example was constructed by replacing a portion of the cement in traditional cement mortar with mechanically activated, ammonia-removed, washed, electrolytic manganese slag (30% by weight of cement) from Example 2 at different mechanical activation times. These mortars were named BM0.5-30, BM1-30, BM2-30, BM3-30, and BM4-30, respectively. With increasing mechanical activation time, the fluidity of the cement mortar first decreased and then increased, both significantly lower than that of the pure cement PI 42.5 group. Among them, the BM0.5-30 group exhibited the best fluidity at 162.5 mm, a 23.71% decrease compared to the 213 mm of the pure cement group. The BM3-30 group had the second best fluidity at 157.5 mm, a 26.05% decrease compared to the pure cement group. The corresponding compressive strength of the cement mortar is as follows: Figure 5As shown in section 'a', the addition of 30% mechanically activated, deammoniated, water-washed electrolytic manganese slag significantly reduced the compressive strength of cement mortar at all ages. Among these, the BM3-30 group exhibited higher compressive strength at all ages. The pure cement group showed compressive strengths of 3d, 40.86MPa, and 57.95MPa at 28d, respectively. The BM3-30 group showed compressive strengths of 16.02MPa, 16.33MPa, and 25.00MPa at 28d, respectively.

[0045] Figure 4 In Figure b, it is indicated that the cement mortar in this embodiment is composed of 5%-30% by mass of mechanically activated, deammoniated, water-washed, electrolytic manganese slag from Example 2, replacing a portion of the cement in the traditional cement mortar. These mortars are named BM3-5, BM3-10, BM3-15, BM3-20, BM3-25, and BM3-30, respectively. With increasing BM3 content, the fluidity of the cement mortar gradually decreases. The fluidity of group BM3-10 is 200 mm, a decrease of 6.10% compared to the pure cement group. The fluidity of group BM3-15 is 191.5 mm, a decrease of 10.09% compared to the pure cement group. With further increases in BM3 content, the fluidity of the cement mortar decreases further, with group BM3-30 reaching 157.5 mm, a decrease of 26.06% compared to the pure cement group. The corresponding compressive strength of the cement mortar is as follows: Figure 5 From b, we can know that Figure 5 The value of 'b' indicates that with increasing BM3 content, the 3-day and 7-day compressive strength of cement mortar first increases and then decreases, while the 28-day compressive strength gradually decreases. The 3-day and 7-day compressive strengths of the BM3-5 group are 38.02 MPa and 41.55 MPa, respectively, showing an increase compared to the pure cement group, with a 28-day compressive strength of 52.11 MPa. The 3-day and 7-day compressive strengths of the BM3-10 group are comparable to those of the pure cement group, at 31.80 MPa and 39.84 MPa, respectively, with a 28-day strength of 50.60 MPa, similar to the BM3-5 group. The 3-day, 7-day, and 28-day compressive strengths of the BM3-15 group are 20.86 MPa, 28.92 MPa, and 45.33 MPa, respectively. With further increases in BM3 content, the compressive strength at all ages decreases significantly; however, when the content exceeds 25%, the compressive strength at all ages remains almost unchanged.

[0046] like Figure 4As shown in c, the cement mortars in this example were constructed by replacing a portion of the cement in traditional cement mortar with mechanically-activated deammoniation-washed electrolytic manganese slag (30% by weight of cement) calcined at different temperatures in Example 3. These mortars were named BM3-C3-30, BM3-C4-30, BM3-C5-30, BM3-C6-30, BM3-C7-30, and BM3-C8-30, respectively. With increasing calcination temperature, the fluidity of the cement mortar first decreased and then increased, remaining lower than that of the pure cement group. When the calcination temperature was below 500℃, the fluidity of the cement mortar was lower than that of the BM3-30 group, with a fluidity of 145.5 mm, which was 5.43% and 31.69% lower than that of the BM3-30 and pure cement groups, respectively. With further increases in calcination temperature, the fluidity of the cement mortar first increased and then decreased, reaching its highest value at a calcination temperature of 700℃. The flowability of the BM3-C7-30 group is 197 mm, which is 18.55% higher than that of the BM3-30 group and 7.51% lower than that of the pure cement group. The corresponding compressive strength of the cement mortar is as follows: Figure 5 From c in the equation, we can see that, as Figure 5 As shown in Figure c, the compressive strength of cement mortar composed of mechanically-thermally activated deammoniation-washed electrolytic manganese slag with different calcination temperatures at all ages was lower than that of the pure cement group. Specifically, the compressive strengths of the BM3-C7-30 group at 3d, 7d, and 28d were 17.69 MPa, 19.07 MPa, and 24.32 MPa, respectively. Although the compressive strength of the BM3-C8-30 group further increased to 18.90 MPa, 20.59 MPa, and 26.73 MPa at all ages compared to BM3-C7, the BM3-C7-30 group was superior in terms of overall mortar fluidity.

[0047] Figure 4 The 'd' indicates that the cement mortar in this example is composed of BM3-C7, ammonia-removed and washed electrolytic manganese slag from Example 3 calcined at 700℃, comprising 5%-30% of the cement mass, replacing a portion of the cement in the traditional cement mortar. These mortars are named BM3-C7-5, BM3-C7-10, BM3-C7-15, BM3-C7-20, BM3-C7-25, and BM3-C7-30, respectively. With increasing BM3-C7 content, the fluidity of the cement mortar first increases and then decreases, showing little change compared to the pure cement group. Specifically, the fluidities of BM3-C7-5 and BM3-C7-10 are 218.5 mm and 222.5 mm, respectively, representing increases of 2.58% and 4.46% compared to the pure cement group. With continued increases in BM3-C7 content, the fluidity of the cement mortar decreases somewhat, with the fluidity of the BM3-C7-20 group reaching 200.5 mm, a decrease of 5.87% compared to the pure cement group. When the BM3-C7 content was further increased to 25% and 30%, the flowability of the cement mortar remained almost unchanged. The corresponding compressive strength of the cement mortar was as follows: Figure 5 From d, we can know that Figure 5 The 'd' value indicates that with increasing BM3-C7 content, the 3-day and 7-day compressive strength of cement mortar first increases and then decreases, while the 28-day compressive strength gradually decreases. The 3-day and 7-day compressive strengths of the BM3-C7-5 group are 37.43 MPa and 40.94 MPa, respectively, slightly higher than the pure cement group, with a 28-day compressive strength of 49.52 MPa. The 3-day and 7-day compressive strengths of the BM3-C7-10 group are 29.54 MPa and 38.92 MPa, respectively, comparable to the pure cement group, with a 28-day compressive strength of 51.05 MPa. With continuous increase in BM3-C7 content, the compressive strength at all ages decreases significantly. The 3-day, 7-day, and 28-day compressive strengths of the BM3-C7-20 group are 21.34 MPa, 23.25 MPa, and 30.32 MPa, respectively. When the content exceeds 25%, the compressive strength tends to remain constant.

[0048] This invention utilizes a concrete twin-shaft mixer to pre-disperde the filter cake from water-washed electrolytic manganese slag; and a step-by-step addition of alkaline materials improves the efficiency of alkaline material treatment of water-washed electrolytic manganese slag, thereby eliminating residual NH4 in the water-washed electrolytic manganese slag. + Removal and soluble harmful ions (such as Mn) 2+ and Mg 2+ The invention achieves stable solidification of electrolytic manganese slag (e.g., [missing information]); it employs a mechanical-thermal activation process to further enhance the hydration activity of the electrolytic manganese slag, mitigating the decrease in cement mortar flowability when adding water-washed electrolytic manganese slag, and even improving the flowability of cement mortar. Compared with the traditional process of crushing, drying, ball milling, and then adding reagents for pretreatment, this invention eliminates the need for crushing, drying, and ball milling of the water-washed electrolytic manganese slag filter cake, greatly simplifying the process and significantly reducing treatment costs. Compared with traditional high-temperature desulfurization calcination or direct calcination activation processes, the mechanical-thermal activation process used in this invention removes ammonia in the early stages, eliminating ammonia pollution during calcination. Compared with existing technologies, it has advantages such as simple process, low cost, and strong operability.

[0049] The above description is a preferred embodiment of the present invention, but it does not represent a limitation on the scope of protection of the present invention. Any modifications made to the present invention beyond the essential aspects based on the above description by those skilled in the art shall still fall within the scope of protection of the present invention.

Claims

1. A method for pretreatment and resource utilization of water-washed electrolytic manganese slag filter cake, characterized in that, include: (1) The water-washed electrolytic manganese slag filter cake with a moisture content of 15-30 wt.% is mechanically stirred for a period of time to achieve the pre-dispersion of the water-washed electrolytic manganese slag filter cake. Then, while stirring, 5-10% of the base mass of the filter cake of alkaline material is added in two batches. (2) Take out the above-mentioned well-stirred sample and place it in a dry and ventilated environment for aging; (3) Place the aged electrolytic manganese slag from step (2) into a ball mill and ball mill it; (4) The electrolytic manganese slag after ball milling is placed in a muffle furnace for calcination; (5) Use the electrolytic manganese slag obtained in step (4) to prepare mineral admixtures or cement mortar; In step (1), alkaline materials are added in two batches while stirring. The amount of the first addition is 10-60 wt.% of the total amount of alkaline materials. The stirring time after each addition is 5-30 min and the time for each addition is 10-30 s.

2. The method as described in claim 1, characterized in that, In step (1), the alkaline material is selected from one or more of quicklime, hydrated lime, calcined raw meal, steel slag, and carbide slag.

3. The method as described in claim 1, characterized in that, In step (1), alkaline materials are added in two batches while stirring. The amount of alkaline materials added in the first batch is 20-50 wt.% of the total amount of alkaline materials.

4. The method as described in claim 1, characterized in that, In step (1), alkaline materials are added in two batches while stirring. The amount of alkaline materials added in the first batch is 40 wt.% of the total amount of alkaline materials.

5. The method as described in claim 1, characterized in that, In step (1), the water-washed electrolytic manganese slag filter cake with a moisture content of 15-30 wt.% is mechanically stirred for 5-30 min to achieve pre-dispersion of the water-washed electrolytic manganese slag filter cake.

6. The method as described in claim 1, characterized in that, In step (2), the aging process lasts for more than 48 hours.

7. The method as described in claim 1, characterized in that, In step (3), the ball-to-material ratio is 10:1, the rotation speed is 30 r / min, and the ball milling time is 0.5~7 h.

8. The method as described in claim 1, characterized in that, In step (3), the ball milling time is 3 hours.

9. The method as described in claim 1, characterized in that, In step (4), the calcination temperature is 300-900 ℃ and the calcination time is 0.5-3 h.

10. The method as described in claim 1, characterized in that, In step (4), the calcination temperature is 300-700 ℃.

11. The method as described in claim 1, characterized in that, In step (4), the calcination time is 1 h.

12. The method as described in claim 1, characterized in that, In step (5), the electrolytic manganese slag obtained in step (4) replaces 5~50 wt.% of cement to prepare mineral admixtures or cement mortar.

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