A cementing material based on electrolytic manganese residue and multiple solid wastes and a preparation method thereof

Abstract

The application provides a cementing material based on electrolytic manganese residue and a preparation method thereof; the preparation method comprises the following steps: S1, electrolytic manganese residue powder, slag powder, steel slag powder, silica ash and sodium hydroxide are mixed to obtain solid waste mixed raw materials; the mass ratio of the electrolytic manganese residue powder, the slag powder, the steel slag powder, the silica ash and the sodium hydroxide is 15-25:35-45:25-35:8-12:2-6; S2, water and the solid waste mixed raw materials are secondly mixed at a mass ratio of 0.4-0.6:1 to obtain a solid waste-based slurry; and S3, the solid waste-based slurry is sequentially subjected to preliminary curing and re-curing to obtain the cementing material. The cementing material is prepared based on electrolytic manganese residue and multiple industrial solid wastes, harmless treatment and resource utilization of the electrolytic manganese residue are realized, and the use of cement is omitted in the cementing material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental materials, and particularly relates to a cementing material based on electrolytic manganese residue and a preparation method thereof. BACKGROUND

[0002] In the production process of metallic manganese, electrolytic manganese residue is generated; at present, the main method for treating electrolytic manganese residue is to stack it in the open air or to carry out landfill treatment. However, electrolytic manganese residue contains manganese and other heavy metal ions, as well as ammonia-nitrogen compounds, and in the process of rainwater washing or percolation, harmful substances will flow into the natural environment, including soil, rivers and groundwater, thereby posing a potential threat to the ecological system and human health. Therefore, it is of great significance for environmental protection and resource conservation to develop new technologies to realize the harmless treatment and high-value comprehensive utilization of electrolytic manganese residue.

[0003] Cementing materials are an indispensable part of building engineering, among which the most commonly used is Portland cement, which is widely used in various structures due to its excellent hydraulicity and adaptability. However, the production of cement is a high-energy process, which will result in a large amount of carbon dioxide emissions and have a negative impact on global climate change. Therefore, it is urgent to find a way to reduce the use of cement.

[0004] Chinese patent application with publication number CN114605123A discloses a manganese residue-based ultra-high performance composite cementing material and concrete material, and the cementing material thereof comprises cement 60-65%, electrolytic manganese residue powder 11-15%, silica fume 16-24%, limestone powder 3-5%, and calcium sulfate whisker 2-5%. Although electrolytic manganese residue is used to replace part of the cement in the patent application; the amount of cement is still as high as 60-65%, and no large amount of other solid waste is treated, and how to reduce the ammonia-nitrogen leaching concentration and manganese leaching concentration of the cementing material is not explored.

[0005] Therefore, it is necessary to provide a cementing material based on electrolytic manganese residue and a preparation method thereof, to solve or at least alleviate the technical problems of how to omit the use of cement in the cementing material and how to reduce the ammonia-nitrogen leaching concentration and manganese leaching concentration of the cementing material based on solid waste materials. SUMMARY

[0006] The main purpose of the present application is to provide a cementing material based on electrolytic manganese residue and a preparation method thereof, which aims to solve the technical problems of how to omit the use of cement in the cementing material and how to reduce the ammonia-nitrogen leaching concentration and manganese leaching concentration of the cementing material based on solid waste materials.

[0007] To achieve the above-mentioned purpose, the present application provides a preparation method of a cementing material based on electrolytic manganese residue and a preparation method thereof, comprising the following steps:

[0008] S1, the electrolytic manganese slag is sequentially subjected to water washing and mechanical pulverization to obtain electrolytic manganese slag powder; the electrolytic manganese slag powder, slag powder, steel slag powder, silica fume and sodium hydroxide are first mixed to obtain solid waste mixed raw material;

[0009] The mass ratio of the electrolytic manganese slag powder, the slag powder, the steel slag powder, the silica fume, and the sodium hydroxide is 15-25:35-45:25-35:8-12:2-6;

[0010] S2, water and the solid waste mixture are mixed in a second mixing ratio of 0.4-0.6:1 to obtain a solid waste-based slurry;

[0011] S3, the solid waste-based slurry is subjected to preliminary curing and secondary curing in sequence to obtain a cementitious material.

[0012] Furthermore, the method for obtaining the electrolytic manganese slag powder includes: washing the electrolytic manganese slag with water and drying it to obtain washed electrolytic manganese slag; mechanically pulverizing the washed electrolytic manganese slag and then passing it through a 200-mesh sieve, taking the sieve-underfill material as the electrolytic manganese slag powder.

[0013] Furthermore, the water washing process includes: stirring the electrolytic manganese slag and water at a mass ratio of 1:5-20 for 12-30 hours, and then filtering to obtain water-washed manganese slag sludge to be dried.

[0014] Furthermore, the mechanical pulverization process includes: sequentially crushing and vibrating the water-washed electrolytic manganese slag, wherein the vibrating grinding time is 2-6 minutes.

[0015] Further, the second mixing includes: sequentially subjecting water and the solid waste mixture to a first stirring and a second stirring;

[0016] The first stirring speed is 40-80 r / min and the duration is 80-200 s; the second stirring speed is 100-150 r / min and the duration is 80-200 s.

[0017] Furthermore, the first stirring and the second stirring are spaced 10-30 seconds apart; during the interval, stirring is stopped.

[0018] Furthermore, the temperature for both the initial curing and the second curing is 18-30℃, and the humidity is 80-99%; the duration of the initial curing is not less than 1 day, and the duration of the second curing is not less than 3 days.

[0019] Furthermore, before performing the initial curing, the solid waste-based slurry is injected into the mold; after the initial curing is completed, the mold is removed, and then the second curing is performed.

[0020] Further, the chemical composition of the electrolytic manganese residue includes silicon dioxide, calcium oxide, aluminum oxide; the electrolytic manganese residue contains ammonia nitrogen and soluble divalent manganese.

[0021] The application further provides a cementing material based on electrolytic manganese residue and multiple solid wastes.

[0022] Compared with the prior art, the application has at least the following advantages:

[0023] The cementing material is prepared based on electrolytic manganese residue and multiple industrial solid wastes, harmless treatment and resource utilization of the electrolytic manganese residue are realized, and multiple industrial solid wastes are absorbed; the application omits the use of cement in the cementing material, and can efficiently solidify ammonia nitrogen and Mn(II) in the electrolytic manganese residue, meets the first-level standard of the Comprehensive Sewage Discharge Standard, avoids pollution to the surrounding environment and occupation of a large amount of land resources.

[0024] The raw materials used in the application are mainly solid wastes, which are easy to obtain, can reduce the influence of the wastes on the environment, alleviate the pressure on the landfill site, and reduce the risk of secondary pollution. The preparation method is simple and efficient, a large number of solid wastes are absorbed, and the method is easy to be applied in a manganese residue industrial solid waste site on a large scale; the application can reduce the cost of building materials, and the obtained cementing material has good mechanical properties, which can improve the durability and strength of the concrete structure. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the application, and for those skilled in the art, other drawings can be obtained from the structures shown in the drawings without creative labor.

[0026] Figure 1 XRD pattern of the original electrolytic manganese residue in Example 1 of the application;

[0027] Figure 2 Actual picture of the solid waste-based cementing material test block with a curing age of 28d in Example 1 of the application;

[0028] Figure 3 Compressive strength columnar chart of the solid waste-based cementing material test block with a curing age of 3d, 7d and 28d in Example 1 of the application;

[0029] Figure 4 Micrograph of the solid waste-based cementing material test block with a curing age of 7d in Example 1 of the application;

[0030] Figure 5 Figure 3 is a column chart of ammonia nitrogen content of water control (sampling test of ammonia nitrogen concentration of water for leaching), positive control leachate and solid waste-based cementitious material test block leachate with curing age of 3d, 7d and 28d in Example 1 of the present application;

[0031] Figure 6 Figure 4 is a column chart of Mn(II) content of positive control leachate and solid waste-based cementitious material test block leachate with curing age of 3d, 7d and 28d in Example 1 of the present application; soluble Mn in the chart corresponds to Mn(II).

[0032] The implementation, functional features and advantages of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work under the premise that the technical solutions are not contradictory or unachievable, belong to the scope of protection of the present application.

[0034] Moreover, the technical solutions in each embodiment of the present application can be combined with each other, but it must be based on the fact that the technical solutions can be realized by those skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the scope of protection required by the present application.

[0035] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified by the present application, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are consistent with the mastery of the prior art by those skilled in the art and the description of the present application, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the embodiments of the present application can be used to realize the present application.

[0036] It is understood that the chemical composition of electrolytic manganese residue mainly includes silicon dioxide (SiO2), aluminum oxide (Al2O3) and calcium oxide (CaO), and the above components are the key factors to determine whether it has cementitious potential. Among them, silicon dioxide and aluminum oxide are the main source of active silicate and aluminate, which can react with water to form a stable cementitious structure during hydration; and calcium oxide helps to adjust the pH value of the system, promote the progress of hydration reaction, and in some cases, it can also participate in the hydration reaction to form hydration products with strength. Due to the presence of the above active components, electrolytic manganese residue shows good cementitious performance, making it a potential choice to replace traditional cementitious materials, especially in the preparation of high-performance concrete and environmentally friendly building materials.

[0037] Slag (blast furnace slag), steel slag and silica fume are all by-products of industrial production, and the present application jointly utilizes electrolytic manganese residue, blast furnace slag, steel slag and silica fume to form the required substances for the hydration stage of cementitious materials, while absorbing various industrial solid wastes, harmless resource recycling and application in the field of construction.

[0038] The present application provides a preparation method of cementitious material based on electrolytic manganese residue and multiple solid wastes, comprising the following steps:

[0039] S1, the electrolytic manganese residue is sequentially subjected to water washing treatment and mechanical powdering treatment to obtain electrolytic manganese residue powder; the electrolytic manganese residue powder, slag powder (blast furnace slag powder), steel slag powder, silica fume and sodium hydroxide are first mixed to obtain solid waste mixed raw materials; the mass ratio of the electrolytic manganese residue powder, the slag powder, the steel slag powder, the silica fume and the sodium hydroxide is 15-25:35-45:25-35:8-12:2-6, and specifically can be 20:40:30:10:4.

[0040] The electrolytic manganese residue powder can be obtained by: subjecting the electrolytic manganese residue to the water washing treatment, drying to obtain water-washed electrolytic manganese residue; subjecting the water-washed electrolytic manganese residue to the mechanical powdering treatment, then passing through a 200-mesh sieve, and taking the undersize as the electrolytic manganese residue powder; the electrolytic manganese residue powder can be understood as a mechanically modified electrolytic manganese residue raw material. In addition, in the present application, the slag powder is the undersize passing through a 200-mesh sieve, the steel slag powder is the undersize passing through a 200-mesh sieve, and the silica fume is the undersize passing through a 200-mesh sieve.

[0041] The process of the water washing treatment comprises: stirring the electrolytic manganese residue and water at a mass ratio of 1:5-20 for 12-30 hours or 12-24 hours, and filtering to obtain the water-washed manganese residue mud to be dried; preferably, stirring the electrolytic manganese residue and water at a mass ratio of 1:8-12 for 20-30 hours, and filtering to obtain the water-washed manganese residue mud; specifically, stirring the electrolytic manganese residue and water at a mass ratio of 1:10 for 24 hours, and vacuum filtering to obtain the water-washed manganese residue mud.

[0042] The process of the drying comprises: drying the water-washed manganese residue mud at 105-110 DEG C, specifically at 105 DEG C, until the water content is less than or equal to 1%; and the drying time can be 6-48 hours, specifically 12 hours.

[0043] The process of the mechanical powdering treatment comprises: sequentially crushing and vibrating the water-washed electrolytic manganese residue; the vibrating time is 2-6 minutes, preferably 3 minutes; and the vibrating can be performed in a vibrating mill.

[0044] As further description of the electrolytic manganese residue, the slag, the steel slag and the silica fume:

[0045] In the present application, the chemical composition of the electrolytic manganese residue comprises, in the form of oxides, silicon dioxide, calcium oxide and aluminum oxide, or the chemical composition of the electrolytic manganese residue comprises, in the form of oxides, silicon dioxide, calcium oxide, aluminum oxide, magnesium oxide, diiron trioxide, potassium oxide, manganese oxide, sodium oxide and sulfur trioxide; further, the chemical composition of the electrolytic manganese residue comprises, in the form of oxides and by mass ratio, 20-50% of silicon dioxide, 10-25% of calcium oxide, 5-15% of aluminum oxide, 1-8% of magnesium oxide, 2-12% of diiron trioxide, 1-5% of potassium oxide, 1-5% of manganese oxide (MnO), 1-5% of sodium oxide and 20-40% of sulfur trioxide; further, the electrolytic manganese residue contains 25-35% of silicon dioxide, 10-20% of calcium oxide, 5-10% of aluminum oxide, 1-3% of magnesium oxide, 5-8% of diiron trioxide, 2-3% of potassium oxide, 2-3% of manganese oxide (MnO), 1-2% of sodium oxide and 25-35% of sulfur trioxide.

[0046] In the present application, the electrolytic manganese residue is from Dongfang Mining Industry in Huaiyuan County, Xiangxi Autonomous Prefecture, Hunan Province; in the present application, sulfuric acid and ammonia water are added in the production process of electrolytic manganese, and the filter residue is the electrolytic manganese residue through multiple pressure filtrations; therefore, the electrolytic manganese residue contains ammonia nitrogen and soluble divalent manganese, and both of them can be dissolved in water. That is, in the present application, the electrolytic manganese residue is from the production process of electrolytic manganese, and the production process of electrolytic manganese introduces sulfuric acid and ammonia water.

[0047] In the present application, the ammonia nitrogen and the soluble divalent manganese are not included in the chemical composition analysis of the electrolytic manganese residue, but the leaching concentration of the ammonia nitrogen and the soluble divalent manganese is analyzed separately; the reason is that: because the characterization means X-ray fluorescence spectrometer (XRF) is mainly used for detecting the element composition and content in the substance, the elements attached to the surface of the substance cannot be detected, the ammonia nitrogen involved in the present application is caused by the ammonia water reagent in the process of generating the residue sample, so it cannot be reflected in the XRF detection result; because the characterization means X-ray fluorescence spectrometer (XRF) is mainly used for detecting the element composition and content in the substance, the elements attached to the surface of the substance cannot be detected, the soluble divalent manganese involved in the present application is caused by the sulfuric acid dissolution of manganese carbonate or the sulfuric acid dissolution of manganese dioxide in the process of generating the residue sample, so it does not belong to MnO in the XRF detection result.

[0048] In the present application, the electrolytic manganese residue is crushed and water is added at a solid-liquid ratio of 1g:10mL for water immersion, the water immersion time is 24h, the water immersion is carried out under the condition of 20-30℃ (specifically room temperature) and oscillation, and then solid-liquid separation is carried out after water immersion; the leaching concentration of ammonia nitrogen (NH4 + -N) of the electrolytic manganese residue is 350-450mg / L, and the leaching concentration of soluble divalent manganese (Mn 2+ ) of the electrolytic manganese residue is 850-950mg / L; specifically, the leaching concentration of ammonia nitrogen of the electrolytic manganese residue is 392.96mg / L, and the leaching concentration of soluble divalent manganese of the electrolytic manganese residue is 896.65mg / L.

[0049] In the present application, the electrolytic manganese residue powder and water are added at a solid-liquid ratio of 1g:10mL for water immersion, the water immersion time is 24h, the water immersion is carried out under the condition of 20-30℃ (specifically room temperature) and oscillation, and then solid-liquid separation is carried out after water immersion; the leaching concentration of ammonia nitrogen of the electrolytic manganese residue powder is 45-55mg / L, and the leaching concentration of soluble divalent manganese of the electrolytic manganese residue powder is 150-160mg / L; specifically, the leaching concentration of ammonia nitrogen of the electrolytic manganese residue powder is 51.84mg / L, and the leaching concentration of soluble divalent manganese of the electrolytic manganese residue powder is 155.45mg / L.

[0050] In the present application, the slag powder is derived from the blast furnace ironmaking process; the chemical composition of the slag powder includes, in terms of mass ratio and oxide form, 20-40% silicon dioxide, 35-55% calcium oxide, 10-20% aluminum oxide, 5-15% magnesium oxide, 0-1% diiron trioxide, 0-1% potassium oxide, 0-1% manganese oxide (MnO), 0-1% sodium oxide, and 0-5% sulfur trioxide; further, the slag powder contains 25-30% silicon dioxide, 40-46% calcium oxide, 10-15% aluminum oxide, 5-10% magnesium oxide, 0.1-1% diiron trioxide, 0.2-1% potassium oxide, 0.1-1% manganese oxide (MnO), 0.3-1% sodium oxide, and 1-5% sulfur trioxide.

[0051] In the present application, the steel slag powder is derived from the steelmaking process in the steel industry; the chemical composition of the steel slag powder includes, in terms of mass ratio and oxide form, 10-20% silicon dioxide, 35-55% calcium oxide, 5-15% aluminum oxide, 5-15% magnesium oxide, 10-20% diiron trioxide, 0-1% potassium oxide, 0-5% manganese oxide (MnO), 0-1% sodium oxide, and 0-3% sulfur trioxide; further, the steel slag powder contains 10-20% silicon dioxide, 40-50% calcium oxide, 5-10% aluminum oxide, 7-13% magnesium oxide, 10-20% diiron trioxide, 0.1-1% potassium oxide, 1-5% manganese oxide (MnO), 0.1-1% sodium oxide, and 0.5-3% sulfur trioxide.

[0052] In the present application, the silica ash is derived from the process of high-temperature smelting industrial silicon and ferrosilicon in industrial electric furnaces; the chemical composition of the silica ash includes, in terms of mass ratio and oxide form, 90-99% silicon dioxide, 0-3% calcium oxide, 0-1% aluminum oxide, 0-1% magnesium oxide, 0-1% diiron trioxide, 0-1% potassium oxide, 0-1% manganese oxide (MnO), 0-1% sodium oxide, and 0-1% sulfur trioxide; further, the silica ash contains 90-99% silicon dioxide, 0.5-3% calcium oxide, 0.1-1% aluminum oxide, 0.1-1% magnesium oxide, 0.1-1% diiron trioxide, 0.1-1% potassium oxide, 0.001-0.1% manganese oxide (MnO), 0.1-1% sodium oxide, and 0.1-1% sulfur trioxide.

[0053] S2, the water and the solid waste mixed raw material are mixed at a mass ratio of 0.4-0.6:1 to obtain a solid waste-based slurry; preferably, the mass ratio of the water and the solid waste mixed raw material is 0.43-0.47:1; specifically, the water and the solid waste mixed raw material are mixed at a mass ratio of 0.45:1 to obtain a solid waste-based slurry.

[0054] In the present application, the second mixing comprises or is: sequentially performing first stirring and second stirring on water and the solid waste mixed raw material; the second mixing can be performed in a net slurry stirrer.

[0055] The rotation speed of the first stirring is 40-80 r / min, and the time length is 80-200 s; preferably, the rotation speed of the first stirring is 50-70 r / min, and the time length is 100-150 s; specifically, the rotation speed of the first stirring is 60 r / min, and the time length is 120 s.

[0056] The rotation speed of the second stirring is 100-150 r / min, and the time length is 80-200 s; preferably, the rotation speed of the second stirring is 110-130 r / min, and the time length is 100-150 s; specifically, the rotation speed of the second stirring is 120 r / min, and the time length is 120 s.

[0057] The interval between the first stirring and the second stirring is 10-30 s, specifically 20 s; during the interval, the stirring is stopped.

[0058] S3, sequentially performing preliminary curing and re-curing on the solid waste-based slurry to obtain a cementitious material.

[0059] In the present application, the temperature of the preliminary curing condition and the re-curing is 18-30 DEG C, and the humidity is 80-99%; preferably, the temperature of the preliminary curing condition and the re-curing is 18-22 DEG C, and the humidity is 93-97%; the time length of the preliminary curing is not less than 1 d, specifically 1 d; the time length of the re-curing is not less than 3 d or not less than 7 d or not less than 28 d, and further can be 3-28 d or 7-28 d or 26-30 d.

[0060] In the present application, before the preliminary curing, the solid waste-based slurry is injected into a mold; after the preliminary curing is completed, the mold is demolded, and then the re-curing is performed. That is, the solid waste-based slurry is injected into a mold for molding, preliminary curing, demolding, and then re-curing. When the solid waste-based slurry is injected into the mold, compaction is performed by vibration; the preliminary curing and the re-curing are performed in a constant temperature and humidity box.

[0061] The present application also provides a cementitious material based on electrolytic manganese residue and cooperated with multiple solid wastes, which is prepared by the cementitious material preparation method as described above.

[0062] The present application utilizes the cementitious activity of electrolytic manganese residue, cooperates with multiple solid wastes, realizes cementitious setting under the action of alkali excitation, and solidifies ammonia nitrogen and soluble divalent manganese in the original electrolytic manganese residue. In this process, no cement is added, the electrolytic manganese residue is realized as a resource, the preparation cost and energy consumption are reduced.

[0063] In the present application, the mechanical properties of the cementitious material are: 3d compressive strength of 5-15 MPa, 7d compressive strength of 20-30 MPa, and 28d compressive strength of 35-45 MPa.

[0064] The cementitious material is crushed and immersed in water at a solid-liquid ratio of 1g:10mL, the water immersion time is 24h, the water immersion is carried out under the conditions of 20-30℃ (specifically room temperature) and shaking, and then the solid-liquid separation is carried out after water immersion; the ammonia-nitrogen leaching concentration of the cementitious material is less than 15mg / L, and the Mn(II) leaching concentration of the cementitious material is less than 2mg / L. Further, the ammonia-nitrogen leaching concentration of the cementitious material is 0.02-8.00mg / L, and the Mn(II) leaching concentration of the cementitious material is 0.01-0.10mg / L; further, the ammonia-nitrogen leaching concentration of the cementitious material is 1.5-5.5mg / L or 1.5-2.5mg / L, and the Mn(II) leaching concentration of the cementitious material is 0.01-0.05mg / L.

[0065] The following are specific examples of the present application:

[0066] Example 1

[0067] I. The preparation steps of the cementitious material are:

[0068] S1, electrolytic manganese residue (raw electrolytic manganese residue) is mixed with water at a mass ratio of 1:10 and stirred for 24h (water washing), and then filtered by vacuum filtration to obtain water-washed manganese residue mud; the water-washed manganese residue mud is placed in an electric heating air drying oven and dried at 105℃ for 12h to obtain water-washed electrolytic manganese residue.

[0069] The water-washed electrolytic manganese residue is crushed by a jaw crusher and then placed in a vibration mill for vibration milling for 3min, and then sieved through a 200-mesh sieve, and the undersize material is taken as the electrolytic manganese residue powder.

[0070] The electrolytic manganese residue powder, blast furnace slag (blast furnace slag powder passing through a 200-mesh sieve), steel slag (steel slag powder passing through a 200-mesh sieve), silica ash (silica ash passing through a 200-mesh sieve), and sodium hydroxide are fully mixed (first mixing) at a mass ratio of 20:40:30:10:4 to obtain solid waste mixed raw materials.

[0071] The main chemical compositions and mass percentages of the electrolytic manganese residue (raw electrolytic manganese residue), blast furnace slag, steel slag, and silica ash are analyzed by an X-ray fluorescence analyzer (XRF), as shown in Table 1; in addition, the XRD analysis of the raw electrolytic manganese residue is shown in Table 2. Figure 1

[0072] Table 1 Chemical analysis of solid waste (wt%)

[0073] ​

[0074] S2, water and solid waste mixed raw materials are mixed in a second mixing process at a mass ratio of 0.45:1 (water-cement ratio) to obtain solid waste-based slurry.

[0075] In this embodiment, the second mixing is carried out in a paste mixer; the second mixing is divided into a first stage and a second stage in sequence. The first stage is stirred at a slow speed of 60 r / min for 120 s, and the second stage is stirred at a fast speed of 120 r / min for 120 s. The mixing is stopped for 20 s between the first stage and the second stage.

[0076] S3. The solid waste-based slurry was injected into a 20mm×20mm×20mm cube six-piece mold, vibrated to compact it, and then placed in a constant temperature and humidity chamber for curing. The parameters of the constant temperature and humidity chamber were set as follows: temperature 20℃, humidity 95%. After curing for 1 day (preliminary curing) under the set parameters, the test block was removed and demolded. Then, the test block was placed back into the constant temperature and humidity chamber for curing with the same parameters (second curing). The curing ages were 3 days, 7 days, and 28 days. After reaching the specified age, the test block was removed to obtain a solid waste-based cementitious material test block (a cementitious material based on electrolytic manganese slag and multiple solid wastes). The curing age refers to the time of the second curing. When the curing age is 3 days, 7 days, and 28 days, the solid waste-based cementitious material test block is recorded as a 3-day test block, a 7-day test block, and a 28-day test block, respectively. See the physical image of the 28-day test block. Figure 2 As shown.

[0077] II. Experimental Results:

[0078] 1. Test the compressive strength of solid waste-based cementitious material test blocks cured to the specified age using a T-shaped workbench testing machine. The compression speed of the test specimen is 1 mm / min.

[0079] See Figure 3 As shown, the compressive strength of the 3-day specimen was 12.26 MPa, the 7-day specimen was 24.23 MPa, and the 28-day specimen was 38.82 MPa. The compressive strength increased with the curing age, and the 28-day specimen's compressive strength met the strength requirements of various building materials. Furthermore, see [link to relevant documentation]. Figure 4 As shown, taking the 7d test block as an example, a large amount of flocculent gel is generated in the 7d test block.

[0080] 2. The solid waste-based cementitious material test blocks that have been cured to the specified age are crushed. Water is used as the extractant, and the cementitious material test blocks are extracted with a solid-liquid ratio of 1g:10mL (the original electrolytic manganese slag is crushed and used as a positive control for extraction, and the electrolytic manganese slag powder is used as an intermediate control). The mixture is shaken in a shaker at room temperature for 24 hours, and the leachate is obtained after filtration.

[0081] (1) The NH4 + -N in the leaching solution was detected by the Nessler's reagent spectrophotometric method for ammonia nitrogen in water quality.

[0082] As shown in Figure 5 , the detection results show that the ammonia nitrogen leaching concentration of the positive control (original electrolytic manganese residue) leaching solution is 392.96 mg / L; the ammonia nitrogen concentration of the 3d test block leaching solution is 5.16 mg / L, the 7d test block leaching solution is 2.28 mg / L, and the 28d test block leaching solution is 1.99 mg / L. The ammonia nitrogen concentration decreases with the increase of the curing age, and the removal rate of NH4 + -N is faster in the early curing period. Compared with the NH4 + -N concentration of 392.96 mg / L in the positive control leaching solution, the removal rate is close to 99.5%, and at the same time, the NH4 + -N concentration of all the cementitious material test block leaching solutions does not exceed the first level standard 15 mg / L of ammonia nitrogen in the Integrated Wastewater Discharge Standard (GB8978-1996); in addition, the ammonia nitrogen leaching concentration of the intermediate control (electrolytic manganese residue powder) leaching solution is 51.84 mg / L.

[0083] (2) The content of Mn(II) in the leaching solution was detected by an inductively coupled plasma emission spectrometer.

[0084] As shown in Figure 6 , the detection results show that the Mn(II) concentration of the positive control (original electrolytic manganese residue) leaching solution is 896.65 mg / L; the Mn(II) concentration of the 3d test block leaching solution is 0.04 mg / L, the 7d test block leaching solution is 0.01 mg / L, and the 28d test block leaching solution is 0.01 mg / L. Compared with the Mn(II) concentration of 896.65 mg / L in the positive control leaching solution, the solidification rate is more than 99.9%, and at the same time, the Mn(II) concentration of all the cementitious material test block leaching solutions does not exceed the first level standard 2 mg / L of soluble manganese in the Integrated Wastewater Discharge Standard (GB8978-1996); in addition, the Mn(II) leaching concentration of the intermediate control (electrolytic manganese residue powder) leaching solution is 155.45 mg / L.

[0085] The leaching toxicity detection results of the cementitious material test block show that all the indicators meet the current national environmental protection standards, which highlights the superior performance of the material in environmental protection; and confirms that the product can effectively reduce the pollution risk to the soil and groundwater in actual application, which embodies its high ecological compatibility.

[0086] Comparative Example 1

[0087] I. The preparation steps of the cementitious material are:

[0088] The comparative example 1, the electrolytic manganese residue powder, the blast furnace slag (the blast furnace slag powder of 200 mesh), the steel slag (the steel slag powder of 200 mesh), the silica ash (the silica ash of 200 mesh) and sodium hydroxide are fully mixed according to the mass ratio of 50:20:20:10:0, and the solid waste mixed raw material is obtained; and the water and the solid waste mixed raw material are secondly mixed according to the mass ratio of 0.4:1 (water-cement ratio), and the solid waste base paste is obtained; and other conditions remain unchanged.

[0089] II. Experimental results:

[0090] The comparative example 1 adopts the same detection mode.

[0091] In the comparative example 1, the 3d test block has a compressive strength of 0.60 MPa, the 7d test block has a compressive strength of 1.12 MPa, and the 28d test block has a compressive strength of 2.42 MPa.

[0092] In the comparative example 1, the 3d test block has a compressive strength of 0.60 MPa, the 7d test block has a compressive strength of 1.12 MPa, and the 28d test block has a compressive strength of 2.42 MPa.

[0093] In the comparative example 1, the 3d test block has a compressive strength of 0.60 MPa, the 7d test block has a compressive strength of 1.12 MPa, and the 28d test block has a compressive strength of 2.42 MPa.

[0094] The compressive strength of the product prepared in the comparative example 1 does not meet the use standard, and cannot be used as a base material.

[0095] Comparative Example 2

[0096] I. The preparation steps of the cementitious material are:

[0097] Compared with the example 1, the second mixing only performs the first stage of stirring (omitting the second stage of stirring), and other conditions remain unchanged; since the material prepared in the comparative example 1 cannot be shaped when demoulded after 1d curing, the comparative example 1 only obtains the unshaped gelatinous material after preliminary curing.

[0098] II. Experimental results:

[0099] The comparative example 1 adopts the same detection mode.

[0100] In the comparative example 1, the material prepared is demoulded after 1d curing, and cannot be shaped, which is a gelatinous material without compressive strength.

[0101] In the comparative example, the ammonia nitrogen concentration of the leaching solution corresponding to the colloidal material is 35.23 mg / L, which does not meet the first level standard of 15 mg / L of ammonia nitrogen in the Integrated Wastewater Discharge Standard (GB8978-1996).

[0102] In the comparative example, the Mn(II) concentration of the leaching solution corresponding to the colloidal material is 12.47 mg / L, which does not meet the first level standard of 2 mg / L of soluble manganese in the Integrated Wastewater Discharge Standard (GB8978-1996).

[0103] Comparative Example 3

[0104] I. The preparation steps of the cementitious material are:

[0105] In the comparative example of Example 1, the curing condition of the re-curing is adjusted to curing exposed to natural air, and the temperature and humidity are not controlled, and the other conditions remain unchanged.

[0106] II. Experimental results:

[0107] The comparative example uses the same detection method as Example 1.

[0108] In the comparative example, the 3d test block compressive strength is 11.45 MPa, the 7d test block compressive strength is 16.37 MPa, and the 28d test block compressive strength is 18.15 MPa, which is lower than the standard curing compressive strength. The reason is that the humidity in the air is not high, and the cementitious material test block cannot have sufficient water to continue hydration, and the hydration degree is slow.

[0109] In the comparative example, the ammonia nitrogen concentration of the leaching solution of the 3d test block is 4.29 mg / L, the ammonia nitrogen concentration of the leaching solution of the 7d test block is 4.03 mg / L, and the ammonia nitrogen concentration of the leaching solution of the 28d test block is 3.95 mg / L.

[0110] In the comparative example, the Mn(II) concentration of the leaching solution of the 3d test block is 0.06 mg / L, the Mn(II) concentration of the leaching solution of the 7d test block is 0.04 mg / L, and the Mn(II) concentration of the leaching solution of the 28d test block is 0.04 mg / L.

[0111] In the above technical solution of the present application, the above is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made by using the contents of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method for preparing a cementitious material based on electrolytic manganese slag and multiple solid wastes, characterized in that, Including the following steps: S1, the electrolytic manganese slag is sequentially subjected to water washing and mechanical pulverization to obtain electrolytic manganese slag powder; the electrolytic manganese slag powder, slag powder, steel slag powder, silica fume, and sodium hydroxide are mixed for the first time to obtain a solid waste mixed raw material; the ammonia nitrogen leaching concentration of the electrolytic manganese slag powder is 45-55 mg / L, and the soluble divalent manganese leaching concentration of the electrolytic manganese slag powder is 150-160 mg / L; The mass ratio of the electrolytic manganese slag powder, the slag powder, the steel slag powder, the silica fume, and the sodium hydroxide is 15-25:35-45:25-35:8-12:2-6; S2, water and the solid waste mixture are mixed in a second mixing ratio of 0.4-0.6:1 to obtain a solid waste-based slurry; The second mixing includes: sequentially subjecting water and the solid waste mixture to a first stirring and a second stirring; the first stirring speed is 40-80 r / min and the duration is 80-200 s; the second stirring speed is 100-150 r / min and the duration is 80-200 s; S3, the solid waste-based slurry is subjected to preliminary curing and secondary curing in sequence to obtain a cementitious material.

2. The method for preparing the cementitious material according to claim 1, characterized in that, The method for obtaining the electrolytic manganese slag powder includes: washing the electrolytic manganese slag with water and drying it to obtain washed electrolytic manganese slag; mechanically pulverizing the washed electrolytic manganese slag and then passing it through a 200-mesh sieve, taking the sieve-underfill material as the electrolytic manganese slag powder.

3. The method for preparing the cementitious material according to claim 2, characterized in that, The water washing process includes: stirring the electrolytic manganese slag and water at a mass ratio of 1:5-20 for 12-30 hours, and then filtering to obtain water-washed manganese slag mud to be dried.

4. The method for preparing the cementitious material according to claim 2, characterized in that, The mechanical pulverization process includes: sequentially crushing and vibrating the water-washed electrolytic manganese slag, with the vibrating time being 2-6 minutes.

5. The method for preparing cementitious materials according to claim 1, characterized in that, The first stirring and the second stirring are spaced 10-30 seconds apart; during the interval, stirring is stopped.

6. The method for preparing the cementitious material according to claim 1, characterized in that, The temperature for both the initial curing and the second curing is 18-30℃, and the humidity is 80-99%; the duration of the initial curing is no less than 1 day, and the duration of the second curing is no less than 3 days.

7. The method for preparing the cementitious material according to claim 1, characterized in that, Before the initial curing, the solid waste-based slurry is injected into the mold; after the initial curing is completed, the mold is removed, and then the second curing is performed.

8. The method for preparing the cementitious material according to claim 1, characterized in that, The chemical composition of the electrolytic manganese slag includes silicon dioxide, calcium oxide, and aluminum oxide; the electrolytic manganese slag contains ammonia nitrogen and soluble divalent manganese.

9. A cementitious material based on electrolytic manganese slag and multiple solid wastes, characterized in that, The cementitious material is prepared using the method described in any one of claims 1-8.

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